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Extensible In-band Processing (EIP) Architecture and Framework
draft-eip-arch-06

Document Type Active Internet-Draft (individual)
Authors Stefano Salsano , Hesham ElBakoury , Diego Lopez
Last updated 2025-07-24
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draft-eip-arch-06
WG Working Group                                              S. Salsano
Internet-Draft                          Univ. of Rome Tor Vergata / CNIT
Intended status: Informational                              H. ElBakoury
Expires: 26 January 2026                                      Consultant
                                                                D. Lopez
                                                         Telefonica, I+D
                                                            25 July 2025

     Extensible In-band Processing (EIP) Architecture and Framework
                           draft-eip-arch-06

Abstract

   Extensible In-band Processing (EIP) extends the functionality of the
   IPv6 protocol considering the needs of future Internet services / 6G
   networks.  This document discusses the architecture and framework of
   EIP.  Two separate documents respectively analyze a number of use
   cases for EIP and provide the protocol specifications of EIP.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at https://eip-
   home.github.io/eip-arch/draft-eip-arch.html.  Status information for
   this document may be found at https://datatracker.ietf.org/doc/draft-
   eip-arch/.

   Discussion of this document takes place on the EIP SIG mailing list
   (mailto:eip@cnit.it), which is archived at http://postino.cnit.it/
   cgi-bin/mailman/private/eip/.

   Source for this draft and an issue tracker can be found at
   https://github.com/eip-home/eip-arch.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

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   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 January 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   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
   2.  Basic principles for EIP  . . . . . . . . . . . . . . . . . .   3
   3.  Benefits of a common EIP header for multiple use cases. . . .   5
     3.1.  Considerations on Hop-by-hop Options allocation . . . . .   5
   4.  Review of recent activities that propose to extend the IP
           networking layer  . . . . . . . . . . . . . . . . . . . .   6
     4.1.  Standardized and proposed evolutions of IPv6  . . . . . .   6
     4.2.  Additional relevant activities  . . . . . . . . . . . . .   8
   5.  Integration of EIP into the IOAM Framework  . . . . . . . . .   9
   6.  Conventions and Definitions . . . . . . . . . . . . . . . . .   9
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Networking architectures need to evolve to support the needs of
   future Internet services and 6G networks.  The networking research
   and standardization communities have considered different approaches
   for this evolution, that can be broadly classified in 3 different
   categories:

   1.  Clean slate and "revolutionary" solutions.  Throw away the legacy
       IP networking layer.

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   2.  Solutions above the layer 3.  Do not touch the legacy networking
       layer (IP).

   3.  Evolutionary solutions.  Improve the IP layer (and try to
       preserve backward compatibility).

   The proposed EIP (Extensible In-band Processing) solution belongs to
   the third category, it extends the current IPv6 architecture without
   requiring a clean-slate revolution.

   The use cases for EIP are discussed in [id-eip-use-cases].  The
   specification of the EIP header format is provided in
   [id-eip-headers].

2.  Basic principles for EIP

   An ongoing trend is extending the functionality of the IPv6
   networking layer, going beyond the plain packet forwarding.  An
   example of this trend is the rise of the SRv6 "network programming"
   model.  With the SRv6 network programming model, the routers can
   implement "complex" functionalities and they can be controlled by a
   "network program" that is embedded in IPv6 packet headers.  Another
   example is the INT (IN band Telemetry) solution for monitoring.
   These (and other) examples are further discussed in Section 4.

   The EIP solution is aligned with this trend, which will ensure a
   future proof evolution of networking architectures.  EIP supports a
   feature-rich and extensible IPv6 networking layer, in which complex
   dataplane functions can be executed by end-hosts, routers, virtual
   functions, servers in datacenters so that services can be implemented
   in the smartest and more efficient way.

   The EIP solution foresees the introduction of an EIP header in the
   IPv6 packet header.  The proposed EIP header is extensible and it is
   meant to support a number of different use cases.  In general, both
   end-hosts and transit routers can read and write the content of this
   header.  Depending of the specific use-case, only specific nodes will
   be capable and interested in reading or writing the EIP header.  The
   use of the EIP header can be confined to a single domain or to a set
   of cooperating domains, so there is no need of a global, Internet-
   wide support of the new header for its introduction.  Moreover, there
   can be usage scenarios in which legacy nodes can simply ignore the
   EIP header and provide transit to packets containing the EIP header.

   The EIP header could be carried in different ways inside the IPv6
   Header: 1) EIP Option for Hop-by-Hop Extension Header; 2) EIP TLV for
   Segment Routing Header; 3) EIP as a new IOAM-Data-Field-Type within
   the IOAM framework (discussed in Section 5).

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   An important usage scenario considers the transport of user packets
   over a provider network.  In this scenario, we consider the network
   portion from the provider ingress edge node to the provider egress
   edge node.  The ingress edge node can encapsulate the user packet
   coming from an access network into an outer packet.  The outer packet
   travels in the provider network until the egress edge node, which
   will decapsulate the inner packet and deliver it to the destination
   access network or to another transit network, depending on the
   specific topology and service.  Assuming that the IPv6/SRv6 dataplane
   is used in the provider network, the ingress edge node will be the
   source of an outer IPv6 packet in which it is possible to add the EIP
   header.  The outer IPv6 packet (containing the EIP header) will be
   processed inside the "limited domain" (see [RFC8799]) of the provider
   network, so that the operator can make sure that all the transit
   routers either are EIP aware or at least they can forward packets
   containing the EIP header.  In this usage scenario, the EIP framework
   operates "edge-to-edge" and the end-user packets are "tunneled" over
   the EIP domain.

   The architectural framework for EIP is depicted in Figure 1.  We
   refer to nodes that are not EIP capable as legacy nodes.  An EIP
   domain is made up by EIP aware routers (EIP R) and can also include
   legacy routers (LEG R).  At the border of the EIP domain, EIP edge
   nodes (EIP ER) are used to interact with legacy End Hosts / Servers
   (LEG H) and with other domains.  It is also possible that an End Host
   / Server is EIP aware (EIP H), in this case the EIP framework could
   operate "edge-to-end" or "end-to-end".

                                                          LEG domain
                                                        +------------+

    +---+             +---+      +---+                +---+
    |EIP|_           _|EIP|______|EIP|             ___|LEG|
    | H | \__+---+__/ | R |      | R |__   +---+__/   | R | ...
    +---+    |EIP|    +---+      +---+  \__|EIP|      +---+
           __|ER |__    |          |     __|ER |__
    +---+_/  +---+  \_+---+      +---+__/  +---+  \___+---+
    |LEG|             |LEG|______|LEG|                |EIP|
    | H |             | R |      | R |                |ER | ...
    +---+             +---+      +---+                +---+

               +-----------------------------+          +------------+
                         EIP domain                       EIP domain

                           Figure 1: EIP framwork

   As shown in Figure 1, an EIP domain can communicate with other
   domains, which can be legacy domains or EIP capable domains.

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3.  Benefits of a common EIP header for multiple use cases.

   The EIP header will carry different EIP Information Elements that are
   defined to support the different use cases.  There are reasons why it
   is beneficial to define a single common EIP header that supports
   multiple use cases using the EIP Information Elements.

   1.  The number of available Option Types in HBH header is limited
       (see Section 3.1).  Likewise the number of available TLVs in the
       Segment Routing Header (SRH) and the number of IOAM-Data-Field-
       Type are limited.  Defining multiple Option Types (or SRH TLVs or
       IOAM-Data-Field-Type) for multiple use case is not scalable and
       puts pressure on the allocation of such codepoints.

   2.  The definition and standardization of specific EIP Information
       Elements for the different use cases will be simplified, compared
       to the need of requiring the definition of a new Option Type or
       SRH TLVs or IOAM-Data-Field-Type.

   3.  Different use cases may share a subset of common EIP Information
       Elements.

   4.  Efficient mechanism for the processing of the EIP header (both in
       software and in hardware) can be defined when the different EIP
       Information Elements are carried inside the same EIP header.

3.1.  Considerations on Hop-by-hop Options allocation

   Several proposals and already standardized solutions use the IPv6
   Hop-by-Hop Options, as discussed below in Section 4.  The Hop-by-Hop
   Options are represented with a 8 bits code.  The first two bits
   represent the action to be taken if the Options is unknown to a node
   that receives it, the third bit is used to specify if the content of
   the Options can be changed in flight.  In particular the Option Types
   that start with 001 should be ignored if unknown and can be changed
   in flight, which is the most common combination.  The current IANA
   allocation for Option Types starting with 001 is (see
   https://www.iana.org/assignments/ipv6-parameters/
   ipv6-parameters.xhtml (https://www.iana.org/assignments/ipv6-
   parameters/ipv6-parameters.xhtml))

   32 possible Option Types starting with 001 5 allocated by RFCs
   (including IOAM and AltMark) 27 not allocated

   We observe that there is a potential scarcity of the code points, as
   there are many scenarios that could require the definition of a new
   Hop-by-Hop option.  We also observe that having only 1 code point
   allocated for experiments is a very restrictive limitation.

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4.  Review of recent activities that propose to extend the IP networking
    layer

4.1.  Standardized and proposed evolutions of IPv6

   In the last few years, we have witnessed important innovations in
   IPv6 networking, centered around the emergence of Segment Routing for
   IPv6 (SRv6) [RFC8754] and of the SRv6 "Network Programming model"
   [RFC8986].  With SRv6 it is possible to insert a _Network program_,
   i.e. a sequence of instructions (called _segments_), in a header of
   the IPv6 protocol, called Segment Routing Header (SRH).  Recent
   updates (see [RFC9800]) introduced compression mechanisms for segment
   lists, improving scalability for long segment chains.

   Another recent activity that proposed to extend the networking layer
   to support more complex functions concerns network monitoring.  The
   concept of INT "In-band Network Telemetry" has been proposed since
   2015 [onf-int] in the context of the definition of use cases for P4
   based data plane programmability.  The latest version of INT
   specifications dates November 2020 [int-spec]. [int-spec] specifies
   the format of headers that carry monitoring instructions and
   monitoring information along with data plane packets.  The specific
   location for INT Headers is intentionally not specified: an INT
   Header can be inserted as an option or payload of any encapsulation
   type.  The In-band Telemetry concept has been adopted by the IPPM
   IETF Working Group, renaming it "In-situ Operations, Administration,
   and Maintenance" (IOAM).  [RFC9197] discusses the data fields and
   associated data types for IOAM.  The in-situ OAM data fields can be
   encapsulated in a variety of protocols, including IPv6.  The
   specification details for carrying IOAM data inside IPv6 headers are
   provided in [RFC9486].  In particular, IOAM data fields can be
   encapsulated in IPv6 using either Hop-by-Hop Options header or
   Destination options header.  A Direct Export variant has been defined
   in [RFC9326], enabling nodes to export telemetry data directly
   without per-hop accumulation.

   Another example of extensions to IPv6 for network monitoring is
   specified in [RFC8250], which defines an IPv6 Destination Options
   header called Performance and Diagnostic Metrics (PDM).  The PDM
   option header provides sequence numbers and timing information as a
   basis for measurements.

   The "Alternate Marking Method" is a recently proposed performance
   measurement approach described in [RFC9341].  [RFC9343] defines a new
   Hop-by-Hop Option to support this approach.

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   "Path Tracing" [I-D.draft-filsfils-ippm-path-tracing] proposes an
   efficient solution for recording the route taken by a packet
   (including timestamps and load information taken at each hop along
   the route).  This solution needs a new Hop-by-Hop Option to be
   defined.  A new lightweight telemetry mechanism has been proposed in
   [I-D.draft-mzbc-ippm-transit-measurement-option], which accumulates
   end-to-end delay and congestion flags in a fixed-size structure.

   [RFC8558] analyses the evolution of transport protocols.  It
   recommends that explicit signals should be used when the endpoints
   desire that network elements along the path become aware of events
   related to transport protocol.  Among the solutions, [RFC8558]
   considers the use of explicit signals at the network layer, and in
   particular it mentions that IPv6 hop-by-hop headers might suit this
   purpose.

   [RFC9268] specifies a new IPv6 Hop-by-Hop option that is used to
   record the minimum Path MTU between a source and a destination.

   The Internet Draft [I-D.draft-ietf-6man-enhanced-vpn-vtn-id] proposes
   a new Hop-by-Hop option of IPv6 extension header to carry the Network
   Resource Partition (NRP) information, which could be used to identify
   the NRP-specific processing to be performed on the packets by each
   network node along a network path in the NRP.

   The Internet Draft [I-D.draft-ietf-6man-vpn-dest-opt] proposes an
   experiment in which VPN service information for both layer 2 and
   layer 3 VPNs is encoded in a new IPv6 Destination Option.  The new
   IPv6 Destination Option is called the VPN Service Option.

   The Internet-Draft [I-D.draft-guan-6man-ipv6-id-authentication]
   proposes an IPv6 based address label terminal identity authentication
   mechanism, which uses a new Hop-by-Hop option, called Address Label
   Extension (ALE).

   The Internet-Draft [I-D.draft-herbert-fast] (currently expired)
   proposed the Firewalls and Service Tickets (FAST) protocol.  This is
   a generic and extensible protocol for hosts to signal network nodes
   to request services or to gain admission into a network.  Tickets are
   sent in IPv6 Hop-by-Hop options.

   The Internet-Draft [I-D.draft-eckert-6man-qos-exthdr-discuss]
   (currently expired) provided considerations for common QoS IPv6
   extension header, in the context of the functionality under
   definition in the Deterministic Networking (detnet) IETF Working
   Group [detnet-wg].

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   The Internet-Draft [I-D.draft-li-6man-topology-id] (currently
   expired) proposed a new Hop-by-Hop option of IPv6 extension header to
   carry the topology identifier, which is used to identify the
   forwarding table instance created by the Multi Topology Routing or
   Flexible Algorithm.

   The Internet-Draft [I-D.draft-iurman-6man-carry-identifier]
   (currently expired) discussed the need of having a generic approach
   for carrying identifiers in IPv6 Destination Options and Hop-by-Hop
   Options.  The EIP proposal can be seen as a superset and a further
   generalization of the proposal of
   [I-D.draft-iurman-6man-carry-identifier].

4.2.  Additional relevant activities

   The IETF has shown interest in carrying application or service-level
   metadata in IPv6.  The Application-aware Networking (APN) BoF
   discussed embedding such metadata, leading to proposals like APN6.
   The recently chartered CATS (Compute-Aware Traffic Steering) WG
   explores approaches where traffic is steered based on in-packet
   compute-related information.  The GREEN WG (Getting Ready for Energy-
   Efficient Networking), formed in 2024, investigates telemetry for
   carbon-aware routing.  The COIN IRTF RG has discussed in-network
   processing requirements that also point to in-band metadata handling.

   The FANTEL BoF (IETF 123, Madrid, 2025) discussed the Fast
   Notification for Traffic Engineering and Load Balancing framework
   [ietf-fantel].  FANTEL proposes in-band mechanisms to signal network
   conditions such as congestion or link degradation using IPv6 packets.
   These notifications are inserted by routers to support real-time
   traffic steering decisions.  The goals of FANTEL align with the EIP
   approach, which provides an extensible container for in-band metadata
   through EIP Information Elements.  The EIP header could encapsulate
   FANTEL notifications without requiring additional Hop-by-Hop Option
   codepoints, supporting both domain-specific and broader deployments.

   Outside the IETF, the P4.org community continues its efforts on
   programmable dataplanes and has proposed updated INT mechanisms.
   Recent research includes the use of in-band headers for on-path
   inference and service-specific packet handling, showing increasing
   interest in general, extensible frameworks like EIP.

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5.  Integration of EIP into the IOAM Framework

   The IOAM (In-situ Operations, Administration, and Maintenance)
   framework [RFC9197] defines a set of data fields and associated
   semantics for recording telemetry and operational information within
   packets as they traverse a network.  The IOAM data can be
   encapsulated in IPv6 via Hop-by-Hop or Destination Options headers,
   as specified in [RFC9486], and can be processed by IOAM-capable nodes
   along the path.

   While the EIP architecture has primarily been conceived as a
   standalone extensible header format, an additional integration
   possibility is to define EIP as a new IOAM-Data-Field-Type within the
   IOAM framework.  In this scenario, EIP would become one of the
   possible information elements that can be included in IOAM data
   fields, extending the telemetry model to support richer and more
   general-purpose in-band processing capabilities.

   This approach offers the following advantages:

   1.  It enables the reuse of the existing IOAM encapsulation and
       processing pipeline.

   2.  It allows EIP-aware nodes to operate within IOAM-enabled networks
       without introducing separate Hop-by-Hop options.

   3.  It leverages the existing IOAM data export and analytics tooling
       to interpret EIP-related metadata.

   Integrating EIP as a new IOAM data type would require defining a
   specific EIP Data-Field-Type value in the IOAM registry
   [IANA-ioam-types] and specifying how EIP Information Elements are
   encoded and parsed within the IOAM format.  This integration path is
   not mutually exclusive with the standalone deployment of EIP as an
   independent IPv6 extension header but rather represents an additional
   deployment possibility for network operators already adopting the
   IOAM framework.

6.  Conventions and Definitions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "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.

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7.  Security Considerations

   TODO Security

8.  IANA Considerations

   The definition of the EIP header as an Option for the IPv6 Hop-by-Hop
   Extension header requires the allocation of a codepoint from the
   "Destination Options and Hop-by-Hop Options" registry in the
   "Internet Protocol Version 6 (IPv6) Parameters"
   [IANA-ipv6-parameters].

   The definition of the EIP header as a TLV in the Segment Routing
   Header requires the allocation of a codepoint from the "Segment
   Routing Header TLVs" registry in the "Internet Protocol Version 6
   (IPv6) Parameters" [IANA-ipv6-parameters].

   The definition of EIP Information Elements in the EIP header will
   require the creation of a new IANA registry to manage EIP Information
   Element type values.

   In the case that EIP is integrated into the IOAM framework as a new
   Data-Field-Type, an additional allocation will be required from the
   "IOAM Data Field Types" registry [IANA-ioam-types].

9.  References

9.1.  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/rfc/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/rfc/rfc8174>.

9.2.  Informative References

   [detnet-wg]
              IETF, "Deterministic Networking (DetNet) IETF Working
              Group", 2025,
              <https://datatracker.ietf.org/wg/detnet/about/>.

   [I-D.draft-eckert-6man-qos-exthdr-discuss]
              Eckert, T. T., Joung, J., Peng, S., and X. Geng,
              "Considerations for common QoS IPv6 extension header(s)",

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              Work in Progress, Internet-Draft, draft-eckert-6man-qos-
              exthdr-discuss-00, 4 March 2024,
              <https://datatracker.ietf.org/doc/html/draft-eckert-6man-
              qos-exthdr-discuss-00>.

   [I-D.draft-filsfils-ippm-path-tracing]
              Filsfils, C., Abdelsalam, A., Camarillo, P., Yufit, M.,
              Su, Y., Matsushima, S., Valentine, M., and Dhamija, "Path
              Tracing in SRv6 networks", Work in Progress, Internet-
              Draft, draft-filsfils-ippm-path-tracing-04, 4 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-filsfils-
              ippm-path-tracing-04>.

   [I-D.draft-guan-6man-ipv6-id-authentication]
              Guan, J., Yao, S., Liu, K., Hu, X., and J. Liu, "Terminal
              Identity Authentication Based on Address Label", Work in
              Progress, Internet-Draft, draft-guan-6man-ipv6-id-
              authentication-03, 20 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-guan-6man-
              ipv6-id-authentication-03>.

   [I-D.draft-herbert-fast]
              Herbert, T., "Firewall and Service Tickets", Work in
              Progress, Internet-Draft, draft-herbert-fast-07, 7 October
              2023, <https://datatracker.ietf.org/doc/html/draft-
              herbert-fast-07>.

   [I-D.draft-ietf-6man-enhanced-vpn-vtn-id]
              Dong, J., Li, Z., Xie, C., Ma, C., and G. S. Mishra,
              "Carrying Network Resource (NR) related Information in
              IPv6 Extension Header", Work in Progress, Internet-Draft,
              draft-ietf-6man-enhanced-vpn-vtn-id-12, 7 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-6man-
              enhanced-vpn-vtn-id-12>.

   [I-D.draft-ietf-6man-vpn-dest-opt]
              Bonica, R., Li, X., Farrel, A., Kamite, Y., and L. Jalil,
              "The IPv6 VPN Service Destination Option", Work in
              Progress, Internet-Draft, draft-ietf-6man-vpn-dest-opt-11,
              14 May 2025, <https://datatracker.ietf.org/doc/html/draft-
              ietf-6man-vpn-dest-opt-11>.

   [I-D.draft-iurman-6man-carry-identifier]
              Iurman, J., "Carrying an Identifier in IPv6 packets", Work
              in Progress, Internet-Draft, draft-iurman-6man-carry-
              identifier-00, 8 February 2023,
              <https://datatracker.ietf.org/doc/html/draft-iurman-6man-
              carry-identifier-00>.

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   [I-D.draft-li-6man-topology-id]
              Li, Z., Hu, Z., and J. Dong, "Topology Identifier in IPv6
              Extension Header", Work in Progress, Internet-Draft,
              draft-li-6man-topology-id-00, 20 March 2022,
              <https://datatracker.ietf.org/doc/html/draft-li-6man-
              topology-id-00>.

   [I-D.draft-mzbc-ippm-transit-measurement-option]
              Mizrahi, T., Zhou, T., Belkar, S., and R. Cohen, "The
              Transit Measurement Option", Work in Progress, Internet-
              Draft, draft-mzbc-ippm-transit-measurement-option-06, 2
              July 2025, <https://datatracker.ietf.org/doc/html/draft-
              mzbc-ippm-transit-measurement-option-06>.

   [IANA-ioam-types]
              IANA, "IOAM Data Field Types", n.d.,
              <https://www.iana.org/assignments/ioam/ioam.xhtml#data-
              field-types>.

   [IANA-ipv6-parameters]
              IANA, "Internet Protocol Version 6 (IPv6) Parameters",
              n.d., <https://www.iana.org/assignments/ipv6-parameters/
              ipv6-parameters.xhtml>.

   [id-eip-headers]
              Salsano, S. and H. ElBakoury, "Extensible In-band
              Processing (EIP) Headers Definitions", 2022, <https://eip-
              home.github.io/eip-headers/draft-eip-headers-
              definitions.txt>.

   [id-eip-use-cases]
              Salsano, S. and H. ElBakoury, "Extensible In-band
              Processing (EIP) Use Cases", 2022, <https://eip-
              home.github.io/use-cases/draft-eip-use-cases.txt>.

   [ietf-fantel]
              IETF, "Fast Notification for Traffic Engineering and Load
              Balancing (FANTEL) BoF", 2025,
              <https://datatracker.ietf.org/meeting/123/materials/
              bofdraft-fantel-00>.

   [int-spec] Group, T. P. A. W., "In-band Network Telemetry (INT)
              Dataplane Specification, version 2.1", 2022,
              <https://p4.org/p4-spec/docs/INT v2 1.pdf>.

Salsano, et al.          Expires 26 January 2026               [Page 12]
Internet-Draft              EIP Architecture                   July 2025

   [onf-int]  P4.org, "Improving Network Monitoring and Management with
              Programmable Data Planes", 2015,
              <https://opennetworking.org/news-and-events/blog/
              improving-network-monitoring-and-management-with-
              programmable-data-planes/>.

   [RFC8250]  Elkins, N., Hamilton, R., and M. Ackermann, "IPv6
              Performance and Diagnostic Metrics (PDM) Destination
              Option", RFC 8250, DOI 10.17487/RFC8250, September 2017,
              <https://www.rfc-editor.org/rfc/rfc8250>.

   [RFC8558]  Hardie, T., Ed., "Transport Protocol Path Signals",
              RFC 8558, DOI 10.17487/RFC8558, April 2019,
              <https://www.rfc-editor.org/rfc/rfc8558>.

   [RFC8754]  Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
              Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
              (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
              <https://www.rfc-editor.org/rfc/rfc8754>.

   [RFC8799]  Carpenter, B. and B. Liu, "Limited Domains and Internet
              Protocols", RFC 8799, DOI 10.17487/RFC8799, July 2020,
              <https://www.rfc-editor.org/rfc/rfc8799>.

   [RFC8986]  Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
              D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
              (SRv6) Network Programming", RFC 8986,
              DOI 10.17487/RFC8986, February 2021,
              <https://www.rfc-editor.org/rfc/rfc8986>.

   [RFC9197]  Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
              Ed., "Data Fields for In Situ Operations, Administration,
              and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
              May 2022, <https://www.rfc-editor.org/rfc/rfc9197>.

   [RFC9268]  Hinden, R. and G. Fairhurst, "IPv6 Minimum Path MTU Hop-
              by-Hop Option", RFC 9268, DOI 10.17487/RFC9268, August
              2022, <https://www.rfc-editor.org/rfc/rfc9268>.

   [RFC9326]  Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
              Mizrahi, "In Situ Operations, Administration, and
              Maintenance (IOAM) Direct Exporting", RFC 9326,
              DOI 10.17487/RFC9326, November 2022,
              <https://www.rfc-editor.org/rfc/rfc9326>.

Salsano, et al.          Expires 26 January 2026               [Page 13]
Internet-Draft              EIP Architecture                   July 2025

   [RFC9341]  Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T.,
              and T. Zhou, "Alternate-Marking Method", RFC 9341,
              DOI 10.17487/RFC9341, December 2022,
              <https://www.rfc-editor.org/rfc/rfc9341>.

   [RFC9343]  Fioccola, G., Zhou, T., Cociglio, M., Qin, F., and R.
              Pang, "IPv6 Application of the Alternate-Marking Method",
              RFC 9343, DOI 10.17487/RFC9343, December 2022,
              <https://www.rfc-editor.org/rfc/rfc9343>.

   [RFC9486]  Bhandari, S., Ed. and F. Brockners, Ed., "IPv6 Options for
              In Situ Operations, Administration, and Maintenance
              (IOAM)", RFC 9486, DOI 10.17487/RFC9486, September 2023,
              <https://www.rfc-editor.org/rfc/rfc9486>.

   [RFC9800]  Cheng, W., Ed., Filsfils, C., Li, Z., Decraene, B., and F.
              Clad, Ed., "Compressed SRv6 Segment List Encoding",
              RFC 9800, DOI 10.17487/RFC9800, June 2025,
              <https://www.rfc-editor.org/rfc/rfc9800>.

Acknowledgments

   TODO acknowledge.

Authors' Addresses

   Stefano Salsano
   Univ. of Rome Tor Vergata / CNIT
   Email: stefano.salsano@uniroma2.it

   Hesham ElBakoury
   Consultant
   Email: helbakoury@gmail.com

   Diego R. Lopez
   Telefonica, I+D
   Email: diego.r.lopez@telefonica.com

Salsano, et al.          Expires 26 January 2026               [Page 14]