Internet DRAFT - draft-irtf-icnrg-icntraceroute
draft-irtf-icnrg-icntraceroute
ICNRG S. Mastorakis
Internet-Draft University of Notre Dame
Intended status: Experimental D. Oran
Expires: 18 February 2024 Network Systems Research and Design
I. Moiseenko
Apple Inc
J. Gibson
R. Droms
Unaffiliated
17 August 2023
ICN Traceroute Protocol Specification
draft-irtf-icnrg-icntraceroute-11
Abstract
This document presents the design of an ICN Traceroute protocol.
This includes the operation of both the client and the forwarder.
This document is a product of the Information-Centric Networking
Research Group (ICNRG) of the IRTF.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 18 February 2024.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Background on IP-Based Traceroute Operation . . . . . . . . . 3
3. Traceroute Functionality Challenges and Opportunities in
ICN . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. ICN Traceroute CCNx Packet Format . . . . . . . . . . . . . . 6
4.1. ICN Traceroute Request CCNx Packet Format . . . . . . . . 6
4.2. Traceroute Reply CCNx Packet Format . . . . . . . . . . . 8
5. ICN Traceroute NDN Packet Format . . . . . . . . . . . . . . 12
5.1. ICN Traceroute Request NDN Packet Format . . . . . . . . 12
5.2. Traceroute Reply NDN Packet Format . . . . . . . . . . . 13
6. Forwarder Operation . . . . . . . . . . . . . . . . . . . . . 14
7. Protocol Operation For Locally-Scoped Namespaces . . . . . . 15
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
10.1. Normative References . . . . . . . . . . . . . . . . . . 17
10.2. Informative References . . . . . . . . . . . . . . . . . 17
Appendix A. Traceroute Client Application (Consumer)
Operation . . . . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction
In TCP/IP, routing and forwarding are based on IP addresses. To
ascertain the route to an IP address and to measure the transit
delays, the traceroute utility is commonly used. In ICN, routing and
forwarding are based on name prefixes. To this end, the problem of
ascertaining the characteristics (i.e., transit forwarders and
delays) of at least one of the available routes to a name prefix is a
fundamendal requirement for instrumentation and network management.
In order to carry out meaningful experimentation and deployment of
ICN protocols, tools to manage and debug the operation of ICN
architectures and protocols are needed analogous to ping and
traceroute used for TCP/IP. This document describes the design of a
management and debugging protocol analogous to the traceroute
protocol of TCP/IP, which will aid the experimental deployment of ICN
protocols. As the community continues its experimentation with ICN
architectures and protocols, the design of ICN Traceroute might
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change accordingly. ICN Traceroute is designed as a tool to
troubleshoot ICN architectures and protocols. As such, this document
is classified as an experimental RFC.
This specification uses the terminology defined in [RFC8793].
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation. This document defines an Experimental Protocol for the
Internet community. This document is a product of the Internet
Research Task Force (IRTF). The IRTF publishes the results of
Internet-related research and development activities. These results
might not be suitable for deployment. This RFC represents the
consensus of the Information-Centric Networking Research Group of the
Internet Research Task Force (IRTF). Documents approved for
publication by the IRSG are not candidates for any level of Internet
Standard; see Section 2 of RFC 7841.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14 [RFC2119]
[RFC8174] when, and only when, they appear in all capitals, as shown
here.
2. Background on IP-Based Traceroute Operation
In IP-based networks, traceroute is based on the expiration of the
Time To Live (TTL) IP header field. Specifically, a traceroute
client sends consecutive packets (depending on the implementation and
the user-specified behavior such packets can be either UDP datagrams,
ICMP Echo Request or TCP SYN packets) with a TTL value increased by
1, essentially performing a expanding ring search. In this way, the
first IP packet sent will expire at the first router along the path,
the second IP packet at the second router along the path, etc, until
the router (or host) with the specified destination IP address is
reached. Each router along the path towards the destination,
responds by sending back an ICMP Time Exceeded packet, unless
explicitly prevented from doing so by a security policy.
The IP-based traceroute utility operates on IP addresses, and in
particular depends on the IP packets having source IP addresses that
are used as the destination address for replies. Given that ICN
forwards based on names rather than destination IP addresses, that
the names do not refer to unique endpoints (multi-destination), and
that the packets do not contain source addresses, a substantially
different approach is needed.
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3. Traceroute Functionality Challenges and Opportunities in ICN
In the NDN and CCN protocols, the communication paradigm is based
exclusively on named objects. An Interest is forwarded across the
network based on its name. Eventually, it retrieves a content object
either from a producer application or some forwarder's Content Store
(CS).
An ICN network differs from an IP network in at least 4 important
ways:
* IP identifies interfaces to an IP network with a fixed-length
address, and delivers IP packets to one or more interfaces. ICN
identifies units of data in the network with a variable length
name consisting of a hierarchical list of segments.
* An IP-based network depends on the IP packets having source IP
addresses that are used as the destination address for replies.
On the other hand, ICN Interests do not have source addresses and
they are forwarded based on names, which do not refer to a unique
end-point. Data packets follow the reverse path of the Interests
based on hop-by-hop state created during Interest forwarding.
* An IP network supports multi-path, single destination, stateless
packet forwarding and delivery via unicast, a limited form of
multi-destination selected delivery with anycast, and group-based
multi-destination delivery via multicast. In contrast, ICN
supports multi-path and multi-destination stateful Interest
forwarding and multi-destination data delivery to units of named
data. This single forwarding semantic subsumes the functions of
unicast, anycast, and multicast. As a result, consecutive (or
retransmitted) ICN Interest messages may be forwarded through an
ICN network along different paths, and may be forwarded to
different data sources (e.g., end-node applications, in-network
storage) holding a copy of the requested unit of data. The
ability to discover multiple available (or potentially all) paths
towards a name prefix is a desirable capability for an ICN
traceroute protocol, since it can be beneficial for congestion
control purposes. Knowing the number of available paths for a
name can also be useful in cases that Interest forwarding based on
application semantics/preferences is desirable.
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* In the case of multiple Interests with the same name arriving at a
forwarder, a number of Interests may be aggregated in a common
Pending Interest Table (PIT) entry. Depending on the lifetime of
a PIT entry, the round-trip time an Interest-Data exchange might
significantly vary (e.g., it might be shorter than the full round-
trip time to reach the original content producer). To this end,
the round-trip time experienced by consumers might also vary even
under constant network load.
These differences introduce new challenges, new opportunities and new
requirements in the design of ICN traceroute. Following this
communication model, a traceroute client should be able to express
traceroute requests directed to a name prefix and receive responses.
Our goals are the following:
* Trace one or more paths towards an ICN forwarder (for
troubleshooting purposes).
* Trace one or more paths along which an named data of an
application can be reached in the sense that Interest packets can
be forwarded toward it.
* Test whether a specific named object is cached in some on-path CS,
and, if so, trace the path towards it and return the identity of
the corresponding forwarder.
* Perform transit delay network measurements.
To this end, a traceroute target name can represent:
* An administrative name that has been assigned to a forwarder.
Assigning a name to a forwarder implies the presence of a
management application running locally, which handles Operations,
Administration and Management (OAM) operations.
* A name that includes an application's namespace as a prefix.
* A named object that might reside in some in-network storage.
In order to provide stable and reliable diagnostics, it is desirable
that the packet encoding of a traceroute request enable the
forwarders to distinguish this request from a normal Interest, while
also preserving forwarding behavior as similar as possible to that
for an Interest packet. In the same way, the encoding of a
traceroute reply should allow for processing as similar as possible
to that of a data packet by the forwarders.
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The term "traceroute session" is used for an iterative process during
which an endpoint client application generates a number of traceroute
requests to successively traverse more distant hops in the path until
it receives a final traceroute reply from a forwarder. It is
desirable that ICN traceroute be able to discover a number of paths
towards the expressed prefix within the same session or subsequent
sessions. To discover all the hops in a path, we need a mechanism
(Interest Steering) to steer requests along different paths. Such a
capability was initially published in [PATHSTEERING] and has been
specified for CCNx and NDN in [I-D.irtf-icnrg-pathsteering].
It is also important, in the case of traceroute requests for the same
prefix from different sources, to have a mechanism to avoid
aggregating those requests in the PIT. To this end, we need some
encoding in the traceroute requests to make each request for a common
prefix unique, and hence avoid PIT aggregation and further enabling
the exact matching of a response with a particular traceroute packet.
The packet types and format are presented in Section 4. The
procedures, e.g. the procedures for determining and indicating that a
destination has been reached, are specified in Section 6.
4. ICN Traceroute CCNx Packet Format
In this section, we present the CCNx packet format [RFC8609] of ICN
traceroute, where messages exist within outermost containments
(packets). Specifically, we propose two types of traceroute packets,
a traceroute request and a traceroute reply packet type.
4.1. ICN Traceroute Request CCNx Packet Format
The format of the traceroute request packet is presented below:
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | | |
| Version | TrRequest | PacketLength |
| | | |
+---------------+---------------+---------------+---------------+
| | | | |
| HopLimit | Reserved | Flags | HeaderLength |
| | | | |
+---------------+---------------+---------------+---------------+
/ /
/ Path label TLV /
/ /
+---------------+---------------+---------------+---------------+
| |
| Traceroute Request Message TLVs |
| |
+---------------+---------------+---------------+---------------+
Figure 1: Traceroute Request CCNx Packet Format
The existing packet header fields have similar functionality to the
header fields of a CCNx Interest packet. The value of the packet
type field is TrRequest. See Section 9 for the value assignment.
Compared to the typical format of a CCNx packet header [RFC8609],
there is a new optional fixed header added to the packet header:
* A Path Steering hop-by-hop header TLV, which is constructed hop-
by-hop in the traceroute reply and included in the traceroute
request to steer consecutive requests expressed by a client
towards a common or different forwarding paths. The Path label
TLV is specified in [I-D.irtf-icnrg-pathsteering]
The message of a traceroute request is presented below:
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | |
| MessageType = 1 | MessageLength |
| | |
+---------------+---------------+---------------+---------------+
| |
| Name TLV |
| |
+---------------+---------------+---------------+---------------+
Figure 2: Traceroute Request Message Format
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The traceroute request message is of type Interest in order to
leverage the Interest forwarding behavior provided by the network.
The Name TLV has the structure described in [RFC8609]. The name
consists of the target (destination) prefix appended with a nonce
typed name as its last segment. The nonce can be encoded as a
base64-encoded string with the URL-safe alphabet as defined in
Section 5 of [RFC4648], with padding omitted. The format of this TLV
is a 64-bit nonce. See Section 9 for the value assignment. The
purpose of the nonce is to avoid Interest aggregation and allow
client matching of replies with requests. As described below, the
nonce is ignored for CS checking.
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | |
| Name_Nonce_Type | Name_Nonce_Length = 8 |
| | |
+---------------+---------------+---------------+---------------+
| |
| |
| |
| Name_Nonce_Value |
| |
| |
+---------------+---------------+---------------+---------------+
Figure 3: Name Nonce Typed Segment TLV
4.2. Traceroute Reply CCNx Packet Format
The format of a traceroute reply packet is presented below:
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | | |
| Version | TrReply | PacketLength |
| | | |
+---------------+---------------+---------------+---------------+
| | | |
| Reserved | Flags | HeaderLength |
| | | |
+---------------+---------------+---------------+---------------+
| |
| Path label TLV |
| |
+---------------+---------------+---------------+---------------+
| |
| Traceroute Reply Message TLVs |
| |
+---------------+---------------+---------------+---------------+
Figure 4: Traceroute Reply CCNx Packet Format
The header of a traceroute reply consists of the header fields of a
CCNx Content Object and a hop-by-hop path steering TLV. The value of
the packet type field is TrReply. See Section 9 for the value
assignment.
A traceroute reply message is of type Content Object, contains a Name
TLV (name of the corresponding traceroute request), a PayloadType TLV
and an ExpiryTime TLV with a value of 0 to indicate that replies must
not be returned from network caches.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | |
| MessageType = 2 | MessageLength |
| | |
+---------------+---------------+---------------+---------------+
| |
| Name TLV |
| |
+---------------+---------------+---------------+---------------+
| |
| PayloadType TLV |
| |
+---------------+---------------+---------------+---------------+
| |
| ExpiryTime TLV |
| |
+---------------+---------------+---------------+---------------+
Figure 5: Traceroute Reply Message Format
The PayloadType TLV is presented below. It is of type
T_PAYLOADTYPE_DATA, and the data schema consists of 3 TLVs:
1) the name of the sender of this reply (with the same structure as
a CCNx Name TLV),
2) the sender's signature of their own name (with the same structure
as a CCNx ValidationPayload TLV),
3) a TLV with return codes to indicate whether the request was
satisfied due to the existence of a local application, a CS hit
or a match with a forwarder's name, or the HopLimit value of the
corresponding request reached 0.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | |
| T_PAYLOADTYPE_DATA | Length |
| | |
+---------------+---------------+---------------+---------------+
| |
| Sender's Name TLV |
| |
+---------------+---------------+---------------+---------------+
| |
| Sender's Signature TLV |
| |
+---------------+---------------+---------------+---------------+
| |
| TrReply Code TLV |
| |
+---------------+---------------+---------------+---------------+
Figure 6: Traceroute Reply Message Format
The goal of including the name of the sender in the reply is to
enable the user to reach this entity directly to ask for further
management/administrative information using generic Interest-Data
exchanges or by employing a more comprehensive management tool such
as CCNInfo [RFC9344] after a successful verification of the sender's
name.
The structure of the TrReply Code TLV is presented below (16-bit
value). The assigned values are the following:
1: Indicates that the target name matched the administrative name of
a forwarder (as served by its internal management application).
2: Indicates that the target name matched a prefix served by an
application (other than the internal management application of a
forwarder).
3: Indicates that the target name matched the name of an object in a
forwarder's CS.
4: Indicates that the the Hop limit reached the 0 value.
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+---------------+---------------+
| | |
| TrReply_Code_Type | TrReply_Code_Length = 2 |
| | |
+---------------+---------------+---------------+---------------+
| |
| TrReply_Code_Value |
| |
+---------------+---------------+---------------+---------------+
Figure 7: TrReply Code TLV
5. ICN Traceroute NDN Packet Format
In this section, we present the ICN traceroute Request and Reply
Format according to the NDN packet specification [NDNTLV].
5.1. ICN Traceroute Request NDN Packet Format
A traceroute request is encoded as an NDN Interest packet. Its
format is the following:
TracerouteRequest = INTEREST-TYPE TLV-LENGTH
Name
MustBeFresh
Nonce
HopLimit
ApplicationParameters?
Figure 8: Traceroute Request NDN Packet Format
The name of a request consists of the target name, a nonce value (it
can be the value of the Nonce field) and the suffix "traceroute" to
denote that this Interest is a traceroute request (added as a
KeywordNameComponent). When the "ApplicationParameters" element is
present, a ParametersSha256DigestComponent is added as the last name
segment.
A traceroute request MAY carry a Path label TLV in the NDN Link
Adaptation Protocol [NDNLPv2] as specified in
[I-D.irtf-icnrg-pathsteering].
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Since the NDN packet format does not provide a mechanism to prevent
the network from caching specific data packets, we instead use the
MustBeFresh selector for requests (in combination with a Freshness
Period TLV of value 1 for replies) to avoid fetching cached
traceroute replies with a freshness period that has expired
[REALTIME].
5.2. Traceroute Reply NDN Packet Format
A traceroute reply is encoded as an NDN Data packet. Its format is
the following:
TracerouteReply = DATA-TLV TLV-LENGTH
Name
MetaInfo
Content
Signature
Figure 9: Traceroute Reply NDN Packet Format
A traceroute reply MAY carry a Path label TLV in the NDN Link
Adaptation Protocol [NDNLPv2] as specified in
[I-D.irtf-icnrg-pathsteering], since it might be modified in a hop-
by-hop fashion by the forwarders along the reverse path.
The name of a traceroute reply is the name of the corresponding
traceroute request, while the format of the MetaInfo field is the
following:
MetaInfo = META-INFO-TYPE TLV-LENGTH
ContentType
FreshnessPeriod
Figure 10: MetaInfo TLV
The value of the ContentType TLV is 0. The value of the
FreshnessPeriod TLV is 1, so that the replies are treated as stale
data (almost instantly) as they are received by a forwarder.
The content of a traceroute reply consists of the following 2 TLVs:
Sender's name (an NDN Name TLV) and Traceroute Reply Code. There is
no need to have a separate TLV for the sender's signature in the
content of the reply, since every NDN data packet carries the
signature of the data producer.
The Traceroute Reply Code TLV format is the following (with the
values specified in Section 4.2):
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TrReplyCode = TRREPLYCODE-TLV-TYPE TLV-LENGTH 2*OCTET
Figure 11: Traceroute Reply Code TLV
6. Forwarder Operation
When a forwarder receives a traceroute request, the hop limit value
is checked and decremented and the target name (i.e, the name of the
traceroute request without the last nonce name segment as well as the
suffix "traceroute" and the ParametersSha256DigestComponent in the
case of a request with the NDN packet format) is extracted.
If the HopLimit has not expired (its value is greater than 0), the
forwarder will forward the request upstream based on CS lookup, PIT
creation, LPM lookup and the path steering value, if present. If no
valid next-hop is found, an InterestReturn indicating "No Route" in
the case of CCNx or a network NACK in the case of NDN is sent
downstream.
If the HopLimit value is equal to zero, the forwarder generates a
traceroute reply. This reply includes the forwarder's administrative
name and signature, and a Path label TLV. This TLV initially has a
null value since the traceroute reply originator does not forward the
request and, thus, does not make a path choice. The reply will also
include the corresponding TrReply Code TLV.
A traceroute reply will be the final reply of a traceroute session if
any of the following conditions are met:
* If a forwarder has been given one or more administrative names,
the target name matches one of them.
* The target name exactly matches the name of a content-object
residing in the forwarder's CS (unless the traceroute client
application has chosen not to receive replies due to CS hits as
specified in Appendix A).
* The target name matches (in a Longest Prefix Match manner) a FIB
entry with an outgoing face referring to a local application.
The TrReply Code TLV value of the reply is set to indicate the
specific condition that was met. If none of those conditions was
met, the TrReply Code is set to 4 to indicate that the hop limit
value reached 0.
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A received traceroute reply will be matched to an existing PIT entry
as usual. On the reverse path, the path steering TLV of a reply will
be updated by each forwarder to encode its choice of next-hop(s).
When included in subsequent requests, this path steering TLV allows
the forwarders to steer the requests along the same path.
7. Protocol Operation For Locally-Scoped Namespaces
In this section, we elaborate on 2 alternative design approaches in
cases that the traceroute target prefix corresponds to a locally-
scoped namespace not directly routable from the client's local
network.
The first approach leverages the NDN Link Object [SNAMP].
Specifically, the traceroute client attaches to the expressed request
a LINK Object that contains a number of routable name prefixes, based
on which the request can be forwarded across the Internet until it
reaches a network region, where the request name itself is routable.
A LINK Object is created and signed by a data producer allowed to
publish data under a locally-scoped namespace. The way that a client
retrieves a LINK Object depends on various network design factors and
is out of the scope of the current draft.
Based on the current deployment of the LINK Object by the NDN team, a
forwarder at the border of the region, where an Interest name becomes
routable has to remove the LINK Object from the incoming Interests.
The Interest state maintained along the entire forwarding path is
based on the Interest name regardless of whether it was forwarded
based on this name or a prefix in the LINK Object.
The second approach is based on prepending a routable prefix to the
locally-scoped name. The resulting prefix will be the name of the
traceroute requests expressed by the client. In this way, a request
will be forwarded based on the routable part of its name. When it
reaches the network region where the original locally-scoped name is
routable, the border forwarder rewrites the request name and deletes
its routable part. There are two conditions for a forwarder to
perform this rewriting operation on a request:
1) the routable part of the request name matches a routable name of
the network region adjacent to the forwarder (assuming that a
forwarder is aware of those names), and
2) the remaining part of the request name is routable across the
network region of this forwarder.
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The state maintained along the path, where the locally-scoped name is
not routable, is based on the routable prefix along with the locally-
scoped prefix, while within the network region that the locally-
scoped prefix is routable is based only on it. To ensure that the
generated replies will reach the client, the border forwarder has
also to rewrite the name of a reply and prepend the routable prefix
of the corresponding request.
8. Security Considerations
A reflection attack could occur in the case of a traceroute reply
with the CCNx packet format if a compromised forwarder includes in
the reply the name of a victim forwarder. This could redirect the
future administrative traffic towards the victim. To foil such
reflection attacks, the forwarder that generates a traceroute reply
MUST sign the name included in the payload. In this way, the client
is able to verify that the included name is legitimate and refers to
the forwarder that generated the reply. Alternatively, the forwarder
could include in the reply payload their routable prefix(es) encoded
as a signed NDN Link Object [SNAMP].
This approach does not protect against on-path attacks, where a
compromised forwarder that receives a traceroute reply replaces the
forwarder's name and the signature in the message with its own name
and signature to make the client believe that the reply was generated
by the compromised forwarder. To foil such attack scenarios, a
forwarder can sign the reply message itself. In such cases, the
forwarder does not have to sign its own name in reply message, since
the message signature protects the message as a whole and will be
invalidated in the case of an on-path attack. Additionally, a
forwarder could swap out the name of a traceroute request with the
name of its choosing. In this case, however, the response with the
spoofed name will not be received by a client, since the change of
name would invalidate the state in PIT on the path back to the
client.
Signing each traceroute reply message can be expensive and can
potentially lead to computation attacks against forwarders. To
mitigate such attack scenarios, the processing of traceroute requests
and the generation of the replies SHOULD be handled by a separate
management application running locally on each forwarder. Serving
traceroute replies therefore is thereby separated from load on the
forwarder itself. The approaches used by ICN applications to manage
load may also apply to the forwarder's management application.
Interest flooding attack amplification is possible in the case of the
second approach to deal with locally-scoped namespaces described in
Section 7. A border forwarder will have to maintain extra state to
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prepend the correct routable prefix to the name of an outgoing reply,
since the forwarder might be attached to multiple network regions
(reachable under different prefixes) or a network region attached to
this forwarder might be reachable under multiple routable prefixes.
We also note that traceroute requests have the same privacy
characteristics as regular Interests.
9. IANA Considerations
IANA will assign TBD1 to "TrRequest" and TBD2 to "TrReplay" in the
CCNx Packet Types registry established by [RFC8609].
IANA will assign TBD3 to "Nonce" in the CCNx Name Segment Types
registry established by [RFC8609].
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8793] Wissingh, B., Wood, C., Afanasyev, A., Zhang, L., Oran,
D., and C. Tschudin, "Information-Centric Networking
(ICN): Content-Centric Networking (CCNx) and Named Data
Networking (NDN) Terminology", RFC 8793,
DOI 10.17487/RFC8793, June 2020,
<https://www.rfc-editor.org/info/rfc8793>.
10.2. Informative References
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[I-D.irtf-icnrg-pathsteering]
Moiseenko, I. and D. R. Oran, "Path Steering in CCNx and
NDN", Work in Progress, Internet-Draft, draft-irtf-icnrg-
pathsteering-03, 23 July 2023,
<https://datatracker.ietf.org/doc/html/draft-irtf-icnrg-
pathsteering-03>.
[NDNLPv2] "Named Data Networking Link Adaptation Protocol v2",
various, <https://redmine.named-
data.net/projects/nfd/wiki/NDNLPv2>.
[NDNTLV] "NDN Packet Format Specification.", 2021,
<https://named-data.net/doc/NDN-packet-spec/current/>.
[PATHSTEERING]
Moiseenko, I. and D. Oran, "Path switching in content
centric and named data networks", in Proceedings of the
4th ACM Conference on Information-Centric Networking,
2017.
[REALTIME] Mastorakis, S., Gusev, P., Afanasyev, A., and L. Zhang,
"Real-Time Data Retrieval in Named Data Networking", in
Proceedings of the 1st IEEE International Conference on
Hot Topics in Information-Centric Networking, 2017.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>.
[RFC9344] Asaeda, H., Ooka, A., and X. Shao, "CCNinfo: Discovering
Content and Network Information in Content-Centric
Networks", RFC 9344, DOI 10.17487/RFC9344, February 2023,
<https://www.rfc-editor.org/info/rfc9344>.
[SNAMP] Afanasyev, A. and , "SNAMP: Secure namespace mapping to
scale NDN forwarding", IEEE Conference on Computer
Communications Workshops (INFOCOM WKSHPS), 2015.
Appendix A. Traceroute Client Application (Consumer) Operation
This section is an informative appendix regarding the proposed
traceroute client operation.
The client application is responsible for generating traceroute
requests for prefixes provided by users.
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The overall process can be iterative: the first traceroute request of
each session will have a HopLimit of value 1 to reach the first hop
forwarder, the second of value 2 to reach the second hop forwarder
and so on and so forth.
When generating a series of requests for a specific name, the first
one will typically not include a Path label TLV, since no TLV value
is known. After a traceroute reply containing a Path label TLV is
received, each subsequent request might include the received path
steering value in the Path label header TLV to drive the requests
towards a common path as part of checking the network performance.
To discover more paths, a client can omit the Path label TLV in
future requests. Moreover, for each new traceroute request, the
client has to generate a new nonce and record the time that the
request was expressed. It will also set the lifetime of a request,
which will have semantics similar to the lifetime of an Interest.
Moreover, the client application might not wish to receive replies
due to CS hits. In CCNx, a mechanism to achieve that would be to use
a Content Object Hash Restriction TLV with a value of 0 in the
payload of a traceroute request message. In NDN, the exclude filter
selector can be used.
When it receives a traceroute reply, the client would typically match
the reply to a sent request and compute the round-trip time of the
request. It should parse the Path label value and decode the reply's
payload to parse the sender's name and signature. The client should
verify that both the received message and the forwarder's name have
been signed by the key of the forwarder, whose name is included in
the payload of the reply (by fetching this forwarder's public key and
verifying the contained signature). In the case that the client
receives an TrReply Code TLV with a valid value, it can stop sending
requests with increasing HopLimit values and potentially start a new
traceroute session.
In the case that a traceroute reply is not received for a request
within a certain time interval (lifetime of the request), the client
should time-out and send a new request with a new nonce value up to a
maximum number of requests to be sent specified by the user.
Authors' Addresses
Spyridon Mastorakis
University of Notre Dame
South Bend, IN
United States of America
Email: smastor2@nd.edu
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Dave Oran
Network Systems Research and Design
Cambridge, MA
United States of America
Email: daveoran@orandom.net
Ilya Moiseenko
Apple Inc
Cupertino, CA
United States of America
Email: iliamo@mailbox.org
Jim Gibson
Unaffiliated
Belmont, MA
United States of America
Email: jcgibson61@gmail.com
Ralph Droms
Unaffiliated
Hopkinton, MA
United States of America
Email: rdroms.ietf@gmail.com
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