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Computing Service Metric Definitions and Operation under CATS
draft-zhangb-cats-service-metrics-op-03

Document Type Active Internet-Draft (individual)
Authors Bin Zhang , Yina Dai , Zongpeng Du , Guanming Zeng , Chuanyang Miao
Last updated 2026-06-30
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draft-zhangb-cats-service-metrics-op-03
Computing-Aware Traffic Steering                           B. Zhang, Ed.
Internet-Draft                                      Pengcheng Laboratory
Intended status: Standards Track                             Y. Dai, Ed.
Expires: 2 January 2027                           Sun Yat-sen University
                                                              Z. Du, Ed.
                                                            China Mobile
                                                                 G. Zeng
                                                     Huawei Technologies
                                                            C. Miao, Ed.
                                                         ZTE Corporation
                                                             1 July 2026

     Computing Service Metric Definitions and Operation under CATS
                draft-zhangb-cats-service-metrics-op-03

Abstract

   Computing-Aware Traffic Steering (CATS) optimizes traffic forwarding
   by considering both computing and networking metrics.  While the
   existing framework and metric drafts provide theoretical models
   (e.g., L1/L2 normalized metrics), they face significant challenges to
   achieve direct operational execution in real-world deployments.
   Normalization methods vary across providers, and aggregated unitless
   scores often lose critical operational information, making it
   difficult for routers to make precise decisions.

   This document is proposed to fill this gap by providing an executable
   approach.  It defines a set of Computing Service Metrics and their
   operations under the CATS framework.  Instead of transmitting low-
   level raw hardware metrics, service sites dynamically evaluate and
   report service-oriented metrics (e.g., Global Available Slots) to the
   control plane.  The document also clarifies how such service-oriented
   metrics can be derived from basic resource information, service
   reference information, and local policy, and how updates can be
   controlled in large-scale deployments.  This enables efficient and
   precise traffic-steering policies without negating the value of
   existing normalized metrics.

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 2 January 2027.

Copyright Notice

   Copyright (c) 2026 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
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Motivation and Problem Statement  . . . . . . . . . . . . . .   4
   4.  Service Information and Metrics Definition  . . . . . . . . .   5
     4.1.  Derivation from Basic and Reference Information . . . . .   5
     4.2.  Mandatory Computing Service Information . . . . . . . . .   5
       4.2.1.  Global Available Slots (GAS)  . . . . . . . . . . . .   5
       4.2.2.  Computing Time  . . . . . . . . . . . . . . . . . . .   6
     4.3.  Optional Extension Metrics  . . . . . . . . . . . . . . .   7
       4.3.1.  Cost  . . . . . . . . . . . . . . . . . . . . . . . .   7
       4.3.2.  Reputation  . . . . . . . . . . . . . . . . . . . . .   7
       4.3.3.  Security Label  . . . . . . . . . . . . . . . . . . .   7
       4.3.4.  Capability (L1/L2 Compatibility)  . . . . . . . . . .   8
   5.  Operation under CATS Framework  . . . . . . . . . . . . . . .   8
     5.1.  Dynamic Metric Reporting  . . . . . . . . . . . . . . . .   8
     5.2.  Information Collection and Routing Policies . . . . . . .   9
   6.  Use Case Example  . . . . . . . . . . . . . . . . . . . . . .  10
     6.1.  Service Distribution and Table Formation  . . . . . . . .  10
     6.2.  Service Consumption and Resource Allocation . . . . . . .  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     9.1.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

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1.  Introduction

   The Computing-Aware Traffic Steering (CATS)
   [I-D.ietf-cats-framework-24] architecture aims to steer service
   traffic to the most suitable service contact instance by evaluating
   both network state and computing resource availability.  To achieve
   this, CATS Service Metric Agents (C-SMAs) collect computing metrics
   and advertise them to CATS Path Selectors (C-PSes).

   [I-D.ietf-cats-metric-definition-10] introduces a multi-level metric
   framework (Level 0, Level 1, Level 2) and proposes normalizing
   heterogeneous computing metrics into unitless scores (e.g.,
   compute_norm).  While this establishes a solid theoretical baseline,
   mapping diverse hardware capabilities (CPUs, GPUs, NPUs) into a
   single normalized score is highly complex and provider-dependent.  In
   practice, additional service-oriented abstractions are useful for
   expressing the actual service capacity needed for fine-grained
   traffic steering.

   To fill the gap between theoretical metric definitions and practical
   implementation, this document introduces a set of Computing Service
   Metrics.  By decoupling the service capacity from hardware-specific
   raw metrics, service sites can directly expose actionable metrics
   that describe their concrete ability to handle specific services.
   These metrics complement the existing normalized metric framework and
   focus on operational use under the CATS architecture.

2.  Terminology

   This document makes use of the terms defined in
   [I-D.ietf-cats-framework-24] and
   [I-D.ietf-cats-metric-definition-10].  In particular, CS-ID and CSCI-
   ID are used as CATS identifiers.  They provide stable service and
   service-contact-instance references for lookup and forwarding, but
   are not treated as computing metrics in this document.  Additionally,
   the following terms are used:

   *  Global Available Slots (GAS): The maximum number of concurrent
      clients a service site is willing and able to serve for a specific
      CS-ID at a given time.

   *  CS-ID (CATS Service ID): An identifier for a service.  It is used
      as a stable lookup key in the C-PS Computing Service Table.

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   *  CSCI-ID (CATS Service Contact Instance ID): An identifier for
      contact information of a service instance that provides a specific
      CS-ID at a service site.  In this document, it is interpreted
      operationally as a locator, such as an IP address and port number,
      used to establish the data tunnel.

3.  Motivation and Problem Statement

   The CATS working group has made significant progress in defining how
   computing metrics should be collected and distributed.  In
   particular, existing works introduce a comprehensive framework that
   categorizes computing metrics into Raw Metrics (Level 0) and
   Normalized Metrics (Level 1 and Level 2).  However, a critical gap
   remains: how exactly to use these hardware-centric metrics to
   effectively steer traffic in operational networks.

   This document does not negate the value of L1/L2 normalized metrics;
   rather, it identifies that relying solely on the normalization of raw
   hardware metrics poses operational challenges during routing
   execution:

   1.  The Implementation Gap (HOW to normalize?): In a real-world
       multi-vendor network, computing resources are highly
       heterogeneous.  It is extremely difficult to establish a unified
       mathematical model that fairly normalizes a GPU's capacity and a
       CPU's capacity into the same 0-10 score.

   2.  The Information Loss Gap (WHY disseminate raw features?):
       Normalizing diverse hardware capabilities into a single unitless
       score results in the loss of actionable information.  A
       normalized compute score of "7" cannot explicitly guarantee a
       client's <10 ms delay requirement.

   3.  The Routing Mechanism Gap (WHO uses this data?): Routers (C-PS)
       do not need to know whether a service is backed by a CPU or a
       GPU.  They only care about routing parameters: "Is there
       capacity?", "How long will it take?", and "Where is the
       destination?".

   To bridge this gap, CATS requires a Service-Oriented Abstraction.  We
   explicitly divide the required service information into Mandatory
   Computing Service Metrics and Optional Extension Metrics to support
   executable traffic-steering policies.

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4.  Service Information and Metrics Definition

   This section defines the service information used by CATS control-
   plane components.  Some fields are identifiers or locators, while
   others are service-oriented metrics.  This document focuses on the
   semantics and operational use of these metrics, rather than defining
   new routing, transport, signaling, or wire-encoding mechanisms.

4.1.  Derivation from Basic and Reference Information

   The Computing Service Metrics defined in this document are not raw
   hardware readings.  They are service-oriented abstractions produced
   by each service site based on local monitoring and deployment policy.
   This allows heterogeneous hardware details and frequent local
   resource changes to be hidden from the CATS control plane while still
   exposing actionable information for traffic steering.

   These metrics can be derived from basic resource metrics, status
   metrics, service requirements, and local policy at the service site.
   The public service platform described in [I-D.zhangb-cats-cmas-04]
   can provide reference information, such as Computing Requirement,
   Storage Requirement, Reference Computing Time, software dependency,
   and Reference GAS, that a service site can use when deploying a
   service.

   For example, if the resources allocated to a service instance just
   meet the listed Computing Requirement and Storage Requirement, the
   service site can use the Reference GAS as a starting value.  If more
   resources are allocated, the reported GAS is evaluated by the service
   site and is generally expected to be larger than the Reference GAS.
   Similarly, Computing Time can be measured or estimated based on the
   runtime behavior of the deployed service instance.  The specific
   derivation algorithm is a local matter and is not standardized by
   this document.

4.2.  Mandatory Computing Service Information

   These fields are essential for the C-PS to make fundamental traffic
   steering decisions.  CS-ID and CSCI-ID are identifiers, while GAS and
   Computing Time are service-oriented metrics.

4.2.1.  Global Available Slots (GAS)

   GAS is the core contribution of this metric framework.  It represents
   the maximum number of concurrent clients that a service site is
   willing and able to serve for a specific CS-ID through a specific
   CSCI-ID at a given time.

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   Crucially, GAS acts as a direct abstraction layer over the complex
   and fluctuating raw computing metrics (CPU, GPU, Memory, Storage) and
   status metrics (load and health).  Instead of exposing highly dynamic
   raw metrics to the network, the service site absorbs these variations
   internally.  The site can initially provide a GAS value based on its
   fixed resource allocation and service reference information, and then
   adjust it according to local policy.

   As the number of concurrent users increases, the GAS value naturally
   decreases.  Furthermore, the site monitoring system dynamically
   reduces the GAS value upon detecting abnormal status metrics, such
   as:

   *  Load changes: Sudden increase in internal resources occupied by
      local users or tasks.

   *  Health changes: Sudden performance drop, possibly due to a cyber
      attack.

   *  Reachability: The site crashes or becomes unresponsive.

   Note: The C-SMA proactively reports significant adjustments to the
   control plane according to local policy, thresholds, or aggregation
   intervals.  Small per-session changes do not necessarily need to be
   reported immediately.  When GAS drops to 0, it means the instance
   cannot allocate any more resources, and no new requests will be
   steered to it.

   Basic fields:
     Metric Type: gas
     Level: L0/TBD
     Value: 500
     Source: estimation

   Encoding details, including field length and wire format, are TBD.

4.2.2.  Computing Time

   The time required for the site to perform one service request.  The
   service site can initialize this metric based on service reference
   information and then measure or estimate it according to the runtime
   behavior of the deployed service instance.  The service site
   dynamically adjusts this metric based on real-time load and local
   policy.

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   Basic fields:
     Metric Type: comp_time
     Level: L0/TBD
     Unit: ms
     Value: 5
     Source: estimation

   Encoding details, including field length and wire format, are TBD.

4.3.  Optional Extension Metrics

   To accommodate advanced traffic-steering scenarios and maintain
   backward compatibility, the following optional fields are defined.

4.3.1.  Cost

   Self-defined by the service site to apply administrative or economic
   billing policies.

   Basic fields:
     Metric Type: cost
     Level: L0/TBD
     Value: 100
     Source: nominal

   Encoding details, including field length and wire format, are TBD.

4.3.2.  Reputation

   A dynamic quality score based on user feedback.  Upon completion, if
   a user experiences long delays or inaccurate results, feedback is
   returned to the C-PS *along with the resource release message*.

   Basic fields:
     Metric Type: reputation
     Level: L0/TBD
     Value: 8
     Source: estimation (user feedback)

   Encoding details, including field length and wire format, are TBD.

4.3.3.  Security Label

   The Security Label reflects the security status of a service site.  A
   higher score indicates a more secure site.

   Score range: 0-10 (0 indicates the poorest security; 10 indicates
   optimal security).

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   Basic fields:
     Metric Type: security_label
     Level: L0/TBD
     Value: 9
     Source: estimation

   Encoding details, including field length and wire format, are TBD.

4.3.4.  Capability (L1/L2 Compatibility)

   To maintain compatibility with L1/L2 normalized metrics, this
   optional field represents the overall computing and storage
   capability allocated by the site.  It can correspond to a Level 1 or
   Level 2 overall capability score when such a normalized value is
   available.

   Basic fields:
     Metric Type: site_cap
     Level: L1/L2/TBD
     Value: 7
     Source: normalization

   Encoding details, including field length and wire format, are TBD.

5.  Operation under CATS Framework

5.1.  Dynamic Metric Reporting

   Service sites proactively monitor their internal instances.  In
   large-scale deployments, service sites can use a delta-threshold
   reporting model.  Each service site or C-SMA maintains a local metric
   cache.  Per-session allocation and release events update local GAS
   values, but do not necessarily trigger immediate reports to the C-PS.

   Updates are reported when they become operationally significant.
   Examples include GAS crossing a configured threshold, Computing Time
   deviating beyond a configured percentage band, or health status
   changing due to failure, attack detection, or unreachability.  A
   periodic heartbeat or soft-state synchronization can also be used to
   refresh the C-PS view and avoid stale metrics even when no trigger
   event occurs.

   Choosing appropriate protocols for conveying CATS metrics is
   important.  For distributed systems, existing routing protocols such
   as BGP extensions[RFC4760] and GRASP [RFC8990] may serve as a
   baseline.  However, considering that the CATS working group focuses
   on single-domain models, centralized approaches are highly suitable.
   In an SDN context [RFC7149] [RFC7426], the metric agent acts as an

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   application that uses a RESTful API via the northbound interface to
   report CATS metrics directly to the centralized C-PS (or SDN
   controller) for centralized decision-making.

5.2.  Information Collection and Routing Policies

   To ensure separation of concerns between computing resources and
   network states, the C-PS maintains two distinct data structures.
   Network metrics do not need to be normalized or redefined in CATS;
   they rely on existing network mechanisms.

   *  Computing Service Table: Formed by the C-SMA.  It gathers service
      identifiers and service-oriented metrics (GAS, Computing Time,
      etc.) and is indexed by CS-ID.

   *  Network Service Table (e.g., TEDB in SDN controller): Formed by
      the C-NMA.  C-NMA leverages existing techniques (e.g.,[RFC7471],
      [RFC8570], and [RFC8571]) to generate it.  The Network Service
      Table contains network topology and link information (including
      delay, jitter, bandwidth, and availability).  As an example, when
      the C-PS is implemented using an SDN Controller, the Network
      Service Table corresponds to the TEDB in the SDN control plane.

   When a user request arrives, the C-PS combines the Computing Service
   Table and the Network Service Table (e.g., TEDB in SDN controller).
   The routing policy works by first querying the Computing Service
   Table to find candidate CSCI-IDs that meet the service requirements.
   Then, it queries the Network Service Table to determine the path and
   delay from the user's Ingress CATS-Forwarder to the candidate Egress
   CATS-Forwarder.  The service node may be outside the ingress domain,
   so this document does not require measuring delay directly from the
   ingress to the service node.  Finally, the C-PS selects the optimal
   CSCI-ID by minimizing the total service time, i.e., computing time
   plus ingress-to-egress network delay.

   +-------------------------+      +-------------------------+
   | Computing Service Table |      |  Network Service Table  |
   | (CS-ID, CSCI-ID, GAS,   |      | (Ingress, Egress,       |
   |  Comp Time)             |      |  delay, jitter, bw)     |
   +-----------+-------------+      +-----------+-------------+
               |                                |
               v                                v
   +----------------------------------------------------------+
   |                           C-PS                           |
   |   1. Query Computing Service Table for candidates        |
   |   2. Query Network Service Table for ingress-egress path |
   |   3. Select CSCI-ID by computing time plus network delay |
   +----------------------------------------------------------+

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   Figure 1: Service Selection Process Combining Computing and Network
   Metrics

6.  Use Case Example

   To illustrate the integrated routing logic of Service Metrics,
   consider a scenario where the C-PS combines both computing and
   network information.  In this example, the C-PS filters candidates
   based on CS-ID and Computing Time, and combines that with the network
   delay between the Ingress and Egress CATS-Forwarders.

6.1.  Service Distribution and Table Formation

   Multiple service sites deploy various instances (e.g., AR1, AR2,
   LLM1).  During deployment, a service site can use reference
   information from a public service table, such as the one described in
   [I-D.zhangb-cats-cmas-04], together with local resource allocation
   and policy to derive the service-oriented metrics that it reports.
   The C-SMA at each site pushes its local service information to the
   C-PS in the message format (CS-ID, CSCI-ID, Computing Time, GAS,
   [Optional Metrics]), forming the following unified Computing Service
   Table:

   Figure 2 illustrates the metric dissemination process across the
   network:

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          AR1, 188.3.67.3:67, 5ms, 400, cost=10
          AR2, 188.3.67.3:68, 15ms, 100, cost=20

                 :<----------------------:
                 :                       :               +---------+
                 :                       :               |  AR1    |
                 :                       :            .--|CSCI-ID 1|
                 :              +----------------+    |  +---------+
                 :              |    C-SMA       |----|   Service Site 2
                 :              +----------------+    |  +---------+
                 :              |CATS-Forwarder 2|    '--|  AR2    |
 +--------+      :              +----------------+       |CSCI-ID 2|
 | Client |      :                        |              +---------+
 +--------+      :  Network +----------------------+
      |          :  delay   | +-------+            |
      |          : :<---------| C-NMA |            |
      |          : :        | +-------+            |
 +---------------------+    |                      |
 |CATS-Forwarder 1|C-PS|----|                      |
 +---------------------+    |       Underlay       |
                 :Computing |     Infrastructure   |     +---------+
                 :Service   |                      |     |  AR1    |
                 :Table     +----------------------+ .---|CSCI-ID 3|
                 :                    |              |   +---------+
                 :          +----------------+  +------+
                 :          |CATS-Forwarder 3|--|C-SMA | Service Site 3
                 :          +----------------+  +------+
                 :                                :  |
                 :                                :  |   +-----------+
                 :                                :  '---|  LLM1     |
                 :<-------------------------------:      |CSCI-ID 4  |
          AR1, 188.3.67.4:69, 6ms, 600, cost=5           +-----------+
          LLM1, 188.3.67.4:70, 12ms, 300, cost=15

   Figure 2: An Example of Service Metric Dissemination under CATS

   The C-PS stores the C-SMA reports in the Computing Service Table:

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   +=======+===================+=====+===============+=================+
   | CS-ID | CSCI-ID (IP:Port) | GAS | Comp Time(ms) | Cost            |
   |       |                   |     |               | (Optional)      |
   +=======+===================+=====+===============+=================+
   | AR1   | 188.3.67.3:67     | 400 | 5             | 10              |
   +-------+-------------------+-----+---------------+-----------------+
   | AR2   | 188.3.67.3:68     | 100 | 15            | 20              |
   +-------+-------------------+-----+---------------+-----------------+
   | AR1   | 188.3.67.4:69     | 600 | 6             | 5               |
   +-------+-------------------+-----+---------------+-----------------+
   | LLM1  | 188.3.67.4:70     | 300 | 12            | 15              |
   +-------+-------------------+-----+---------------+-----------------+

                                  Table 1

   The C-PS also maintains the Network Service Table (e.g., TEDB in an
   SDN controller) for network path information.  An example subset
   relevant to the Ingress CATS-Forwarder is shown below:

      +========================+=======================+============+
      | Ingress CATS-Forwarder | Egress CATS-Forwarder | Network    |
      |                        |                       | Delay (ms) |
      +========================+=======================+============+
      | 10.0.0.1               | 188.3.67.3            | 8          |
      +------------------------+-----------------------+------------+
      | 10.0.0.1               | 188.3.67.4            | 6          |
      +------------------------+-----------------------+------------+

                                  Table 2

   Network delay information is maintained in the Network Service
   Table rather than being merged into the Computing Service Table.  In
   this example, network delay refers to the Ingress-to-Egress delay.

6.2.  Service Consumption and Resource Allocation

   A client requests the AR1 service with a requirement for the shortest
   total service time (computing time plus Ingress-to-Egress network
   delay).  Cost is omitted in this example to focus on the combined
   metric.

   1.  Match CS-ID (Control Plane): The C-PS scans the Computing Service
       Table and isolates entries matching CS-ID = AR1.  Candidates:
       188.3.67.3:67 (Comp Time = 5ms) and 188.3.67.4:69 (Comp Time =
       6ms).

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   2.  Query Network Service Table for Network Delay: The C-PS queries
       the Network Service Table (e.g., TEDB in an SDN controller) using
       the user's Ingress CATS-Forwarder and each candidate Egress CATS-
       Forwarder: path to the egress attached to 188.3.67.3 has a
       network delay of 8 ms; path to the egress attached to 188.3.67.4
       has a network delay of 6 ms.

   3.  Calculate Total Service Time: The C-PS sums computing time and
       Ingress-to-Egress network delay for each candidate: candidate
       188.3.67.3:67 has 5 ms + 8 ms = 13 ms; candidate 188.3.67.4:69
       has 6 ms + 6 ms = 12 ms.  The C-PS selects 188.3.67.4:69 because
       it offers the shortest total service time (12 ms), even though
       its computing time is slightly higher than candidate 67.

   4.  Allocate: The selected service site or its C-SMA updates the
       local GAS value for 188.3.67.4:69 according to its local resource
       allocation policy.  The C-SMA does not need to report every per-
       session adjustment to the C-PS when the change is operationally
       insignificant; it may report aggregated or threshold-based
       updates.

   5.  Return Contact IP (Control Plane): The C-PS sends the selected
       contact IP (188.3.67.4:69) to the Ingress CATS-Forwarder (CATS-
       Forwarder 1).  The Ingress CATS-Forwarder then forwards this
       information to the client.  The internal metrics (computing time,
       network delay, cost, etc.) are shielded from the user.

   6.  Data Plane Establishment: The client sends the concrete service
       data to the Ingress CATS-Forwarder (CATS-Forwarder 1).  The
       Ingress CATS-Forwarder encapsulates the packets and forwards them
       over the CATS-computed path to the selected Egress CATS-Forwarder
       (e.g., CATS-Forwarder 2 or 3).  The Egress CATS-Forwarder
       decapsulates the packets and sends them to the target service
       site.  After processing, the service site returns the response to
       the same Egress CATS-Forwarder, which forwards it back to the
       Ingress CATS-Forwarder and then to the client.

   7.  Release: Once the service session is completed, the selected
       service site or its C-SMA restores the local GAS value according
       to its local resource release policy.  The updated value is
       synchronized to the C-PS according to the same local reporting
       policy, threshold, or aggregation interval.

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7.  Security Considerations

   The dynamic reporting of Service Metrics introduces potential attack
   vectors.  Authentication mechanisms between service sites and C-SMAs
   MUST be enforced.  The Security Label (Section 4.3.3) can be utilized
   by the C-PS to prevent routing sensitive traffic to compromised
   sites.

   Service Metric reports influence service selection and therefore need
   integrity protection, source authentication, and authorization
   checks.  Deployments should protect against forged, replayed, or
   stale metric reports, for example by using freshness information and
   aging out old metric state.  Implementations should also consider
   rate limiting or aggregation policies so that abnormal local events
   do not create excessive update bursts toward the C-PS.

8.  IANA Considerations

   This document has no IANA actions at this time.

9.  References

9.1.  Informative References

   [I-D.ietf-cats-framework-24]
              Li, C., Du, Z., Boucadair, M., Contreras, L. M., and J.
              Drake, "A Framework for Computing-Aware Traffic Steering
              (CATS)", April 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-cats-
              framework-24>.

   [I-D.ietf-cats-metric-definition-10]
              Kehan, Y., Li, C., Contreras, L. M., Ros-Giralt, J., and
              G. Zeng, "CATS Metrics Definition", 22 June 2026,
              <https://datatracker.ietf.org/doc/html/draft-ietf-cats-
              metric-definition-10>.

   [I-D.zhangb-cats-cmas-04]
              Zhang, B., Dai, Y., Du, Z., Li, C., and C. Miao, "Public
              Service Platform for Computing-Aware Traffic Steering
              (CATS)", 13 May 2026,
              <https://datatracker.ietf.org/doc/html/draft-zhangb-cats-
              cmas-04>.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", January 2007,
              <https://www.rfc-editor.org/info/rfc4760>.

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Internet-Draft   Computing Service Metrics and Operation       July 2026

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

   [RFC7471]  Giacalone, S., Ward, D., Drake, J., Atlas, A., and S.
              Previdi, "OSPF Traffic Engineering (TE) Metric
              Extensions", March 2015,
              <https://www.rfc-editor.org/info/rfc7471>.

   [RFC8570]  Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
              D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
              Metric Extensions", March 2019,
              <https://www.rfc-editor.org/info/rfc8570>.

   [RFC8571]  Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and
              C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of
              IGP Traffic Engineering Performance Metric Extensions",
              March 2019, <https://www.rfc-editor.org/info/rfc8571>.

   [RFC7149]  Boucadair, M. and C. Jacquenet, "Software-Defined
              Networking: A Perspective from within a Service Provider
              Environment", March 2014,
              <https://www.rfc-editor.org/info/rfc7149>.

   [RFC7426]  Haleplidis, E., Ed., Pentikousis, K., Ed., Denazis, S.,
              Salim, J. H., Meyer, D., and O. Koufopavlou, "Software-
              Defined Networking (SDN): Layers and Architecture
              Terminology", January 2015,
              <https://www.rfc-editor.org/info/rfc7426>.

Authors' Addresses

   Bin Zhang (editor)
   Pengcheng Laboratory
   Email: zhangb@pcl.ac.cn

   Yina Dai (editor)
   Sun Yat-sen University
   Email: daiyn5@mail2.sysu.edu.cn

   Zongpeng Du (editor)
   China Mobile
   Email: duzongpeng@chinamobile.com

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   Guanming Zeng
   Huawei Technologies
   China
   Email: zengguanming@huawei.com

   Chuanyang Miao (editor)
   ZTE Corporation
   Email: miao.chuanyang@zte.com.cn

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