Internet DRAFT - draft-iannone-internet-addressing-considerations
draft-iannone-internet-addressing-considerations
Network Working Group L. Iannone
Internet-Draft D. Trossen
Intended status: Informational Huawei
Expires: 9 March 2023 P. Mendes
Airbus
N. Shenoy
R.I.T.
L. Toutain
IMT-Atlantique
A.Y. Chen
Avinta
D. Farinacci
lispers.net
J. Finkhaeuser
AnyWi
Y. Jia
5 September 2022
Internet Addressing Considerations
draft-iannone-internet-addressing-considerations-01
Abstract
There exist many extensions to Internet addressing, as it is defined
in RFC 791 for IPv4 and RFC 8200 for IPv6, respectively. Those
extensions have been developed to evolve the addressing capabilities
beyond the basic properties of Internet addressing. This document
outlines those properties as a baseline against which the extensions
are categorized in terms of methodology used to extend the addressing
model, together with examples of solutions doing so.
While introducing such extensions, we outline the shortcomings we see
with those extensions. This ultimately leads to consider whether or
not a more consistent approach to tackling the identified use cases,
beyond point-wise extensions as done so far, would be beneficial.
The benefits are the ones detailed in the companion document
[I-D.iannone-scenarios-problems-addressing], where, leveraging on the
shortcomings identified in this memo and scenarios provided in
[I-D.iannone-scenarios-problems-addressing], a clear problem
statement is provided.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Properties of Internet Addressing . . . . . . . . . . . . . . 4
2.1. Property 1: Fixed Address Length . . . . . . . . . . . . 4
2.2. Property 2: Ambiguous Address Semantic . . . . . . . . . 4
2.3. Property 3: Limited Address Semantic Support . . . . . . 5
3. Extending the Internet Addressing Properties . . . . . . . . 5
3.1. Length Extensions . . . . . . . . . . . . . . . . . . . . 5
3.1.1. Shorter Address Length . . . . . . . . . . . . . . . 6
3.1.2. Longer Address Length . . . . . . . . . . . . . . . . 8
3.1.3. Summary . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Identity Extensions . . . . . . . . . . . . . . . . . . . 10
3.2.1. Anonymous Address Identity . . . . . . . . . . . . . 10
3.2.2. Authenticated Address Identity . . . . . . . . . . . 14
3.2.3. Summary . . . . . . . . . . . . . . . . . . . . . . . 16
3.3. Semantic Extensions . . . . . . . . . . . . . . . . . . . 16
3.3.1. Utilizing Extended Address Semantics . . . . . . . . 17
3.3.2. Utilizing Existing or Extended Header Semantics . . . 20
3.3.3. Summary . . . . . . . . . . . . . . . . . . . . . . . 23
4. Overview of Approaches to Extend Internet Addressing . . . . 24
5. A System View on Address . . . . . . . . . . . . . . . . . . 26
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6. Concerns in Extensions to Internet Addressing . . . . . . . . 27
6.1. Limiting Address Semantics . . . . . . . . . . . . . . . 27
6.2. Complexity and Efficiency . . . . . . . . . . . . . . . . 27
6.2.1. Repetitive encapsulation . . . . . . . . . . . . . . 28
6.2.2. Compounding concerns with header compression . . . . 29
6.2.3. Introducing Path Stretch . . . . . . . . . . . . . . 29
6.2.4. Complicating Traffic Engineering . . . . . . . . . . 29
6.3. Security . . . . . . . . . . . . . . . . . . . . . . . . 30
6.4. Fragility . . . . . . . . . . . . . . . . . . . . . . . . 30
7. Summary of concernss . . . . . . . . . . . . . . . . . . . . 31
8. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 33
9. Security Considerations . . . . . . . . . . . . . . . . . . . 34
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
11. Informative References . . . . . . . . . . . . . . . . . . . 34
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 45
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 45
1. Introduction
[I-D.iannone-scenarios-problems-addressing] outlines scenarios and
problems in Internet addressing through presenting a number of cases
of communication that have emerged over the many years of utilizing
the Internet and for which various extensions to the network
interface-centric addressing of IPv6 have been developed. In order
to continue the discussion on the emerging needs for addressing,
initiated with [I-D.iannone-scenarios-problems-addressing], this memo
aims at identifying evolutions from the original Internet addressing
model to add desirable features that have been added by various
extensions, in various contexts.
The approach to identifying the main evolution directions is guided
by key properties of Internet addressing, outlined in Section 2,
namely (i) the fixed length of the IP addresses, (ii) the ambiguity
of IP addresses semantic, while still (iii) providing limited IP
address semantic support. Those properties are derived directly as a
consequence of the respective standards that provide the basis for
Internet addressing, most notably [RFC0791] for IPv4 and [RFC8200]
for IPv6, respectively.
Those basic properties, and the potential shortcomings that arise
from those properties, give way to extensions that have been proposed
over the course of deploying new Internet technologies. Section 3
discusses those extensions, summarized as evolution with respect to
the the basic properties in Section 4.
Finally, this memo outlines considerations and concerns that arise
with the extension-driven approach to the basic Internet addressing,
discussed in Section 6, arguing that any requirements for solutions
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that would revise the basic Internet addressing would require to
address those concerns.
2. Properties of Internet Addressing
As the Internet Protocol adoption has grown towards the global
communication system we know today, its characteristics have evolved
subtly, with [RFC6250] documenting various aspects of the IP service
model and its frequent misconceptions, including Internet addressing.
In this section, the three most acknowledged properties related to
_Internet addressing_ are detailed. Those are (i) fixed IP address
length, (ii) ambiguous IP address semantic, and (iii) limited IP
address semantic support.
Section 3 elaborates on various extensions that aim to expand
Internet addressing beyond those properties; those extensions are
positioned as intentions to go beyond perceived shortcomings of those
key properties.
2.1. Property 1: Fixed Address Length
The fixed IP address length is specified as a key property of the
design of Internet addressing, with 32 bits for IPv4 ([RFC0791]), and
128 bits for IPv6 ([RFC8200]), respectively. Given the capability of
the hardware at the time of IPv4 design, a fixed length address was
considered as a more appropriate choice for efficient packet
forwarding. Although the address length was once considered to be
variable during the design of Internet Protocol Next Generation
("IPng", cf., [RFC1752]) in the 1990s, it finally inherited the
design of IPv4 and adopted a fixed length address towards the current
IPv6. As a consequence, the 128-bit fixed address length of IPv6 is
regarded as a balance between fast forwarding (i.e., fixed length)
and practically boundless cyberspace (i.e., enabled by using 128-bit
addresses).
2.2. Property 2: Ambiguous Address Semantic
Initially, the meaning of an IP address has been to identify an
interface on a network device, although, when [RFC0791] was written,
there were no explicit definitions of the IP address semantic.
With the global expansion of the Internet protocol, the semantic of
the IP address is commonly believed to contain at least two notions,
i.e., the explicit 'locator', and the implicit 'identifier'. Because
of the increasing use of IP addresses to both identify a node and to
indicate the physical or virtual location of the node, the
intertwined address semantics of identifier and locator was then
gradually observed and first documented in [RFC2101] as 'locator/
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identifier overload' property. With this, the IP address is used as
an identification for host and server, very often directly used,
e.g., for remote access or maintenance.
2.3. Property 3: Limited Address Semantic Support
Although IPv4 [RFC0791] did not add any semantic to IP addresses
beyond interface identification (and location), time has proven that
additional semantics are desirable (c.f., the history of 127/8
[HISTORY127] or the introduction of private addresses [RFC1918]),
hence, IPv6 [RFC4291] introduced some form of additional semantics
based on specific prefix values, for instance link-local addresses or
a more structured multicast addressing. Nevertheless, systematic
support for rich address semantics remains limited and basically
prefix-based.
3. Extending the Internet Addressing Properties
Over the years, a plethora of extensions has been proposed in order
to move beyond the native properties of IP addresses, outlined in the
previous section. The development of those extensions can be
interpreted as attempts, in a limited scope, to go beyond the
original properties of Internet addressing and desired new
capabilities that those developing the extensions identified as being
missing and yet needed and desirable.
3.1. Length Extensions
Extensions in this subsection aim at extending the property described
in Section 2.1, i.e., the fixed IP address length.
When IPv6 was designed, the main objective was to create an address
space that would not lead to the same situation as IPv4, namely to
address exhaustion. To this end, while keeping the same addressing
model like IPv4, IPv6 adopted a 128-bit address length with the aim
of providing a sufficient and future-proof address space. The choice
was also founded on the assumption that advances in hardware and
Moore's law would still allow to make routing and forwarding faster,
and the IPv6 routing table manageable.
We observe, however, that the rise of new use cases but also the
number of new, e.g., industrial/home or small footprint devices, was
possibly unforeseen. Sensor networks and more generally the Internet
of Things (IoT) emerged after the core body of work on IPv6, thus
different from IPv6 assumptions, 128-bit addresses were costly in
certain scenarios. On the other hand, given the huge investments
that IPv6 deployment involved, certain solutions are expected to
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increase the addressing space of IPv4 in a compatible way, and thus
extend the lifespan of the sunk investment on IPv4.
At the same time, it may also be possible to use variable and longer
address lengths to address current networking demands. For example
in content delivery networks, longer addresses such as URLs are
required to fetch content, an approach that Information-Centric
Networking (ICN) applied for any data packet sent in the network,
using information-based addressing at the network layer.
Furthermore, as an approach to address the routing challenges faced
in the Internet, structured addresses may be used in order to avoid
the need for routing protocols. Using variable length addresses
allow as well to have shorter addresses. So for requirements for
smaller network layer headers, shorter addresses could be used, maybe
alleviating the need to compress other fields of the header.
Furthermore, transport layer port numbers can be considered short
addresses, where the high order bits of the extended address is the
public IP of a NAT. Hence, in IoT deployments, the addresses of the
devices can be really small and based on the port number, but they
all share the global address of the gateway to make each one have a
globally unique address.
3.1.1. Shorter Address Length
3.1.1.1. Description:
In the context of IoT [RFC7228], where bandwidth and energy are very
scarce resources, the static length of 128-bit for an IP address is
more a hindrance than a benefit since 128-bit for an IP address may
occupy a lot of space, even to the point of being the dominant part
of a packet. In order to use bandwidth more efficiently and use less
energy in end-to-end communication, solutions have been proposed that
allow for very small network layer headers instead.
3.1.1.2. Methodology:
* Header Compression/Translation: One of the main approaches to
reduce header size in the IoT context is by compressing it. Such
technique is based on a stateful approach, utilizing what is
usually called a 'context' on the IoT sensor and the gateway for
communications between an IoT device and a server placed somewhere
in the Internet - from the edge to the cloud.
The role of the 'context' is to provide a way to 'compress' the
original IP header into a smaller one, using shorter address
information and/or dropping some field(s); the context here serves
as a kind of dictionary.
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* Separate device from locator identifier: Approaches that can offer
customized address length that is adequate for use in such
constrained domains are preferred. Using different namespaces for
the 'device identifier' and the 'routing' or 'locator identifier'
is one such approach.
3.1.1.3. Examples
* Header Compression/Translation: Considering one base station is
supposed to serve hundreds of user devices, maximizing the
effectiveness for specific spectrum directly improves user quality
of experience. To achieve the optimal utilization of the spectrum
resource in the wireless area, the RObust Header Compression
(ROHC) [RFC5795] mechanism, which has been widely adopted in
cellar network like WCDMA, LTE, and 5G, utilizes header
compression to shrink existing IPv6 headers onto shorter ones.
Similarly, header compression techniques for IPv6 over Low-Power
Wireless Personal Area Networks (6LoWPAN) have been around for
several years now, constituting a main example of using the notion
of a 'shared context' in order to reduce the size of the network
layer header ([RFC6282], [RFC7400], [ITU9959]). More recently,
other compression solutions have been proposed for Low Power Wide
Area Networks (LPWAN - [RFC8376]). Among them, the Static Context
Header Compression (SCHC - [RFC8724]) generalized the compression
mechanism developed by 6lo. Instead of a standard compression
behavior implemented in all 6lo nodes, SCHC introduces the notion
of rule shared by two nodes. The SCHC compression technique is
generic and can be applied to IPv6 and above layers. Regarding
the nature of the traffic, IPv6 addresses (source and destination)
can be elided, partially sent, or replaced by a small index.
Instead of the versatile IP packet, SCHC defines new packet
formats dedicated to specific applications. SCHC rules are
equivalence functions mapping this format to standard IP packets.
Also, constraints coming from either devices or carrier links
would lead to mixed scenarios and compound requirements for
extraordinary header compression. For native IPv6 communications
on DECT ULE and MS/TP Networks [RFC6282], dedicated compression
mechanisms are specified in [RFC8105] and [RFC8163], while the
transmission of IPv6 packets over NFC and PLC, specifications are
being developed in [I-D.ietf-6lo-nfc] and [I-D.ietf-6lo-plc].
* Separate device from locator identifier: Solutions such as
proposed in Expedited Internet Bypass Protocol [EIBP] and
[I-D.ietf-lisp-rfc6830bis] can utilize a separation of device from
locator, where only the latter is used for routing between the
different domains using the same technology, therefore enabling
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the use of shorter addresses in the (possibly constrained) local
environment. Device IDs used within such domains are carried as
part of the payload by EIBP and hence can be of shorter size
suited to the domain, while, for instance, in LISP a flexible
address encoding [RFC8060] allows shorter addresses to be
supported in the LISP control plane [I-D.ietf-lisp-rfc6833bis].
3.1.2. Longer Address Length
3.1.2.1. Description
Historically, obtaining adequate address space is considered as the
primary and raw motivation to invent IPv6. Longer address (more than
32-bit of IPv4 address), which can accommodate almost inexhaustible
devices, used to be considered as the surest direction in 1990s.
Nevertheless, to protect the sunk cost of IPv4 deployment, certain
efforts focus on IPv4 address space depletion question but engineer
IPv4 address length in a more practical way. Such effort, i.e., NAT
(Network Address Translation), unexpectedly and significantly slows
IPv6 deployment because of its high cost-effectiveness in practice.
Another crucial need for longer address lengths comes from "semantic
extensions" to IP addresses, where the extensions themselves do not
fit within the length limitation of the IP address. This sub-section
focuses on address length extensions that aim at reducing the IPv4
addresses depletion, while Section 3.3, i.e., address sematic
extensions, may still refer to extensions when longer address length
are suitable to accommodate different address semantic. See
Section 3.3 for details of sematic-driven address lengthening.
3.1.2.2. Methodology
* Split address zone by network realm: This methodology first split
the network realm into two types: one public realm (i.e., the
Internet), and innumerable private realms (i.e., local networks,
which may be embedded and/or having different scope). Then, it
splits the IP address space into two type of zones: global address
zone (i.e., public address) and local address zone (e.g., private
address, reserved address). Based on this, it is assumed that in
public realm, all devices attached to it should be assigned an
address that belongs to the global address zone. While for
devices attached to private realms, only addresses belonging to
the local address zone will be assigned. Local realms may have
different scope or even be embedded one in another, like for
instance, light switches local network being part of the building
local network, which in turn connects to the Internet. In the
local realms, addresses may have a pure identification purpose.
For instance in the last example, addresses of the light switches
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identify the switches themselves, while the building local network
is used to locate them.
Given that the local address zone is not globally unique, certain
mechanisms are designed to express the relationship between the
global address zone (in public realm) and the local address zone
(in any private realm). In this case, global addresses are used
for forwarding when a packet is in the public realm, and local
addresses are used for forwarding when a packet is in a private
realms.
3.1.2.3. Examples
* Split address zone by network realm: Network Address Translation
(NAT), which was first laid out in [RFC2663], using private
address and a stateful address binding to translate between the
realms. As outlined in [RFC2663], basic address translation is
usually extended to include port number information in the
translation process, supporting bidirectional or simple outbound
traffic only. Because the 16-bits port number is used in the
address translation, NAT theoretically increase IPv4 address
length from 32-bit to 48-bit, i.e., 281 trillion address space.
Similarly, EzIP [EzIP] expects to utilize a reserved address
block, i.e., 240/4, and an IPv4 header option to include it.
Based on this, it can be regarded as EzIP is carrying a
hierarchical address with two parts, where each part is a partial
32-bit IPv4 address. The first part is a public address residing
in the "address field" of the header from globally routable IPv4
pool [IPv4pool], i.e., ca. 3.84 billion address space. The second
part is the reserved address residing in "option field" and
belongs to the 240/4 prefix, i.e., ca. 2^28=268 million. Based on
that, each EzIP deployment is tethered on the existing Internet
via one single IPv4 address, and EzIP then have 3.84B * 268M
address, ca. 1,000,000 trillion. Collectively, the 240/4 can also
be used as end point identifier and form an overlay network
providing services parallel to the current Internet, yet
independent of the latter in other aspects.
Compared to NAT, EzIP is able to establish a communication session
from either side of it, hence being completely transparent, and
facilitating a full end-to-end networking configuration.
3.1.3. Summary
Table 1 summarizes methodologies and examples towards filling gaps on
IP address length extensions.
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+------------------------+----------------------+-------------+
| | Methodology | Examples |
+========================+======================+=============+
| Shorter Address Length | Header compression/ | 6LoWPAN, |
| | translation | ROHC, SCHC |
+------------------------+----------------------+-------------+
| | Separate device from | EIBP, LISP, |
| | locator identifier | ILNP, HIP |
+------------------------+----------------------+-------------+
| Longer Address Length | Split address zone | NAT, EzIP |
| | by network realm | |
+------------------------+----------------------+-------------+
Table 1: Summary Length Extensions
3.2. Identity Extensions
Extensions in this subsection attempt extending the property
described in Section 2.2, i.e., 'locator/identifier overload' of the
ambiguous address semantic.
From the perspective of Internet users, on the one hand, the implicit
identifier semantic results in a privacy concern due to network
behavior tracking and association. Despite that IP address
assignments may be dynamic, they are nowadays considered as 'personal
data' and as such undergoes privacy protection regulations like
General Data Protection Regulation ("GDPR" [GDPR]). Hence,
additional mechanisms are necessary in order to protect end user
privacy.
For network regulation of sensitive information, on the other hand,
dynamically allocated IP addresses are not sufficient to guarantee
device or user identification. As such, different address allocation
systems, with stronger identification properties are necessary where
security and authentication are at highest priority. Hence, in order
to protect information security within a network, additional
mechanism are necessary to identify the users or the devices attached
to the network.
3.2.1. Anonymous Address Identity
3.2.1.1. Description
As discussed in Section 2.2, IP addresses reveal both 'network
locations' as well as implicit 'identifier' information to both
traversed network elements and destination nodes alike. This enables
recording, correlation, and profiling of user behaviors and
historical network traces, possibly down to individual real user
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identity. The IETF, e.g., in [RFC7258], has taken a clear stand on
preventing any such pervasive monitoring means by classifying them as
an attack on end users' right to be left alone (i.e., privacy).
Regulations such as the EU's General Data Protection Regulation
(GDPR) classifies, for instance, the 'online identifier' as personal
data which must be carefully protected; this includes end users' IP
addresses [GDPR].
Even before pervasive monitoring [RFC7258], IP addresses have been
seen as something that some organizational owners of networked system
may not want to reveal at the individual level towards any non-member
of the same organization. Beyond that, if forwarding is based on
semantic extensions, like other fields of the header, extension
headers, or any other possible extension, if not adequately protected
it may introduce privacy leakage and/or new attack vectors.
3.2.1.2. Methodology:
* Traffic Proxy: Detouring the traffic to a trusted proxy is a
heuristic solution. Since nodes between trusted proxy and
destination (including the destination per se) can only observe
the source address of the proxy, the 'identification' of the
origin source can thereby be hidden. To obfuscate the nodes
between origin and the proxy, the traffic on such route would be
encrypted via a key negotiated either in-band or off-band.
Considering that all applications' traffic in such route can be
seen as a unique flow directed to the same 'unknown' node, i.e.,
the trusted proxy, eavesdroppers in such route have to make more
efforts to correlate user behavior through statistical analysis
even if they are capable of identifying the users via their source
addresses. The protection lays in the inability to isolate single
application specific flows. According to the methodology, such
approach is IP version independent and works for both IPv4 and
IPv6.
* Source Address Rollover: Privacy concerns related to address
'identifier' semantic can be mitigated through regular change
(beyond the typical 24 hours lease of DHCP). Due to the semantics
of 'identifier' that an IP address carries, such approach promotes
to change the source IP address at a certain frequency. Under
such methodology, the refresh cycling window may reach to a
balance between privacy protection and address update cost. Due
to the limited space that IPv4 contains, such approach usually
works for IPv6 only.
* Private Address Spaces: Their introduction in [RFC1918] foresaw
private addresses (assigned to specific address spaces by the
IANA) as a means to communicate purely locally, e.g., within an
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enterprise, by separating private from public IP addresses.
Considering that private addresses are never directly reachable
from the Internet, hosts adopting private addresses are invisible
and thus 'anonymous' for the Internet. Besides, hosts for purely
local communication used the latter while hosts requiring public
Internet service access would still use public IP addresses.
* Address Translation: The aforementioned original intention for
using private IP addresses, namely for purely local communication,
resulted in a lack of flexibility in changing from local to public
Internet access on the basis of what application would require
which type of service.
If eventually every end-system in an organization would require
some form of public Internet access in addition to local one, an
adequate number of public Internet addresses would be required for
providing to all end systems. Instead, address translation
enables to utilize many private IP addresses within an
organization, while only relying on one (or few) public IP
addresses for the overall organization.
In principle, address translation can be applied recursively.
This can be seen in modern broadband access where Internet
providers may rely on carrier-grade address translation for all
their broadband customers, who in turn employ address translation
of their internal home or office addresses to those (private
again) IP addresses assigned to them by their network provider.
Two benefits arise from the use of (private to public IP) address
translation, namely (i) the hiding of local end systems at the
level of the (address) assigned organization, and (ii) the
reduction of public IP addresses necessary for communication
across the Internet. While the latter has been seen for long as a
driver for address translation, in this section, we focus on the
first one, also since we see such privacy benefit as well as
objective as still being valid in addressing systems like IPv6
where address scarcity is all but gone [GNATCATCHER].
* Separate device from locator identifier: Solutions that make a
clear separation between the routing locator and the identifier,
can allow for a device ID of any size, which in turn can be
encrypted by a network element deployed at the border of routing
domain (e.g., access/edge router). Both source and end-domain
addresses can be encrypted and transported, as in the routing
domain, only the routing locator is used.
3.2.1.3. Examples:
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* Traffic Proxy: Although not initially designed as a traffic proxy
approach, a Virtual Private Network (VPN [VPN]) is widely utilized
for packets origin hiding as a traffic detouring methodology. As
it evolved, VPN derivatives like WireGuard [WireGuard] have become
a mainstream instance for user privacy and security enhancement.
With such methodology in mind, onion routing [ONION], instantiated
in the Tor Project [TOR], achieves high anonymity through traffic
hand over via intermediates, before reaching the destination.
Since the architecture of Tor requires at least three proxies,
none of them is aware of the entire route. Given that the proxies
themselves can be deployed all over cyberspace, trust is not the
prerequisite if proxies are randomly selected.
In addition, dedicated protocols are also expected to be
customized for privacy improvement via traffic proxy. For
example, Oblivious DNS over HTTPS (ODoH [RFC9230]) use a third-
party proxy to obscure identifications of user source addresses
during DNS over HTTPS (DoH [RFC8484]) resolution. Similarly,
Oblivious HTTP [OHTTP] involve proxy alike in the HTTP
environment.
* Source Address Rollover: As for source address rollover, it has
been standardized that IP addresses for Internet users should be
dynamic and temporary every time they are being generated
[RFC8981]. This benefits from the available address space in the
case of IPv6, through which address generation or assignment
should be unpredictable and stochastic for outside observers.
More radically, [EPHEMERALv6] advocates an 'ephemeral address',
changing over time, for each process. Through this, correlating
user behaviors conducted by different identifiers (i.e., source
address) becomes much harder, if not impossible, if based on the
IP packet header alone.
* Private Addresses: The use and assignment of private addresses for
IPv4 is laid out in [RFC1918], while unique local addresses (ULAs)
in IPv6 [RFC4193] take over the role of private address spaces in
IPv4.
* Network Address Translation: Given address translation can be
performed several times in cascade, NATs may exist as part of
existing customer premise equipment (CPE), such as a cable or an
Ethernet router, with private wired/wireless connectivity, or may
be provided in a carrier environment to further translate ISP-
internal private addresses to a pool of (assigned) public IP
addresses. The latter is often dynamically assigned to CPEs
during its bootstrapping.
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* Separate device from locator identifier: EIBP [EIBP] utilizes a
structured approach to addressing. It separates the routing ID
from the device ID, where only the former is used for routing. As
such, the device IDs can be encrypted, protecting the end device
identity. Similarly, LISP uses separate namespaces for routing
and identification allowing to 'hide' identifiers in encrypted
LISP packets that expose only known routing information [RFC8061].
3.2.2. Authenticated Address Identity
3.2.2.1. Description
In some scenarios (e.g., corporate networks) it is desirable to being
able authenticate IP addresses in order to prevent malicious
attackers spoofing IP addresses. This is usually achieved by using a
mechanism that allows to prove ownership of the IP address. Another
growing use case where identity verification is necessary for
security and safety reasons is in the aeronautical context, for both
manned and unmanned aerial vehicles ([RFC9153],
[I-D.haindl-lisp-gb-atn]).
3.2.2.2. Methodology
* Self-certified addresses: This method is usually based on the use
of nodes' public/private keys. A node creates its own interface
ID (IID) by using a cryptographic hash of its public key (with
some additional parameters). Messages are then signed using the
nodes' private key. The destination of the message will verify
the signature through the information in the IP address. Self-
certification has the advantage that no third party or additional
security infrastructure is needed. Any node can generate its own
address locally and then only the address and the public key are
needed to verify the binding between the public key and the
address.
* Collision-resistant addresses: When self-certification cannot be
used, an alternative approach is to generate addresses in a way
that is statistically unique (collision-resistant).
Authentication of the address then occurs in an out-of-band
protocol, where the unique identifier is resolved to
authenticating information.
* Third party granted addresses: DHCP (Dynamic Host Configuration
Protocol) is widely used to provide IP addresses, however, in its
basic form, it does not perform any check and even an unauthorized
user without the right to use the network can obtain an IP
address. To solve this problem, a trusted third party has to
grant access to the network before generating an address (via DHCP
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or other) that identifies the user. User authentication done
securely either based on physical parameters like MAC addresses or
based on an explicit login/password mechanism.
3.2.2.3. Examples
* Self-certified Addresses: As an example of this methodology serves
[RFC3972], defining IPv6 cryptographically Generated Addresses
(CGA). A Cryptographically Generated Address is formed by
replacing the least-significant 64 bits of an IPv6 address with
the cryptographic hash of the public key of the address owner.
Packets are then signed with the private key of the sender.
Packets can be authenticate by the receiver by using the public
key of the sender and the address of the sender. The original
specifications have been already amended (cf., [RFC4581] and
[RFC4982]) in order to support multiple (stronger) cryptographic
algorithms.
* Collision-resistant addresses: In order to provide a mechanism for
IP mobility considerations, [RFC7343] defines Overlay Routable
Cryptographic Hash Identifiers (ORCHIDv2). ORCHIDs use a
determinstic scheme for generating statistically unique addresses
by concatenating a designated IPv6 prefix, a hash function
identifier, and a truncated hash. The hash input is a unique,
statically assigned context identifier concatenated with random
data. A variation of this scheme is proposed to solve
requirements of [RFC9153] in identification of unmanned aerial
vehicles using Drone Remote Identification Protocol Entity Tags
(DRIP Entity Tag; DET) [I-D.ietf-drip-rid]. This variation
proposes a distinct IPv6 prefix and new hash functions, but the
major change is to further truncate the hash, and use the freed
bits for a two-level registration authority hierarchy. The
hierarchy is intended for delegation both when registering and
validating DETs globally.
* Third party granted addresses: [RFC3118] defines a DHCP option
through which authorization tickets can be generated and newly
attached hosts with proper authorization can be automatically
configured from an authenticated DHCP server. Solutions exist
where separate servers are used for user authentication like
[UA-DHCP] and [RFC4014]. The former proposing to enhance the DHCP
system using registered user login and password before actually
providing an IP address lease and recording the MAC address of the
device the user used to sign-in. The latter, couples the RADIUS
authentication protocol ([RFC2865]) with DHCP, basically
piggybacking RADIUS attributes in a DHCP sub-option, with the DHCP
server contacting the RADIUS server to authenticate the user.
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3.2.3. Summary
Table 2, summarize the methodologies and the examples towards filling
the gaps on identity extensions.
+----------------------------+----------------------+-------------+
| | Methodology | Examples |
+============================+======================+=============+
| Anonymous Address Identity | Traffic Proxy | VPN, TOR, |
| | | ODoH |
+----------------------------+----------------------+-------------+
| | Source Address | SLAAC |
| | Rollover | |
+----------------------------+----------------------+-------------+
| | Private Address | ULA |
| | Spaces | |
+----------------------------+----------------------+-------------+
| | Address Translation | NAT |
+----------------------------+----------------------+-------------+
| | Separate device from | EIBP, LISP |
| | locator identifier | |
+----------------------------+----------------------+-------------+
| Authenticated Address | Self-certified | CGA |
| Identity | Addresses | |
+----------------------------+----------------------+-------------+
| | Third party granted | DHCP-Option |
| | addresses | |
+----------------------------+----------------------+-------------+
Table 2: Summary Identity Extensions
3.3. Semantic Extensions
Extensions in this subsection try extending the property described in
Section 2.3, i.e., limited address semantic support.
As explained in Section 2.2, IP addresses carry both locator and
identification semantic. Some efforts exist that try to separate
these semantics either in different address spaces or through
different address formats. Beyond just identification, location, and
the fixed address size, other efforts extended the semantic through
existing or additional header fields (or header options) outside the
Internet address.
How much unique and globally routable an address should be? With the
effect of centralization, edges communicate with (rather) local DCs,
hence a unique address globally routable is not a requirement
anymore. There is no need to use globally unique addresses all the
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time for communication, however, there is the need of having a unique
address as a general way to communicate to any connected entity
without caring what transmission networks the packets traverse.
3.3.1. Utilizing Extended Address Semantics
3.3.1.1. Description
Several extensions have been developed to extend beyond the limited
IPv6 semantics. Those approaches may include to apply structure to
the address, utilize specific prefixes, or entirely utilize the IPv6
address for different semantics, while re-encapsulating the original
packet to restore the semantics in another part of the network. For
instance, structured addresses have the capability to introduce
delimiters to identify semantic information in the header, therefore
not constraining any semantic by size limitations of the address
fields.
We note here that extensions often start out as being proposed as an
extended header semantic, while standardization may drive the
solution to adopt an approach to accommodate their semantic within
the limitations of an IP address. This section does include examples
of this kind.
3.3.1.2. Methodology
* Semantic prefixes: Semantic prefixes are used to separate the IPv6
address space. Through this, new address families, such as for
information-centric networking [HICN], service routing or other
semantically rich addressing, can be defined, albeit limited by
the prefix length and structure as well as the overall length
limitation of the IPv6 address.
* Separate device/resource from locator identifier: The option to
use separate namespaces for the device address would offer more
freedom for the use of different semantics. For instance, the
static binding of IP addresses to servers creates a strong binding
between IP addresses and service/resources, which may be a
limitation for large Content Distribution networks (CDNs)
[FAYED21].
As an extreme form of separating resource from locator identifier,
recent engineering approaches, described in [CLOUDFLARE_SIGCOMM],
decouple web service (semantics) from the routing address
assignments by using virtual hosting capabilities, thereby
effectively mapping possibly millions of services onto a single IP
address.
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* Structured addressing: One approach to address the routing
challenges faced in the Internet is the use of structured
addresses, e.g., to void the need for routing protocols. Benefits
of this approach can be significant, with the structured addresses
capturing the relative physical or virtual position of routers in
the network as well as being variable in length. Key to the
approach, however, is that the structured addresses capturing the
relative physical or virtual position of routers in the network,
or networks in an internetwork may not fit within the fixed and
limited IP address length (cf., Section 3.1.2). Other structured
approaches may be the use of application-specific structured
binary components for identification, generalizing URL schema used
for HTTP-level communication but utilized at the network level for
traffic steering decisions.
* Localized forwarding semantics: Layer 2 hardware, such as SDN
switches, are limited to the use of specific header fields for
forwarding decisions. Hence, devising new localized forwarding
mechanisms may be based on re-using differently existing header
fields, such as the IPv6 source/destination fields, to achieve the
desired forwarding behavior, while encapsulating the original
packets in order to be restored at the local forwarding network
boundary. Networks in those solutions are limited by the size of
the utilized address field, e.g., 256 bits for IPv6, thereby
limiting the way such techniques could be used.
3.3.1.3. Examples
* Semantic prefixes: Newer approaches to IP anycast suggest the use
of service identification in combination with a binding IP address
model [SFCANYCAST] as a way to allow for metric-based traffic
steering decisions; approaches for Service Function Chaining (SFC)
[RFC7665] utilize the Network Service Header (NSH) information and
packet classification to determine the destination of the next
service.
Another example of the usage of different packet header extensions
based on IP addressing is Segment Routing. In this case, the
source chooses a path and encodes it in the packet header as an
ordered list of segments. Segments are encoded using new Routing
Extensions Header type, the Segment Routing Header (SRH), which
contains the Segment List, similar to what is already specified in
[RFC8200], i.e., a list of segment ID (SID) that dictate the path
to follow in the network. Such segment IDs are coded as 128 bit
IPv6 addresses [RFC8986].
Approaches such as [HICN] utilize semantic prefixing to allow for
ICN forwarding behavior within an IPv6 network. In this case, an
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HICN name is the hierarchical concatenation of a name prefix and a
name suffix, in which the name prefix is encoded as an IPv6 128
bits word and carried in IPv6 header fields, while the name suffix
is encoded in transport headers fields such as TCP. However, it
is a challenge to determine which IPv6 prefixes should be used as
name prefixes. In order to know which IPv6 packets should be
interpreted based on an ICN semantic, it is desirable to be able
to recognize that an IPv6 prefix is a name prefix, e.g. to define
a specific address family (AF_HICN, b0001::/16). This
establishment of a specific address family allows the management
and control plane to locally configure HICN prefixes and announce
them to neighbors for interconnection.
* Separate device from locator identifier: EIBP [EIBP] separates the
routing locator from the device identifier, relaxing therefore any
semantic constraints on the device identifier. Similarly, LISP
uses a flexible encoding named LISP Canonical Address Format (LCAF
[RFC8061]), which allows to associate to routing locators any
possible form (and length) of identifier. ILNP [RFC6740]
introduces as well a different semantic of IP addresses, while
aligning to the IPv6 address format (128 bits). Basically, ILNP
introduces a sharper logical separation between the 64 most
significant bits and the 64 least significant bits of an IPv6
address. The former being a global locator, while the latter
being an identifier that can have different semantics (rather than
just being an interface identifier).
* Structured addressing: Network topology captures the physical
connectivity among devices in the network. There is a structure
associated with the topology. Examples are the core-distribution-
access router structure commonly used in enterprise networks and
clos topologies that are used to provide multiple connections
between Top of Rack (ToR) devices and multiple layers of spine
devices. Internet service providers use a tier structure that
defines their business relationships. A clear structure of
connected networks can be noticed in the Internet. EIBP [EIBP]
proposes to leverage the physical structure (or a virtual
structure overlaid on the physical structure) to auto assign
addresses to routers in a network or networks in an internetwork
to capture their relative position in the physical/virtual
topology. EIBP proposes to administratively identify routers/
networks with a tier value based on the structure.
* Localized forwarding semantics: Approaches such as those outlined
in [REED] suggest using a novel forwarding semantic based on path
information carried in the packet itself, said path information
consists in a fixed size bit-field (see [REED] for more
information on how to represent the path information in said bit-
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field). In order to utilize existing, e.g., SDN-based, forwarding
switches, the direct use of the IPv6 source/destination address is
suggested for building appropriate match-action rules (over the
suitable binary information representing the local output ports),
while preserving the original IPv6 information in the encapsulated
packet. As mentioned above, such use of the existing IPv6 address
fields limits the size of the network to a maximum of 256 bits
(therefore paths in the network over which such packets can be
forwarded). [ICNIP], however, goes a step further by suggesting
to use the local forwarding as direct network layer mechanism,
removing the IP packet and only leaving the transport/application
layer, with the path identifier constituting the network-level
identifier albeit limited by using the existing IP header for
backward compatibility reasons (the next section outlines the
removal of this limitation).
3.3.2. Utilizing Existing or Extended Header Semantics
3.3.2.1. Description:
While the former sub-section explored extended address semantic,
thereby limiting any such extended semantic with that of the existing
IPv6 semantic and length, additional semantics may also be placed
into the header of the packet or the packet itself, utilized for the
forwarding decision to the appropriate endpoint according to the
extended semantic.
Reasons for embedding such new semantics may be related to traffic
engineering since it has long been shown that the IP address itself
is not enough to steer traffic properly since the IP address itself
is not semantically rich enough to adequately describe the forwarding
decision to be taken in the network, not only impacting _where_ the
packet will need to go, but also _how_ it will need to be sent.
3.3.2.2. Methodology:
* In-Header extensions: One way to add additional semantics besides
the address fields is to use other fields already present in the
header.
* Headers option extensions: Another mechanism to add additional
semantics is to actually add additional fields, e.g., through
Header Options in IPv4 or through Extension Headers in IPv6.
* Re-encapsulation extension: A more radical approach for additional
semantics is the use of a completely new header that is designed
so to carry the desired semantics in an efficient manner (often as
a shim header).
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* Structured addressing: Similar to the methodology that structures
addresses within the limitations of the IPv6 address length,
outlined in the previous sub-sections, structured addressing can
also be applied within existing or extended header semantics,
e.g., utilizing a dedicated (extension) header to carry the
structured address information.
* Localized forwarding semantics: This set of solutions applies
capabilities of newer (programmable) forwarding technology, such
as [P4], to utilize any header information for a localized
forwarding decision. This removes any limitation to use existing
header or address information for embedding a new address semantic
into the transferred packet.
3.3.2.3. Examples:
* In-Header extensions: In order to allow additional semantic with
respect to the pure Internet addressing, the original design of
IPv4 included the field 'Type of Service' [RFC2474], while IPv6
introduced the 'Flow label' and the 'Traffic Class' [RFC8200]
fields. In a certain way, those fields can be considered
'semantic extensions' of IP addresses, and they are 'in-header'
because natively present in the IP header (differently from
options and extension headers). However, they proved not to be
sufficient. Very often a variety of network operations are
performed on the well-known 5-tuple (source and destination
addresses; source and destination port number; and protocol
number). In some contexts all of the above-mentioned fields are
used in order to have a very fine grained solution ([RFC8939]).
* Headers option extensions: Header options have been largely under-
exploited in IPv4. However, the introduction of the more
efficient extension header model in IPv6 along with technology
progress made the use of header extensions more widespread in
IPv6. Segment Routing re-introduced the possibility to add path
semantic to the packet by encoding a loosely defined source
routing ([RFC8402]). Similarly, in the aim to overcome the
inherent shortcoming of the multi-homing in the IP context, SHIM6
([RFC5533]) also proposed the use of an extension header able to
carry multi-homing information which cannot be accommodated
natively in the IPv6 header.
To serve a moving endpoint, mechanisms like Mobile IPv6 [RFC6275]
are used for maintaining connection continuity by a dedicated IPv6
extension header. In such case, the IP address of the home agent
in Mobile IPv6 is basically an identification of the on-going
communication. In order to go beyond the interface identification
model of IP, the Host Identity Protocol (HIP) tries to introduce
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an identification layer to provide (as the name says) host
identification. The architecture here relies on the use of
another type of extension header [RFC7401].
* Re-encapsulation extension: Differently from the previous
approach, re-encapsulation prepends complete new IP headers to the
original packet introducing a completely custom shim header
between the outer and inner header. This is the case for LISP,
adding a LISP specific header right after an IP+UDP header
([I-D.ietf-lisp-rfc6830bis]). A similar design is used by VxLAN
([RFC7348]) and GENEVE ([RFC8926]), even if they are designed for
a data center context. IP packets can also be wrapped with
headers using more generic and semantically rich names, for
instance with ICN [ICNIP].
* Structured addressing: Solutions such as those described in the
previous sub-section, e.g., EIBP [EIBP], can provide structured
addresses that are not limited to the IPv6 address length but
instead carry the information in an extension header to remove
such limitation.
Also, Information-Centric Networking (ICN) naming approaches
usually introduce structures in the (information) names without
limiting themselves to the IP address length; more so, ICN
proposes its own header format and therefore radically breaks with
not only IP addressing semantic but the format of the packet
header overall. For this, approaches such as those described in
[RFC8609] define a TLV-based binary application component
structure that is carried as a 'name' part of the CCN messages.
Such a name is a hierarchical structure for identifying and
locating a data object, which contains a sequence of name
components. Names are coded based on 2-level nested Type-Length-
Value (TLV) encodings, where the name-type field in the outer TLV
indicates this is a name, while the inner TLVs are name components
including a generic name component, an implicit SHA-256 digest
component and a SHA-256 digest of Interest parameters. For
textual representation, URIs are normally used to represent names,
as defined in [RFC3986].
In geographic addressing, position based routing protocols use the
geographic location of nodes as their addresses, and packets are
forwarded when possible in a greedy manner towards the
destination. For this purpose, the packet header includes a field
coding the geographic coordinates (x, y, z) of the destination
node, as defined in [RFC2009]. Some proposals also rely on extra
fields in the packet header to code the distance towards the
destination, in which case only the geographic coordinates of
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neighbors are exchanged. This way the location of the destination
is protected even if routing packets are eavesdropped.
* Localized forwarding semantics: Unlike the original suggestion in
[REED] to use existing SDN switches, the proliferation of P4 [P4]
opens up the possibility to utilize a locally limited address
semantic, e.g., expressed through the path identifier, as an
entirely new header (including its new address) with an
encapsulation of the IP packet for E2E delivery (including further
delivery outside the localized forwarding network or positioning
the limited address semantic directly as the network address
semantic for the packet, i.e., removing any IP packet
encapsulation from the forwarded packet, as done in [ICNIP].
Removing the IPv6 address size limitation by not utilizing the
existing IP header for the forwarding decision also allows for
extensible length approaches for building the path identifier with
the potential for increasing the supported network size. On the
downside, this approach requires to encapsulate the original IP
packet header for communication beyond the local domain in which
the new header is being used, such as discussed in the previous
point above on 're-encapsulation extension'.
3.3.3. Summary
Table 3, summarize the methodologies and the examples towards filling
the gaps on semantic extensions.
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+---------------------------+----------------------+-------------+
| | Methodology | Examples |
+===========================+======================+=============+
| Utilizing Extended | Semantic prefixes | HICN |
| Address Semantics | | |
+---------------------------+----------------------+-------------+
| | Separate device from | EIBP, ILNP, |
| | locator identifier | LISP, HIP |
+---------------------------+----------------------+-------------+
| | Structured | EIBP, ILNP |
| | addressing | |
+---------------------------+----------------------+-------------+
| | Localized forwarding | REED |
| | semantics | |
+---------------------------+----------------------+-------------+
| Utilizing Existing or | In-Header extensions | DetNet |
| Extended Header Semantics | | |
+---------------------------+----------------------+-------------+
| | Headers option | SHIM6, |
| | extensions | SRv6, HIP |
+---------------------------+----------------------+-------------+
| | Re-encapsulation | VxLAN, |
| | extension | ICNIP |
+---------------------------+----------------------+-------------+
| | Structured | EIBP |
| | addressing | |
+---------------------------+----------------------+-------------+
| | Localized forwarding | REED |
| | semantics | |
+---------------------------+----------------------+-------------+
Table 3: Summary Semantic Extensions
4. Overview of Approaches to Extend Internet Addressing
The following Table 4 describes the objectives of the extensions
discussed in this memo with respect to the properties of Internet
addressing (Section 2}. As summarized, extensions may aim to extend
one property of the Internet addressing, or extend other properties
at the same time.
+------------+------------------+--------------------+-----------+
| | Length Extension | Identity Extension | Semantic |
| | | | Extension |
+============+==================+====================+===========+
| 6LoWPAN | x | | |
+------------+------------------+--------------------+-----------+
| ROHC | x | | |
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+------------+------------------+--------------------+-----------+
| EzIP | x | | |
+------------+------------------+--------------------+-----------+
| TOR | | x | |
+------------+------------------+--------------------+-----------+
| ODoH | | x | |
+------------+------------------+--------------------+-----------+
| SLAAC | | x | |
+------------+------------------+--------------------+-----------+
| CGA | | x | x |
+------------+------------------+--------------------+-----------+
| NAT | x | x | |
+------------+------------------+--------------------+-----------+
| HICN | | x | x |
+------------+------------------+--------------------+-----------+
| ICNIP | x | x | x |
+------------+------------------+--------------------+-----------+
| CCNx names | x | x | x |
+------------+------------------+--------------------+-----------+
| EIBP | x | x | x |
+------------+------------------+--------------------+-----------+
| Geo | x | | x |
| addressing | | | |
+------------+------------------+--------------------+-----------+
| REED | x (with P4) | | x |
+------------+------------------+--------------------+-----------+
| DetNet | | x | |
+------------+------------------+--------------------+-----------+
| Mobile IP | | | x |
+------------+------------------+--------------------+-----------+
| SHIM6 | | | x |
+------------+------------------+--------------------+-----------+
| SRv6 | | | x |
+------------+------------------+--------------------+-----------+
| HIP | | x | x |
+------------+------------------+--------------------+-----------+
| VxLAN | | x | x |
+------------+------------------+--------------------+-----------+
| LISP | | x | x |
+------------+------------------+--------------------+-----------+
| SFC | | x | x |
+------------+------------------+--------------------+-----------+
Table 4: Relationship between Extensions and Internet Addressing
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5. A System View on Address
In the following, we investigate in which parts of the overall
Internet system extensions have been proposed and developed. For
this, we divide the possible innovation across two dimensions:
* Horizontal: Internet edge vs core. The criticality, scale,
investment on the core of the Internet makes it more difficult to
introduce innovation, while at the edges there is more
flexibility. As general purpose processors have drastically
improved in performance, data-plane features can be implemented in
software. At the edge of the Internet, it easier to introduce
innovation for several reasons: Economics, faster ROI because of
faster deployment; No need of large scale deployment (and hence
less standardization effort); less stakeholders involved
(sometimes just one, see following point). Furthermore, the fact
that the edge is a place where there is less coordination and
cooperation from the core, is another factor that ease the
innovation.
* Vertical: at which layer of the protocol stack. The difficulty to
innovate varies as well depending at which layer the innovation
takes place. One thing is to innovate at application layer where
the app developer has large degree of freedom, another is to
innovate at network layer, which is more constrained because of
its central point in the architecture. Innovation at higher
layers sometimes leads to walled gardens (aka limited domains
[RFC8799]). Indeed, because of the centralization phenomena, an
actor offering a certain service may very well develop and deploy
a custom technology that does not need to be actually standardized
because it is done for its own internal usage.
* Horizontal vs Vertical Innovation:
- In the public Internet, core innovation at lower layer is
harder, often reduced to app-level innovation or building an
overlay limited domain (aka a walled garden).
- At the edges it is easier to innovate at lower layers (more
vertical flexibility) but some form of adaptation is needed if
global reachability is wanted.
Despite these two orthogonal dimensions, innovation does not happen
either horizontally or vertically, rather in both dimensions
simultaneously at various degree.
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6. Concerns in Extensions to Internet Addressing
While the extensions to the original Internet properties, discussed
in Section 3, demonstrate the benefits of more flexibility in
addressing, they also raise a number of concerns, which are discussed
in the following section. To this end, the problems hereafter
outlined link to the approaches to extensions summarized in
Section 4. These considerations may not be present all the time and
everywhere, since as explained in Section 5, extensions are developed
and deployed in different part of the Internet, which may worsen
things.
6.1. Limiting Address Semantics
Many approaches changing the semantics of communication, e.g.,
through separating host identification from network node
identification [RFC7401], separating the device identifier from the
routing locator ([EIBP], [I-D.ietf-lisp-introduction]), or through
identifying content and services directly [HICN], are limited by the
existing packet size and semantic constraints of IPv6, e.g., in the
form of its source and destination network addresses.
While approaches such as [ICNIP] may override the addressing
semantics, e.g., by replacing IPv6 source and destination information
with path identification, a possible unawareness of endpoints still
requires the carrying of other address information as part of the
payload.
Also, the expressible service or content semantic may be limited, as
in [HICN] or the size of supported networks [REED] due to relying on
the limited bit positions usable in IPv6 addresses.
6.2. Complexity and Efficiency
A crucial concern is the additional complexity introduced for
realizing the additional addressing semantics. This is particularly
a concern since we see those additional semantics particularly at the
edge of the Internet, utilizing the existing addressing semantic of
the Internet to interconnect the domains that require those
additional semantics.
Furthermore, any additional complexity often comes with an efficiency
and cost penalty, particularly at the edge of the network, where
resource constraints may play a significant role. Compression
processes, taking [ROHC] as an example, require additional resources
both for the sender generating the compressed header but also the
gateway linking to the general Internet by re-establishing the full
IP header.
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Conversely, the performance requirements of core networks, in terms
of packet processing speed, makes the accommodation of extensions to
addressing often prohibitive. This is not only due to the necessary
extra processing that is specific to the extension, but also due to
the complexity that will need to be managed in doing so at
significantly higher speeds than at the edge of the network. The
observations on the dropping of packets with IPv6 extension headers
in the real world is (partially) due to such a implementation
complexity [RFC7872].
Another example for lowering the efficiency of packet forwarding is
the routing in systems like Tor [TOR]. As detailed before, traffic
in Tor, for anonymity purposes, should be handed over by at least
three intermediates before reaching the destination. Frequent
relaying enhances the privacy, however, because such kind of
solutions are implemented at application level, they come at the cost
of lower communication efficiency. May be a different privacy
enhanced address semantic would enable efficient implementation of
Tor-like solutions at network layer.
6.2.1. Repetitive encapsulation
Repetitive encapsulation is a concern since it bloats the packets
size due to additional encapsulation headers. Addressing proposals
such as those in [ICNIP] utilize path identification within an
alternative forwarding architecture that acts upon the provided path
identification. However, due to the limitation of existing flow-
based architectures with respect to the supported header structures
(in the form of IPv4 or IPv6 headers), the new routing semantics are
being inserted into the existing header structure, while repeating
the original, sender-generated header structure, in the payload of
the packet as it traverses the local domain, effectively doubling the
per-packet header overhead.
The problem is also present in a number of solutions tackling
different use-cases, e.g., mobility [I-D.ietf-lisp-mn], data center
networking ([RFC8926], [RFC7348], [I-D.ietf-intarea-gue]), traffic
engineering [RFC8986], and privacy ([TOR], [SPHINX]). Certainly
these solutions are able to avoid issues like path lengthening or
privacy concerns, as described before, but they come at the price of
multiple encapsulations that reduce the effective payload. This, not
only hampers efficiency in terms of header-to-payload ratio, but also
introduces 'encapsulation points', which in turn add complexity to
the (often edge) network as well as fragility due to the addition of
possible failure points; this aspect is discussed in further details
in Section 6.4.
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6.2.2. Compounding concerns with header compression
IP header overhead requires header compression in constrained
environments, such as wireless sensor networks and IoT in general.
Together with fragmentation, both tasks constitute significant energy
consumption, as shown in [HEADER_COMP_ISSUES1], negatively impacting
resource limited devices that often rely on battery for operation.
Further, the reliance on the compression/decompression points creates
a dependence on such gateways, which may be a problem for
intermittent scenarios.
According to the implementation of _contiki-ng_ [CONTIKI], an example
of operating system for IoT devices, the source codes for 6LowPan
requires at least 600Kb to include a header compression process. In
certain use cases, such requirement can be an obstacle for extremely
constrained devices, especially for the RAM and energy consumption.
6.2.3. Introducing Path Stretch
Mobile IP [RFC6275], which was designed for connection continuity in
the face of moving endpoints, is a typical case for path stretch.
Since traffic must follow a triangular route before arriving at the
destination, such detour routing inevitably impacts transmission
efficiency as well as latency.
6.2.4. Complicating Traffic Engineering
While many extensions to the original IP address semantic target to
enrich the decisions that can be taken to steer traffic, according to
requirements like QoS, mobility, chaining, compute/network metrics,
flow treatment, path usage, etc., the realization of the mechanisms
as individual solutions likely complicates the original goal of
traffic engineering when individual solutions are being used in
combination. Ultimately, this may even prevent the combined use of
more than one mechanism and/or policy with a need to identify and
prevent incompatibilities of mechanisms. Key here is not the
concerns arising from using conflicting traffic engineering policies,
rather conflicting realizations of policies that may well generally
work well alongside ([ROBUSTSDN], [TRANSACTIONSDN]).
This not only increases fragility, as discussed separately in
Section 6.4, but also requires careful planning of which mechanisms
to use and in which combination, likely needing human-in-the-loop
approaches alongside possible automation approaches for the
individual solutions.
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6.3. Security
The properties described in Section 2 have, obviously, also
consequences in terms of security and privacy related concerns, as
already mentioned in other parts of this document.
For instance, in the effort of being somehow backward compatible, HIP
[RFC7401] uses a 128-bit Host Identity, which may be not sufficiently
cryptographically strong in the future, because of the limited size
(future computational power may erode 128-bit security). Similarly,
CGA [RFC3972] also aligns to the 128-bit limit, but may use only 59
bits of them, hence, the packet signature may not be sufficiently
robust to attacks [I-D.rafiee-6man-cga-attack].
IP addresses, even temporary ones meant to protect privacy, have been
long recognized as a 'Personal Identification Information' that
allows even to geolocate the communicating endpoints [RFC8280]. The
use of temporary addresses provides sufficient privacy protection
only if the renewal rate is high [EPHEMERALv6]. However, this may
raise some issues, like the large overhead due to the Duplicate
Address Detection, the impact on the Neighbor Discovery mechanism, in
particular the cache, which can even lead to communication
disruption. With such drawbacks, the extensions may even lead to
defeat the target, actually lowering security rather than increasing
it.
The introduction of alternative addressing semantics has also been
used to help in (D)DoS attacks mitigation. This leverages on
changing the service identification model so to avoid topological
information exposure, making the potential disruptions likely remain
limited [ADDRLESS]. However, this increased robustness to DDoS comes
at the price of important communication setup latency and fragility,
as discussed next.
6.4. Fragility
From the extensions discussed in Section 3, it is evident that having
alternative or additional address semantic and formats available for
making routing as well as forwarding decisions dependent on these, is
common place in the Internet. This, however, adds many extension-
specific translation/adaptation points, mapping the semantic and
format in one context into what is meaningful in another context, but
also, more importantly, creating a dependency towards an additional
component, often without explicit exposure to the endpoints that
originally intended to communicate.
For instance, the re-writing of IP addresses to facilitate the use of
private address spaces throughout the public Internet, realized
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through network address translators (NATs), conflicts with the end-
to-end nature of communication between two endpoints. Additional
(flow) state is required at the NAT middle-box to smoothly allow
communication, which in turn creates a dependency between the NAT and
the end-to-end communication between those endpoints, thus increasing
the fragility of the communication relation.
A similar situation arises when supporting constrained environments
through a header compression mechanism, adding the need for, e.g., a
ROHC [RFC5795] element in the communication path, with communication-
related compression state being held outside the communicating
endpoints. Failure will introduce some inefficiencies due to context
regeneration, which may affects the communicating endpoints,
increasing fragility of the system overall.
Such translation/adaptation between semantic extensions to the
original 'semantic' of an IP address is generally not avoidable when
accommodating more than a single universal semantic. However, the
solution-specific nature of every single extension is likely to
noticeably increase the fragility of the overall system, since
individual extensions will need to interact with other extensions
that may be deployed in parallel, but were not designed taking into
account such deployment scenario (cf., [I-D.ietf-intarea-tunnels]).
Considering that extensions to traditional per-hop-behavior (based on
IP addresses) can essentially be realized over almost 'any' packet
field, the possible number of conflicting behaviors or diverging
interpretation of the semantic and/or content of such fields, among
different extensions, may soon become an issue, requiring careful
testing and delineation at the boundaries of the network within which
the specific extension has been realized.
7. Summary of concernss
Table 5, derived from Section 6, summarizes the concerns related to
each extension. While each extension involves at least one concern,
some others, like ICNIP, may create several at the same time.
+------------+------------------+------------+----------+-----------+
| | Limiting | Complexity | Security | Fragility |
| | Address | and | | |
| | Semantics | Efficiency | | |
+============+==================+============+==========+===========+
| 6LoWPAN | | x | | x |
+------------+------------------+------------+----------+-----------+
| ROHC | | x | | x |
+------------+------------------+------------+----------+-----------+
| EzIP | | x | | |
+------------+------------------+------------+----------+-----------+
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| TOR | | x | | x |
+------------+------------------+------------+----------+-----------+
| ODoH | | x | | |
+------------+------------------+------------+----------+-----------+
| SLAAC | | x | | |
+------------+------------------+------------+----------+-----------+
| CGA | x | | x | |
+------------+------------------+------------+----------+-----------+
| NAT | | x | | x |
+------------+------------------+------------+----------+-----------+
| HICN | x | | | |
+------------+------------------+------------+----------+-----------+
| ICNIP | x | x | | |
+------------+------------------+------------+----------+-----------+
| CCNx name | x | | | |
+------------+------------------+------------+----------+-----------+
| EIBP | | | | x |
+------------+------------------+------------+----------+-----------+
| Geo | x | | | x |
| addressing | | | | |
+------------+------------------+------------+----------+-----------+
| REED | x | | | |
+------------+------------------+------------+----------+-----------+
| DetNet | | x | | |
+------------+------------------+------------+----------+-----------+
| Mobile IP | | x | | x |
+------------+------------------+------------+----------+-----------+
| SHIM6 | | | | x |
+------------+------------------+------------+----------+-----------+
| SRv6 | | | | x |
+------------+------------------+------------+----------+-----------+
| HIP | | | x | x |
+------------+------------------+------------+----------+-----------+
| VxLAN | | x | | |
+------------+------------------+------------+----------+-----------+
| LISP | | x | | x |
+------------+------------------+------------+----------+-----------+
| SFC | | x | | x |
+------------+------------------+------------+----------+-----------+
Table 5: Concerns in Extensions to Internet Addressing
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8. Conclusions
The examples of extensions discussed in Section 3 to the original
Internet addressing scheme show that extensibility beyond the
original model (and its underlying per-hop behavior) is a desired
capability for networking technologies and has been so for a long
time. Generally, we can observe that those extensions are driven by
the requirements of stakeholders, expecting a desirable extended
functionality from the introduction of the specific extension. If
interoperability is required, those extensions require
standardization of possibly new fields, new semantics as well as
(network and/or end system) operations alike.
The consideration documented in this memo, with the extension-
specific solution approach, point to the need for a discussion on
Internet addressing, as formulated in the companion document
[I-D.iannone-scenarios-problems-addressing] that formalizes the
problem statement through scenarios that highlight the shortcomings
of the Internet addressing model.
It is our conclusion that the existence of the many extensions to the
original Internet addressing is clear evidence for evolution paths
that have been identified over time by the wider Internet community,
each of which come with a raft of issues that we need to deal with
daily: We believe that it is time to develop an architectural but
more importantly a sustainable approach to make Internet addressing
extensible in order to capture the many new use cases that will still
be identified for the Internet to come.
To jumpstart any such effort from an addressing perspective, it will
be key to suitable define what an address is at which layer of the
overall system, let alone the network layer. We argue that any
answer to this question must be derived from what features we may
want from the network instead of being guided by the answers that the
Internet can give us today, e.g., being a mere ephemeral token for
accessing PoP-based services (as indicated in related arch-d mailing
list discussions).
This is not to 'second guess' the market and its possible evolution,
but to outline clear features from which to derive clear principles
for a design. Any such design must not skew the technical
capabilities of addressing to the current economic situation of the
Internet since this bears the danger of locking down innovation
capabilities as an outcome of those technical limitations introduced.
Instead, addressing must be aligned with enabling the model of
permissionless innovation that the IETF has been promoting,
ultimately enabling the serendipity of new applications that has led
to many of those applications we can see in the Internet today. Most
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importantly, any inaction on our side in that regard will only
compound the identified concerns, eventually hampering the future
Internet's readiness for those new uses.
9. Security Considerations
The present memo does not introduce any new technology and/or
mechanism and as such does not introduce any new security threat to
the TCP/IP protocol suite.
As an additional note, and as discussed in this document, security
and privacy aspects were not considered as part of the key properties
for Internet addressing, which led to the introduction of a number of
extensions intending to fix those gaps. The analysis presented in
this memo (non-exhaustively) shows those concerns are either solved
in an ad-hoc manner at application level, or at transport layer,
while at network level only few extensions tackling specific aspects
exist, albeit often with limitations due to the adherence to the
Internet addressing model and its properties.
10. IANA Considerations
This document does not include any IANA request.
11. Informative References
[ADDRLESS] Hao, S., Liu, R., Weng, Z., Chang, D., Bao, C., Li, X.,
Wang, H., Ed., and Public Library of Science (PLoS),
"Addressless: A new internet server model to prevent
network scanning", PLOS ONE, vol. 16, no. 2, pp. e0246293,
DOI 10.1371/journal.pone.0246293, 2 February 2021,
<http://dx.doi.org/10.1371/journal.pone.0246293>.
[CLOUDFLARE_SIGCOMM]
Fayed, M., Bauer, L., Giotsas, V., Kerola, S., Majkowski,
M., Odintsov, P., Sitnicki, J., Chung, T., Levin, D.,
Mislove, A., Wood, C. A., Sullivan, N., and ACM, "The ties
that un-bind", Proceedings of the 2021 ACM SIGCOMM 2021
Conference, DOI 10.1145/3452296.3472922, 9 August 2021,
<http://dx.doi.org/10.1145/3452296.3472922>.
[CONTIKI] "Contiki-NG: The OS for Next Generation IoT Devices",
n.d., <https://github.com/contiki-ng/contiki-ng>.
[EIBP] Willis, N.Shenoy, S.Chandraiah, P., "A Structured Approach
to Routing in the Internet", June 2021, <First Intl
Workshop on Semantic Addressing and Routing for Future
Networks>.
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[EPHEMERALv6]
Gont, F. and G. Gont, "IPv6 Addressing Considerations",
Work in Progress, Internet-Draft, draft-gont-v6ops-ipv6-
addressing-considerations-02, 1 June 2022,
<https://www.ietf.org/archive/id/draft-gont-v6ops-ipv6-
addressing-considerations-02.txt>.
[EzIP] Chen, A. Y., Ati, R. R., Karandikar, A., and D. R. Crowe,
"Adaptive IPv4 Address Space", Work in Progress, Internet-
Draft, draft-chen-ati-adaptive-ipv4-address-space-11, 10
June 2022, <https://www.ietf.org/archive/id/draft-chen-
ati-adaptive-ipv4-address-space-11.txt>.
[FAYED21] Fayed, M., Bauer, L., Giotsas, V., Kerola, S., Majkowski,
M., Odintsov, P., Sitnicki, J., Chung, T., Levin, D.,
Mislove, A., Wood, C. A., Sullivan, N., and ACM, "The ties
that un-bind", Proceedings of the 2021 ACM SIGCOMM 2021
Conference, DOI 10.1145/3452296.3472922, 9 August 2021,
<http://dx.doi.org/10.1145/3452296.3472922>.
[GDPR] Voigt, P., Bussche, A. V. D., and Springer International
Publishing, "The EU General Data Protection Regulation
(GDPR)", DOI 10.1007/978-3-319-57959-7, 2017,
<http://dx.doi.org/10.1007/978-3-319-57959-7>.
[GNATCATCHER]
"Global Network Address Translation Combined with Audited
and Trusted CDN or HTTP-Proxy Eliminating
Reidentification", n.d.,
<https://github.com/bslassey/ip-blindness>.
[HEADER_COMP_ISSUES1]
Mesrinejad, F., Hashim, F., Noordin, N. K., Rasid, M. F.
A., Abdullah, R. S. A. R., and IEEE, "The effect of
fragmentation and header compression on IP-based sensor
networks (6LoWPAN)", The 17th Asia Pacific Conference on
Communications, DOI 10.1109/apcc.2011.6152926, October
2011, <http://dx.doi.org/10.1109/apcc.2011.6152926>.
[HICN] Muscariello, L., "Hybrid Information-Centric Networking:
ICN inside the Internet Protocol", March 2018,
<https://datatracker.ietf.org/meeting/interim-2018-icnrg-
01/materials/slides-interim-2018-icnrg-01-sessa-hybrid-
icn-hicn-luca-muscariello>.
[HISTORY127]
"History of 127/8 as localhost/loopback addresses", n.d.,
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<https://elists.isoc.org/pipermail/internet-
history/2021-January/006920.html>.
[I-D.haindl-lisp-gb-atn]
Haindl, B., Lindner, M., Moreno, V., Comeras, M. P.,
Maino, F., and B. Venkatachalapathy, "Ground-Based LISP
for the Aeronautical Telecommunications Network", Work in
Progress, Internet-Draft, draft-haindl-lisp-gb-atn-07, 22
March 2022, <https://www.ietf.org/archive/id/draft-haindl-
lisp-gb-atn-07.txt>.
[I-D.iannone-scenarios-problems-addressing]
Iannone, L., Trossen, D., Shenoy, N., Mendes, P., 3rd, D.
E. E., Liu, P., Farinacci, D., Finkhaeuser, J., and Y.
Jia, "Challenging Scenarios and Problems in Internet
Addressing", Work in Progress, Internet-Draft, draft-
iannone-scenarios-problems-addressing-00, 5 September
2022, <https://www.ietf.org/archive/id/draft-iannone-
scenarios-problems-addressing-00.txt>.
[I-D.ietf-6lo-nfc]
Choi, Y., Hong, Y., Youn, J., Kim, D., and J. Choi,
"Transmission of IPv6 Packets over Near Field
Communication", Work in Progress, Internet-Draft, draft-
ietf-6lo-nfc-17, 23 August 2020,
<https://www.ietf.org/archive/id/draft-ietf-6lo-nfc-
17.txt>.
[I-D.ietf-6lo-plc]
Hou, J., Liu, B., Hong, Y., Tang, X., and C. E. Perkins,
"Transmission of IPv6 Packets over PLC Networks", Work in
Progress, Internet-Draft, draft-ietf-6lo-plc-11, 18 May
2022, <https://www.ietf.org/archive/id/draft-ietf-6lo-plc-
11.txt>.
[I-D.ietf-drip-rid]
Moskowitz, R., Card, S. W., Wiethuechter, A., and A.
Gurtov, "DRIP Entity Tag (DET) for Unmanned Aircraft
System Remote ID (UAS RID)", Work in Progress, Internet-
Draft, draft-ietf-drip-rid-32, 3 August 2022,
<https://www.ietf.org/archive/id/draft-ietf-drip-rid-
32.txt>.
[I-D.ietf-intarea-gue]
Herbert, T., Yong, L., and O. Zia, "Generic UDP
Encapsulation", Work in Progress, Internet-Draft, draft-
ietf-intarea-gue-09, 26 October 2019,
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<https://www.ietf.org/archive/id/draft-ietf-intarea-gue-
09.txt>.
[I-D.ietf-intarea-tunnels]
Touch, J. and M. Townsley, "IP Tunnels in the Internet
Architecture", Work in Progress, Internet-Draft, draft-
ietf-intarea-tunnels-10, 12 September 2019,
<https://www.ietf.org/archive/id/draft-ietf-intarea-
tunnels-10.txt>.
[I-D.ietf-lisp-introduction]
Cabellos, A. and D. S. (Ed.), "An Architectural
Introduction to the Locator/ID Separation Protocol
(LISP)", Work in Progress, Internet-Draft, draft-ietf-
lisp-introduction-15, 20 September 2021,
<https://www.ietf.org/archive/id/draft-ietf-lisp-
introduction-15.txt>.
[I-D.ietf-lisp-mn]
Farinacci, D., Lewis, D., Meyer, D., and C. White, "LISP
Mobile Node", Work in Progress, Internet-Draft, draft-
ietf-lisp-mn-12, 24 July 2022,
<https://www.ietf.org/archive/id/draft-ietf-lisp-mn-
12.txt>.
[I-D.ietf-lisp-rfc6830bis]
Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
Cabellos, "The Locator/ID Separation Protocol (LISP)",
Work in Progress, Internet-Draft, draft-ietf-lisp-
rfc6830bis-38, 7 May 2022,
<https://www.ietf.org/archive/id/draft-ietf-lisp-
rfc6830bis-38.txt>.
[I-D.ietf-lisp-rfc6833bis]
Farinacci, D., Maino, F., Fuller, V., and A. Cabellos,
"Locator/ID Separation Protocol (LISP) Control-Plane",
Work in Progress, Internet-Draft, draft-ietf-lisp-
rfc6833bis-31, 2 May 2022,
<https://www.ietf.org/archive/id/draft-ietf-lisp-
rfc6833bis-31.txt>.
[I-D.rafiee-6man-cga-attack]
Rafiee, H. and C. Meinel, "Possible Attack on
Cryptographically Generated Addresses (CGA)", Work in
Progress, Internet-Draft, draft-rafiee-6man-cga-attack-03,
8 May 2015, <https://www.ietf.org/archive/id/draft-rafiee-
6man-cga-attack-03.txt>.
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[ICNIP] Trossen, D., Robitzsch, S., Reed, M., Al-Naday, M., and J.
Riihijarvi, "Internet Services over ICN in 5G LAN
Environments", Work in Progress, Internet-Draft, draft-
trossen-icnrg-internet-icn-5glan-04, 1 October 2020,
<https://www.ietf.org/archive/id/draft-trossen-icnrg-
internet-icn-5glan-04.txt>.
[IPv4pool] "IANA IPv4 Address Space Registry", n.d.,
<https://www.iana.org/assignments/ipv4-address-space/ipv4-
address-space.xhtml>.
[ITU9959] Badenhop, C., Fuller, J., Hall, J., Ramsey, B., Rice, M.,
and Springer International Publishing, "Evaluating ITU-T
G.9959 Based Wireless Systems Used in Critical
Infrastructure Assets", IFIP Advances in Information and
Communication Technology, pp. 209-227,
DOI 10.1007/978-3-319-26567-4_13, 2015,
<http://dx.doi.org/10.1007/978-3-319-26567-4_13>.
[OHTTP] Thomson, M. and C. A. Wood, "Oblivious HTTP", Work in
Progress, Internet-Draft, draft-thomson-http-oblivious-02,
24 August 2021, <https://www.ietf.org/archive/id/draft-
thomson-http-oblivious-02.txt>.
[ONION] Goldschlag, D., Reed, M., Syverson, P., and Association
for Computing Machinery (ACM), "Onion routing",
Communications of the ACM, vol. 42, no. 2, pp. 39-41,
DOI 10.1145/293411.293443, February 1999,
<http://dx.doi.org/10.1145/293411.293443>.
[P4] Bosshart, P., Daly, D., Gibb, G., Izzard, M., McKeown, N.,
Rexford, J., Schlesinger, C., Talayco, D., Vahdat, A.,
Varghese, G., Walker, D., and Association for Computing
Machinery (ACM), "P4", ACM SIGCOMM Computer Communication
Review, vol. 44, no. 3, pp. 87-95,
DOI 10.1145/2656877.2656890, 28 July 2014,
<http://dx.doi.org/10.1145/2656877.2656890>.
[REED] Reed, M. J., Al-Naday, M., Thomos, N., Trossen, D.,
Petropoulos, G., Spirou, S., and IEEE, "Stateless
multicast switching in software defined networks", 2016
IEEE International Conference on Communications (ICC),
DOI 10.1109/icc.2016.7511036, May 2016,
<http://dx.doi.org/10.1109/icc.2016.7511036>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>.
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[RFC1752] Bradner, S. and A. Mankin, "The Recommendation for the IP
Next Generation Protocol", RFC 1752, DOI 10.17487/RFC1752,
January 1995, <https://www.rfc-editor.org/info/rfc1752>.
[RFC1918] Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.
J., and E. Lear, "Address Allocation for Private
Internets", BCP 5, RFC 1918, DOI 10.17487/RFC1918,
February 1996, <https://www.rfc-editor.org/info/rfc1918>.
[RFC2009] Imielinski, T. and J. Navas, "GPS-Based Addressing and
Routing", RFC 2009, DOI 10.17487/RFC2009, November 1996,
<https://www.rfc-editor.org/info/rfc2009>.
[RFC2101] Carpenter, B., Crowcroft, J., and Y. Rekhter, "IPv4
Address Behaviour Today", RFC 2101, DOI 10.17487/RFC2101,
February 1997, <https://www.rfc-editor.org/info/rfc2101>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<https://www.rfc-editor.org/info/rfc2474>.
[RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address
Translator (NAT) Terminology and Considerations",
RFC 2663, DOI 10.17487/RFC2663, August 1999,
<https://www.rfc-editor.org/info/rfc2663>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<https://www.rfc-editor.org/info/rfc2865>.
[RFC3118] Droms, R., Ed. and W. Arbaugh, Ed., "Authentication for
DHCP Messages", RFC 3118, DOI 10.17487/RFC3118, June 2001,
<https://www.rfc-editor.org/info/rfc3118>.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, DOI 10.17487/RFC3972, March 2005,
<https://www.rfc-editor.org/info/rfc3972>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC4014] Droms, R. and J. Schnizlein, "Remote Authentication Dial-
In User Service (RADIUS) Attributes Suboption for the
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Dynamic Host Configuration Protocol (DHCP) Relay Agent
Information Option", RFC 4014, DOI 10.17487/RFC4014,
February 2005, <https://www.rfc-editor.org/info/rfc4014>.
[RFC4193] Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
<https://www.rfc-editor.org/info/rfc4193>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[RFC4581] Bagnulo, M. and J. Arkko, "Cryptographically Generated
Addresses (CGA) Extension Field Format", RFC 4581,
DOI 10.17487/RFC4581, October 2006,
<https://www.rfc-editor.org/info/rfc4581>.
[RFC4982] Bagnulo, M. and J. Arkko, "Support for Multiple Hash
Algorithms in Cryptographically Generated Addresses
(CGAs)", RFC 4982, DOI 10.17487/RFC4982, July 2007,
<https://www.rfc-editor.org/info/rfc4982>.
[RFC5533] Nordmark, E. and M. Bagnulo, "Shim6: Level 3 Multihoming
Shim Protocol for IPv6", RFC 5533, DOI 10.17487/RFC5533,
June 2009, <https://www.rfc-editor.org/info/rfc5533>.
[RFC5795] Sandlund, K., Pelletier, G., and L-E. Jonsson, "The RObust
Header Compression (ROHC) Framework", RFC 5795,
DOI 10.17487/RFC5795, March 2010,
<https://www.rfc-editor.org/info/rfc5795>.
[RFC6250] Thaler, D., "Evolution of the IP Model", RFC 6250,
DOI 10.17487/RFC6250, May 2011,
<https://www.rfc-editor.org/info/rfc6250>.
[RFC6275] Perkins, C., Ed., Johnson, D., and J. Arkko, "Mobility
Support in IPv6", RFC 6275, DOI 10.17487/RFC6275, July
2011, <https://www.rfc-editor.org/info/rfc6275>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>.
[RFC6740] Atkinson, RJ. and SN. Bhatti, "Identifier-Locator Network
Protocol (ILNP) Architectural Description", RFC 6740,
DOI 10.17487/RFC6740, November 2012,
<https://www.rfc-editor.org/info/rfc6740>.
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[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an
Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May
2014, <https://www.rfc-editor.org/info/rfc7258>.
[RFC7343] Laganier, J. and F. Dupont, "An IPv6 Prefix for Overlay
Routable Cryptographic Hash Identifiers Version 2
(ORCHIDv2)", RFC 7343, DOI 10.17487/RFC7343, September
2014, <https://www.rfc-editor.org/info/rfc7343>.
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<https://www.rfc-editor.org/info/rfc7348>.
[RFC7400] Bormann, C., "6LoWPAN-GHC: Generic Header Compression for
IPv6 over Low-Power Wireless Personal Area Networks
(6LoWPANs)", RFC 7400, DOI 10.17487/RFC7400, November
2014, <https://www.rfc-editor.org/info/rfc7400>.
[RFC7401] Moskowitz, R., Ed., Heer, T., Jokela, P., and T.
Henderson, "Host Identity Protocol Version 2 (HIPv2)",
RFC 7401, DOI 10.17487/RFC7401, April 2015,
<https://www.rfc-editor.org/info/rfc7401>.
[RFC7665] Halpern, J., Ed. and C. Pignataro, Ed., "Service Function
Chaining (SFC) Architecture", RFC 7665,
DOI 10.17487/RFC7665, October 2015,
<https://www.rfc-editor.org/info/rfc7665>.
[RFC7872] Gont, F., Linkova, J., Chown, T., and W. Liu,
"Observations on the Dropping of Packets with IPv6
Extension Headers in the Real World", RFC 7872,
DOI 10.17487/RFC7872, June 2016,
<https://www.rfc-editor.org/info/rfc7872>.
[RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060,
February 2017, <https://www.rfc-editor.org/info/rfc8060>.
[RFC8061] Farinacci, D. and B. Weis, "Locator/ID Separation Protocol
(LISP) Data-Plane Confidentiality", RFC 8061,
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DOI 10.17487/RFC8061, February 2017,
<https://www.rfc-editor.org/info/rfc8061>.
[RFC8105] Mariager, P., Petersen, J., Ed., Shelby, Z., Van de Logt,
M., and D. Barthel, "Transmission of IPv6 Packets over
Digital Enhanced Cordless Telecommunications (DECT) Ultra
Low Energy (ULE)", RFC 8105, DOI 10.17487/RFC8105, May
2017, <https://www.rfc-editor.org/info/rfc8105>.
[RFC8163] Lynn, K., Ed., Martocci, J., Neilson, C., and S.
Donaldson, "Transmission of IPv6 over Master-Slave/Token-
Passing (MS/TP) Networks", RFC 8163, DOI 10.17487/RFC8163,
May 2017, <https://www.rfc-editor.org/info/rfc8163>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8280] ten Oever, N. and C. Cath, "Research into Human Rights
Protocol Considerations", RFC 8280, DOI 10.17487/RFC8280,
October 2017, <https://www.rfc-editor.org/info/rfc8280>.
[RFC8376] Farrell, S., Ed., "Low-Power Wide Area Network (LPWAN)
Overview", RFC 8376, DOI 10.17487/RFC8376, May 2018,
<https://www.rfc-editor.org/info/rfc8376>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS
(DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018,
<https://www.rfc-editor.org/info/rfc8484>.
[RFC8609] Mosko, M., Solis, I., and C. Wood, "Content-Centric
Networking (CCNx) Messages in TLV Format", RFC 8609,
DOI 10.17487/RFC8609, July 2019,
<https://www.rfc-editor.org/info/rfc8609>.
[RFC8724] Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC.
Zuniga, "SCHC: Generic Framework for Static Context Header
Compression and Fragmentation", RFC 8724,
DOI 10.17487/RFC8724, April 2020,
<https://www.rfc-editor.org/info/rfc8724>.
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[RFC8799] Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
<https://www.rfc-editor.org/info/rfc8799>.
[RFC8926] Gross, J., Ed., Ganga, I., Ed., and T. Sridhar, Ed.,
"Geneve: Generic Network Virtualization Encapsulation",
RFC 8926, DOI 10.17487/RFC8926, November 2020,
<https://www.rfc-editor.org/info/rfc8926>.
[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
Bryant, "Deterministic Networking (DetNet) Data Plane:
IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
<https://www.rfc-editor.org/info/rfc8939>.
[RFC8981] Gont, F., Krishnan, S., Narten, T., and R. Draves,
"Temporary Address Extensions for Stateless Address
Autoconfiguration in IPv6", RFC 8981,
DOI 10.17487/RFC8981, February 2021,
<https://www.rfc-editor.org/info/rfc8981>.
[RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
(SRv6) Network Programming", RFC 8986,
DOI 10.17487/RFC8986, February 2021,
<https://www.rfc-editor.org/info/rfc8986>.
[RFC9153] Card, S., Ed., Wiethuechter, A., Moskowitz, R., and A.
Gurtov, "Drone Remote Identification Protocol (DRIP)
Requirements and Terminology", RFC 9153,
DOI 10.17487/RFC9153, February 2022,
<https://www.rfc-editor.org/info/rfc9153>.
[RFC9230] Kinnear, E., McManus, P., Pauly, T., Verma, T., and C.A.
Wood, "Oblivious DNS over HTTPS", RFC 9230,
DOI 10.17487/RFC9230, June 2022,
<https://www.rfc-editor.org/info/rfc9230>.
[ROBUSTSDN]
Canini, M., Kuznetsov, P., Levin, D., Schmid, S., and
IEEE, "A distributed and robust SDN control plane for
transactional network updates", 2015 IEEE Conference on
Computer Communications (INFOCOM),
DOI 10.1109/infocom.2015.7218382, April 2015,
<http://dx.doi.org/10.1109/infocom.2015.7218382>.
[ROHC] Fitzek, F. H. P., Rein, S., Seeling, P., Reisslein, M.,
and Springer Science and Business Media LLC, "RObust
Header Compression (ROHC) Performance for Multimedia
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Transmission over 3G/4G Wireless Networks", Wireless
Personal Communications, vol. 32, no. 1, pp. 23-41,
DOI 10.1007/s11277-005-7733-2, January 2005,
<http://dx.doi.org/10.1007/s11277-005-7733-2>.
[SFCANYCAST]
Wion, A., Bouet, M., Iannone, L., Conan, V., and ACM,
"Distributed Function Chaining with Anycast Routing",
Proceedings of the 2019 ACM Symposium on SDN Research,
DOI 10.1145/3314148.3314355, 3 April 2019,
<http://dx.doi.org/10.1145/3314148.3314355>.
[SPHINX] Danezis, G., Goldberg, I., and IEEE, "Sphinx: A Compact
and Provably Secure Mix Format", 2009 30th IEEE Symposium
on Security and Privacy, DOI 10.1109/sp.2009.15, May 2009,
<http://dx.doi.org/10.1109/sp.2009.15>.
[TOR] "The Tor Project", n.d., <https://www.torproject.org/>.
[TRANSACTIONSDN]
Curic, M., Despotovic, Z., Hecker, A., Carle, G., and
IEEE, "Transactional Network Updates in SDN", 2018
European Conference on Networks and Communications
(EuCNC), DOI 10.1109/eucnc.2018.8442793, June 2018,
<http://dx.doi.org/10.1109/eucnc.2018.8442793>.
[UA-DHCP] Komori, T., Saito, T., and IEEE Comput. Soc, "The secure
DHCP system with user authentication", 27th Annual IEEE
Conference on Local Computer Networks, 2002. Proceedings.
LCN 2002., DOI 10.1109/lcn.2002.1181774, 27 August 2003,
<http://dx.doi.org/10.1109/lcn.2002.1181774>.
[VPN] Khanvilkar, S., Khokhar, A., and Institute of Electrical
and Electronics Engineers (IEEE), "Virtual private
networks: an overview with performance evaluation", IEEE
Communications Magazine, vol. 42, no. 10, pp. 146-154,
DOI 10.1109/mcom.2004.1341273, October 2004,
<http://dx.doi.org/10.1109/mcom.2004.1341273>.
[WireGuard]
Donenfeld, J. A. and Internet Society, "WireGuard: Next
Generation Kernel Network Tunnel", Proceedings 2017
Network and Distributed System Security Symposium,
DOI 10.14722/ndss.2017.23160, 2017,
<http://dx.doi.org/10.14722/ndss.2017.23160>.
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Acknowledgments
Thanks to all the people that shared insightful comments both
privately to the authors as well as on various mailing list,
especially on the INTArea Mailing List. Also thanks for the
interesting discussions to Carsten Borman, Brian E. Carpenter, and
Eric Vyncke.
Authors' Addresses
Luigi Iannone
Huawei Technologies France S.A.S.U.
18, Quai du Point du Jour
92100 Boulogne-Billancourt
France
Email: luigi.iannone@huawei.com
Dirk Trossen
Huawei Technologies Duesseldorf GmbH
Riesstr. 25C
80992 Munich
Germany
Email: dirk.trossen@huawei.com
Paulo Mendes
Airbus
Willy-Messerschmitt Strasse 1
81663 Munich
Germany
Email: paulo.mendes@airbus.com
Nirmala Shenoy
Rochester Institute of Technology
New-York, 14623
United States of America
Email: nxsvks@rit.edu
Laurent Toutain
IMT-Atlantique
2 rue de la Chataigneraie
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CS 17607
35576 Cesson-Sevigne Cedex
France
Email: laurent.toutain@imt-atlantique.fr
Abraham Y. Chen
Avinta Communications, Inc.
142 N. Milpitas Blvd.
Milpitas, CA, 95035-4401
United States of America
Email: AYChen@Avinta.com
Dino Farinacci
lispers.net
United States of America
Email: farinacci@gmail.com
Jens Finkhaeuser
AnyWi Technologies B.V.
3e Binnenvestgracht 23H
2312 NR Leiden
Netherlands
Email: jens.finkhaeuser@anywi.com
Yihao Jia
Email: yhjia03@gmail.com
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