RFC 7747 INFORMATIONAL ROUTING · BENCHMARKING · BGP

BGP Convergence Bench: Basic BGP Convergence Benchmarking Methodology for Data-Plane Convergence

How to measure how fast routers switch to backup paths when a link fails

On rfc-editor.org ↗
PUBLISHED
April 2016
AUTHORS
R. Papneja, B. Parise, S. Hares, D. Lee, I. Varlashkin
STREAM
IETF
FOCUS
Data-plane (FIB) convergence
BGP TYPES
eBGP and iBGP
IP VERSIONS
IPv4 and IPv6
STANDARD TOPOLOGIES
3 or 4 nodes
DOI
10.17487/RFC7747

RFC text

Contents
Original text · RFC Editor View on rfc-editor.org ↗
Internet Engineering Task Force (IETF)                        R. Papneja
Request for Comments: 7747                           Huawei Technologies
Category: Informational                                        B. Parise
ISSN: 2070-1721                                          Skyport Systems
                                                                S. Hares
                                                     Huawei Technologies
                                                                  D. Lee
                                                                    IXIA
                                                           I. Varlashkin
                                                                  Google
                                                              April 2016


             Basic BGP Convergence Benchmarking Methodology
                       for Data-Plane Convergence

Abstract

   BGP is widely deployed and used by several service providers as the
   default inter-AS (Autonomous System) routing protocol.  It is of
   utmost importance to ensure that when a BGP peer or a downstream link
   of a BGP peer fails, the alternate paths are rapidly used and routes
   via these alternate paths are installed.  This document provides the
   basic BGP benchmarking methodology using existing BGP convergence
   terminology as defined in RFC 4098.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7747.

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   Copyright (c) 2016 IETF Trust and the persons identified as the
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   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Benchmarking Definitions  . . . . . . . . . . . . . . . .   4
     1.2.  Purpose of BGP FIB (Data-Plane) Convergence . . . . . . .   4
     1.3.  Control-Plane Convergence . . . . . . . . . . . . . . . .   5
     1.4.  Benchmarking Testing  . . . . . . . . . . . . . . . . . .   5
   2.  Existing Definitions and Requirements . . . . . . . . . . . .   5
   3.  Test Topologies . . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  General Reference Topologies  . . . . . . . . . . . . . .   7
   4.  Test Considerations . . . . . . . . . . . . . . . . . . . . .   8
     4.1.  Number of Peers . . . . . . . . . . . . . . . . . . . . .   9
     4.2.  Number of Routes per Peer . . . . . . . . . . . . . . . .   9
     4.3.  Policy Processing/Reconfiguration . . . . . . . . . . . .   9
     4.4.  Configured Parameters (Timers, etc.)  . . . . . . . . . .   9
     4.5.  Interface Types . . . . . . . . . . . . . . . . . . . . .  11
     4.6.  Measurement Accuracy  . . . . . . . . . . . . . . . . . .  11
     4.7.  Measurement Statistics  . . . . . . . . . . . . . . . . .  11
     4.8.  Authentication  . . . . . . . . . . . . . . . . . . . . .  11
     4.9.  Convergence Events  . . . . . . . . . . . . . . . . . . .  12
     4.10. High Availability . . . . . . . . . . . . . . . . . . . .  12
   5.  Test Cases  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     5.1.  Basic Convergence Tests . . . . . . . . . . . . . . . . .  13
       5.1.1.  RIB-IN Convergence  . . . . . . . . . . . . . . . . .  13
       5.1.2.  RIB-OUT Convergence . . . . . . . . . . . . . . . . .  15
       5.1.3.  eBGP Convergence  . . . . . . . . . . . . . . . . . .  16
       5.1.4.  iBGP Convergence  . . . . . . . . . . . . . . . . . .  16
       5.1.5.  eBGP Multihop Convergence . . . . . . . . . . . . . .  17
     5.2.  BGP Failure/Convergence Events  . . . . . . . . . . . . .  18
       5.2.1.  Physical Link Failure on DUT End  . . . . . . . . . .  18
       5.2.2.  Physical Link Failure on Remote/Emulator End  . . . .  19
       5.2.3.  ECMP Link Failure on DUT End  . . . . . . . . . . . .  20
     5.3.  BGP Adjacency Failure (Non-Physical Link Failure) on
           Emulator  . . . . . . . . . . . . . . . . . . . . . . . .  20
     5.4.  BGP Hard Reset Test Cases . . . . . . . . . . . . . . . .  21
       5.4.1.  BGP Non-Recovering Hard Reset Event on DUT  . . . . .  21
     5.5.  BGP Soft Reset  . . . . . . . . . . . . . . . . . . . . .  22
     5.6.  BGP Route Withdrawal Convergence Time . . . . . . . . . .  24
     5.7.  BGP Path Attribute Change Convergence Time  . . . . . . .  26
     5.8.  BGP Graceful Restart Convergence Time . . . . . . . . . .  27
   6.  Reporting Format  . . . . . . . . . . . . . . . . . . . . . .  29
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  32
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  32
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  32
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  33
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  34
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  35

1.  Introduction

   This document defines the methodology for benchmarking data-plane
   Forwarding Information Base (FIB) convergence performance of BGP in
   routers and switches using topologies of three or four nodes.  The
   methodology proposed in this document applies to both IPv4 and IPv6,
   and if a particular test is unique to one version, it is marked
   accordingly.  For IPv6 benchmarking, the Device Under Test (DUT) will
   require the support of Multiprotocol BGP (MP-BGP) [RFC4760]
   [RFC2545].  Similarly, both Internal BGP (iBGP) and External BGP
   (eBGP) are covered in the tests as applicable.

   The scope of this document is to provide methodology for BGP FIB
   convergence measurements with BGP functionality limited to IPv4 and
   IPv6 as defined in [RFC4271] and MP-BGP [RFC4760] [RFC2545].  Other
   BGP extensions to support Layer 2 and Layer 3 Virtual Private
   Networks (VPNs) are outside the scope of this document.  Interaction
   with IGPs (IGP interworking) is outside the scope of this document.

1.1.  Benchmarking Definitions

   The terminology used in this document is defined in [RFC4098].  One
   additional term is defined in this document as follows.

   FIB (data-plane) convergence is defined as the completion of all FIB
   changes so that all forwarded traffic then takes the newly proposed
   route.  RFC 4098 defines the terms 'BGP device', 'FIB', and
   'forwarded traffic'.  Data-plane convergence is different than
   control-plane convergence within a node.

   This document defines methodology to test

   o  data-plane convergence on a single BGP device that supports the
      BGP functionality with a scope as outlined above; and

   o  using test topology of three or four nodes that are sufficient to
      recreate the convergence events used in the various tests of this
      document.

1.2.  Purpose of BGP FIB (Data-Plane) Convergence

   In the current Internet architecture, the inter-AS transit is
   primarily available through BGP.  To maintain reliable connectivity
   within intra-domains or across inter-domains, fast recovery from
   failures remains most critical.  To ensure minimal traffic losses,
   many service providers are requiring BGP implementations to converge
   the entire Internet routing table within sub-seconds at FIB level.

   Furthermore, to compare these numbers amongst various devices,
   service providers are also looking at ways to standardize the
   convergence measurement methods.  This document offers test methods
   for simple topologies.  These simple tests will provide a quick high-
   level check of BGP data-plane convergence across multiple
   implementations from different vendors.

1.3.  Control-Plane Convergence

   The convergence of BGP occurs at two levels: Routing Information Base
   (RIB) and FIB convergence.  RFC 4098 defines terms for BGP control-
   plane convergence.  Methodologies that test control-plane convergence
   are out of scope for this document.

1.4.  Benchmarking Testing

   In order to ensure that the results obtained in tests are repeatable,
   careful setup of initial conditions and exact steps are required.

   This document proposes these initial conditions, test steps, and
   result checking.  To ensure uniformity of the results, all optional
   parameters SHOULD be disabled and all settings SHOULD be changed to
   default; these may include BGP timers as well.

2.  Existing Definitions and Requirements

   "Benchmarking Terminology for Network Interconnect Devices" [RFC1242]
   and "Benchmarking Terminology for LAN Switching Devices" [RFC2285]
   SHOULD be reviewed in conjunction with this document.  WLAN-specific
   terms and definitions are also provided in Clauses 3 and 4 of the
   IEEE 802.11 standard [IEEE.802.11].  Commonly used terms may also be
   found in RFC 1983 [RFC1983].

   For the sake of clarity and continuity, this document adopts the
   general template for benchmarking terminology set out in Section 2 of
   [RFC1242].  Definitions are organized in alphabetical order and
   grouped into sections for ease of reference.  The following terms are
   assumed to be taken as defined in RFC 1242 [RFC1242]: Throughput,
   Latency, Constant Load, Frame Loss Rate, and Overhead Behavior.  In
   addition, the following terms are taken as defined in [RFC2285]:
   Forwarding Rates, Maximum Forwarding Rate, Loads, Device Under Test
   (DUT), and System Under Test (SUT).

   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].

3.  Test Topologies

   This section describes the test setups for use in BGP benchmarking
   tests measuring convergence of the FIB (data-plane) after BGP updates
   have been received.

   These test setups have three or four nodes with the following
   configuration:

   1.  Basic test setup

   2.  Three-node setup for iBGP or eBGP convergence

   3.  Setup for eBGP multihop test Scenario

   4.  Four-node setup for iBGP or eBGP convergence

   Individual tests refer to these topologies.

   Figures 1 through 4 use the following conventions:

   o  AS-X: Autonomous System X

   o  Loopback Int: Loopback interface on a BGP-enabled device

   o  HLP, HLP1, HLP2: Helper routers running the same version of BGP as
      the DUT

   o  All devices MUST be synchronized using NTP or some other clock
      synchronization mechanism

3.1.  General Reference Topologies

   Emulator acts as one or more BGP peers for different test cases.

           +----------+                             +------------+
           |          |   Traffic Interfaces        |            |
           |          |-----------------------1---- | tx         |
           |          |-----------------------2---- | tr1        |
           |          |-----------------------3-----| tr2        |
           |    DUT   |                             | Emulator   |
           |          |    Routing Interfaces       |            |
           |      Dp1 |---------------------------  |Emp1        |
           |          |      BGP Peering            |            |
           |      Dp2 |---------------------------- |Emp2        |
           |          |      BGP Peering            |            |
           +----------+                             +------------+

                        Figure 1: Basic Test Setup


         +------------+        +-----------+           +-----------+
         |            |        |           |           |           |
         |            |        |           |           |           |
         |   HLP      |        |  DUT      |           | Emulator  |
         |  (AS-X)    |--------| (AS-Y)    |-----------|  (AS-Z)   |
         |            |        |           |           |           |
         |            |        |           |           |           |
         |            |        |           |           |           |
         +------------+        +-----------+           +-----------+
                 |                                            |
                 |                                            |
                 +--------------------------------------------+

         Figure 2: Three-Node Setup for eBGP and iBGP Convergence

              +----------------------------------------------+
              |                                              |
              |                                              |
         +------------+        +-----------+           +-----------+
         |            |        |           |           |           |
         |            |        |           |           |           |
         |   HLP      |        |  DUT      |           | Emulator  |
         |  (AS-X)    |--------| (AS-Y)    |-----------|  (AS-Z)   |
         |            |        |           |           |           |
         |            |        |           |           |           |
         |            |        |           |           |           |
         +------------+        +-----------+           +-----------+
              |Loopback-Int         |Loopback-Int
              |                     |
              +                     +

           Figure 3: BGP Convergence for eBGP Multihop Scenario


          +---------+     +--------+     +--------+     +---------+
          |         |     |        |     |        |     |         |
          |         |     |        |     |        |     |         |
          |  HLP1   |     |  DUT   |     |  HLP2  |     |Emulator |
          | (AS-X)  |-----| (AS-X) |-----| (AS-Y) |-----| (AS-Z)  |
          |         |     |        |     |        |     |         |
          |         |     |        |     |        |     |         |
          |         |     |        |     |        |     |         |
          +---------+     +--------+     +--------+     +---------+
               |                                             |
               |                                             |
               +---------------------------------------------+

          Figure 4: Four-Node Setup for eBGP and iBGP Convergence

4.  Test Considerations

   The test cases for measuring convergence for iBGP and eBGP are
   different.  Both iBGP and eBGP use different mechanisms to advertise,
   install, and learn the routes.  Typically, an iBGP route on the DUT
   is installed and exported when the next hop is valid.  For eBGP, the
   route is installed on the DUT with the remote interface address as
   the next hop, with the exception of the multihop test case (as
   specified in the test).

4.1.  Number of Peers

   "Number of Peers" is defined as the number of BGP neighbors or
   sessions the DUT has at the beginning of the test.  The peers are
   established before the tests begin.  The relationship could be either
   iBGP or eBGP peering depending upon the test case requirement.

   The DUT establishes one or more BGP peer sessions with one or more
   emulated routers or Helper Nodes.  Additional peers can be added
   based on the testing requirements.  The number of peers enabled
   during the testing should be well documented in the report matrix.

4.2.  Number of Routes per Peer

   "Number of Routes per Peer" is defined as the number of routes
   advertised or learned by the DUT per session or through a neighbor
   relationship with an emulator or Helper Node.  The Tester, emulating
   as a BGP neighbor, MUST advertise at least one route per BGP peer.

   Each test run must identify the route stream in terms of route
   packing, route mixture, and number of routes.  This route stream must
   be well documented in the reporting stream.  RFC 4098 defines these
   terms.

   It is RECOMMENDED that the user consider advertising the entire
   current Internet routing table per peering session using an Internet
   route mixture with unique or non-unique routes.  If multiple peers
   are used, it is important to precisely document the timing sequence
   between the peer sending routes (as defined in RFC 4098).

4.3.  Policy Processing/Reconfiguration

   The DUT MUST run one baseline test where policy is the Minimal policy
   as defined in RFC 4098.  Additional runs may be done with the policy
   that was set up before the tests began.  Exact policy settings MUST
   be documented as part of the test.

4.4.  Configured Parameters (Timers, etc.)

   There are configured parameters and timers that may impact the
   measured BGP convergence times.

   The benchmark metrics MAY be measured at any fixed values for these
   configured parameters.

   It is RECOMMENDED these configure parameters have the following
   settings: a) default values specified by the respective RFC, b)
   platform-specific default parameters, and c) values as expected in
   the operational network.  All optional BGP settings MUST be kept
   consistent across iterations of any specific tests

   Examples of the configured parameters that may impact measured BGP
   convergence time include, but are not limited to:

      1.  Interface failure detection timer

      2.  BGP keepalive timer

      3.  BGP holdtime

      4.  BGP update delay timer

      5.  ConnectRetry timer

      6.  TCP segment size

      7.  Minimum Route Advertisement Interval (MRAI)

      8.  MinASOriginationInterval (MAOI)

      9.  Route flap damping parameters

      10.  TCP Authentication Option (TCP AO or TCP MD5)

      11.  Maximum TCP window size

      12.  MTU

   The basic-test settings for the parameters should be:

      1.  Interface failure detection timer (0 ms)

      2.  BGP keepalive timer (1 min)

      3.  BGP holdtime (3 min)

      4.  BGP update delay timer (0 s)

      5.  ConnectRetry timer (1 s)

      6.  TCP segment size (4096 bytes)

      7.  Minimum Route Advertisement Interval (MRAI) (0 s)
      8.  MinASOriginationInterval (MAOI) (0 s)

      9.  Route flap damping parameters (off)

      10.  TCP Authentication Option (off)

4.5.  Interface Types

   The type of media dictates which test cases may be executed; each
   interface type has a unique mechanism for detecting link failures,
   and the speed at which that mechanism operates will influence the
   measurement results.  All interfaces MUST be of the same media and
   throughput for all iterations of each test case.

4.6.  Measurement Accuracy

   Since observed packet loss is used to measure the route convergence
   time, the time between two successive packets offered to each
   individual route is the highest possible accuracy of any packet-loss-
   based measurement.  When packet jitter is much less than the
   convergence time, it is a negligible source of error, and hence, it
   will be treated as within tolerance.

   Other options to measure convergence are the Time-Based Loss Method
   (TBLM) and Timestamp-Based Method (TBM) [RFC6414].

   An exterior measurement on the input media (such as Ethernet) is
   defined by this specification.

4.7.  Measurement Statistics

   The benchmark measurements may vary for each trial due to the
   statistical nature of timer expirations, CPU scheduling, etc.  It is
   recommended to repeat the test multiple times.  Evaluation of the
   test data must be done with an understanding of generally accepted
   testing practices regarding repeatability, variance, and statistical
   significance of a small number of trials.

   For any repeated tests that are averaged to remove variance, all
   parameters MUST remain the same.

4.8.  Authentication

   Authentication in BGP is done using the TCP Authentication Option
   [RFC5925].  (In some legacy situations, the authentication may still
   be with TCP MD5).  The processing of the authentication hash,
   particularly in devices with a large number of BGP peers and a large
   amount of update traffic, can have an impact on the control plane of
   the device.  If authentication is enabled, it MUST be documented
   correctly in the reporting format.

   Also, it is recommended that trials MUST be with the same Secure
   Inter-Domain Routing (SIDR) features [RFC7115] [BGPsec].  The best
   convergence tests would be with no SIDR features and then to repeat
   the convergence tests with the same SIDR features.

4.9.  Convergence Events

   Convergence events or triggers are defined as abnormal occurrences in
   the network, which initiate route flapping in the network and hence
   forces the reconvergence of a steady state network.  In a real
   network, a series of convergence events may cause convergence latency
   operators desire to test.

   These convergence events must be defined in terms of the sequences
   defined in RFC 4098.  This basic document begins all tests with a
   router initial setup.  Additional documents will define BGP data-
   plane convergence based on peer initialization.

   The convergence events may or may not be tied to the actual failure.
   A soft reset [RFC4098] does not clear the RIB or FIB tables.  A hard
   reset clears BGP peer sessions, RIB tables, and FIB tables.

4.10.  High Availability

   Due to the different Non-Stop-Routing (sometimes referred to High-
   Availability) solutions available from different vendors, it is
   RECOMMENDED that any redundancy available in the routing processors
   should be disabled during the convergence measurements.  For cases
   where the redundancy cannot be disabled, the results are no longer
   comparable and the level of impact on the measurements is out of
   scope of this document.

5.  Test Cases

   All tests defined under this section assume the following:

   a.  BGP peers are in Established state.

   b.  BGP state should be cleared from Established state to Idle prior
       to each test.  This is recommended to ensure that all tests start
       with BGP peers being forced back to Idle state and databases
       flushed.

   c.  Furthermore, the traffic generation and routing should be
       verified in the topology to ensure there is no packet loss
       observed on any advertised routes.

   d.  The arrival timestamp of advertised routes can be measured by
       installing an inline monitoring device between the emulator and
       the DUT or by using the span port of the DUT connected with an
       external analyzer.  The time base of such an inline monitor or
       external analyzer needs to be synchronized with the protocol and
       traffic emulator.  Some modern emulators may have the capability
       to capture and timestamp every NLRI packet leaving and arriving
       at the emulator ports.  The timestamps of these NLRI packets will
       be almost identical to the arrival time at the DUT if the cable
       distance between the emulator and DUT is relatively short.

5.1.  Basic Convergence Tests

   These test cases measure characteristics of a BGP implementation in
   non-failure scenarios like:

   1.  RIB-IN Convergence

   2.  RIB-OUT Convergence

   3.  eBGP Convergence

   4.  iBGP Convergence

5.1.1.  RIB-IN Convergence

   Objective:

      This test measures the convergence time taken to receive and
      install a route in RIB using BGP.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1

   Procedure:

   A.  All variables affecting convergence should be set to a basic test
       state (as defined in Section 4.4).

   B.  Establish BGP adjacency between the DUT and one peer of the
       emulator, Emp1.

   C.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   D.  Start the traffic from the emulator tx towards the DUT targeted
       at a route specified in the route mixture (e.g., routeA).
       Initially, no traffic SHOULD be observed on the egress interface
       as routeA is not installed in the forwarding database of the DUT.

   E.  Advertise routeA from the peer (Emp1) to the DUT and record the
       time.

          This is Tup(Emp1,Rt-A), also named XMT-Rt-time(Rt-A).

   F.  Record the time when routeA from Emp1 is received at the DUT.

          This is Tup(DUT,Rt-A), also named RCV-Rt-time(Rt-A).

   G.  Record the time when the traffic targeted towards routeA is
       received by the emulator on the appropriate traffic egress
       interface.

          This is TR(TDr,Rt-A), also named DUT-XMT-Data-Time(Rt-A).

   H.  The difference between the Tup(DUT,RT-A) and traffic received
       time (TR (TDr, Rt-A) is the FIB convergence time for routeA in
       the route mixture.  A full convergence for the route update is
       the measurement between the first route (Rt-A) and the last route
       (Rt-last).

          Route update convergence is

          TR(TDr, Rt-last)- Tup(DUT, Rt-A), or

          (DUT-XMT-Data-Time - RCV-Rt-Time)(Rt-A).

   Note: It is recommended that a single test with the same route
   mixture be repeated several times.  A report should provide the
   standard deviation and the average of all tests.

   Running tests with a varying number of routes and route mixtures is
   important to get a full characterization of a single peer.

5.1.2.  RIB-OUT Convergence

   Objective:

      This test measures the convergence time taken by an implementation
      to receive, install, and advertise a route using BGP.

   Reference Test Setup:

      This test uses the setup as shown in Figure 2.

   Procedure:

   A.  The Helper Node (HLP) MUST run same version of BGP as the DUT.

   B.  All devices MUST be synchronized using NTP or some local
       reference clock.

   C.  All configuration variables for the Helper Node, DUT, and
       emulator SHOULD be set to the same values.  These values MAY be
       basic test or a unique set completely described in the test
       setup.

   D.  Establish BGP adjacency between the DUT and the emulator.

   E.  Establish BGP adjacency between the DUT and the Helper Node.

   F.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   G.  Start the traffic from the emulator towards the Helper Node
       targeted at a specific route (e.g., routeA).  Initially, no
       traffic SHOULD be observed on the egress interface as routeA is
       not installed in the forwarding database of the DUT.

   H.  Advertise routeA from the emulator to the DUT and note the time.

          This is Tup(EMx, Rt-A), also named EM-XMT-Data-Time(Rt-A).

   I.  Record when routeA is received by the DUT.

          This is Tup(DUTr, Rt-A), also named DUT-RCV-Rt-Time(Rt-A).

   J.  Record the time when routeA is forwarded by the DUT towards the
       Helper Node.

          This is Tup(DUTx, Rt-A), also named DUT-XMT-Rt-Time(Rt-A).

   K.  Record the time when the traffic targeted towards routeA is
       received on the Route Egress Interface.  This is TR(EMr, Rt-A),
       also named DUT-XMT-Data Time(Rt-A).

          FIB convergence = (DUT-XMT-Data-Time -DUT-RCV-Rt-Time)(Rt-A)

          RIB convergence = (DUT-XMT-Rt-Time - DUT-RCV-Rt-Time)(Rt-A)

          Convergence for a route stream is characterized by

          a) individual route convergence for FIB and RIB, and

          b) all route convergence of

          FIB-convergence = DUT-XMT-Data-Time(last) - DUT-RCV-Rt-
          Time(first), and

          RIB-convergence = DUT-XMT-Rt-Time(last) - DUT-RCV-Rt-
          Time(first).

5.1.3.  eBGP Convergence

   Objective:

      This test measures the convergence time taken by an implementation
      to receive, install, and advertise a route in an eBGP Scenario.

   Reference Test Setup:

      This test uses the setup as shown in Figure 2, and the scenarios
      described in RIB-IN and RIB-OUT are applicable to this test case.

5.1.4.  iBGP Convergence

   Objective:

      This test measures the convergence time taken by an implementation
      to receive, install, and advertise a route in an iBGP Scenario.

   Reference Test Setup:

      This test uses the setup as shown in Figure 2, and the scenarios
      described in RIB-IN and RIB-OUT are applicable to this test case.

5.1.5.  eBGP Multihop Convergence

   Objective:

      This test measures the convergence time taken by an implementation
      to receive, install, and advertise a route in an eBGP Multihop
      Scenario.

   Reference Test Setup:

      This test uses the setup as shown in Figure 3.  The DUT is used
      along with a Helper Node.

   Procedure:

   A.  The Helper Node MUST run the same version of BGP as the DUT.

   B.  All devices MUST be synchronized using NTP or some local
       reference clock.

   C.  All variables affecting convergence, like authentication,
       policies, and timers, SHOULD be set to basic settings.

   D.  All three devices, the DUT, emulator, and Helper Node, are
       configured with different ASs.

   E.  Loopback interfaces are configured on the DUT and Helper Node,
       and connectivity is established between them using any config
       options available on the DUT.

   F.  Establish BGP adjacency between the DUT and the emulator.

   G.  Establish BGP adjacency between the DUT and the Helper Node.

   H.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test

   I.  Start the traffic from the emulator towards the DUT targeted at a
       specific route (e.g., routeA).

   J.  Initially, no traffic SHOULD be observed on the egress interface
       as routeA is not installed in the forwarding database of the DUT.

   K.  Advertise routeA from the emulator to the DUT and note the time
       (Tup(EMx,RouteA), also named Route-Tx-time(Rt-A).

   L.  Record the time when the route is received by the DUT.  This is
       Tup(EMr,DUT), also named Route-Rcv-time(Rt-A).

   M.  Record the time when the traffic targeted towards routeA is
       received from the egress interface of the DUT on the emulator.
       This is Tup(EMd,DUT) named Data-Rcv-time(Rt-A)

   N.  Record the time when routeA is forwarded by the DUT towards the
       Helper Node.  This is Tup(EMf,DUT), also named Route-Fwd-time(Rt-
       A).

          FIB Convergence = (Data-Rcv-time - Route-Rcv-time)(Rt-A)

          RIB Convergence = (Route-Fwd-time - Route-Rcv-time)(Rt-A)

   Note: It is recommended that the test be repeated with a varying
   number of routes and route mixtures.  With each set route mixture,
   the test should be repeated multiple times.  The results should
   record the average, mean, standard deviation.

5.2.  BGP Failure/Convergence Events

5.2.1.  Physical Link Failure on DUT End

   Objective:

      This test measures the route convergence time due to a local link
      failure event at the DUT's Local Interface.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1.  The shutdown event
      is defined as an administrative shutdown event on the DUT.

   Procedure:

   A.  All variables affecting convergence, like authentication,
       policies, and timers, should be set to basic-test policy.

   B.  Establish two BGP adjacencies from the DUT to the emulator, one
       over the peer interface and the other using a second peer
       interface.

   C.  Advertise the same route, routeA, over both adjacencies with
       preferences so that the Best Egress Interface for the preferred
       next hop is (Emp1) interface.

   D.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   E.  Start the traffic from the emulator towards the DUT targeted at a
       specific route (e.g., routeA).  Initially, traffic would be
       observed on the best egress route, Emp1, instead of Emp2.

   F.  Trigger the shutdown event of Best Egress Interface on the DUT
       (Dp1).  This time is called Shutdown time.

   G.  Measure the convergence time for the event to be detected and
       traffic to be forwarded to Next-Best Egress Interface (Dp2).

          Time = Data-detect(Emp2) - Shutdown time

   H.  Stop the offered load and wait for the queues to drain.  Restart
       the data flow.

   I.  Bring up the link on the DUT's Best Egress Interface.

   J.  Measure the convergence time taken for the traffic to be rerouted
       from Dp2 to Best Egress Interface, Dp1.

          Time = Data-detect(Emp1) - Bring Up time

   K.  It is recommended that the test be repeated with a varying number
       of routes and route mixtures or with a number of routes and route
       mixtures closer to what is deployed in operational networks.

5.2.2.  Physical Link Failure on Remote/Emulator End

   Objective:

      This test measures the route convergence time due to a local link
      failure event at the Tester's Local Interface.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1.  The shutdown event
      is defined as a shutdown of the local interface of the Tester via
      a logical shutdown event.  The procedure used in Section 5.2.1 is
      used for the termination.

5.2.3.  ECMP Link Failure on DUT End

   Objective:

      This test measures the route convergence time due to a local link
      failure event at the ECMP member.  The FIB configuration and BGP
      are set to allow two ECMP routes to be installed.  However, policy
      directs the routes to be sent only over one of the paths.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1, and the procedure
      used in Section 5.2.1.

5.3.  BGP Adjacency Failure (Non-Physical Link Failure) on Emulator

   Objective:

      This test measures the route convergence time due to BGP Adjacency
      Failure on the emulator.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1.

   Procedure:

   A.  All variables affecting convergence, like authentication,
       policies, and timers, should be set to basic-policy.

   B.  Establish two BGP adjacencies from the DUT to the emulator: one
       over the Best Egress Interface and the other using the Next-Best
       Egress Interface.

   C.  Advertise the same route, routeA, over both adjacencies with
       preferences so that the Best Egress Interface for the preferred
       next hop is (Emp1) interface.

   D.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   E.  Start the traffic from the emulator towards the DUT targeted at a
       specific route (e.g., routeA).  Initially, traffic would be
       observed on the Best Egress Interface.

   F.  Remove BGP adjacency via a software adjacency down on the
       emulator on the Best Egress Interface.  This time is called
       BGPadj-down-time, also termed BGPpeer-down.

   G.  Measure the convergence time for the event to be detected and
       traffic to be forwarded to Next-Best Egress Interface.  This time
       is Tr-rr2, also called TR2-traffic-on.

          Convergence = TR2-traffic-on - BGPpeer-down

   H.  Stop the offered load and wait for the queues to drain and
       restart the data flow.

   I.  Bring up BGP adjacency on the emulator over the Best Egress
       Interface.  This time is BGP-adj-up, also called BGPpeer-up.

   J.  Measure the convergence time taken for the traffic to be rerouted
       to the Best Egress Interface.  This time is Tr-rr1, also called
       TR1-traffic-on.

          Convergence = TR1-traffic-on - BGPpeer-up

5.4.  BGP Hard Reset Test Cases

5.4.1.  BGP Non-Recovering Hard Reset Event on DUT

   Objective:

      This test measures the route convergence time due to a hard reset
      on the DUT.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1.

   Procedure:

   A.  The requirement for this test case is that the hard reset event
       should be non-recovering and should affect only the adjacency
       between the DUT and the emulator on the Best Egress Interface.

   B.  All variables affecting the test SHOULD be set to basic-test
       values.

   C.  Establish two BGP adjacencies from the DUT to the emulator: one
       over the Best Egress Interface and the other using the Next-Best
       Egress Interface.

   D.  Advertise the same route, routeA, over both adjacencies with
       preferences so that the Best Egress Interface for the preferred
       next hop is (Emp1) interface.

   E.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   F.  Start the traffic from the emulator towards the DUT targeted at a
       specific route (e.g., routeA).  Initially, traffic would be
       observed on the Best Egress Interface.

   G.  Trigger the hard reset event of the Best Egress Interface on the
       DUT.  This time is called time reset.

   H.  This event is detected and traffic is forwarded to the Next-Best
       Egress Interface.  This time is called time-traffic flow.

   I.  Measure the convergence time for the event to be detected and
       traffic to be forwarded to Next-Best Egress Interface.

          Time of convergence = time-traffic flow - time-reset

   J.  Stop the offered load and wait for the queues to drain and
       restart.

   K.  It is recommended that the test be repeated with a varying number
       of routes and route mixtures or with a number of routes and route
       mixtures closer to what is deployed in operational networks.

   L.  When varying number of routes are used, convergence time is
       measured using the Loss-Derived method [RFC6412].

   M.  Convergence time in this scenario is influenced by failure
       detection time on the Tester, BGP keepalive time and routing, and
       forwarding table update time.

5.5.  BGP Soft Reset

   Objective:

      This test measures the route convergence time taken by an
      implementation to service a BGP Route Refresh message and
      advertise a route.

   Reference Test Setup:

      This test uses the setup as shown in Figure 2.

   Procedure:

   A.  The BGP implementation on the DUT and Helper Node needs to
       support BGP Route Refresh Capability [RFC2918].

   B.  All devices MUST be synchronized using NTP or some local
       reference clock.

   C.  All variables affecting convergence, like authentication,
       policies, and timers, should be set to basic-test defaults.

   D.  The DUT and the Helper Node are configured in the same AS,
       whereas the emulator is configured under a different AS.

   E.  Establish BGP adjacency between the DUT and the emulator.

   F.  Establish BGP adjacency between the DUT and the Helper Node.

   G.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   H.  Configure a policy under the BGP on the Helper Node to deny
       routes received from the DUT.

   I.  Advertise routeA from the emulator to the DUT.

   J.  The DUT will try to advertise the route to the Helper Node; it
       will be denied.

   K.  Wait for three keepalives.

   L.  Start the traffic from the emulator towards the Helper Node
       targeted at a specific route, say routeA.  Initially, no traffic
       would be observed on the egress interface, as routeA is not
       present.

   M.  Remove the policy on the Helper Node and issue a route refresh
       request towards the DUT.  Note the timestamp of this event.  This
       is the RefreshTime.

   N.  Record the time when the traffic targeted towards routeA is
       received on the egress interface.  This is RecTime.

   O.  The following equation represents the Route Refresh Convergence
       Time per route.

          Route Refresh Convergence Time = (RecTime - RefreshTime)

5.6.  BGP Route Withdrawal Convergence Time

   Objective:

      This test measures the route convergence time taken by an
      implementation to service a BGP withdraw message and advertise the
      withdraw.

   Reference Test Setup:

      This test uses the setup as shown in Figure 2.

   Procedure:

   A.  This test consists of two steps to determine the Total Withdraw
       Processing Time.

   B.  Step 1:

       (1)   All devices MUST be synchronized using NTP or some local
             reference clock.

       (2)   All variables should be set to basic-test parameters.

       (3)   The DUT and Helper Node are configured in the same AS,
             whereas the emulator is configured under a different AS.

       (4)   Establish BGP adjacency between the DUT and the emulator.

       (5)   To ensure adjacency establishment, wait for three
             keepalives to be received from the DUT or a configurable
             delay before proceeding with the rest of the test.

       (6)   Start the traffic from the emulator towards the DUT
             targeted at a specific route (e.g., routeA).  Initially, no
             traffic would be observed on the egress interface as routeA
             is not present on the DUT.

       (7)   Advertise routeA from the emulator to the DUT.

       (8)   The traffic targeted towards routeA is received on the
             egress interface.

       (9)   Now the Tester sends a request to withdraw routeA to the
             DUT.  TRx(Awith) is also called WdrawTime1(Rt-A).

       (10)  Record the time when no traffic is observed as determined
             by the emulator.  This is the RouteRemoveTime1(Rt-A).

       (11)  The difference between the RouteRemoveTime1 and WdrawTime1
             is the WdrawConvTime1.

                WdrawConvTime1(Rt-A) = RouteRemoveTime1(Rt-A) -
                WdrawTime1(Rt-A)

   C.  Step 2:

       (1)  Continuing from Step 1, re-advertise routeA back to the DUT
            from the Tester.

       (2)  The DUT will try to advertise routeA to the Helper Node
            (this assumes there exists a session between the DUT and
            Helper Node).

       (3)  Start the traffic from the emulator towards the Helper Node
            targeted at a specific route (e.g., routeA).  Traffic would
            be observed on the egress interface after routeA is received
            by the Helper Node.

               WATime=time traffic first flows

       (4)  Now the Tester sends a request to withdraw routeA to DUT.
            This is the WdrawTime2(Rt-A).

               WAWtime-TRx(Rt-A) = WdrawTime2(Rt-A)

       (5)  DUT processes the withdraw and sends it to the Helper Node.

       (6)  Record the time when no traffic is observed as determined by
            the emulator.  This is:

               TR-WAW(DUT,RouteA) = RouteRemoveTime2(Rt-A)

       (7)  Total Withdraw Processing Time is:

               TotalWdrawTime(Rt-A) = ((RouteRemoveTime2(Rt-A) -
               WdrawTime2(Rt-A)) - WdrawConvTime1(Rt-A))

5.7.  BGP Path Attribute Change Convergence Time

   Objective:

      This test measures the convergence time taken by an implementation
      to service a BGP Path Attribute Change.

   Reference Test Setup:

      This test uses the setup as shown in Figure 1.

   Procedure:

   A.  This test only applies to Well-Known Mandatory Attributes like
       origin, AS path, and next hop.

   B.  In each iteration of the test, only one of these mandatory
       attributes need to be varied whereas the others remain the same.

   C.  All devices MUST be synchronized using NTP or some local
       reference clock.

   D.  All variables should be set to basic-test parameters.

   E.  Advertise the same route, routeA, over both adjacencies with
       preferences so that the Best Egress Interface for the preferred
       next hop is (Emp1) interface.

   F.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   G.  Start the traffic from the emulator towards the DUT targeted at
       the specific route (e.g., routeA).  Initially, traffic would be
       observed on the Best Egress Interface.

   H.  Now advertise the same route, routeA, on the Next-Best Egress
       Interface but by varying one of the well-known mandatory
       attributes to have a preferred value over that interface.  We
       call this Tbetter.  The other values need to be the same as what
       was advertised on the Best-Egress adjacency.

          TRx(Path-Change(Rt-A)) = Path Change Event Time(Rt-A)

   I.  Measure the convergence time for the event to be detected and
       traffic to be forwarded to Next-Best Egress Interface.

          DUT(Path-Change, Rt-A) = Path-switch time(Rt-A)

          Convergence = Path-switch time(Rt-A) - Path Change Event
          Time(Rt-A)

   J.  Stop the offered load and wait for the queues to drain and
       restart.

   K.  Repeat the test for various attributes.

5.8.  BGP Graceful Restart Convergence Time

   Objective:

      This test measures the route convergence time taken by an
      implementation during a Graceful Restart Event as detailed in the
      terminology document [RFC4098].

   Reference Test Setup:

      This test uses the setup as shown in Figure 4.

   Procedure:

   A.  It measures the time taken by an implementation to service a BGP
       Graceful Restart Event and advertise a route.

   B.  The Helper Nodes are the same model as the DUT and run the same
       BGP implementation as the DUT.

   C.  The BGP implementation on the DUT and Helper Node needs to
       support the BGP Graceful Restart Mechanism [RFC4724].

   D.  All devices MUST be synchronized using NTP or some local
       reference clock.

   E.  All variables are set to basic-test values.

   F.  The DUT and Helper Node 1 (HLP1) are configured in the same AS,
       whereas the emulator and Helper Node 2 (HLP2) are configured
       under different ASs.

   G.  Establish BGP adjacency between the DUT and Helper Nodes.

   H.  Establish BGP adjacency between the Helper Node 2 and the
       emulator.

   I.  To ensure adjacency establishment, wait for three keepalives to
       be received from the DUT or a configurable delay before
       proceeding with the rest of the test.

   J.  Configure a policy under the BGP on Helper Node 1 to deny routes
       received from the DUT.

   K.  Advertise routeA from the emulator to Helper Node 2.

   L.  Helper Node 2 advertises the route to the DUT and the DUT will
       try to advertise the route to Helper Node 1, which will be
       denied.

   M.  Wait for three keepalives.

   N.  Start the traffic from the emulator towards the Helper Node 1
       targeted at the specific route (e.g., routeA).  Initially, no
       traffic would be observed on the egress interface as routeA is
       not present.

   O.  Perform a Graceful Restart Trigger Event on the DUT and note the
       time.  This is the GREventTime.

   P.  Remove the policy on Helper Node 1.

   Q.  Record the time when the traffic targeted towards routeA is
       received on the egress interface.

          This is TRr(DUT, routeA), also called RecTime(Rt-A).

   R.  The following equation represents the Graceful Restart
       Convergence Time.

          Graceful Restart Convergence Time(Rt-A) = ((RecTime(Rt-A) -
          GREventTime) - RIB-IN)

   S.  It is assumed in this test case that after a switchover is
       triggered on the DUT, it will not have any cycles to process the
       BGP Refresh messages.  The reason for this assumption is that
       there is a narrow window of time where after switchover, when we
       remove the policy from Helper Node 1, implementations might
       generate Route Refresh automatically and this request might be
       serviced before the DUT actually switches over and re-establishes
       BGP adjacencies with the peers.

6.  Reporting Format

   For each test case, it is recommended that the reporting tables below
   are completed, and all time values SHOULD be reported with resolution
   as specified in [RFC4098].

 Parameter                        Units or Description
 ===========================      ==========================
 Test case                        Test case number

 Test topology                    1, 2, 3, or 4

 Parallel links                   Number of parallel links

 Interface type                   Gigabit Ethernet (GigE),
                                  Packet over SONET (POS), ATM, other

 Convergence Event                Hard reset, soft reset, link
                                  failure, or other defined

 eBGP sessions                    Number of eBGP sessions

 iBGP sessions                    Number of iBGP sessions

 eBGP neighbor                    Number of eBGP neighbors

 iBGP neighbor                    Number of iBGP neighbors

 Routes per peer                  Number of routes

 Total unique routes              Number of routes

 Total non-unique routes          Number of routes

 IGP configured                   IS-IS, OSPF, static, or other

 Route mixture                    Description of route mixture

 Route packing                    Number of routes included in an update

 Policy configured                Yes, No

 SIDR origin authentication       Yes, No
 [RFC7115]

 bgp-sec [BGPsec]                 Yes, No
 Packet size offered              Bytes
 to the DUT

 Offered load                     Packets per second

 Packet sampling interval         Seconds
 on Tester

 Forwarding delay threshold       Seconds

 Timer values configured on DUT

   Interface failure              Seconds
    indication delay
   Hold time                      Seconds
   MinRouteAdvertisementInterval  Seconds
      (MRAI)
   MinASOriginationInterval       Seconds
      (MAOI)
   Keepalive time                 Seconds
   ConnectRetry                   Seconds

 TCP parameters for DUT and Tester
   Maximum Segment Size (MSS)     Bytes
   Slow start threshold           Bytes
   Maximum window size            Bytes

   Test Details:

   a.  If the Offered Load matches a subset of routes, describe how this
       subset is selected.

   b.  Describe how the convergence event is applied; does it cause
       instantaneous traffic loss or not?

   c.  If there is any policy configured, describe the configured
       policy.

   Complete the table below for the initial convergence event and the
   reversion convergence event.

        Parameter                        Unit
        ===========================      ==========================
        Convergence Event                Initial or reversion

        Traffic Forwarding Metrics
          Total number of packets        Number of packets
           offered to the DUT
          Total number of packets        Number of packets
           forwarded by the DUT
          Connectivity packet loss       Number of packets
          Convergence packet loss        Number of packets
          Out-of-order packets           Number of packets
          Duplicate packets              Number of packets

        Convergence Benchmarks

          Rate-Derived Method [RFC6412]:
           First route convergence       Seconds
            time
           Full convergence time         Seconds

          Loss-Derived Method [RFC6412]:
           Loss-Derived convergence      Seconds
            time

          Route-Specific (R-S) Loss-Derived
          Method:
           Minimum R-S convergence       Seconds
            time
           Maximum R-S convergence       Seconds
            time
           Median R-S convergence        Seconds
            time
           Average R-S convergence       Seconds
            time

        Loss of Connectivity (LoC) Benchmarks

          Loss-Derived Method:
           Loss-Derived loss of          Seconds
            connectivity period
          Route-Specific Loss-Derived
           Method:
           Minimum LoC period [n]        Array of seconds
           Minimum Route LoC period      Seconds
           Maximum Route LoC period      Seconds
           Median Route LoC period       Seconds
           Average Route LoC period      Seconds

7.  Security Considerations

   Benchmarking activities as described in this memo are limited to
   technology characterization using controlled stimuli in a laboratory
   environment, with dedicated address space and the constraints
   specified in the sections above.

   The benchmarking network topology is an independent test setup and
   MUST NOT be connected to devices that may forward the test traffic
   into a production network or misroute traffic to the test management
   network.

   Further, benchmarking is performed on a "black-box" basis, relying
   solely on measurements observable and external to the DUT/SUT.

   Special capabilities SHOULD NOT exist in the DUT/SUT specifically for
   benchmarking purposes.  Any implications for network security arising
   from the DUT/SUT SHOULD be identical in the lab and in production
   networks.

8.  References

8.1.  Normative References

   [IEEE.802.11]
              IEEE, "IEEE Standard for Information technology --
              Telecommunications and information exchange between
              systems Local and metropolitan area networks -- Specific
              requirements Part 11: Wireless LAN Medium Access Control
              (MAC) and Physical Layer (PHY) Specifications",
              IEEE 802.11-2012, DOI 10.1109/ieeestd.2012.6178212, April
              2012, <http://ieeexplore.ieee.org/servlet/
              opac?punumber=6178209>.

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

   [RFC2918]  Chen, E., "Route Refresh Capability for BGP-4", RFC 2918,
              DOI 10.17487/RFC2918, September 2000,
              <http://www.rfc-editor.org/info/rfc2918>.

   [RFC4098]  Berkowitz, H., Davies, E., Ed., Hares, S., Krishnaswamy,
              P., and M. Lepp, "Terminology for Benchmarking BGP Device
              Convergence in the Control Plane", RFC 4098,
              DOI 10.17487/RFC4098, June 2005,
              <http://www.rfc-editor.org/info/rfc4098>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <http://www.rfc-editor.org/info/rfc4271>.

   [RFC6412]  Poretsky, S., Imhoff, B., and K. Michielsen, "Terminology
              for Benchmarking Link-State IGP Data-Plane Route
              Convergence", RFC 6412, DOI 10.17487/RFC6412, November
              2011, <http://www.rfc-editor.org/info/rfc6412>.

8.2.  Informative References

   [BGPsec]   Lepinski, M. and K. Sriram, "BGPsec Protocol
              Specification", Work in Progress, draft-ietf-sidr-bgpsec-
              protocol-15, March 2016.

   [RFC1242]  Bradner, S., "Benchmarking Terminology for Network
              Interconnection Devices", RFC 1242, DOI 10.17487/RFC1242,
              July 1991, <http://www.rfc-editor.org/info/rfc1242>.

   [RFC1983]  Malkin, G., Ed., "Internet Users' Glossary", FYI 18,
              RFC 1983, DOI 10.17487/RFC1983, August 1996,
              <http://www.rfc-editor.org/info/rfc1983>.

   [RFC2285]  Mandeville, R., "Benchmarking Terminology for LAN
              Switching Devices", RFC 2285, DOI 10.17487/RFC2285,
              February 1998, <http://www.rfc-editor.org/info/rfc2285>.

   [RFC2545]  Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol
              Extensions for IPv6 Inter-Domain Routing", RFC 2545,
              DOI 10.17487/RFC2545, March 1999,
              <http://www.rfc-editor.org/info/rfc2545>.

   [RFC4724]  Sangli, S., Chen, E., Fernando, R., Scudder, J., and Y.
              Rekhter, "Graceful Restart Mechanism for BGP", RFC 4724,
              DOI 10.17487/RFC4724, January 2007,
              <http://www.rfc-editor.org/info/rfc4724>.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <http://www.rfc-editor.org/info/rfc4760>.

   [RFC5925]  Touch, J., Mankin, A., and R. Bonica, "The TCP
              Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
              June 2010, <http://www.rfc-editor.org/info/rfc5925>.

   [RFC6414]  Poretsky, S., Papneja, R., Karthik, J., and S. Vapiwala,
              "Benchmarking Terminology for Protection Performance",
              RFC 6414, DOI 10.17487/RFC6414, November 2011,
              <http://www.rfc-editor.org/info/rfc6414>.

   [RFC7115]  Bush, R., "Origin Validation Operation Based on the
              Resource Public Key Infrastructure (RPKI)", BCP 185,
              RFC 7115, DOI 10.17487/RFC7115, January 2014,
              <http://www.rfc-editor.org/info/rfc7115>.

Acknowledgements

   We would like to thank Anil Tandon, Arvind Pandey, Mohan Nanduri, Jay
   Karthik, and Eric Brendel for their input and discussions on various
   sections in the document.  We also like to acknowledge Will Liu,
   Hubert Gee, Semion Lisyansky, and Faisal Shah for their review and
   feedback on the document.

Authors' Addresses

   Rajiv Papneja
   Huawei Technologies

   Email: rajiv.papneja@huawei.com


   Bhavani Parise
   Skyport Systems

   Email: bparise@skyportsystems.com


   Susan Hares
   Huawei Technologies

   Email: shares@ndzh.com


   Dean Lee
   IXIA

   Email: dlee@ixiacom.com

   Ilya Varlashkin
   Google

   Email: ilya@nobulus.com

AI ELI5

On this page
PROBLEMInternet routing depends on BGP to switch traffic to alternate paths when links fail. Service providers want to know: how fast does a router converge? But without a standard way to measure, vendors report different numbers and comparisons are meaningless.
MECHANISMThis RFC defines a standardized methodology for benchmarking BGP data-plane convergence. It specifies test topologies with three or four nodes, documented procedures for triggering failures and measuring timing, parameter settings, and how to report results so that different routers can be compared fairly.
WHY IT MATTERSService providers can now measure and compare how quickly routers update their forwarding tables after BGP route changes or failures, enabling informed purchasing decisions and network design choices.

§1BGP Convergence and Data-Plane Performance

The Border Gateway Protocol (BGP) is the routing protocol of the Internet. When a link fails or a BGP peer goes down, BGP must find an alternate path. The routing information base (RIB) receives updates, and the forwarding information base (FIB) is recalculated and updated to switch traffic to the new route.

Convergence time is how long this takes. Service providers care about convergence time because even a few seconds of packet loss can affect critical applications. Network operators want to minimize convergence time and ensure their routers are fast.

However, vendors reported convergence times in different ways, making it impossible to compare a Cisco router to a Juniper router, or to compare older versions to newer ones. This RFC solves that problem by defining a standard methodology.

The focus is on data-plane convergence (how fast the FIB updates), not control-plane convergence (how fast the RIB updates). It applies to both IPv4 and IPv6, and covers both eBGP (external, between autonomous systems) and iBGP (internal, within an autonomous system).

BGP is the system that tells routers how to send traffic across the Internet. When a route breaks, it takes time to find a new one. This explains how to measure that time fairly so routers can be compared.

§2Test Topologies and Setup

The RFC defines four standard test topologies, each with three to four nodes:

Basic test setup: A Device Under Test (DUT) has two routing interfaces connected to an emulator that simulates multiple BGP peers and generates traffic. This is used for basic convergence tests.

Three-node setup: A Helper Node runs the same BGP version as the DUT. The DUT is connected to both the Helper Node and an emulator. This setup measures RIB-OUT convergence (how fast the DUT forwards new routes to its neighbors).

eBGP Multihop setup: Similar to three-node but includes loopback interfaces. It measures multihop eBGP convergence where the BGP session is not directly between adjacent routers.

Four-node setup: A more complex topology with two Helper Nodes connected in series with the DUT. It can measure convergence in iBGP or eBGP scenarios with more intermediate nodes.

All devices must be synchronized using NTP to ensure timestamps are accurate. Traffic flows in and out of the DUT, and convergence is measured by watching when traffic successfully traverses the DUT after a route change.

The test uses a simple network with a router being tested (DUT) and other devices that pretend to be neighbors. When a route breaks, the test measures how long until traffic flows again.

§3Convergence Test Cases

The RFC defines multiple test cases to measure different aspects of convergence:

RIB-IN Convergence: Measures how fast a route received from a neighbor is installed in the routing information base. A neighbor advertises a route, and the test records when the DUT sends data traffic over that route.

RIB-OUT Convergence: Measures how fast the DUT receives a route, installs it, and advertises it to another neighbor. This involves three devices: emulator (source), DUT (middle), and Helper Node (destination).

eBGP and iBGP Convergence: Similar to RIB-OUT but specifically for external BGP (between autonomous systems) or internal BGP (within an autonomous system).

eBGP Multihop Convergence: Tests convergence when BGP peers are not directly connected but several hops apart.

Failure-triggered convergence: Instead of advertising a new route, the test simulates a physical link failure, BGP adjacency failure, or other error condition on the DUT, and measures how long until traffic reroutes.

Route withdrawal: Measures convergence when a route is withdrawn (deleted), forcing traffic to use an alternate path.

Path attribute changes and graceful restart: Test how convergence is affected when route attributes change or when BGP graceful restart mechanisms are used.

For each test, the procedure specifies exactly what to do: establish peers, start traffic, advertise routes, record timestamps, and calculate convergence time as the difference between when a route is received and when data traffic is observed on the egress interface.

Different tests measure different things: how fast a route is learned, how fast it is shared with neighbors, and how fast traffic switches when a route breaks. Each test has exact steps so everyone does it the same way.

§4Configuration and Measurement Parameters

Many parameters affect BGP convergence time. To enable fair comparison, the RFC specifies which parameters to use in baseline tests:

BGP timers: Keepalive interval (default 1 minute), holdtime (default 3 minutes), update delay timer (default 0 seconds), ConnectRetry timer (default 1 second), and MinASOriginationInterval (default 0).

TCP parameters: Segment size (default 4096 bytes), maximum window size, MTU (maximum transmission unit), and authentication method (TCP AO or TCP MD5).

Route advertisement parameters: Minimum Route Advertisement Interval (MRAI, default 0 seconds) controls how fast consecutive route updates are sent.

Link failure detection: Interface failure detection timer (default 0 ms for immediate detection).

Policy settings: Route filtering policies should be set to a minimal policy for baseline tests.

For baseline tests, most of these should be set to defaults or zero. However, operators might also run tests with their real-world parameters to see how convergence is affected. All settings must be documented in the test report.

Tests should be repeated multiple times with different route mixtures and numbers of routes. Results should report average, mean, and standard deviation to account for variability.

Many things can slow down convergence: waiting for timer to expire, authentication processing, route filtering. The test says which settings to use so that different routers are tested fairly.

§5Measurement Accuracy and Reporting

Convergence is measured using packet loss as the timing signal. When data traffic targeted at a route stops arriving at the egress interface, that is when the FIB has not yet been updated. When traffic starts arriving again, the FIB has been updated and convergence is complete. The convergence time is the gap between when the route change occurred and when traffic arrives.

Accuracy depends on the packet transmission interval. If packets are sent every 100 milliseconds, convergence can be measured with a resolution of 100 ms. For better accuracy, the RFC mentions alternative methods: Time-Based Loss Method (TBLM) and Timestamp-Based Method (TBM) defined in RFC 6414.

Devices must have synchronized time (using NTP) and measurement instruments must capture the exact moment of route advertisement and the moment traffic is received.

Results should be reported in a standard format documenting:

  • Test setup (topology, number of peers, number of routes per peer)
  • Configuration parameters (all timer values, policies, authentication)
  • Route mixture and advertisement rate
  • For each test run: the route that triggered convergence, the convergence time in milliseconds, and packet loss during convergence
  • Statistical summary: average, standard deviation, minimum, and maximum convergence times across multiple runs

The test watches when traffic stops arriving and when it starts again after a route change. The time between those two events is the convergence time. Tests should be done several times and results should show the average and how much they vary.

§6Status and Use

RFC 7747 is an Informational RFC published in April 2016 and has not been obsoleted. It has become the industry standard for benchmarking BGP convergence and is widely used by vendors and service providers.

The RFC defines methodology for basic convergence tests using simple topologies. More complex scenarios (IGP interaction, VPN convergence, segment routing) are not covered and may be defined in future documents.

The methodology enables standardized, repeatable measurements that can be compared across different router platforms and software versions, allowing operators to make informed decisions about network equipment and network design.

This document set the standard that everybody uses now. It makes it possible to fairly compare how fast different routers are at switching to backup paths.

§7References