



anima                                                        M. Han, Ed.
Internet-Draft                                              J. Zhao, Ed.
Intended status: Standards Track                                 Z. Ruan
Expires: 25 October 2026                                        S. Zhang
                                                            China Unicom
                                                           23 April 2026


   Automatic Network Congestion Relief in GeneRic Autonomic Signaling
                            Protocol (GRASP)
               draft-han-anima-grasp-congestion-relief-01

Abstract

   This draft defines new autonomic technical objectives for automatic
   congestion relief using the Grasp protocol acording to the [RFC
   9222].  In operator networks, network devices can automatically
   respond and achieve real-time self-healing for network failures such
   as fiber optic cable faults and optical module malfunctions

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
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   This Internet-Draft will expire on 25 October 2026.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.










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   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
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   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Definitions . . . . . . . . . . . . . . . . .   3
   3.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Intended User and Administrator Experience  . . . . . . .   4
   4.  Approach of Automatic Network Congestion Relief . . . . . . .   4
   5.  Automatic Network Congestion Relief Objectives  . . . . . . .   5
     5.1.  LinkStatus Objective  . . . . . . . . . . . . . . . . . .   5
     5.2.  LinkPriorityAdjust Objective  . . . . . . . . . . . . . .   5
   6.  Example of an Application Scenario  . . . . . . . . . . . . .   5
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

1.1.  Overview

   GeneRic Autonomic Signaling Protocol (GRASP) [RFC8990] is intended to
   be used for Service Announcement, Discovery and Selection especially
   in network or for network services intended to be deployable without
   dependencies against centralized "server" entities, such as fully
   autonomous networks or Autonomous Service Agents (ASA).

   To support these goals, GRASP provides a hop-by-hop network wide
   flooding of announcement or discover messages reliably and secured
   and without looping messages.  This flooding is achieved with a per-
   hop GRASP agent responsible for per-hop flooding of GRASP messages.









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   Automatic Network Congestion Relief is introduced by
   [I-D.zhao-anima-automatic-congestion-relief].  The ntwork congestion
   caused by fiber or optoelectronics devices failures becoming a common
   issue for operators, which caused by the disaster and construction
   work.  It requires dedicated staff to perform daily traffic
   inspections and manually adjust configurations on an hourly basis,
   which significantly increases the difficulty of network maintenance.

   This draft introduces an automatic congestion relief mechanism based
   on traffic analysis and auto-regulation.  In the event of failures
   congestion, it can respond to congestion and initiate real-time self-
   healing processes, solving the network congestion and maintenance
   challenges faced by operators fiber or optoelectronics devices
   failures, and ensuring the stable operation of the network.

   The mechanism in this document enables the Automatic Network
   Congestion Relief through GRASP.

2.  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.

3.  Problem Statement

   When a failure occurs in a carrier network, such as a power outage of
   core equipment caused by a fire, it may affect tens of millions of
   mobile users' voice and short message services, as well as multiple
   dedicated lines for government or enterprise customers.  Traditional
   troubleshooting and reconfiguration performed manually consume a
   significant amount of time.

   Meanwhile, centralized control solutions like Software-Defined
   Networking (SDN), while offering a global view, face bottlenecks in
   scalability and real-time performance due to their core reliance on a
   central controller and periodic link-state polling mechanisms.  This
   makes them ill-suited to handle sudden failures and severe
   fluctuations that may occur in large-scale carrier networks.
   Particularly when physical-layer failures such as fiber cuts trigger
   abrupt congestion, existing mechanisms often fail to achieve rapid
   and accurate congestion detection and traffic scheduling.

   This problem statement focuses on the operational challenge within
   carrier network edge environments (specifically at the convergence
   points of metropolitan area networks and backbone networks) under



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   such scenarios.  That is, while maintaining basic routing
   reachability, how to effectively detect sudden congestion caused by
   underlying failures and achieve fast, adaptive traffic redirection.
   We propose to explore a solution based on a distributed negotiation
   mechanism (such as the GRASP protocol).  By establishing real-time
   information exchange and collaborative decision-making capabilities
   among routers, this approach aims to overcome the respective
   shortcomings of traditional end-to-end control and centralized SDN
   architectures.  The ultimate goal is to enable autonomous discovery,
   determination, and mitigation of network congestion, thereby
   enhancing the overall resilience and service performance of the
   network.

3.1.  Intended User and Administrator Experience

   For network administrators, the anticipated experience is as follows:
   In large-scale carrier networks, administrators will no longer need
   to frequently conduct traffic inspections and manually adjust
   configurations on an hourly basis.  Ideally, the proposed automatic
   congestion mitigation mechanism will autonomously address sudden
   network congestion events.  Administrators would only need to
   periodically review logs to track potential network failures and
   carry out corresponding troubleshooting, without having to manually
   configure traffic adjustments.

4.  Approach of Automatic Network Congestion Relief

   This section introduces the building blocks for an autonomic network
   congestion relief solution.  It uses the generic discovery and
   negotiation protocol defined by [RFC8990].  The relevant GRASP
   objectives are defined in Section 5.

   The procedures described below are carried out by an ASA in each
   device that participates in the solution.  We will refer to this as
   the Traffic ASA.

   An edge device monitors link conditions (such as link bandwidth,
   bandwidth utilization, and link priority) to detect congestion or
   link degradation.  When the traffic on a link exceeds a predefined
   bandwidth threshold, the edge device lowers the priority of the
   excess traffic and notifies the backbone router.  The backbone router
   then updates the Link Priority Table and selects alternative paths
   based on the priorities, bypassing the current link.








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5.  Automatic Network Congestion Relief Objectives

   This section defines the GRASP Objective used to support autonomic
   network congestion relief.  In accordance with RFC 8990, an Objective
   is a named data structure used for negotiation or synchronization,
   while its encoding within GRASP messages is referred to as an
   Objective option.  This document defines the Objective semantics and
   data content, while the encoding follows the standard GRASP
   specification.

5.1.  LinkStatus Objective

   The LinkStatus Objective option is a GRASP Objective option
   conforming to the GRASP specification [RFC8990] which is designed for
   synchronization.  It carries the link state information as its value:
   the bandwidth and the utilization rate of bandwidth.  This Objective
   is used for sharing locally observed link quality data between edge
   devices.

5.2.  LinkPriorityAdjust Objective

   The LinkPriorityAdjust Objective carries a routing adjustment policy
   that indicates which traffic flows should have their priority
   adjusted under current network conditions.  This Objective enables an
   edge device to proactively send an adjustment request to a backbone
   router to modify the routing preference of its upstream traffic.

6.  Example of an Application Scenario

   Measurement and Advertisement: Gateway1 and Gateway2 measure in real
   time the link utilized bandwidth and traffic to Router1 and Router2.

   Edge State Synchronization: Gateway1 requests Gateway2's LinkStatus
   via M_REQ_SYN, or proactively publishes its own LinkStatus.

   Congestion Detection and Intelligent Decision: Based on aggregated
   link states (bandwidth, utilization) and algorithms on ASA, Gateway1
   determines that the link to Router1 is congested and and decides to
   lower the priority of traffic that exceeds the threshold.

   Policy Delivery to the Backbone: Gateway1 constructs a
   LinkPriorityAdjust Objective and sends it directly to the backbone
   Router1 via M_REQ_SYN or M_SYNCH.

   Backbone Application and Flooding: After receiving and applying the
   new priority table, Router1 notifies upstream routers to adjust paths
   via route flooding, so that more traffic is eventually directed to
   Router2.



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      --------------------------------------------------------------
      | --------------------                 --------------------  |
      | | Backbone Router2 |    Network2     | Backbone Router1 |  |
      | --------------------                 --------------------  |
      -----------|-------------------------------------|------------
                 |                                     |
                 |                                     x
                 | 100GB x 9                           x 100GB x 3(9)
                 |                                     |
      -----------|-------------------------------------|-----------
      | --------------------                 -------------------- |
      | |  Edge Gateway2   |    Network1     |  Edge Gateway1   | |
      | --------------------                 -------------------- |
      |                                                           |
      -------------------------------------------------------------

                         Figure 1: Application Case

7.  Security Considerations

   TBD.

8.  IANA Considerations

   TBD.

9.  References

9.1.  Normative References

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, DOI 10.17487/RFC5305, October
              2008, <https://www.rfc-editor.org/info/rfc5305>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC9222]  Carpenter, B., Ciavaglia, L., Jiang, S., and P. Peloso,
              "Guidelines for Autonomic Service Agents", RFC 9222,
              DOI 10.17487/RFC9222, March 2022,
              <https://www.rfc-editor.org/info/rfc9222>.




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9.2.  Informative References

   [RFC8990]  Bormann, C., Carpenter, B., Ed., and B. Liu, Ed., "GeneRic
              Autonomic Signaling Protocol (GRASP)", RFC 8990,
              DOI 10.17487/RFC8990, May 2021,
              <https://www.rfc-editor.org/info/rfc8990>.

   [I-D.zhao-anima-automatic-congestion-relief]
              Zhao, J. and S. Zhang, "Automatic Network Congestion
              Relief", Work in Progress, Internet-Draft, draft-zhao-
              anima-automatic-congestion-relief-00, 3 March 2025,
              <https://datatracker.ietf.org/doc/html/draft-zhao-anima-
              automatic-congestion-relief-00>.

Authors' Addresses

   Mengyao Han (editor)
   China Unicom
   Beijing
   China
   Email: hanmy12@chinaunicom.cn


   Jing Zhao (editor)
   China Unicom
   Beijing
   China
   Email: zhaoj501@chinaunicom.cn


   Zheng Ruan
   China Unicom
   Beijing
   China
   Email: ruanz6@chinaunicom.cn


   Shuai Zhang
   China Unicom
   Beijing
   China
   Email: zhangs633@chinaunicom.cn









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