[Docs] [txt|pdf] [Tracker] [Email] [Nits]

Versions: 00 01

Network Working Group                                              Y. Gu
Internet-Draft                                                   S. Chen
Intended status: Standards Track                                  Huawei
Expires: May 6, 2021                                             H. Chen
                                                           China Telecom
                                                                   Z. Li
                                                                  Huawei
                                                        November 2, 2020


                       Network Monitoring For IGP
               draft-gu-opsawg-network-monitoring-igp-00

Abstract

   To evolve towards automated network OAM (Operations, administration
   and management), the monitoring of control plane protocols is a
   fundamental necessity.  This document proposes network monitoring for
   IGP to facilitate troubleshooting by collecting the IGP monitoring
   data and reporting it to the network monitoring server in real-time.
   In this document, the operations of network monitoring for ISIS are
   described, and the corresponding network monitoring message types and
   message formats are defined.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

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/.

   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 May 6, 2021.





Gu, et al.                 Expires May 6, 2021                  [Page 1]


Internet-Draft         Network Monitoring For IGP          November 2020


Copyright Notice

   Copyright (c) 2020 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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  IS-IS Route Flapping  . . . . . . . . . . . . . . . . . .   5
     3.2.  IS-IS LSDB Synchronization Failure  . . . . . . . . . . .   6
   4.  Message Format  . . . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Protocol Selection Options  . . . . . . . . . . . . . . .   7
     4.2.  Message Types . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Message Format  . . . . . . . . . . . . . . . . . . . . .   8
       4.3.1.  Common Header . . . . . . . . . . . . . . . . . . . .   8
       4.3.2.  Per Adjacency Header  . . . . . . . . . . . . . . . .   8
       4.3.3.  Initiation Message  . . . . . . . . . . . . . . . . .   9
       4.3.4.  Adjacency Status Change Notification  . . . . . . . .   9
       4.3.5.  ISIS Statistic Report Message . . . . . . . . . . . .  11
       4.3.6.  IS-IS PDU Monitoring Message  . . . . . . . . . . . .  13
       4.3.7.  Termination Message . . . . . . . . . . . . . . . . .  13
   5.  IANA  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  13
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

1.1.  Motivation

   The requirement for better network OAM approaches has been greatly
   driven by the network evolvement.  The concept of network Telemetry
   has been proposed to meet the current and future OAM demands w.r.t.,



Gu, et al.                 Expires May 6, 2021                  [Page 2]


Internet-Draft         Network Monitoring For IGP          November 2020


   massive and real-time data storage, collection, process, export, and
   analysis, and an architectural framework of existing Telemetry
   approaches is introduced in [I-D.song-ntf].  Network Telemetry
   provides visibility to the network health conditions, and is
   beneficial for faster network troubleshooting, network OpEx
   (operating expenditure) reduction, and network optimization.
   Telemetry can be applied to the data plane, control plane and
   management plane.  There have been various methods proposed for each
   plane:

   o  Management plane: For example, SNMP (Simple Network Management
      Protocol) [RFC1157], NETCONF (Network Configuration Protocol)
      [RFC6241] and gNMI (gRPC Network Management Interface)
      [I-D.openconfig-rtgwg-gnmi-spec] are three typical widely adopted
      management plane Telemetry approaches.  Various YANG modules are
      defined for network operational state retrieval and configuration
      management.  Subscription to specific YANG datastore can be
      realized in combination with gRPC/NETCONF.

   o  Data plane: For example, In-situ OAM (iOAM)
      [I-D.brockners-inband-oam-requirements] embeds an instruction
      header to the user data packets, and collects the requested data
      and adds it to the use packet at each network node along the
      forwarding path.  Applications such as path verification, SLA
      (service-level agreement) assurance can be enabled with iOAM.

   o  Control Plane: BGP monitoring protocol (BMP) [RFC7854] is proposed
      to monitor BGP sessions and intended to provide a convenient
      interface for obtaining BGP route views.  Date collected using BMP
      can be further analyzed with big data platforms for network health
      condition visualization, diagnose and prediction applications.

   The general idea of most Telemetry approaches is to collect various
   information from devices and export to the centralized server for
   further analysis, and thus providing more network insight.  It should
   not be surprising that any future and even current Telemetry
   applications may require the fusion of data acquired from more than
   one single approach/one single plane.  For example, for network
   troubleshooting purposes, it requires the collection of comprehensive
   information from devices, such system ID/router ID, interface status,
   PDUs (protocol data units), device/protocol statistics and so on.
   Information such as system ID/router ID can be reported by management
   plane Telemetry approaches, while the protocol related data
   (especially PDUs) are more fit to be monitored using the control
   plane Telemetry.  With rich information collected in real time at the
   centralized server, network issues can be localized faster and more
   accurately, and the root cause analysis can be also provided.




Gu, et al.                 Expires May 6, 2021                  [Page 3]


Internet-Draft         Network Monitoring For IGP          November 2020


   The conventional troubleshooting logic is to log in a faulty router,
   physically or through Telnet, and by using CLI to display related
   information/logs for fault source localization and further analysis.
   There are several concerns with the conventional troubleshooting
   methods:

   1.  It requires rich OAM experience for the OAM operator to know what
   information to check on the device, and the operation is complex;

   2.  In a multi-vendor network, it requires the understanding and
   familiarity of vendor specific operations and configurations;

   3.  Locating the fault source device could be non-trivial work, and
   is often realized through network-wide device-by-device check, which
   is both time-consuming and labor-consuming; and finally,

   4.  The acquisition of troubleshooting data can be difficult under
   some cases, e.g., when auto recovery is used.

   This document proposes the network monitoring for IGP to monitor the
   running state of IGP, e.g., PDUs, protocol statistics and peer
   status, which have not been systematically covered by any other
   Telemetry approach, to facilitate network troubleshooting.

1.2.  Overview

   Like BMP, a networking monitoring session is established between each
   monitored router (NM client) and the NM monitoring station (NM
   server) through TCP connection.  Information are collected directly
   from each monitored router and reported to the NM server.  The NM
   message can be both periodic and event-triggered, depending on the
   message type.

   IS-IS [RFC1195], as one of the most commonly adopted network layer
   protocols, builds the fundamental network connectivity of an
   autonomous system (AS).  The disfunction of IS-IS, e.g., IS-IS
   neighbor down, route flapping, MTU mismatch, and so on, could lead to
   network-wide instability and service interruption.  Thus, it is
   critical to keep track of the health condition of IS-IS, and the
   availability of information, related to IS-IS running status, is the
   fundamental requirement.  In this document, typical network issues
   are identified as the use cases of network monitoring.  Then the
   operations and the message formats of network monitoring for IS-IS
   are defined.  Network monitoring for OSPF will be included in the
   future version.






Gu, et al.                 Expires May 6, 2021                  [Page 4]


Internet-Draft         Network Monitoring For IGP          November 2020


2.  Terminology

   IGP: Interior Gateway Protocol

   IS-IS: Intermediate System to Intermediate System

   NM: Network Monitoring

   IMP: Network Monitoring for IGP

   BMP: BGP monitoring protocol

   IIH: IS-IS Hello Packet

   LSP: Link State Packet

   CSNP: Complete Sequence Number Packet

   NSNP: Partial Sequence Number Packet

3.  Use Cases

   We have identified two typical network issues due to IS-IS
   disfunction that are currently difficult to detect or localize.

3.1.  IS-IS Route Flapping

   The IS-IS Route Flapping refers to the situation that one or more
   routes appear and then disappear in the routing table repeatedly.
   Route flapping usually comes with massive PDUs interactions (e.g.,
   LSP, LSP purge...), which consume excessive network bandwidth, and
   excessive CPU processing.  In addition, the impact is often network-
   wide.  The localizing of the flapping source and the identifying of
   root causes haven't been easy work due to various reasons.

   The flapping can be caused by system ID conflict, IS-IS neighborship
   flapping, route source flapping (caused by import route policy
   misconfiguration) , device clock dis-function with abnormal LSP purge
   (e.g., 100 times faster) and so on.

   o  The system ID conflict check is a network-wide work.  If such
      information is collected centrally to a controller/server, the
      issues can be identified in seconds, and more importantly, in
      advance of the actual flapping event.

   o  The IS-IS neighborship flapping is typically caused by interface
      flapping, BFD flapping, CPU high and so on.  Conventionally, to
      located the issue, operators typically identify the target



Gu, et al.                 Expires May 6, 2021                  [Page 5]


Internet-Draft         Network Monitoring For IGP          November 2020


      device(s), and then log in the devices to check related
      statistics, parsed protocol PDU data and configurations.  The
      manual check often requires a combination of multiple CLIs (check
      cost/next hop/exit interface/LSP age...) in a repeated manner,
      which is time-consuming and requires rich OAM experience.  If such
      statistics and configuration data were collected at the server in
      real-time, the server may analyze them automatically or semi-
      automatically with troubleshooting algorithms implemented at the
      server.

   o  In the case that route policies are misconfigured, which then
      causes the route flapping, it's typically difficult to directly
      identify the responsible policy in a short time.  Thus, if the
      route change history is recorded in correlation with the route
      policy, then with such record collected at the server, the server
      can directly identify the responsible policy with the one-to-one
      mapping between policy processing and the route attribute change.

   o  In the case that flapping comes with abnormal LSP purges, it may
      be due to continuous LSP corruptions with falsified shorter
      Remaining Lifetime, or the clock running 100 times faster with 100
      times more purge LSPs generated.  In order to identify the purge
      originator, RFC 6232 [RFC6232] proposes to carry the Purge
      Orginator Identification (POI) TLV in IS-IS.  However, to analyze
      the root cause of such abnormal purges, the collection and
      analysis of LSP PDUs are needed.

3.2.  IS-IS LSDB Synchronization Failure

   During the IS-IS flooding, sometimes the LSP synchronization failure
   happens.  The synchronization failure causes can be generally
   classified into three cases:

   o  Case 1, the LSP is not correctly advertised.  For example, an LSP
      sent by Router A fails to be synchronized at Router B.  It can be
      due to incorrect route export policy, or too many prefixes being
      advertised which exceeds the LSP/MTU threshold, and so on at
      Router A.

   o  Case 2, LSP transmission error, which is typically caused by IS-IS
      adjacency failure, .e.g., link down/BFD down/authentication
      failure.

   o  Case 3, the LSP is received but not correctly processed.  The
      problem that happens at Router B can be faulty route import
      policy, or Router B being in Overload mode, or the hardware/
      software bugs.




Gu, et al.                 Expires May 6, 2021                  [Page 6]


Internet-Draft         Network Monitoring For IGP          November 2020


   With sufficient ISIS PDU related statistics and parsed PDU
   information recorded at the device, the neighborship failure in Case
   2 can be typically diagnosed at Router A or Router B independently.
   With such diagnosing information collected (e.g., in the format of
   reason code) in real-time, the server can identify the root
   synchronization issue with much less time and labor consumption
   compared with conventional methods.  In Case 1 & 3, the failure is
   mostly caused by incorrect route policy and software/hardware issue.
   By comparing the LSDB with the sent/received LSP, differences can be
   recognized.  Then the difference may further guide the localization
   of the root cause.  Thus, by collecting the LSDBs and sent/received
   LSPs from the two affected neighbors, the server can have more
   insights at the synchronization failure.

4.  Message Format

4.1.  Protocol Selection Options

   Regarding the network monitoring data export, BMP has been a good
   option.  First of all, BMP serves similar purposes of network
   monitoring for IGP that reports routes, route statistics and peer
   status.  In addition, BMP has already been implemented in major
   vendor devices and utilized by operator.

4.2.  Message Types

   The variety of IS-IS troubleshooting use cases requires a systematic
   information report of network monitoring, so that the NM server or
   any third party analyzer could efficiently utilize the reported
   messages to localize and recover various network issues.  We define
   NM messages for IS-IS uses the following types:

   o  Initiation Message: A message used for the monitored device to
      inform the NM monitoring station of its capabilities, vendor,
      software version and so on.  For example, the link MTU can be
      included within the message.  The initiation message is sent once
      the TCP connection between the monitoring station and monitored
      router is set up.  During the monitoring session, any change of
      the initiation message could trigger an Initiation Message update.

   o  Adjacency Status Change Notification Message: A message used to
      inform the NM monitoring station of the adjacency status change of
      the monitored device, i.e., from up to down, from down/initiation
      to up, with possible alarms/logs recorded in the device.  This
      message notifies the NM server of the ongoing IS-IS adjacency
      change event and possible reasons.  If no reason is provided or
      the provided reason is not specific enough, the NM server can
      further analyze the IS-IS PDU or the IS-IS statistics.



Gu, et al.                 Expires May 6, 2021                  [Page 7]


Internet-Draft         Network Monitoring For IGP          November 2020


   o  Statistic Report Message: A message used to report the statistics
      of the ongoing IS-IS process at the monitored device.  For
      example, abnormal LSP count of the monitored device can be a sign
      of route flapping.  This message can be sent periodically or event
      triggered.  If sent periodically, the frequency can be configured
      by the operator depending on the monitoring requirement.  If it's
      event triggered, it could be triggered by a counter/timer
      exceeding the threshold.

   o  IS-IS PDU Monitoring Message: A message used to update the NM
      server of any PDU sent from and received at the monitored device.
      For example, the IIHs collected from two neighbors can be used for
      analyzing the adjacency set up failure issue.  The LSPs collected
      from two neighbors can be analyzed for the LSP synchronization
      issue.

   o  Termination Message: A message for the monitored router to inform
      the monitoring station of why it is closing the NM session.  This
      message is sent when the monitoring session is to be closed.

4.3.  Message Format

4.3.1.  Common Header

   The common header is encapsulated in all messages of network
   monitoring for IGP.  It includes the Version, Message Length and
   Message Type fields.  The common header can reuse the common header
   of BMP and new message types should defined for IGP monitoring.

   o  Type = TBD: Adjacency Status Change Notification

   o  Type = TBD: ISIS Statistic Report

   o  Type = TBD: IS-IS PDU Monitoring

4.3.2.  Per Adjacency Header

   Except the Initiation and Termination Message, all the rest messages
   are per adjacency based.  Thus, a per adjacency header is defined as
   follows.











Gu, et al.                 Expires May 6, 2021                  [Page 8]


Internet-Draft         Network Monitoring For IGP          November 2020


    0                   1                   2                   3
    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
   +---------------------------------------------------------------+
   |          Reserved          |CT|     Neighbor System ID        |
   +---------------------------------------------------------------+
   |                      Neighbor System ID                       |
   +-------------------------------+-------------------------------+
   |        Neighbor Area ID       |                               |
   +-------------------------------+-------------------------------+
   |                     Timestamp (seconds)                       |
   +---------------------------------------------------------------+
   |                   Timestamp (microseconds)                    |
   +---------------------------------------------------------------+

   o  Adjacency Flag (2 bytes): The Circuit Type (2 bits) flag specifies
      if the router is an L1(01), L2(10), or L1/L2(11).  If both bits
      are zeroes (00), the Per Adjacency Header SHALL be ignored.  This
      configuration is used when the statistic is not per-adjacency
      based, e.g., when reporting the number of adjacencies.

   o  Neighbor System ID (6 bytes): identifies the system ID of the
      remote router.

   o  Neighbor Area ID (2 bytes): identifies the area ID of the remote
      router.

   o  Timestamp (4 bytes): records the time when the message is sent/
      received, expressed in seconds and microseconds since midnight
      (zero hour), January 1, 1970 (UTC).

4.3.3.  Initiation Message

   Three new types of Router Capability TLVs should be defined for IGP
   monitoring:

   o  Type = TBD: Local System ID.  The corresponding Router Capability
      Value field SHALL indicate the router's System ID

   o  Type = TBD: Link MTU.  The corresponding Router Capability Value
      field SHALL indicate the router's link MTU.

4.3.4.  Adjacency Status Change Notification

   The Adjacency Status Change Notification Message indicates an IS-IS
   adjacency status change: from up to down or from initiation/down to
   up.  It consists of the Common Header, Per Adjacency Header and the
   Reason TLV.  The Notification is triggered whenever the status




Gu, et al.                 Expires May 6, 2021                  [Page 9]


Internet-Draft         Network Monitoring For IGP          November 2020


   changes.  The Reason TLV is optional, and is defined as follows.
   More Reason types can be defined if necessary.

    0                   1                   2                   3
    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
   +-------------------------------+-------------------------------+
   |    Reserved |S|   Reason Type |        Reason Length          |
   +-------------------------------+-------------------------------+
   +                        Reason Value (variable)                +
   ~                                                               ~
   +---------------------------------------------------------------+

   o  Reason Flags (1 byte): The S flag (1 bit) indicates if the
      Adjacency status is from up to down (set to 0) or from down/
      initial to up (set to 1).  The rest bits of the Flag field are
      reserved.  When the S flag is set to 1, the Reason Type SHALL be
      set to all zeroes (i.e., Type 0), the Reason Length fields SHALL
      be set to all zeroes, and the Reason Value field SHALL be set
      empty.

   o  Reason Type (1 byte): indicates the possible reason that caused
      the adjacency status change.  Currently defined types are:

      *  Type = 0: Adjacency Up.  This type indicates the establishment
         of an adjacency.  For this reason type, the S flag MUST be set
         to 1, indicating it's a adjacency-up event.  There's no further
         reason to be provided.  The reason Length field SHALL be set to
         all zeroes, and the Reason Value field SHALL be set empty.

      *  Type = 1: Circuit Down.  For this data type, the S flag MUST be
         set to 0, indicating it's a adjacency-down event.  The length
         field is set to all zeroes, and the value field is set empty.

      *  Type = 2: Memory Low. For this data type, the S flag MUST be
         set to 0, indicating it's a adjacency-down event.  The length
         field is set to all zeroes, and the value field is set empty.

      *  Type = 3: Hold timer expired.  For this data type, the S flag
         MUST be set to 0, indicating it's a adjacency-down event.  The
         length field is set to all zeroes, and the value field is set
         empty.

      *  Type = 4: String.  For this data type, the S flag MUST be set
         to 0, indicating it's a adjacency-down event.  The
         corresponding Reason Value field indicates the reason specified
         by the monitored router in a free-form UTF-8 string whose
         length is given by the Reason Length field.




Gu, et al.                 Expires May 6, 2021                 [Page 10]


Internet-Draft         Network Monitoring For IGP          November 2020


   o  Reason Length (2 bytes): indicates the length of the Reason Value
      field.

   o  Reason Value (variable): includes the possible reason why the
      Adjacency is down.

4.3.5.  ISIS Statistic Report Message

   The ISIS Statistic Report Message reports the statistics of the
   parameters that are of interest to the operator.  The message
   consists of the Common Header, the Per Adjacency Header and the
   Statistic TLV.  The message include both per-adjacency based
   statistics and non per- adjacency based statistics.  For example, the
   received/sent LSP counts are per-adjacency based statistics, and the
   local LSP change times count and the number of established
   adjacencies are non per- adjacency based statistics.  For the non
   per-adjacency based statistics, the CT Flag (2 bits) in the Per
   Adjacency Header MUST be set to 00.  Upon receiving any message with
   CT flag set to 00, the Per Adjacency Header SHALL be ignored (the
   total length of the Per Adjacency Header is 18 bytes as defined in
   Section 3.2.2, and the message reading/analysis SHALL resume from the
   Statistic TLV part.

   The Statistic TLV is defined as follows.

    0                   1                   2                   3
    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
   +---------------------------------------------------------------+
   |   Reserved  |T| Statistic Type|        Statistic Length       |
   +---------------------------------------------------------------+
   |                       Statistic  Value                        |
   +---------------------------------------------------------------+


   o  Statistic Flags (1 byte): provides information for the reported
      statistics.

      *  T flag (1 bit): indicates if the statistic is for the received-
         from direction (set to 1) or sent-to direction the neighbor
         (set to 0)

   o  Statistic Type (1 byte): specifies the statistic type of the
      counter.  Currently defined types are:

      *  Type = 0: IIH count.  The T flag indicates if it's a sent or
         received Hello PDU.  It is a per-adjacency based statistic
         type, and the CT flag in the Per Adjacency Header MUST NOT be
         set to 00.



Gu, et al.                 Expires May 6, 2021                 [Page 11]


Internet-Draft         Network Monitoring For IGP          November 2020


      *  Type = 1: Incorrect IIH received count.  For this type, the T
         flag MUST be set to 1.  It is a per-adjacency based statistic
         type, and the CT flag in the Per Adjacency Header MUST NOT be
         set to 00.

      *  Type = 2: LSP count.  The T flag indicates if it's a sent or
         received LSP.  It is a per-adjacency based statistic type, and
         the CT flag in the Per Adjacency Header MUST NOT be set to 00.

      *  Type = 3: Incorrect LSP received count.  For this type, the T
         flag MUST be set to 1.  It is a per-adjacency based statistic
         type, and the CT flag in the Per Adjacency Header MUST NOT be
         set to 00.

      *

      *

      *

      *  Type = 4: Retransmitted LSP count.  For this type, the T flag
         MUST be set to 0.  It is a per-adjacency based statistic type,
         and the CT flag in the Per Adjacency Header MUST NOT be set to
         00.

      *  Type = 5: CSNP count.  The T flag indicates if it's a sent or
         received CSNP.  It is a per-adjacency based statistic type, and
         the CT flag in the Per Adjacency Header MUST NOT be set to 00.

      *  Type = 6: PSNP count.  The T flag indicates if it's a sent or
         received PSNP.  It is a per-adjacency based statistic type, and
         the CT flag in the Per Adjacency Header MUST NOT be set to 00.

      *  Type = 7: Number of established adjacencies.  It's a non per-
         adjacency based statistic type, and thus for the monitoring
         station to recognize this type, the CT flag in the Per
         Adjacency Header MUST be set to 00.

      *  Type = 8: LSP change time count.  It's a non per-adjacency
         based statistic type, and thus for the monitoring station to
         recognize this type, the CT flag in the Per Adjacency Header
         MUST be set to 00.

   o  Statistic Length (2 bytes): indicates the length of the Statistic
      Value field.

   o  Statistic Value (4 bytes): specifies the counter value, which is a
      non-negative integer.



Gu, et al.                 Expires May 6, 2021                 [Page 12]


Internet-Draft         Network Monitoring For IGP          November 2020


4.3.6.  IS-IS PDU Monitoring Message

   The IS-IS PDU Monitoring Message is used to update the monitoring
   station of any PDU sent from and received at the monitored device per
   neighbor.  Following the Common Header and the Per Adjacency Header
   is the IS-IS PDU.  To tell whether it's a sent or received PDU, the
   monitoring station can analyze the source and destination addresses
   in the reported PDUs.

4.3.7.  Termination Message

   This document does not change the Termination Message defined by
   RFC7854.

5.  IANA

   TBD

6.  Contributors

   TBD

7.  Acknowledgments

   TBD

8.  References

   [I-D.brockners-inband-oam-requirements]
              Brockners, F., Bhandari, S., Dara, S., Pignataro, C.,
              Gredler, H., Leddy, J., Youell, S., Mozes, D., Mizrahi,
              T., Lapukhov, P., and r. remy@barefootnetworks.com,
              "Requirements for In-situ OAM", draft-brockners-inband-
              oam-requirements-03 (work in progress), March 2017.

   [I-D.chen-npm-use-cases]
              Chen, H., Li, Z., Xu, F., Gu, Y., and Z. Li, "Network-wide
              Protocol Monitoring (NPM): Use Cases", draft-chen-npm-use-
              cases-00 (work in progress), March 2019.

   [I-D.ietf-netconf-yang-push]
              Clemm, A. and E. Voit, "Subscription to YANG Datastores",
              draft-ietf-netconf-yang-push-25 (work in progress), May
              2019.







Gu, et al.                 Expires May 6, 2021                 [Page 13]


Internet-Draft         Network Monitoring For IGP          November 2020


   [I-D.openconfig-rtgwg-gnmi-spec]
              Shakir, R., Shaikh, A., Borman, P., Hines, M., Lebsack,
              C., and C. Morrow, "gRPC Network Management Interface
              (gNMI)", draft-openconfig-rtgwg-gnmi-spec-01 (work in
              progress), March 2018.

   [I-D.song-ntf]
              Song, H., Zhou, T., Li, Z., Fioccola, G., Li, Z.,
              Martinez-Julia, P., Ciavaglia, L., and A. Wang, "Toward a
              Network Telemetry Framework", draft-song-ntf-02 (work in
              progress), July 2018.

   [RFC1157]  Case, J., Fedor, M., Schoffstall, M., and J. Davin,
              "Simple Network Management Protocol (SNMP)", RFC 1157,
              DOI 10.17487/RFC1157, May 1990,
              <https://www.rfc-editor.org/info/rfc1157>.

   [RFC1195]  Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
              dual environments", RFC 1195, DOI 10.17487/RFC1195,
              December 1990, <https://www.rfc-editor.org/info/rfc1195>.

   [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>.

   [RFC6232]  Wei, F., Qin, Y., Li, Z., Li, T., and J. Dong, "Purge
              Originator Identification TLV for IS-IS", RFC 6232,
              DOI 10.17487/RFC6232, May 2011,
              <https://www.rfc-editor.org/info/rfc6232>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC7752]  Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
              S. Ray, "North-Bound Distribution of Link-State and
              Traffic Engineering (TE) Information Using BGP", RFC 7752,
              DOI 10.17487/RFC7752, March 2016,
              <https://www.rfc-editor.org/info/rfc7752>.

   [RFC7854]  Scudder, J., Ed., Fernando, R., and S. Stuart, "BGP
              Monitoring Protocol (BMP)", RFC 7854,
              DOI 10.17487/RFC7854, June 2016,
              <https://www.rfc-editor.org/info/rfc7854>.





Gu, et al.                 Expires May 6, 2021                 [Page 14]


Internet-Draft         Network Monitoring For IGP          November 2020


Authors' Addresses

   Yunan Gu
   Huawei
   156 Beiqing Road
   Beijing, 100095
   P.R. China

   Email: guyunan@huawei.com


   Shuanglong Chen
   Huawei
   156 Beiqing Road
   Beijing,100095
   P.R. China

   Email: chenshuanglong@huawei.com


   Huanan Chen
   China Telecom
   109 West Zhongshan Ave
   Guangzhou
   China

   Email: chenhuanan@gsta.com


   Zhenbin Li
   Huawei
   156 Beiqing Road
   Beijing, 100095
   P.R. China

   Email: lizhenbin@huawei.com















Gu, et al.                 Expires May 6, 2021                 [Page 15]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/