Internet DRAFT - draft-dolson-transport-middlebox
draft-dolson-transport-middlebox
Network Working Group D. Dolson, Ed.
Internet-Draft
Intended status: Informational J. Snellman
Expires: June 9, 2019
M. Boucadair, Ed.
C. Jacquenet
Orange
December 06, 2018
An Inventory of Transport-centric Functions Provided by Middleboxes: An
Operator Perspective
draft-dolson-transport-middlebox-05
Abstract
This document summarizes an operator's perception of the benefits
that may be provided by intermediary devices that execute functions
beyond normal IP forwarding. Such intermediary devices are often
called "middleboxes".
RFC3234 defines a taxonomy of middleboxes and issues in the Internet.
Most of those middleboxes utilize or modify application-layer data.
This document primarily focuses on devices that observe and act on
information carried in the transport layer, and especially
information carried in TCP packets.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 9, 2019.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Operator Perspective . . . . . . . . . . . . . . . . . . 3
1.2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Measurements . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Packet Loss . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. Round Trip Times . . . . . . . . . . . . . . . . . . . . 6
2.3. Measuring Packet Reordering . . . . . . . . . . . . . . . 6
2.4. Throughput and Bottleneck Identification . . . . . . . . 7
2.5. Congestion Responsiveness . . . . . . . . . . . . . . . . 7
2.6. Attack Detection . . . . . . . . . . . . . . . . . . . . 7
2.7. Packet Corruption . . . . . . . . . . . . . . . . . . . . 8
2.8. Application-Layer Measurements . . . . . . . . . . . . . 8
3. Functions Beyond Measurement: A Few Examples . . . . . . . . 9
3.1. NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2. Firewall . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3. DDoS Scrubbing . . . . . . . . . . . . . . . . . . . . . 10
3.4. Implicit Identification . . . . . . . . . . . . . . . . . 11
3.5. Performance-Enhancing Proxies . . . . . . . . . . . . . . 11
3.6. Network Coding . . . . . . . . . . . . . . . . . . . . . 12
3.7. Network-Assisted Bandwidth Aggregation . . . . . . . . . 12
3.8. Prioritization and Differentiated Services . . . . . . . 13
3.9. Measurement-Based Shaping . . . . . . . . . . . . . . . . 13
3.10. Fairness to End-User Quota . . . . . . . . . . . . . . . 14
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
5. Security Considerations . . . . . . . . . . . . . . . . . . . 14
5.1. Confidentiality & Privacy . . . . . . . . . . . . . . . . 14
5.2. Active On-Path Attacks . . . . . . . . . . . . . . . . . 15
5.3. Improved Security . . . . . . . . . . . . . . . . . . . . 15
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
7. Informative References . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
From [RFC3234], "A middlebox is defined as any intermediary device
performing functions other than the normal, standard functions of an
IP router on the datagram path between a source host and destination
host."
Middleboxes are usually (but not exclusively) deployed at locations
permitting observation of bidirectional traffic flows. Such
locations are typically points where leaf networks connect to the
Internet; e.g.,:
o Where a residential or business customer connects to its service
provider(s), which may include multi-homing.
o On the Gi interface where a Gateway GPRS (General Packet Radio
Service) Support Node (GGSN) connects to a Packet Data Network
(PDN) (Section 3.1 of [RFC6459]).
For the purposes of this document (and consistent with the RFC3234
definition), middlebox functions may be found in routers and switches
in addition to dedicated devices.
This document itemizes a variety of features provided by middleboxes
and by ad hoc analysis performed by operators using packet analyzers.
Many of the techniques described in this document require stateful
analysis of transport streams. A generic state machine is described
in [I-D.trammell-plus-statefulness].
This document summarizes an operator's perception of the benefits
that may be provided by middleboxes. A primary goal is to provide
information to the Internet community to aid understanding of what
might be gained or lost by decisions that may affect (or be affected
by) middlebox operation in the design of new transport protocols.
See Section 1.1 for more details.
1.1. Operator Perspective
Network operators are often the ones first called upon when
applications fail to function properly, often with user reports about
application behaviors (not about packet behaviors). Therefore it
isn't surprising that operators (wanting to be helpful) desire some
visibility into flow information to identify how well the problem
flows are progressing and how well other flows are progressing.
Advanced service functions (e.g., Network Address Translators (NATs),
firewalls, etc.) [RFC7498] are widely used to achieve various
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objectives such as IP address sharing, firewalling, avoiding covert
channels, detecting and protect against ever increasing Distributed
Denial of Service (DDoS) attacks, etc. For example, environment-
specific designs may require a number of service functions, such as
those needed at the Gi interface of a mobile infrastructure
[I-D.ietf-sfc-use-case-mobility].
These sophisticated service functions are located in the network but
also in service platforms, or intermediate entities (e.g., Content
Delivery Networks (CDNs)). Network maintenance and diagnostic
operations are complicated, particularly when responsibility is
shared among various players.
Network Providers are challenged to deliver differentiated services
as a competitive business advantage, while mastering the complexity
of the applications, (continuously) evaluating the impacts on
middleboxes, and enhancing customer's quality of experience.
Despite the complexity, removing all those service functions is not
an option because they are used to address constraints that are often
typical of the current (and changing) Internet. Operators must deal
with constraints such as global IPv4 address depletion and must
support a plethora of services with different QoS, security,
robustness, etc. requirements.
1.2. Scope
Although many middleboxes observe and manipulate application-layer
content (e.g., session boarder controllers [RFC5853]) they are out of
scope for this document, the aim being to describe middleboxes using
transport-layer features. An earlier document [RFC8404] describes
the impact of pervasive encryption of application-layer data on
network monitoring, protecting, and troubleshooting.
This document is not intended to recommend (or prohibit) middlebox
deployment. Many operators have found the value provided by
middleboxes to outweigh the added cost and complexity; this document
attempts to provide that perspective as a reference in discussion of
protocol design trade-offs.
This document is not intended to discuss issues related to
middleboxes. These issues are well-known and are recorded in
existing documents such as [RFC3234] and [RFC6269]. This document
aims to elaborate on the motivations leading operators to enable such
functions in spite of complications.
This document takes an operator perspective that measurement and
management of transport connections is of benefit to both parties:
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for the end-user to receive better quality of experience, and for the
network operator to improve resource usage, the former being a
consequence of the latter.
This document does not discuss whether exposing some data to on-path
devices for network assistance purposes can be achieved by using in-
band or out-of-band mechanisms.
2. Measurements
A number of measurements can be made by network devices that are
either on-path or off-path. These measurements can be used either by
automated systems, or for manual network troubleshooting purposes
(e.g., using packet analysis tools). The automated systems can
further be classified as monitoring systems that compute performance
indicators for single or aggregates of connections and generate
aggregated reports from them, and active systems that make decisions
also on how to handle packet flows based on these performance
indicators.
Long-term trends in these measurements can aid an operator in
capacity planning.
Short-term anomalies revealed by these measurements can identify
network breakages, attacks in progress, or misbehaving devices/
applications.
2.1. Packet Loss
It is very useful for an operator to be able to detect and isolate
packet loss in a network.
Network problems and under-provisioning can be detected if packet
loss is measurable. TCP packet loss can be detected by observing
gaps in sequence numbers, retransmitted sequence numbers, and SACK
options. Packet loss can be detected per direction.
Gaps indicate loss upstream of the traffic observation point;
retransmissions indicate loss downstream of the traffic observation
point. Selective acknowledgements (SACKs, [RFC2018]) can be used to
detect either upstream or downstream packet loss (although some care
needs to be taken to avoid mis-identifying packet reordering as
packet loss), and to distinguish between upstream vs. downstream
losses.
Packet loss measurements on both sides of the measurement point are
an important component in precisely diagnosing insufficiently
dimensioned devices or links in networks. Additionally, since packet
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losses are one of the two main ways for congestion to manifest (the
others being queueing delay or Explicit Congestion Notification (ECN,
[RFC3168])), packet loss is an important measurement for any
middlebox that needs to make traffic handling decisions based on
observed levels of congestion.
2.2. Round Trip Times
The ability to measure partial-path round-trip times is valuable in
diagnosing network issues (e.g., abnormal latency, abnormal packet
loss). Knowing if latency is poor on one side of the observation
point or the other provides more information than is available at
either end-point, which can only observe full round-trip times.
For example, a TCP packet stream can be used to measure the round-
trip time on each side of the measurement point. During the
connection handshake, the SYN, SYN/ACK, and ACK timings can be used
to establish a baseline Round-Trip Time (RTT) in each direction.
Once the connection is established, the RTT between the server and
the measurement point can only reliably be determined using TCP
timestamps [RFC7323]. On the side between the measurement point and
the client, the exact timing of data segments and ACKs can be used as
an alternative. For this latter method to be accurate when packet
loss is present, the connection must use selective acknowledgements.
In many networks, congestion will show up as increasing packet
queueing, and congestion-induced packet loss will only happen in
extreme cases. RTTs will also show up as a much smoother signal than
the discrete packet loss events. This makes RTTs a good way to
identify individual subscribers for whom the network is a bottleneck
at a given time, or geographical sites (such as cellular towers) that
are experiencing large scale congestion.
The main limit of RTT measurement as a congestion signal is the
difficulty of reliably distinguishing between the data segments being
queued vs. the ACKs being queued.
2.3. Measuring Packet Reordering
If a network is reordering packets of transport connections, caused
perhaps by Equal-cost multi-path (ECMP) misconfiguration (e.g.,
described in [RFC2991] and [RFC7690]), the end-points may react as if
packet loss is occurring and retransmit packets or reduce forwarding
rates. Therefore a network operator desires the ability to diagnose
packet reordering.
For TCP, packet reordering can be detected by observing TCP sequence
numbers per direction. See for example a number of standard packet
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reordering metrics in [RFC4737] and informational metrics in
[RFC5236].
2.4. Throughput and Bottleneck Identification
Although throughput to or from an IP address can be measured without
transport-layer measurements, the transport layer provides clues
about what the end-points were attempting to do.
One way of quickly excluding the network as the bottleneck during
troubleshooting is to check whether the speed is limited by the
endpoints. For example, the connection speed might instead be
limited by suboptimal TCP options, the sender's congestion window,
the sender temporarily running out of data to send, the sender
waiting for the receiver to send another request, or the receiver
closing the receive window.
This data is also useful for middleboxes used to measure network
quality of service. Connections, or portions of connections, that
are limited by the endpoints do not provide an accurate measure of
network's speed, and can be discounted or completely excluded in such
analyses.
2.5. Congestion Responsiveness
Congestion control mechanisms continue to evolve. Tools exist that
can interpret protocol sequence numbers (e.g., from TCP, RTP) to
infer the congestion response of a flow. Such tools can be used by
operators to help understand the impact of specific transport
protocols on other traffic that shares their network. For example,
analysing packet sequence numbers can be used to help understand
whether an application flow backs-off its load in the face of
persistent congestion (as TCP does), and hence to understand whether
the behaviour is appropriate for sharing limited network capacity.
These tools can also be used to determine whether mechanisms are
needed in the network to prevent flows from acquiring excessive
network capacity under severe congestion (e.g., by deploying rate-
limiters or network transport circuit breakers [RFC8084]).
2.6. Attack Detection
When an application or network resource is under attack, it is useful
to identify this situation from the network perspective, upstream of
the attacked resource.
Although detection methods tend to be proprietary, attack detection
from within the network may comprise:
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o Identifying uncharacteristic traffic volumes or sources;
o Identifying congestion, possibly using techniques in Section 2.1
and Section 2.2;
o Identifying incomplete connections or transactions, from attacks
which attempt to exhaust server resources;
o Fingerprinting based on whatever available fields are determined
to be useful in discriminating an attack from desirable traffic.
Two trends in protocol design will make attack detection more
difficult:
o the desire to encrypt transport-layer fields;
o the desire to avoid statistical fingerprinting by adding entropy
in various forms.
While improving privacy, those approaches may hinder attack
detection.
2.7. Packet Corruption
One notable source of packet loss is packet corruption. This
corruption will generally not be detected until the checksums are
validated by the endpoint, and the packet is dropped. This means
that detecting the exact location where packets are lost is not
sufficient when troubleshooting networks. An operator would like to
find out where packets are being corrupted. IP and TCP checksum
verification allows a measurement device to correctly distinguish
between upstream packet corruption and normal downstream packet loss.
Transport protocol designers should consider whether a middlebox will
be able to detect corrupted or tampered packets.
2.8. Application-Layer Measurements
Network health may also be gleaned from application-layer diagnosis.
E.g.,
o DNS response times and retransmissions by correlating answers to
queries.
o Various protocol-aware voice and video quality analysis.
Could this type of information be provided in a transport layer?
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3. Functions Beyond Measurement: A Few Examples
This section describes features provided by on-path devices that go
beyond measurement by modifying, discarding, delaying, or
prioritizing traffic.
3.1. NAT
Network Address Translators (NATs) allow multiple devices to share a
public address by dividing the transport-layer port space among the
devices.
NAT behavior recommendations are found for UDP in BCP 127 [RFC4787]
and for TCP in BCP 142 [RFC7857].
To support NAT, there must be transport-layer port numbers that can
be modified by the NAT. Note that required fields (e.g., port
numbers) are visible in all IETF-defined transport protocols.
The application-layer must not assume the port number was left
unchanged (e.g., by including it in a checksum or signing it).
Address sharing is also used in the context of IPv6 transition. For
example, DS-Lite AFTR [RFC6333], NAT64 [RFC6146], or A+P
[RFC7596][RFC7597] are features that are enabled in the network to
allow for IPv4 service continuity over an IPv6 network.
Further, because of some multi-homing considerations, IPv6 prefix
translation may be enabled by some enterprises by means of NPTv6
[RFC6296].
3.2. Firewall
Firewalls are pervasive and essential components that inspect
incoming and outgoing traffic. Firewalls are usually the cornerstone
of a security policy that is enforced in end-user premises and other
locations to provide strict guarantees about traffic that may be
authorized to enter/leave the said premises, as well as end-users who
may be assigned different clearance levels regarding which networks
and portions of the Internet they access.
An important aspect of a firewall policy is differentiating
internally-initiated from externally-initiated communications.
For TCP, this is easily done by tracking the TCP state machine.
Furthermore, the ending of a TCP connection is indicated by RST or
FIN flags.
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For UDP, the firewall can be opened if the first packet comes from
an internal user, but the closing is generally done by an idle
timer of arbitrary duration, which might not match the
expectations of the application.
Simple IPv6 firewall capabilities for customer premises equipment
(both stateless and stateful) are described in [RFC6092].
A firewall functions better when it can observe the protocol state
machine, described generally by Transport-Independent Path Layer
State Management [I-D.trammell-plus-statefulness].
3.3. DDoS Scrubbing
In the context of a DDoS attack, the purpose of a scrubber is to
discard attack traffic while permitting useful traffic. E.g., such a
mitigator is described in [I-D.ietf-dots-architecture].
When attacks occur against constrained resources, some traffic will
be discarded before reaching the intended destination. A user
receives better experience and a server runs more efficiently if a
scrubber can discard attack traffic, leaving room for legitimate
traffic.
Scrubbing must be provided by an on-path network device because
neither end-point of a legitimate connection has any control over the
source of the attack traffic.
Source-spoofed DDoS attacks can be mitigated at the source using BCP
38 ([RFC2827]), but it is more difficult if source address filtering
cannot be applied.
In contrast to devices in the core of the Internet, middleboxes
statefully observing bidirectional transport connections can reject
source-spoofed TCP traffic based on the inability to provide sensible
acknowledgement numbers to complete the three-way handshake.
Obviously this requires middlebox visibility into transport-layer
state machine.
Middleboxes may also scrub on the basis of statistical
classification: testing how likely a given packet is legitimate. As
protocol designers add more entropy to headers and lengths, this test
becomes less useful and the best scrubbing strategy becomes random
drop.
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3.4. Implicit Identification
In order to enhance the end-user's quality of experience, some
operators deploy implicit identification features that rely upon the
correlation of network-related information to access some local
services. For example, service portals operated by some operators
may be accessed immediately by end-users without any explicit
identification for the sake of improved service availability. This
is doable thanks to on-path devices that inject appropriate metadata
that can be used by the remote server to enforce per-subscriber
policies. The information can be injected at the application layer
or at the transport layer (when an address sharing mechanism is in
use).
An experimental implementation using a TCP option is described in
[RFC7974].
For the intended use of implicit identification, it is more secure to
have a trusted middlebox mark this traffic than to trust end-user
devices.
3.5. Performance-Enhancing Proxies
Performance-Enhancing Proxies (PEPs) can improve performance in some
types of networks by improving packet spacing or generating local
acknowledgements, and are most commonly used in satellite and
cellular networks. Transport-Layer PEPs are described in
Section 2.1.1 of [RFC3135].
PEPs allow central deployment of congestion control algorithms more
suited to the specific network, most commonly use of delay-based
congestion control. More advanced TCP PEPs deploy congestion control
systems that treat all of a single end-user's TCP connections as a
single unit, improving fairness and allowing faster reaction to
changing network conditions. For example, it was reported that
splitting the TCP connections in some network accesses can result in
a halved page downloading time [ICCRG].
Local acknowledgements generated by PEPs speed up TCP slow start by
splitting the effective latency, and allow for retransmissions to be
done from the PEP rather than from the actual sender. Local
acknowledgements will also allow a PEP to maintain a local buffer of
data appropriate to the actual network conditions, whereas the actual
endpoints would often send too much or too little.
A PEP function requires transport-layer fields that allow chunks of
data to be identified (e.g., TCP sequence numbers), acknowledgements
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to be identified (e.g., TCP ACK numbers), and acknowledgements to be
created from the PEP.
Note that PEPs are only useful in some types of networks. In
particular, PEPs are very useful in contexts wherein the congestion-
control strategies of the endpoints are inappropriate for the network
connecting them. That being said, poor design can result in degraded
performances when PEPs are deployed.
3.6. Network Coding
Network Coding is a technique for improving transmission performance
over low-bandwidth, long-latency links such as some satellite links.
Coding may involve lossless compression and/or adding redundancy to
headers and payload. A Network Coding Taxonomy is provided by
[RFC8406]; an example of End-to-End Coding is FECFRAME [RFC6363]. It
is typically deployed with network-coding gateways at each end of
those links, with a network-coding tunnel between them via the
slow/lossy/long-latency links.
Network coding implementations may be specific to TCP, taking
advantage of known properties of the protocol.
The network coding gateways may employ some techniques of PEPs, such
as creating acknowledgements of queued data, removing retransmissions
and pacing data rates to reduce queue oscillation.
The interest for more network coding in some specific networks is
discussed in [I-D.irtf-nwcrg-network-coding-satellites].
Note: This is not to be confused with transcoding, which performs
lossy compression on transmitted media streams, and not in scope for
this document.
3.7. Network-Assisted Bandwidth Aggregation
The Hybrid Access Aggregation Point is a middlebox that allows
customers to aggregate the bandwidth of multiple access technologies.
One of the approaches uses MPTCP proxies [I-D.ietf-tcpm-converters]
to forward traffic along multiple paths. The MPTCP proxy operates at
the transport layer while being located in the operator's network.
The support of multipath transport capabilities by communicating
hosts remains a privileged target design so that such hosts can
directly use the available resources provided by a variety of access
networks they can connect to. Nevertheless, network operators do not
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control end hosts while the support of MPTCP by content servers
remains marginal.
Network-Assisted MPTCP deployment models are designed to facilitate
the adoption of MPTCP for the establishment of multi-path
communications without making any assumption about the support of
MPTCP capabilities by communicating peers. Network-Assisted MPTCP
deployment models rely upon MPTCP Conversion Points (MCPs) that act
on behalf of hosts so that they can take advantage of establishing
communications over multiple paths [I-D.ietf-tcpm-converters].
Note there are cases when end-to-end MPTCP cannot be used even though
both client and server are MPTCP-compliant. An MPTCP proxy can
provide multipath utilization in these cases. Examples of such cases
are listed below:
1. The use of private IPv4 addresses in some access networks.
Typically, additional subflows can not be added to the MPTCP
connection without the help of an MCP.
2. The assignment of IPv6 prefixes only by some networks. If the
server is IPv4-only, IPv6 subflows cannot be added to an MPTCP
connection established with that server, by definition.
3. Subscription to some service offerings is subject to volume
quota.
3.8. Prioritization and Differentiated Services
Bulk traffic may be served with a higher latency than interactive
traffic with no reduction in throughput. This fact allows a
middlebox function to improve response times in interactive
applications by prioritizing, policing, or remarking interactive
transport connections differently from bulk traffic transport
connections. E.g., gaming traffic may be prioritized over email or
software updates. Configuration guidelines for DiffServ service
classes are discussed in [RFC4594].
Middleboxes may identify different classes of traffic by inspecting
multiple layers of header and length of payload.
3.9. Measurement-Based Shaping
Basic traffic shaping functionality requires no transport-layer
information. All that is needed is a way of mapping each packet to a
traffic shaper quota. For example, there may be a rate limit per
5-tuple or per subscriber IP address. However, such fixed traffic
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shaping rules are wasteful as they end up rate limiting traffic even
when the network has free resources available.
More advanced traffic shaping devices use transport layer metrics
described in Section 2 to detect congestion on either a per-site or
per-user level, and use different traffic shaping rules when
congestion is detected [RFC3272]. This type of device can overcome
limitations of downstream devices that behave poorly (e.g., by
excessive buffering or sub-optimally dropping packets).
3.10. Fairness to End-User Quota
Several service offerings rely upon a volume-based charging model
(e.g., volume-based data plans offered by cellular providers).
Operators may assist end-users in conserving their data quota by
deploying on-path functions that shape traffic that would otherwise
be aggressively transferred.
For example, a fast download of a video that won't be viewed
completely by the subscriber may lead to quick exhaustion of the data
quota. Limiting the video download rate conserves quota for the
benefit of the end-user. Also, discarding unsolicited incoming
traffic prevents the user's quota to be unfairly exhausted.
4. IANA Considerations
This memo includes no request to IANA.
5. Security Considerations
5.1. Confidentiality & Privacy
This document intentionally excludes middleboxes that observe or
manipulate application-layer data.
The measurements and functions described in this document can all be
implemented without violating confidentiality [RFC6973]. However,
there is always the question of whether the fields and packet
properties used to achieve operational benefits may also be used for
harm.
In particular, the question is what confidentiality is lost by
exposing transport-layer fields beyond what can be learned by
observing IP-layer fields:
o Sequence numbers: an observer can learn how much data is
transferred.
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o Start/Stop indicators: an observer can count transactions for some
applications.
o Device fingerprinting: an observer may be more easily able to
identify a device type when different devices use different
default field values or options.
5.2. Active On-Path Attacks
Being able to observe sequence numbers or session identifiers by an
on-path attacker may make it easier to modify or terminate a
transport connection. E.g., observing TCP sequence numbers allows
generation of a RST packet that terminates the connection. However,
signing transport fields softens this attack. The attack and
solution are described for the TCP authentication option [RFC5925].
Still, an on-path attacker can also drop the traffic flow.
5.3. Improved Security
Network maintainability and security can be improved by providing
firewalls and DDoS mechanisms with some information about transport
connections. In contrast, it would be very difficult to secure a
network in which every packet appears unique and filled with random
bits (from the perspective of an on-path device).
Some features providing the ability to mitigate/filter attacks owing
to a network-assisted mechanism will therefore will improve security
(e.g., by means of DOTS signalling [I-D.ietf-dots-signal-channel]).
6. Acknowledgements
The authors thank Brian Trammell, Brian Carpenter, Mirja Kuehlewind,
Kathleen Moriarty, Gorry Fairhurst, Adrian Farrel, and Nicolas Kuhn
for their review and suggestions.
7. Informative References
[I-D.ietf-dots-architecture]
Mortensen, A., Andreasen, F., K, R., Teague, N., Compton,
R., and c. christopher_gray3@cable.comcast.com,
"Distributed-Denial-of-Service Open Threat Signaling
(DOTS) Architecture", draft-ietf-dots-architecture-10
(work in progress), December 2018.
Dolson, et al. Expires June 9, 2019 [Page 15]
Internet-Draft Transport-centric Middlebox Functions December 2018
[I-D.ietf-dots-signal-channel]
K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-25 (work in progress), September
2018.
[I-D.ietf-sfc-use-case-mobility]
Napper, J., Stiemerling, M., Lopez, D., and J. Uttaro,
"Service Function Chaining Use Cases in Mobile Networks",
draft-ietf-sfc-use-case-mobility-08 (work in progress),
May 2018.
[I-D.ietf-tcpm-converters]
Bonaventure, O., Boucadair, M., Gundavelli, S., and S.
Seo, "0-RTT TCP Convert Protocol", draft-ietf-tcpm-
converters-04 (work in progress), October 2018.
[I-D.irtf-nwcrg-network-coding-satellites]
Kuhn, N. and E. Lochin, "Network coding and satellites",
draft-irtf-nwcrg-network-coding-satellites-02 (work in
progress), November 2018.
[I-D.trammell-plus-statefulness]
Kuehlewind, M., Trammell, B., and J. Hildebrand,
"Transport-Independent Path Layer State Management",
draft-trammell-plus-statefulness-04 (work in progress),
November 2017.
[ICCRG] Kuhn, N., "MPTCP and BBR Performance over Internet
Satellite Paths", 2017,
<https://datatracker.ietf.org/meeting/100/materials/
slides-100-iccrg-mptcp-and-bbr-performance-over-satcom-
links-00>.
[RFC2018] Mathis, M., Mahdavi, J., Floyd, S., and A. Romanow, "TCP
Selective Acknowledgment Options", RFC 2018,
DOI 10.17487/RFC2018, October 1996,
<https://www.rfc-editor.org/info/rfc2018>.
[RFC2827] Ferguson, P. and D. Senie, "Network Ingress Filtering:
Defeating Denial of Service Attacks which employ IP Source
Address Spoofing", BCP 38, RFC 2827, DOI 10.17487/RFC2827,
May 2000, <https://www.rfc-editor.org/info/rfc2827>.
Dolson, et al. Expires June 9, 2019 [Page 16]
Internet-Draft Transport-centric Middlebox Functions December 2018
[RFC2991] Thaler, D. and C. Hopps, "Multipath Issues in Unicast and
Multicast Next-Hop Selection", RFC 2991,
DOI 10.17487/RFC2991, November 2000,
<https://www.rfc-editor.org/info/rfc2991>.
[RFC3135] Border, J., Kojo, M., Griner, J., Montenegro, G., and Z.
Shelby, "Performance Enhancing Proxies Intended to
Mitigate Link-Related Degradations", RFC 3135,
DOI 10.17487/RFC3135, June 2001,
<https://www.rfc-editor.org/info/rfc3135>.
[RFC3168] Ramakrishnan, K., Floyd, S., and D. Black, "The Addition
of Explicit Congestion Notification (ECN) to IP",
RFC 3168, DOI 10.17487/RFC3168, September 2001,
<https://www.rfc-editor.org/info/rfc3168>.
[RFC3234] Carpenter, B. and S. Brim, "Middleboxes: Taxonomy and
Issues", RFC 3234, DOI 10.17487/RFC3234, February 2002,
<https://www.rfc-editor.org/info/rfc3234>.
[RFC3272] Awduche, D., Chiu, A., Elwalid, A., Widjaja, I., and X.
Xiao, "Overview and Principles of Internet Traffic
Engineering", RFC 3272, DOI 10.17487/RFC3272, May 2002,
<https://www.rfc-editor.org/info/rfc3272>.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594,
DOI 10.17487/RFC4594, August 2006,
<https://www.rfc-editor.org/info/rfc4594>.
[RFC4737] Morton, A., Ciavattone, L., Ramachandran, G., Shalunov,
S., and J. Perser, "Packet Reordering Metrics", RFC 4737,
DOI 10.17487/RFC4737, November 2006,
<https://www.rfc-editor.org/info/rfc4737>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast
UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
2007, <https://www.rfc-editor.org/info/rfc4787>.
[RFC5236] Jayasumana, A., Piratla, N., Banka, T., Bare, A., and R.
Whitner, "Improved Packet Reordering Metrics", RFC 5236,
DOI 10.17487/RFC5236, June 2008,
<https://www.rfc-editor.org/info/rfc5236>.
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Internet-Draft Transport-centric Middlebox Functions December 2018
[RFC5853] Hautakorpi, J., Ed., Camarillo, G., Penfield, R.,
Hawrylyshen, A., and M. Bhatia, "Requirements from Session
Initiation Protocol (SIP) Session Border Control (SBC)
Deployments", RFC 5853, DOI 10.17487/RFC5853, April 2010,
<https://www.rfc-editor.org/info/rfc5853>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC6092] Woodyatt, J., Ed., "Recommended Simple Security
Capabilities in Customer Premises Equipment (CPE) for
Providing Residential IPv6 Internet Service", RFC 6092,
DOI 10.17487/RFC6092, January 2011,
<https://www.rfc-editor.org/info/rfc6092>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <https://www.rfc-editor.org/info/rfc6146>.
[RFC6269] Ford, M., Ed., Boucadair, M., Durand, A., Levis, P., and
P. Roberts, "Issues with IP Address Sharing", RFC 6269,
DOI 10.17487/RFC6269, June 2011,
<https://www.rfc-editor.org/info/rfc6269>.
[RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011,
<https://www.rfc-editor.org/info/rfc6296>.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, DOI 10.17487/RFC6333, August 2011,
<https://www.rfc-editor.org/info/rfc6333>.
[RFC6363] Watson, M., Begen, A., and V. Roca, "Forward Error
Correction (FEC) Framework", RFC 6363,
DOI 10.17487/RFC6363, October 2011,
<https://www.rfc-editor.org/info/rfc6363>.
[RFC6459] Korhonen, J., Ed., Soininen, J., Patil, B., Savolainen,
T., Bajko, G., and K. Iisakkila, "IPv6 in 3rd Generation
Partnership Project (3GPP) Evolved Packet System (EPS)",
RFC 6459, DOI 10.17487/RFC6459, January 2012,
<https://www.rfc-editor.org/info/rfc6459>.
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[RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J.,
Morris, J., Hansen, M., and R. Smith, "Privacy
Considerations for Internet Protocols", RFC 6973,
DOI 10.17487/RFC6973, July 2013,
<https://www.rfc-editor.org/info/rfc6973>.
[RFC7323] Borman, D., Braden, B., Jacobson, V., and R.
Scheffenegger, Ed., "TCP Extensions for High Performance",
RFC 7323, DOI 10.17487/RFC7323, September 2014,
<https://www.rfc-editor.org/info/rfc7323>.
[RFC7498] Quinn, P., Ed. and T. Nadeau, Ed., "Problem Statement for
Service Function Chaining", RFC 7498,
DOI 10.17487/RFC7498, April 2015,
<https://www.rfc-editor.org/info/rfc7498>.
[RFC7596] Cui, Y., Sun, Q., Boucadair, M., Tsou, T., Lee, Y., and I.
Farrer, "Lightweight 4over6: An Extension to the Dual-
Stack Lite Architecture", RFC 7596, DOI 10.17487/RFC7596,
July 2015, <https://www.rfc-editor.org/info/rfc7596>.
[RFC7597] Troan, O., Ed., Dec, W., Li, X., Bao, C., Matsushima, S.,
Murakami, T., and T. Taylor, Ed., "Mapping of Address and
Port with Encapsulation (MAP-E)", RFC 7597,
DOI 10.17487/RFC7597, July 2015,
<https://www.rfc-editor.org/info/rfc7597>.
[RFC7690] Byerly, M., Hite, M., and J. Jaeggli, "Close Encounters of
the ICMP Type 2 Kind (Near Misses with ICMPv6 Packet Too
Big (PTB))", RFC 7690, DOI 10.17487/RFC7690, January 2016,
<https://www.rfc-editor.org/info/rfc7690>.
[RFC7857] Penno, R., Perreault, S., Boucadair, M., Ed., Sivakumar,
S., and K. Naito, "Updates to Network Address Translation
(NAT) Behavioral Requirements", BCP 127, RFC 7857,
DOI 10.17487/RFC7857, April 2016,
<https://www.rfc-editor.org/info/rfc7857>.
[RFC7974] Williams, B., Boucadair, M., and D. Wing, "An Experimental
TCP Option for Host Identification", RFC 7974,
DOI 10.17487/RFC7974, October 2016,
<https://www.rfc-editor.org/info/rfc7974>.
[RFC8084] Fairhurst, G., "Network Transport Circuit Breakers",
BCP 208, RFC 8084, DOI 10.17487/RFC8084, March 2017,
<https://www.rfc-editor.org/info/rfc8084>.
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[RFC8404] Moriarty, K., Ed. and A. Morton, Ed., "Effects of
Pervasive Encryption on Operators", RFC 8404,
DOI 10.17487/RFC8404, July 2018,
<https://www.rfc-editor.org/info/rfc8404>.
[RFC8406] Adamson, B., Adjih, C., Bilbao, J., Firoiu, V., Fitzek,
F., Ghanem, S., Lochin, E., Masucci, A., Montpetit, M-J.,
Pedersen, M., Peralta, G., Roca, V., Ed., Saxena, P., and
S. Sivakumar, "Taxonomy of Coding Techniques for Efficient
Network Communications", RFC 8406, DOI 10.17487/RFC8406,
June 2018, <https://www.rfc-editor.org/info/rfc8406>.
Authors' Addresses
David Dolson (editor)
Email: ddolson@acm.org
Juho Snellman
Email: jsnell@iki.fi
Mohamed Boucadair (editor)
Orange
4 rue du Clos Courtel
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Christian Jacquenet
Orange
4 rue du Clos Courtel
Rennes 35000
France
Email: christian.jacquenet@orange.com
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