Diff: rfc9507.original.xml

	rfc9507.original.xml	rfc9507.xml

	<?xml version='1.0' encoding='utf-8'?>	<?xml version="1.0" encoding="UTF-8"?>
	<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>


	<rfc	<!DOCTYPE rfc [
	xmlns:xi="http://www.w3.org/2001/XInclude"	<!ENTITY nbsp " ">
		<!ENTITY zwsp "">
		<!ENTITY nbhy "‑">
		<!ENTITY wj "⁠">
		]>

		<rfc xmlns:xi="http://www.w3.org/2001/XInclude"
		submissionType="IRTF"
	category="exp"	category="exp"

		consensus="true"
	docName="draft-irtf-icnrg-icntraceroute-11"	docName="draft-irtf-icnrg-icntraceroute-11"

		number="9507"
	ipr="trust200902"	ipr="trust200902"
	obsoletes=""	obsoletes=""
	updates=""	updates=""

	submissionType="IRTF"
	xml:lang="en"	xml:lang="en"
	tocInclude="true"	tocInclude="true"
	tocDepth="4"	tocDepth="4"
	symRefs="true"	symRefs="true"
	sortRefs="true"	sortRefs="true"
	version="3">	version="3">

	<front>	<front>


	<title abbrev="ICN Traceroute">ICN Traceroute Protocol Specification</title>	<title abbrev="ICN Traceroute">Information-Centric Networking (ICN) Traceroute
	<seriesInfo name="Internet-Draft" value="draft-irtf-icnrg-icntraceroute-11"/>	Protocol Specification</title>
		<seriesInfo name="RFC" value="9507"/>
	<author fullname="Spyridon Mastorakis" initials="S" surname="Mastorakis">	<author fullname="Spyridon Mastorakis" initials="S" surname="Mastorakis">
	<organization>University of Notre Dame</organization>	<organization>University of Notre Dame</organization>
	<address>	<address>
	<postal>	<postal>
	<street/>	<street/>

	<!-- Reorder these if your country does things differently -->
	<city>South Bend</city>	<city>South Bend</city>
	<region>IN</region>	<region>IN</region>
	<code/>	<code/>

	<country>US</country>	<country>United States of America</country>
	</postal>	</postal>
	<email>smastor2@nd.edu</email>	<email>smastor2@nd.edu</email>

	<!-- uri and facsimile elements may also be added -->
	</address>	</address>
	</author>	</author>

	<author fullname="Dave Oran" initials="D" surname="Oran">	<author fullname="Dave Oran" initials="D" surname="Oran">
	<organization>Network Systems Research and Design</organization>	<organization>Network Systems Research and Design</organization>
	<address>	<address>
	<postal>	<postal>
	<street/>	<street/>

	<!-- Reorder these if your country does things differently -->
	<city>Cambridge</city>	<city>Cambridge</city>
	<region>MA</region>	<region>MA</region>
	<code/>	<code/>

	<country>US</country>	<country>United States of America</country>
	</postal>	</postal>
	<email>daveoran@orandom.net</email>	<email>daveoran@orandom.net</email>

	<!-- uri and facsimile elements may also be added -->
	</address>	</address>
	</author>	</author>

	<author fullname="Ilya Moiseenko" initials="I" surname="Moiseenko">	<author fullname="Ilya Moiseenko" initials="I" surname="Moiseenko">

	<organization>Apple Inc</organization>	<organization>Apple Inc.</organization>
	<address>	<address>
	<postal>	<postal>
	<street/>	<street/>

	<!-- Reorder these if your country does things differently -->
	<city>Cupertino</city>	<city>Cupertino</city>
	<region>CA</region>	<region>CA</region>
	<code/>	<code/>

	<country>US</country>	<country>United States of America</country>
	</postal>	</postal>
	<email>iliamo@mailbox.org</email>	<email>iliamo@mailbox.org</email>

	</address>	</address>
	</author>	</author>

	<author fullname="Jim Gibson" initials="J" surname="Gibson">	<author fullname="Jim Gibson" initials="J" surname="Gibson">
	<organization>Unaffiliated</organization>	<organization>Unaffiliated</organization>
	<address>	<address>
	<postal>	<postal>

	skipping to change at line 77 ¶	skipping to change at line 78 ¶
	<email>iliamo@mailbox.org</email>	<email>iliamo@mailbox.org</email>

	</address>	</address>
	</author>	</author>

	<author fullname="Jim Gibson" initials="J" surname="Gibson">	<author fullname="Jim Gibson" initials="J" surname="Gibson">
	<organization>Unaffiliated</organization>	<organization>Unaffiliated</organization>
	<address>	<address>
	<postal>	<postal>
	<street/>	<street/>


	<city>Belmont</city>	<city>Belmont</city>
	<region>MA</region>	<region>MA</region>
	<code/>	<code/>

	<country>US</country>	<country>United States of America</country>
	</postal>	</postal>
	<email>jcgibson61@gmail.com</email>	<email>jcgibson61@gmail.com</email>
	</address>	</address>
	</author>	</author>

	<author fullname="Ralph Droms" initials="R" surname="Droms">	<author fullname="Ralph Droms" initials="R" surname="Droms">
	<organization>Unaffiliated</organization>	<organization>Unaffiliated</organization>
	<address>	<address>
	<postal>	<postal>
	<street/>	<street/>
	<city>Hopkinton</city>	<city>Hopkinton</city>
	<region>MA</region>	<region>MA</region>
	<code/>	<code/>

	<country>US</country>	<country>United States of America</country>
	</postal>	</postal>
	<email>rdroms.ietf@gmail.com</email>	<email>rdroms.ietf@gmail.com</email>
	</address>	</address>
	</author>	</author>


	<date year="2023"/>	<date year="2024" month="March" />
		<workgroup>Information-Centric Networking</workgroup>
	<area>IRTF</area>
	<workgroup>ICNRG</workgroup>

	<keyword>ICN</keyword>	<keyword>ICN</keyword>
	<keyword>Network Management</keyword>	<keyword>Network Management</keyword>

	<abstract>	<abstract>

	<t>This document presents the design of an ICN Traceroute protocol. This inc ludes the operation of both the client and the forwarder.</t>	<t>This document presents the design of an Information-Centric Networking (I CN) Traceroute protocol. This includes the operation of both the client and the forwarder.</t>

	<t>This document is a product of the Information-Centric Networking Resea rch Group (ICNRG) of the IRTF.</t>	<t>This document is a product of the Information-Centric Networking Resea rch Group (ICNRG) of the IRTF.</t>
	</abstract>	</abstract>

	</front>	</front>

	<middle>	<middle>
	<section><name>Introduction</name>	<section><name>Introduction</name>
	<t>In TCP/IP, routing and forwarding are based on IP addresses. To ascertain	<t>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 tracerou te	the route to an IP address and to measure the transit delays, the tracerou te

	utility is commonly used. In ICN, routing and forwarding are based on name	utility is commonly used. In Information-Centric Networking (ICN), routing
	prefixes.	and forwarding are based on name prefixes.
	To this end, the problem of ascertaining the characteristics (i.e., transi	To this end, the ability to ascertain the characteristics of at least one
	t	of
	forwarders and delays) of at least one of the available routes to a name	the available routes to a name prefix is a fundamental requirement for
	prefix is a fundamendal requirement for instrumentation and network manage	instrumentation and network management. These characteristics include, amo
	ment.</t>	ng
		others, route properties such as which forwarders were transited and the
		delay incurred through forwarding.</t>


	<t>In order to carry out meaningful experimentation and deployment of ICN protocols, tools to manage and debug the operatio n of ICN architectures and protocols are needed anal ogous to ping and traceroute used for TCP/IP. This docu ment describes the design of a management and debugging protocol analogous to the traceroute protocol of TCP/IP, which will aid th e experimental deployment of ICN protocols. As the community continues its e xperimentation with ICN architectures and protocols, the design of ICN Tracerout e might change accordingly. ICN Traceroute is designed as a tool to troubleshoot ICN architectures and protocols. As such, this document is classified as an exp erimental RFC.</t>	<t>In order to carry out meaningful experimentation and deployment of ICN protocols, new tools analogous to ping and traceroute used for TCP/IP are neede d to manage and debug the operation of ICN architectures and protocols. This doc ument describes the design of a management and debugging protocol analogous to t he traceroute protocol of TCP/IP; this new management and debugging protocol wil l aid the experimental deployment of ICN protocols. As the community continues i ts experimentation with ICN architectures and protocols, the design of ICN Trace route might change accordingly. ICN Traceroute is designed as a tool to troubles hoot ICN architectures and protocols. As such, this document is classified as an Experimental RFC.</t>

	<t>This specification uses the terminology defined in <xref target="RFC87 93"/>.</t>	<t>This specification uses the terminology defined in <xref target="RFC87 93"/>.</t>


	<t>This document is not an Internet Standards Track specification; it is	<t>This RFC represents the
	published for examination, experimental i	consensus of the Information-Centric Networking Research Group (ICNRG) of the
	mplementation, and evaluation. This document def	Internet Research Task Force (IRTF).</t>
	ines an Experimental Protocol for the Internet community. This document is a pro
	duct of the Internet Research Task Force (IRTF). The IRTF publishes the resu
	lts of Internet-related research and development activities. These result
	s might not be suitable for deployment. This RFC represents the consensus of the
	Information-Centric Networking Research Group of the Internet Research Task For
	ce (IRTF). Documents approved for publication by the IRSG are not candidates for
	any level of Internet Standard; see Section 2 of RFC 7841.</t>

	<section><name>Requirements Language</name>	<section><name>Requirements Language</name>

	<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",	<t>The key words "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this docume	"<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
	nt are to be interpreted as described in BCP 14 <xref target="RFC2119"/> <xref t	"<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
	arget="RFC8174"/> when, and only when, they appear in all capitals, as shown her	"<bcp14>SHOULD NOT</bcp14>",
	e.</t>	"<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
		"<bcp14>MAY</bcp14>", and "<bcp14>OPTIONAL</bcp14>" in this document
		are to be interpreted as described in BCP 14
		<xref target="RFC2119"/> <xref target="RFC8174"/> when, and only
		when, they appear in all capitals, as shown here.</t>
	</section>	</section>
	</section>	</section>

	<section><name>Background on IP-Based Traceroute Operation</name>	<section><name>Background on IP-Based Traceroute Operation</name>

	<t>In IP-based networks, traceroute is based on the expiration of the Time To Live (TTL) IP header field. Specifically, a traceroute client sends consecut ive packets (depending on the implementation and the user-specified behavior suc h packets can be either UDP datagrams, ICMP Echo Request or TCP SYN packets) wit h 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 pa th, the second IP packet at the second router along the path, etc, until the rou ter (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 Ex ceeded packet, unless explicitly prevented from doing so by a security policy.</ t>	<t>In IP-based networks, traceroute is based on the expiration of the Time To Live (TTL) IP header field. Specifically, a traceroute client sends consecut ive packets (depending on the implementation and the user-specified behavior, su ch packets can be either UDP datagrams, ICMP Echo Request packets, or TCP SYN pa ckets) with a TTL value increased by 1, essentially performing an expanding ring search. In this way, the first IP packet sent will expire at the first router a long the path, the second IP packet at the second router along the path, etc., u ntil 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 I CMP Time Exceeded packet, unless explicitly prevented from doing so by a securit y policy.</t>


	<t>The IP-based traceroute utility operates on IP addresses, and in partic ular	<t>The IP-based traceroute utility operates on IP addresses and in particu lar
	depends on the IP packets having source IP addresses that are used as	depends on the IP packets having source IP addresses that are used as
	the destination address for replies. Given that ICN forwards based on name s	the destination address for replies. Given that ICN forwards based on name s
	rather than destination IP addresses, that the names do not	rather than destination IP addresses, that the names do not
	refer to unique endpoints (multi-destination), and that the packets	refer to unique endpoints (multi-destination), and that the packets
	do not contain source addresses, a substantially different approach is nee ded.</t>	do not contain source addresses, a substantially different approach is nee ded.</t>
	</section>	</section>

	<section anchor="challenges" numbered="true" toc="default">	<section anchor="challenges" numbered="true" toc="default">
	<name>Traceroute Functionality Challenges and Opportunities in ICN</name>	<name>Traceroute Functionality Challenges and Opportunities in ICN</name>

	<t> In the NDN and CCN	<t> In the Named Data Networking (NDN) and Content-Centric Networking (CCN x)
	protocols, the communication paradigm is based exclusively on named	protocols, the communication paradigm is based exclusively on named

	objects. An Interest is forwarded across the network based on its name.	objects. An Interest message is forwarded across the network based on its
	Eventually, it retrieves a content object either from a producer	name.
		Eventually, it retrieves a Content Object from either a producer
	application or some forwarder's Content Store (CS).</t>	application or some forwarder's Content Store (CS).</t>


	<t>An ICN network differs from an IP network in at least 4 important ways: </t>	<t>An ICN network differs from an IP network in at least four important wa ys (four of which are as follows):</t>
	<ul spacing="normal">	<ul spacing="normal">

	<li>IP identifies interfaces to an IP network with a fixed-length addres s, and delivers IP packets to one or more interfaces. ICN identifies units of da ta in the network with a variable length name consisting of a hierarchical list of segments.</li>	<li>IP identifies interfaces to an IP network with a fixed-length addres s and delivers IP packets to one or more interfaces. ICN identifies units of dat a in the network with a variable-length name consisting of a hierarchical list o f segments.</li>


	<li>An IP-based network depends on the IP packets having source IP	<li>An IP-based network depends on the IP packets having source IP
	addresses that are used as the destination address for replies. On the othe	addresses that are used as the destination address for replies. On the other han
	r hand, ICN Interests do not have source addresses and they are forwarded based	d, ICN Interests do not have source addresses, and they are forwarded based on n
	on names, which do not refer to a unique end-point. Data packets follow the reve	ames, which do not refer to a unique endpoint. Data packets follow the reverse p
	rse path of the Interests based on hop-by-hop state created during Interest forw	ath of the Interests based on hop-by-hop state created during Interest forwardin
	arding.</li>	g.</li>


	<li>An IP network supports multi-path, single destination, stateless pac	<li>An IP network supports multi-path, single-destination, stateless pac
	ket forwarding and delivery via unicast, a limited form of multi-destination sel	ket forwarding and delivery via unicast; a limited form of multi-destination sel
	ected delivery with anycast, and group-based multi-destination delivery via mult	ected delivery with anycast; and group-based multi-destination delivery via mult
	icast. In contrast, ICN supports multi-path and multi-destination stateful Inter	icast. In contrast, ICN supports multi-path and multi-destination stateful Inter
	est forwarding and multi-destination data delivery to units of named data. This	est forwarding and multi-destination data delivery to units of named data. This
	single forwarding semantic subsumes the functions of unicast, anycast, and	single forwarding semantic subsumes the functions of unicast, anycast, and
	multicast. As a result, consecutive (or retransmitted) ICN Interest messag	multicast. As a result, consecutive (or retransmitted) ICN Interest messages ma
	es may be forwarded through an ICN network along different paths, and may be for	y be forwarded through an ICN network along different paths and may be forwarded
	warded to different data sources (e.g., end-node applications, in-network storag	to different data sources (e.g., end-node applications, in-network storage) hol
	e) holding a copy of the requested unit of data. The ability to discover multipl	ding a copy of the requested unit of data. The ability to discover multiple avai
	e available (or potentially all) paths towards a name prefix is a desir	lable (or
	able capability for an ICN traceroute protocol, since it can be beneficial for c	potentially all) paths towards a name prefix is a desirable capability for an IC
	ongestion control purposes. Knowing the number of available paths for a name can	N Traceroute protocol, since it can be beneficial for congestion control purpose
	also be useful in cases that Interest forwarding based on application semantics	s. Knowing the number of available paths for a name can also be useful in cases
	/preferences is desirable.</li>	where Interest forwarding based on application semantics/preferences is desirabl
		e.</li>


	<li>In the case of multiple Interests with the same name arriving at a f orwarder, a number of Interests may be aggregated in a common Pending Interest T able (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 th an 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 consta nt network load.</li>	<li>In the case of multiple Interests with the same name arriving at a f orwarder, a number of Interests may be aggregated in a common Pending Interest T able (PIT) entry. Depending on the lifetime of a PIT entry, the round-trip time of an Interest-Data exchange might vary significantly (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 con stant network load.</li>
	</ul>	</ul>


	<t>These differences introduce new challenges, new opportunities and new	<t>These differences introduce new challenges, new opportunities, and new
	requirements in the design of ICN traceroute. Following this communication	requirements regarding the design of ICN Traceroute. Following this commun
		ication
	model, a traceroute client should be able to express traceroute requests	model, a traceroute client should be able to express traceroute requests
	directed to a name prefix and receive responses.</t>	directed to a name prefix and receive responses.</t>


	<t>Our goals are the following:</t>	<t>Our goals are as follows:</t>
	<ul>	<ul spacing="normal">
	<li>Trace one or more paths towards an ICN forwarder (for troubleshootin	<li>Trace one or more paths towards an ICN forwarder (for troubleshootin
	g purposes).</li>	g purposes).</li>
	<li>Trace one or more paths along which an named data of an application	<li>Trace one or more paths through which a named data object can be rea
	can be reached in the sense that Interest packets can be forwarded toward it.</l	ched in the sense that Interest packets can be forwarded towards the application
	i>	hosting the object.</li>
	<li>Test whether a specific named object is cached in some on-path CS, a nd, if so, trace the path towards it and return the identity of the correspondin g forwarder.</li>	<li>Test whether a specific named object is cached in some on-path CS, a nd, if so, trace the path towards it and return the identity of the correspondin g forwarder.</li>
	<li>Perform transit delay network measurements.</li>	<li>Perform transit delay network measurements.</li>
	</ul>	</ul>

	<t>To this end, a traceroute target name can represent:</t>	<t>To this end, a traceroute target name can represent:</t>

	<ul>	<ul spacing="normal">
	<li>An administrative name that has been assigned to a forwarder. Assign	<li>An administrative name that has been assigned to a forwarder. Assign
	ing a name to a forwarder implies the presence of a management application runni	ing a name to a forwarder implies the presence of a management application runni
	ng locally, which handles Operations, Administration and Management (OAM) operat	ng locally that handles Operations, Administration, and Maintenance (OAM) operat
	ions.</li>	ions.</li>
	<li>A name that includes an application's namespace as a prefix.</li>	<li>A name that includes an application's namespace as a prefix.</li>
	<li>A named object that might reside in some in-network storage.</li>	<li>A named object that might reside in some in-network storage.</li>
	</ul>	</ul>

	<t>In order to provide stable and reliable diagnostics, it is desirable th at the	<t>In order to provide stable and reliable diagnostics, it is desirable th at the

	packet encoding of a traceroute request enable the forwarders to distingui sh this request from a normal Interest, while also preserving forwarding behavio r as similar as possible to that for an Interest packet. In the same way, the en coding of a traceroute reply should allow for processing as similar as possible to that of a data packet by the forwarders.</t>	packet encoding of a traceroute request enable the forwarders to distingui sh this request from a normal Interest while also diverging as little as possibl e from the forwarding behavior for an Interest packet. In the same way, the enco ding of a traceroute reply should minimize any processing differences from those employed for a data packet by the forwarders.</t>


	<t>The term "traceroute session" is used for an iterative process during w hich an endpoint client application generates a number of traceroute requests to successively traverse more distant hops in the path until it receives a final t raceroute 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 <xref target="PATHSTEERING" format="default"/> and h as been specified for CCNx and NDN in <xref target="I-D.irtf-icnrg-pathsteering" />.</t>	<t>The term "traceroute session" is used for an iterative process during w hich an endpoint client application generates a number of traceroute requests to successively traverse more distant hops in the path until it receives a final t raceroute 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 <xref target="PATHSTEERING" format="default"/> and h as been specified for CCNx and NDN in <xref target="RFC9531"/>.</t>


	<t>It is also important, in the case of traceroute requests for the same p	<t>In the case of traceroute requests for the same prefix from different s
	refix from different sources, to have a mechanism to avoid aggregating those req	ources, it is also important to have a mechanism to avoid aggregating those requ
	uests in the PIT. To this end, we need some encoding in the traceroute requests	ests 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	to make each request for a common prefix unique, hence avoiding PIT aggregation
	and further enabling the exact matching of a response with a particular tracero	and further enabling the exact matching of a response with a particular tracerou
	ute packet.</t>	te packet.</t>


	<t>The packet types and format are presented in <xref target="format"/>.	<t>The packet types and formats are presented in <xref target="format"/>.
	The procedures, e.g. the procedures for determining and indicating that	Procedures for determining and indicating that a destination has been reac
	a destination has been reached, are specified in <xref target="forwarder"/	hed are included in <xref target="forwarder"/>.</t>
	>.</t>
	</section>	</section>


	<section anchor="format"><name>ICN Traceroute CCNx Packet Format</name>	<section anchor="format"><name>ICN Traceroute CCNx Packet Formats</name>
	<t>In this section, we present the CCNx packet format <xref target="RFC860	<t>In this section, we present the CCNx packet formats <xref target="RFC86
	9"/> of ICN traceroute, where messages exist within outermost containments (pack	09"/> of ICN Traceroute where messages exist within outermost containments (pack
	ets). Specifically, we propose two types of traceroute packets, a traceroute req	ets). Specifically, we propose two types of traceroute packets: a traceroute req
	uest and a traceroute reply packet type. </t>	uest and a traceroute reply. </t>

	<section><name>ICN Traceroute Request CCNx Packet Format</name>	<section><name>ICN Traceroute Request CCNx Packet Format</name>
	<t>The format of the traceroute request packet is presented below:</t>	<t>The format of the traceroute request packet is presented below:</t>


	<figure align="center">	<figure align="center">
	<name>Traceroute Request CCNx Packet Format</name>	<name>Traceroute Request CCNx Packet Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| Version \| PT_TR_REQUEST \| PacketLength \|
	\| \| \| \|	\| \| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \| \| \| \|	\| \| \| \| \|
	\| HopLimit \| Reserved \| Flags \| HeaderLength \|	\| HopLimit \| Reserved \| Flags \| HeaderLength \|
	\| \| \| \| \|	\| \| \| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	/ /	/ /

	/ Path label TLV /	/ Path Label TLV /
	/ /	/ /
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Traceroute Request Message TLVs \|	\| Traceroute Request Message TLVs \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>The existing packet header fields have similar functionality to the h eader fields of a CCNx Interest packet. The value of the packet type field is Tr Request. See <xref target="IANA"/> for the value assignment.</t>	<t>The existing packet header fields have functionality similar to that of the header fields of a CCNx Interest packet. The value of the packet type fie ld is PT_TR_REQUEST. See <xref target="IANA"/> for the value assignment.</t>


	<t>Compared to the typical format of a CCNx packet header <xref target=" RFC8609"/>, there is a new optional fixed header added to the packet header:</t >	<t>In contrast to the typical format of a CCNx packet header <xref targe t="RFC8609"/>, there is a new optional fixed header added to the packet header:< /t>


	<ul>	<ul spacing="normal">
	<li>A Path Steering hop-by-hop header TLV, which is constructed hop-by	<li>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	hop in the traceroute reply and included in the traceroute request to steer con
	consecutive requests expressed by a client towards a common or different forward	secutive requests expressed by a client towards a common forwarding path or diff
	ing paths. The Path label TLV is specified in <xref target="I-D.irtf-icnrg-paths	erent forwarding paths. The Path Label TLV is specified in <xref target="RFC9531
	teering"/> </li>	"/>.</li>
	</ul>	</ul>

	<t>The message of a traceroute request is presented below:</t>	<t>The message of a traceroute request is presented below:</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Request Message Format</name>	<name>Traceroute Request Message Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| MessageType = 0x05 \| MessageLength \|
	\| \| \|	\| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Name TLV \|	\| Name TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>The traceroute request message is of type Interest in order to levera	<t>The traceroute request message is of type T_DISCOVERY. The Name TLV h
	ge the Interest forwarding behavior provided by the network. The Name TLV has th	as the structure described in <xref target="RFC8609"/>. The name consists of the
	e structure described in <xref target="RFC8609"/>. The name consists of the targ	target (destination) prefix appended with a nonce typed name as its last segmen
	et (destination) prefix appended with a nonce typed name as its last segment. T	t. The nonce can be encoded as a base64-encoded string with the URL-safe alphabe
	he nonce can be encoded as a base64-encoded string with the URL-safe alphabet as	t as defined in <xref target="RFC4648" sectionFormat="of" section="5"/>,
	defined in Section 5 of <xref target="RFC4648"/>, with padding omitted. The for	with padding omitted. The format of this TLV is a 64-bit nonce. See <xref target
	mat of this TLV is a 64-bit nonce. See <xref target="IANA"/> for the value assig	="RFC9508"/> for the value assignment. The purpose of the nonce is to avoid Inte
	nment. The purpose of the nonce is to avoid Interest aggregation and allow clien	rest aggregation and allow client matching of replies with requests. As describe
	t matching of replies with requests. As described below, the nonce is ignored fo	d below, the nonce is ignored for CS checking.</t>
	r CS checking.</t>

	<figure align="center">	<figure align="center">
	<name>Name Nonce Typed Segment TLV</name>	<name>Name Nonce Typed Segment TLV</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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_Type \| Name_Nonce_Length = 8 \|
	\| \| \|	\| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| \|	\| \|
	\| \|	\| \|
	\| Name_Nonce_Value \|	\| Name_Nonce_Value \|
	\| \|	\| \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>
	</section>	</section>

	<section anchor="CCNxReply">	<section anchor="CCNxReply">

	<name>Traceroute Reply CCNx Packet Format</name>	<name>ICN Traceroute Reply CCNx Packet Format</name>
	<t>The format of a traceroute reply packet is presented below:</t>	<t>The format of a traceroute reply packet is presented below:</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Reply CCNx Packet Format</name>	<name>Traceroute Reply CCNx Packet Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| Version \| PT_TR_REPLY \| PacketLength \|
	\| \| \| \|	\| \| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \| \| \|	\| \| \| \|
	\| Reserved \| Flags \| HeaderLength \|	\| Reserved \| Flags \| HeaderLength \|
	\| \| \| \|	\| \| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|

	\| Path label TLV \|	\| Path Label TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Traceroute Reply Message TLVs \|	\| Traceroute Reply Message TLVs \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>The header of a traceroute reply consists of the header fields of a C CNx Content Object and a hop-by-hop path steering TLV. The value of the packet type field is TrReply. See <xref target="IANA"/> for the value assignment.</t>	<t>The header of a traceroute reply consists of the header fields of a C CNx Content Object and a hop-by-hop Path Steering TLV. The value of the packet t ype field is PT_TR_REPLY. See <xref target="IANA"/> for the value assignment.</t >


	<t>A traceroute reply message is of type Content Object, contains a Name TLV (name of the corresponding traceroute request), a PayloadType TLV and an Ex piryTime TLV with a value of 0 to indicate that replies must not be returned fro m network caches.</t>	<t>A traceroute reply message is of type T_OBJECT and contains a Name TL V (name of the corresponding traceroute request), a PayloadType TLV, and an Expi ryTime TLV with a value of 0 to indicate that replies must not be returned from network caches.</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Reply Message Format</name>	<name>Traceroute Reply Message Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| MessageType = 0x06 \| MessageLength \|
	\| \| \|	\| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Name TLV \|	\| Name TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| PayloadType TLV \|	\| PayloadType TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| ExpiryTime TLV \|	\| ExpiryTime TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>The PayloadType TLV is presented below. It is of type T_PAYLOADTYPE_D ATA, and the data schema consists of 3 TLVs:</t>	<t>The PayloadType TLV is presented below. It is of type T_PAYLOADTYPE_D ATA, and the data schema consists of three TLVs:</t>
	<ol type="%d)">	<ol type="%d)">
	<li>the name of the sender of this reply (with the same structure as a CCNx Name TLV),</li>	<li>the name of the sender of this reply (with the same structure as a CCNx Name TLV),</li>

	<li>the sender's signature of their own name (with the same struc	<li>the sender's signature of their own name (with the same struc
	ture as a CCNx ValidationPayload TLV),</li>	ture as a CCNx ValidationPayload TLV), and</li>
	<li>a TLV with return codes to indicate whether the request was s	<li>a TLV with return codes to indicate whether the request was
	atisfied due to the existence of a local application, a CS hit or a match with a	satisfied due to the existence of a local application, a CS hit,
	forwarder's name, or the HopLimit value of the corresponding request reached 0.	a match with a forwarder's name, or the HopLimit value of the
	</li>	corresponding request reaching 0.</li>
	</ol>	</ol>

	<figure align="center">	<figure align="center">

	<name>Traceroute Reply Message Format</name>	<name>Traceroute Reply PayloadType TLV Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| T_PAYLOADTYPE_DATA \| Length \|
	\| \| \|	\| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Sender's Name TLV \|	\| Sender's Name TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|
	\| Sender's Signature TLV \|	\| Sender's Signature TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|

	\| TrReply Code TLV \|	\| PT_TR_REPLY Code TLV \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+

		]]></artwork>
	]]></artwork>
	</figure>	</figure>


	<t>The goal of including the name of the sender in the reply is to enabl e the user to reach this entity directly to ask for further management/administr ative information using generic Interest-Data exchanges or by employing a more c omprehensive management tool such as <xref target="RFC9344">CCNInfo</xref> after a successful verification of the sender's name.</t>	<t>The goal of including the name of the sender in the reply is to enabl e the user to reach this entity directly to ask for further management/administr ative information using generic Interest-Data exchanges or by employing a more c omprehensive management tool, such as <xref target="RFC9344">CCNinfo</xref>, aft er a successful verification of the sender's name.</t>


	<t>The structure of the TrReply Code TLV is presented below (16-bit valu e). The assigned values are the following:</t>	<t>The structure of the PT_TR_REPLY Code TLV is presented below (16-bit value). The four assigned values are as follows:</t>
	<ol type="%d:" spacing="normal">	<ol type="%d:" spacing="normal">

	<li>Indicates that the target name matched the administrative name of a forwarder (as served by its internal management application).</li>	<li>Indicates that the target name matched the administrative name of a forwarder (as served by its internal management application).</li>
	<li>Indicates that the target name matched a prefix served by an appli cation (other than the internal management application of a forwarder).</li>	<li>Indicates that the target name matched a prefix served by an appli cation (other than the internal management application of a forwarder).</li>
	<li>Indicates that the target name matched the name of an object in a forwarder's CS.</li>	<li>Indicates that the target name matched the name of an object in a forwarder's CS.</li>

	<li>Indicates that the the Hop limit reached the 0 value.</li>	<li>Indicates that the HopLimit reached 0.</li>
	</ol>	</ol>

	<figure align="center">	<figure align="center">

	<name>TrReply Code TLV</name>	<name>PT_TR_REPLY Code TLV</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	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	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 \|	\| PT_TR_REPLY_Code_Type \| PT_TR_REPLY_Code_Length = 2 \|
	\| \| \|	\| \| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	\| \|	\| \|

	\| TrReply_Code_Value \|	\| PT_TR_REPLY_Code_Value \|
	\| \|	\| \|
	+---------------+---------------+---------------+---------------+	+---------------+---------------+---------------+---------------+
	]]></artwork>	]]></artwork>
	</figure>	</figure>
	</section>	</section>
	</section>	</section>


	<section><name>ICN Traceroute NDN Packet Format</name>	<section><name>ICN Traceroute NDN Packet Formats</name>
	<t>In this section, we present the ICN traceroute Request and Reply Format	<t>In this section, we present the ICN Traceroute Request and Reply packet
	according to the NDN packet specification <xref target="NDNTLV"/>.</t>	formats according to the NDN packet format specification <xref target="NDNTLV"/
		>.</t>

	<section><name>ICN Traceroute Request NDN Packet Format</name>	<section><name>ICN Traceroute Request NDN Packet Format</name>

	<t>A traceroute request is encoded as an NDN Interest packet. Its format is the following:</t>	<t>A traceroute request is encoded as an NDN Interest packet. Its format is as follows:</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Request NDN Packet Format</name>	<name>Traceroute Request NDN Packet Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	TracerouteRequest = INTEREST-TYPE TLV-LENGTH	TracerouteRequest = INTEREST-TYPE TLV-LENGTH
	Name	Name
	MustBeFresh	MustBeFresh
	Nonce	Nonce
	HopLimit	HopLimit
	ApplicationParameters?	ApplicationParameters?

	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>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 th e "ApplicationParameters" element is present, a ParametersSha256DigestComponent is added as the last name segment.</t>	<t>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 <xref ta rget="NDNTLV"/>). When the "ApplicationParameters" element is present, a Paramet ersSha256DigestComponent (<xref target="forwarder"/>) is added as the last name segment.</t>


	<t>A traceroute request MAY carry a Path label TLV in the <xref target=" NDNLPv2">NDN Link Adaptation Protocol</xref> as specified in <xref target="I-D.i rtf-icnrg-pathsteering"/>.</t>	<t>A traceroute request <bcp14>MAY</bcp14> carry a Path Label TLV in the <xref target="NDNLPv2">NDN Link Adaptation Protocol</xref> as specified in <xre f target="RFC9531"/>.</t>


	<t>Since the NDN packet format does not provide a mechanism to prevent t he network from caching specific data packets, we instead use the MustBeFresh s elector for requests (in combination with a Freshness Period TLV of value 1 for replies) to avoid fetching cached traceroute replies with a freshness period tha t has expired <xref target="REALTIME"/>.</t>	<t>Since the NDN packet format does not provide a mechanism to prevent t he network from caching specific data packets, we instead use the MustBeFresh TL V for requests (in combination with a FreshnessPeriod TLV with a value of 1 for replies) to avoid fetching cached traceroute replies with a freshness period tha t has expired <xref target="REALTIME"/>.</t>

	</section>	</section>
	<section numbered="true" toc="default">	<section numbered="true" toc="default">

	<name>Traceroute Reply NDN Packet Format</name>	<name>ICN Traceroute Reply NDN Packet Format</name>
	<t>A traceroute reply is encoded as an NDN Data packet. Its format is th	<t>A traceroute reply is encoded as an NDN Data packet. Its format is as
	e following:</t>	follows:</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Reply NDN Packet Format</name>	<name>Traceroute Reply NDN Packet Format</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	TracerouteReply = DATA-TLV TLV-LENGTH	TracerouteReply = DATA-TLV TLV-LENGTH
	Name	Name
	MetaInfo	MetaInfo
	Content	Content
	Signature	Signature

	]]></artwork>	]]></artwork>
	</figure>	</figure>


	<t>A traceroute reply MAY carry a Path label TLV in the <xref target="ND NLPv2">NDN Link Adaptation Protocol</xref> as specified in <xref target="I-D .irtf-icnrg-pathsteering"/>, since it might be modified in a hop-by-hop fashion by the forwarders along the reverse path.</t>	<t>A traceroute reply <bcp14>MAY</bcp14> carry a Path Label TLV in the < xref target="NDNLPv2">NDN Link Adaptation Protocol</xref> as specified in <xref target="RFC9531"/>, since it might be modified in a hop-by-hop fashion by the fo rwarders along the reverse path.</t>


	<t>The name of a traceroute reply is the name of the corresponding trace route request, while the format of the MetaInfo field is the following:</t>	<t>The name of a traceroute reply is the name of the corresponding trace route request while the format of the MetaInfo field is as follows:</t>

	<figure align="center">	<figure align="center">
	<name>MetaInfo TLV</name>	<name>MetaInfo TLV</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[
	MetaInfo = META-INFO-TYPE TLV-LENGTH	MetaInfo = META-INFO-TYPE TLV-LENGTH
	ContentType	ContentType
	FreshnessPeriod	FreshnessPeriod

	]]></artwork>	]]></artwork>
	</figure>	</figure>

	<t>The value of the ContentType TLV is 0. The value of the FreshnessPeri od TLV is 1, so that the replies are treated as stale data (almost instantly) as they are received by a forwarder.</t>	<t>The value of the ContentType TLV is 0. The value of the FreshnessPeri od TLV is 1, so that the replies are treated as stale data (almost instantly) as they are received by a forwarder.</t>


	<t>The content of a traceroute reply consists of the following 2 TLVs: S ender's name (an NDN Name TLV) and Traceroute Reply Code. There is no need to ha ve 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.</t>	<t>The content of a traceroute reply consists of the following two 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, sinc e every NDN Data packet carries the signature of the data producer.</t>


	<t>The Traceroute Reply Code TLV format is the following (with the value s specified in <xref target="CCNxReply"/>):</t>	<t>The Traceroute Reply Code TLV format is as follows (with the values s pecified in <xref target="CCNxReply"/>):</t>

	<figure align="center">	<figure align="center">
	<name>Traceroute Reply Code TLV</name>	<name>Traceroute Reply Code TLV</name>
	<artwork align="left" name="" type="" alt=""><![CDATA[	<artwork align="left" name="" type="" alt=""><![CDATA[

	TrReplyCode = TRREPLYCODE-TLV-TYPE TLV-LENGTH 2*OCTET	PT_TR_REPLYCode = TRREPLYCODE-TLV-TYPE TLV-LENGTH 2*OCTET
	]]></artwork>	]]></artwork>
	</figure>	</figure>
	</section>	</section>

	</section>	</section>
	<section anchor="forwarder" numbered="true" toc="default">	<section anchor="forwarder" numbered="true" toc="default">
	<name>Forwarder Operation</name>	<name>Forwarder Operation</name>

	<t>When a forwarder receives a traceroute request, the hop limit value is	<t>When a forwarder receives a traceroute request, the HopLimit value is
	checked and decremented and the target name (i.e, the name of the tracero	checked and decremented, and the target name (i.e., the name of the traceroute r
	ute request without the last nonce name segment as well as the suffix	equest without the last Nonce name segment as well as the suffix
	"traceroute" and the ParametersSha256DigestComponent in the case of a req	"traceroute" and the ParametersSha256DigestComponent in the case of a request wi
	uest with the NDN packet format) is extracted.</t>	th the NDN packet format) is extracted.</t>


	<t>If the HopLimit has not expired (its value is greater than 0), the forw	<t>If the HopLimit has not expired (i.e., is greater than 0), the forwarde
	arder will forward the request upstream based on CS lookup, PIT creation, LPM lo	r will forward the request upstream based on CS lookup, PIT creation, Longest Na
	okup and the path steering value, if present. If no valid next-hop is found, an	me Prefix Match (LNPM) lookup, and (if present) the path steering value. If no v
	InterestReturn indicating "No Route" in the case of CCNx or a network NAC	alid next hop is found, an
	K in the case of NDN is sent downstream.</t>	InterestReturn indicating "No Route" in the case of CCNx or a network NACK in th
		e case of NDN is sent downstream.
		</t>


	<t>If the HopLimit value is equal to zero, the forwarder generates a trace route reply. This reply includes the forwarder's administrative name and s ignature, and a Path label TLV. This TLV initially has a null value since the traceroute reply originator does not forward the request and, thus, do es not make a path choice. The reply will also include the corresponding TrReply Code TLV.</t>	<t>If HopLimit equals 0, the forwarder generates a traceroute reply. This reply includes the forwarder's administrative name and signature, and a Path Lab el TLV. This TLV initially has a null value, since the traceroute reply originat or does not forward the request and thus does not make a path choice. The reply will also include the corresponding PT_TR_REPLY Code TLV.</t>

	<t>A traceroute reply will be the final reply of a traceroute session if a ny of the following conditions are met:</t>	<t>A traceroute reply will be the final reply of a traceroute session if a ny of the following conditions are met:</t>

	<ul spacing="normal">	<ul spacing="normal">
	<li>If a forwarder has been given one or more administrative names,	<li>If a forwarder has been given one or more administrative names,

	the target name matches one of them.</li>	the target name matches one of them.</li>
	<li>The target name exactly matches the name of a content-object residin	<li>The target name exactly matches the name of a Content Object residin
	g in the forwarder's CS (unless the traceroute client application has chosen not	g in the forwarder's CS (unless the traceroute client application has chosen not
	to receive replies due to CS hits as specified in <xref target="app-additional"	to receive replies due to CS hits as specified in <xref target="app-additional"
	format="default"/>).</li>	format="default"/>).</li>
	<li>The target name matches (in a Longest Prefix Match manner) a FIB ent	<li>The target name matches (in an LNPM manner) a FIB entry with an outg
	ry with an outgoing face referring to a local application.</li>	oing face referring to a local application.</li>
	</ul>	</ul>


	<t>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 i s set to 4 to indicate that the hop limit value reached 0.</t>	<t>The PT_TR_REPLY Code TLV value of the reply is set to indicate the spec ific condition that was met. If none of those conditions were met, the PT_TR_REP LY Code is set to 4 to indicate that the HopLimit reached 0.</t>


	<t>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 update d by each forwarder to encode its choice of next-hop(s). When included in subseq uent requests, this path steering TLV allows the forwarders to steer the request s along the same path.</t>	<t>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 al ong the same path.</t>
	</section>	</section>

	<section anchor="local" numbered="true" toc="default">	<section anchor="local" numbered="true" toc="default">

	<name>Protocol Operation For Locally-Scoped Namespaces</name>	<name>Protocol Operation for Locally Scoped Namespaces</name>
	<t>In this section, we elaborate on 2 alternative design approaches in cas	<t>In this section, we elaborate on two alternative design approaches in c
	es that the traceroute target prefix corresponds to a locally-scoped namespace n	ases where the traceroute target prefix corresponds to a locally scoped namespac
	ot directly routable from the client's local network.</t>	e not directly routable from the client's local network.</t>


	<t>The first approach leverages the NDN Link Object <xref target="SNAMP" f ormat="default"/>. Specifically, the traceroute client attaches to the expressed request a LINK Object that contains a number of routable name prefixes, based o n which the request can be forwarded across the Internet until it reaches a ne twork region, where the request name itself is routable. A LINK Object is create d and signed by a data producer allowed to publish data under a locally-scoped n amespace. The way that a client retrieves a LINK Object depends on various netwo rk design factors and is out of the scope of the current draft.</t>	<t>The first approach leverages the NDN Link Object <xref target="SNAMP" f ormat="default"/>. Specifically, the traceroute client attaches to the expressed request a Link Object that contains a number of routable name prefixes, based o n which the request can be forwarded across the Internet until it reaches a netw ork region where the request name itself is routable. A Link Object is created a nd signed by a data producer allowed to publish data under a locally scoped name space. The way that a client retrieves a Link Object depends on various network design factors and is out of scope for this document.</t>


	<t>Based on the current deployment of the LINK Object by the NDN team, a f	<t> At the time of this writing, and based on the current deployment of
	orwarder at the border of the region, where an Interest name becomes routable ha	the Link Object by the NDN team <xref target="NDNLPv2"/>, a forwarder at the bor
	s to remove the LINK Object from the incoming Interests. The Interest state main	der
	tained along the entire forwarding path is based on the Interest name reg	of the region where an Interest name becomes routable has to remove
	ardless of whether it was forwarded based on this name or a prefix in the LINK O	the Link Object from the incoming Interests.
	bject.</t>	The Interest state maintained along the entire forwarding path is based on the I
		nterest name regardless of whether it was forwarded based on this name or a pref
		ix in the Link Object.</t>


	<t>The second approach is based on prepending a routable prefix to the loc ally-scoped name. The resulting prefix will be the name of the traceroute reques ts expressed by the client. In this way, a request will be forwarded based on th e routable part of its name. When it reaches the network region where the origin al locally-scoped name is routable, the border forwarder rewrites the request na me and deletes its routable part. There are two conditions for a forwarder to pe rform this rewriting operation on a request:</t>	<t>The second approach is based on prepending a routable prefix to the loc ally scoped name. The resulting prefix will be the name of the traceroute reques ts expressed by the client. In this way, a request will be forwarded based on th e routable part of its name. When it reaches the network region where the origin al locally scoped name is routable, the border forwarder rewrites the request na me and deletes its routable part. A forwarder will perform this rewriting operat ion on a request if the following two conditions are met:</t>
	<ol type="%d)">	<ol type="%d)">
	<li>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 </li>	<li>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 </li>

	<li>the remaining part of the request name is routable across the n	<li>the remaining part of the request name is routable across the network
	etwork region of this forwarder.</li>	region of this forwarder.</li>
	</ol>	</ol>


	<t>The state maintained along the path, where the locally-scoped name is not	<t>The state along the path depends on whether the request is traversing the
	routable, is based on the routable prefix along with the locally-scoped prefix,	portion of the network where the locally scoped name is routable. In this case,
	while within the network region that the locally-scoped prefix is routable is b	the forwarding can be based entirely on the locally scoped name. However, where
	ased only on it. To ensure that the generated replies will	a portion of the path lies outside the region where the locally scoped name is
	reach the client, the border forwarder has also to rewrite the name of a	routable, the border router has to rewrite the name of a reply and prepend the r
	reply and prepend the routable prefix of the corresponding request.</t>	outable prefix of the corresponding request to ensure that the generated replies
		will reach the client.</t>
	</section>	</section>

	<section numbered="true" toc="default">	<section numbered="true" toc="default">
	<name>Security Considerations</name>	<name>Security Considerations</name>

	<t>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 nam e of a victim forwarder. This could redirect the future administrative traffic towards the victim. To foil such reflection attacks, the forwarder that generate s a traceroute reply MUST sign the name included in the payload. In this way, th e client is able to verify that the included name is legitimate and refers to th e forwarder that generated the reply. Alternatively, the forwarder could include in the reply payload their routable prefix(es) encoded as a signed NDN Link Obj ect <xref target="SNAMP" format="default"/>.</t>	<t>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 nam e of a victim forwarder. This could redirect the future administrative traffic towards the victim. To foil such reflection attacks, the forwarder that generate s a traceroute reply <bcp14>MUST</bcp14> sign the name included in the payload. In this way, the client is able to verify that the included name is legitimate a nd refers to the forwarder that generated the reply. Alternatively, the forwarde r could include in the reply payload their routable prefix(es) encoded as a sign ed NDN Link Object <xref target="SNAMP" format="default"/>.</t>


	<t>This approach does not protect against on-path attacks, where a comprom ised forwarder that receives a traceroute reply replaces the forwarder's name an d the signature in the message with its own name and signature to make the clien t believe that the reply was generated by the compromised forwarder. To foil suc h 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 m essage 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 r esponse 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.</t>	<t>This approach does not protect against on-path attacks where a compromi sed 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 the reply message, since th e message signature protects the message as a whole and will be invalidated in t he case of an on-path attack. Additionally, a forwarder could swap out the name of a traceroute request with a name of its choosing. In this case, however, the response with the spoofed name will not be received by a client, since the chang e of name would invalidate the state in the PIT on the path back to the client.< /t>


	<t>Signing each traceroute reply message can be expensive and can potentia	<t>Signing each traceroute reply message can be expensive and can potentia
	lly lead to computation attacks against forwarders. To mitigate such attack scen	lly lead to computation attacks against forwarders. To mitigate such attack scen
	arios, the processing of traceroute requests and the generation of the replies S	arios, the processing of traceroute requests and the generation of the replies <
	HOULD be handled by a separate management	bcp14>SHOULD</bcp14> be handled by a separate management
	application running locally on each forwarder. Serving traceroute replies	application running locally on each forwarder. The serving of traceroute r
	therefore is thereby separated from load on the forwarder itself. The approaches	eplies is thereby separated from load on the forwarder itself. The approaches us
	used by ICN applications to manage load may also apply to the	ed by ICN applications to manage load may also apply to the
	forwarder's management application.</t>	forwarder's management application.</t>


	<t>Interest flooding attack amplification is possible in the case of the s econd approach to deal with locally-scoped namespaces described in <xref target= "local" format="default"/>. A border forwarder will have to maintain extra state to prepend the correct routable prefix to the name of an outgoing reply, since the forwarder might be attached to multiple network regions (reachable under dif ferent prefixes) or a network region attached to this forwarder might be reachab le under multiple routable prefixes.</t>	<t>Interest flooding attack amplification is possible in the case of the s econd approach for dealing with locally scoped namespaces as described in <xref target="local" format="default"/>. A border forwarder will have to maintain extr a state to prepend the correct routable prefix to the name of an outgoing reply, since the forwarder might be attached to multiple network regions (reachable un der different prefixes) or a network region attached to this forwarder might be reachable under multiple routable prefixes.</t>

	<t>We also note that traceroute requests have the same privacy characteris tics as regular Interests.</t>	<t>We also note that traceroute requests have the same privacy characteris tics as regular Interests.</t>
	</section>	</section>


	<section anchor="IANA" numbered="true" toc="default">	<section anchor="IANA" numbered="true" toc="default">
	<name>IANA Considerations</name>	<name>IANA Considerations</name>
	<t>IANA will assign TBD1 to "TrRequest" and TBD2 to "TrRe	<t>IANA has assigned 0x07 to "PT_TR_REQUEST" and 0x08 to "PT_TR_REPLY" in
	play" in the CCNx Packet Types registry established by <xref target="RFC8609"/>.	the "CCNx Packet Types" registry established by <xref target="RFC8609"/>.</t>
	</t>	</section>

	<t>IANA will assign TBD3 to "Nonce" in the CCNx Name Segm
	ent Types registry established by <xref target="RFC8609"/>.</t>
	</section>
	</middle>	</middle>

	<back>	<back>

	<references><name>References</name>


	<references><name>Normative References</name>	<references><name>References</name>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/refer
	ence.RFC.2119.xml"/>	<references><name>Normative References</name>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/refer	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.
	ence.RFC.8174.xml"/>	xml"/>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.
	.RFC.8609.xml"/>	xml"/>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8609.
	.RFC.8793.xml"/>	xml"/>
	</references>	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8793.
		xml"/>

		</references>

	<references><name>Informative References</name>	<references><name>Informative References</name>

	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/refer	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9344.
	ence.RFC.9344.xml"/>	xml"/>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/refer	<xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4648.
	ence.RFC.4648.xml"/>	xml"/>
	<xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml3/
	reference.I-D.irtf-icnrg-pathsteering.xml"/>	<!-- draft-irtf-icnrg-icnping (RFC-to-be 9508) -->
		<reference anchor="RFC9508" target="https://www.rfc-editor.org/info/rfc9508">
		<front>
		<title>Information-Centric Networking (ICN) Ping Protocol Specification</t
		itle>
		<author initials="S." surname="Mastorakis" fullname="Spyridon Mastorakis">
		<organization>University of Notre Dame</organization>
		</author>
		<author initials="D." surname="Oran" fullname="Dave Oran">
		<organization>Network Systems Research and Design</organization>
		</author>
		<author initials="J." surname="Gibson" fullname="Jim Gibson">
		<organization>Unaffiliated</organization>
		</author>
		<author initials="I." surname="Moiseenko" fullname="Ilya Moiseenko">
		<organization>Apple Inc</organization>
		</author>
		<author initials="R." surname="Droms" fullname="Ralph Droms">
		<organization>Unaffiliated</organization>
		</author>
		<date month="March" year="2024" />
		</front>
		<seriesInfo name="RFC" value="9508" />
		<seriesInfo name="DOI" value="10.17487/RFC9508"/>
		</reference>

		<!-- draft-irtf-icnrg-pathsteering (RFC-to-be 9531)
		"Long way" to fix author initials -->
		<reference anchor="RFC9531" target="https://www.rfc-editor.org/info/rfc9531">
		<front>
		<title>Path Steering in Content-Centric Networking (CCNx) and Named Data Ne
		tworking (NDN)</title>
		<author fullname="Ilya Moiseenko" initials="I." surname="Moiseenko">
		<organization>Apple, Inc.</organization>
		</author>
		<author fullname="David R. Oran" initials="D." surname="Oran">
		<organization>Network Systems Research and Design</organization>
		</author>
		<date month="March" year="2024"/>
		</front>
		<seriesInfo name="RFC" value="9531"/>
		<seriesInfo name="DOI" value="10.17487/RFC9531"/>
		</reference>

	<reference anchor="NDNTLV" target="https://named-data.net/doc/NDN-packet -spec/current/">	<reference anchor="NDNTLV" target="https://named-data.net/doc/NDN-packet -spec/current/">
	<front>	<front>

	<title>NDN Packet Format Specification.</title>	<title>NDN Packet Format Specification</title>
	<author surname="NDN Project Team">	<author>
	<organization/>	<organization>NDN project team</organization>
	</author>	</author>

	<date year="2021"/>	<date month="February" year="2024"/>
	</front>	</front>
	</reference>	</reference>


	<reference anchor="NDNLPv2" target="https://redmine.named-data.ne t/projects/nfd/wiki/NDNLPv2">	<reference anchor="NDNLPv2" target="https://redmine.named-data.net/proje cts/nfd/wiki/NDNLPv2">
	<front>	<front>

	<title>Named Data Networking Link Adaptation Protocol v2</title>	<title>NDNLPv2: Named Data Networking Link Adaptation Protocol v2</
	<author surname="NDN team"/>	title>
	<date>various</date>	<author>
		<organization>NDN team</organization>
		</author>
		<date month="February" year="2023"></date>
	</front>	</front>
	</reference>	</reference>


	<reference anchor="SNAMP">	<reference anchor="SNAMP" target="https://ieeexplore.ieee.org/abstract/d ocument/7179398">
	<front>	<front>
	<title>SNAMP: Secure namespace mapping to scale NDN forwarding</titl e>	<title>SNAMP: Secure namespace mapping to scale NDN forwarding</titl e>

	<author initials="A" surname="Afanasyev">	<author initials="A" fullname="Alexander Afanasyev" surname="Afanasy ev">
	<organization/>	<organization/>
	</author>	</author>

	<author surname="et al">	<author initials="C" fullname="Cheng Yi" surname="Yi">
	<organization/>	<organization/>
	</author>	</author>

	<date year="2015"/>	<author initials="L" fullname="Lan Wang" surname="Wang">
		<organization/>
		</author>
		<author initials="B" fullname="Beichuan Zhang" surname="Zhang">
		<organization/>
		</author>
		<author initials="L" fullname="Lixia Zhang" surname="Zhang">
		<organization/>
		</author>
		<date month="April" year="2015"/>
	</front>	</front>

	<refcontent>IEEE Conference on Computer Communications Workshops (INFO	<refcontent>2015 IEEE Conference on Computer Communications Workshops
	COM WKSHPS)</refcontent>	(INFOCOM WKSHPS), Hong Kong, China, pp. 281-286</refcontent>
		<seriesInfo name="DOI" value="10.1109/INFCOMW.2015.7179398"/>
	</reference>	</reference>


	<reference anchor="PATHSTEERING">	<reference anchor="PATHSTEERING" target="https://dl.acm.org/doi/10.1145/ 3125719.3125721">
	<front>	<front>
	<title>Path switching in content centric and named data networks</ti tle>	<title>Path switching in content centric and named data networks</ti tle>
	<author initials="I" surname="Moiseenko">	<author initials="I" surname="Moiseenko">
	<organization/>	<organization/>
	</author>	</author>
	<author initials="D" surname="Oran">	<author initials="D" surname="Oran">
	<organization/>	<organization/>
	</author>	</author>

	<date year="2017"/>	<date month="September" year="2017"/>
	</front>	</front>

	<refcontent>in Proceedings of the 4th ACM Conference on Information-Ce	<refcontent>ICN '17: Proceedings of the 4th ACM Conference on Informat
	ntric Networking</refcontent>	ion-Centric Networking, pp. 66-76</refcontent>
		<seriesInfo name="DOI" value="10.1145/3125719.3125721"/>
	</reference>	</reference>


	<reference anchor="REALTIME">	<reference anchor="REALTIME" target="https://ieeexplore.ieee.org/documen t/8605992">
	<front>	<front>
	<title>Real-Time Data Retrieval in Named Data Networking</title>	<title>Real-Time Data Retrieval in Named Data Networking</title>
	<author initials="S" surname="Mastorakis">	<author initials="S" surname="Mastorakis">
	<organization/>	<organization/>
	</author>	</author>
	<author initials="P" surname="Gusev">	<author initials="P" surname="Gusev">
	<organization/>	<organization/>
	</author>	</author>
	<author initials="A" surname="Afanasyev">	<author initials="A" surname="Afanasyev">
	<organization/>	<organization/>
	</author>	</author>
	<author initials="L" surname="Zhang">	<author initials="L" surname="Zhang">
	<organization/>	<organization/>
	</author>	</author>

	<date year="2017"/>	<date month="August" year="2018"/>
	</front>	</front>

	<refcontent>in Proceedings of the 1st IEEE International Conference on	<refcontent>2018 1st IEEE International Conference on Hot Information-
	Hot Topics in Information-Centric Networking</refcontent>	Centric Networking (HotICN), Shenzhen, China, pp. 61-66</refcontent>
		<seriesInfo name="DOI" value="10.1109/HOTICN.2018.8605992"/>
	</reference>	</reference>

	</references>	</references>
	</references>	</references>

	<section anchor="app-additional">	<section anchor="app-additional">
	<name>Traceroute Client Application (Consumer) Operation</name>	<name>Traceroute Client Application (Consumer) Operation</name>
	<t>This section is an informative appendix regarding the proposed tracerou te client operation.</t>	<t>This section is an informative appendix regarding the proposed tracerou te client operation.</t>

	<t>The client application is responsible for generating traceroute request s for prefixes provided by users.</t>	<t>The client application is responsible for generating traceroute request s for prefixes provided by users.</t>


	<t>The overall process can be iterative: the first traceroute request of e ach session will have a HopLimit of value 1 to reach the first hop forwarder, th e second of value 2 to reach the second hop forwarder and so on and so forth.</t >	<t>The overall process can be iterative: the first traceroute request of e ach session will have a HopLimit of 1 to reach the first hop forwarder, the seco nd request will have a HopLimit of 2 to reach the second hop forwarder, and so o n.</t>

	<t>When generating a series of requests for a specific name, the first	<t>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	request will typically not include a Path Label TLV, since no TLV value
	is known. After a traceroute reply containing a Path label TLV is receive	is known. After a traceroute reply containing a Path Label TLV is receive
	d, each subsequent request might include the received path steering value in the	d, 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 ch	Path Label header TLV to drive the requests towards a common path as part of ch
	ecking the network performance. To discover more paths, a client can omit the Pa	ecking network performance. To discover more paths, a client can omit the Path L
	th label TLV in future requests. Moreover, for each new traceroute request, the	abel TLV in future requests. Moreover, for each new traceroute request, the clie
	client has to generate a new nonce and record the time that the request was expr	nt has to generate a new nonce and record the time that the request was expresse
	essed. It will also set the lifetime of a request, which will have semantics sim	d.
	ilar to the lifetime of an Interest.</t>	The client also sets the lifetime of the traceroute request, which carries the s
		ame semantics as the Interest Lifetime <xref target="RFC8609"/> in an Interest.<
		/t>

	<t>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 Objec t 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.</t>	<t>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 Objec t 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.</t>


	<t>When it receives a traceroute reply, the client would typically match t he reply to a sent request and compute the round-trip time of the request. It sh ould parse the Path label value and decode the reply's payload to parse the send er'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 na me 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 incre asing HopLimit values and potentially start a new traceroute session.</t>	<t>When it receives a traceroute reply, the client would typically match t he reply to a sent request and compute the round-trip time of the request. It sh ould parse the Path Label value and decode the reply's payload to parse the send er'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 na me 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 a PT_TR_REPLY Code TLV with a valid value, it can stop sending requests with in creasing HopLimit values and potentially start a new traceroute session.</t>


	<t>In the case that a traceroute reply is not received for a request withi n 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.</t>	<t>In the case that a traceroute reply is not received for a request withi n 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.</t>
	</section>	</section>
	</back>	</back>
	</rfc>	</rfc>

	<!-- Change Log
	v07 02-10-17 DRO Update references, fix NDN encoding
	v08
	-->

End of changes. 131 change blocks.
	294 lines changed or deleted	353 lines changed or added
This html diff was produced by rfcdiff 1.48.