Network Working Group
   INTERNET-DRAFT
   Expires in: July 2004 January 2005
                                                   Scott Poretsky
                                                   Quarry Technologies

                                                   Brent Imhoff
						   Wiltel Communications

						   January

						   July 2004

             	  	Terminology for Benchmarking
		      IGP Data Plane Route Convergence

		<draft-ietf-bmwg-igp-dataplane-conv-term-02.txt>

		<draft-ietf-bmwg-igp-dataplane-conv-term-03.txt>

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   Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

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   ABSTRACT
   This draft describes the terminology for benchmarking IGP Route
   Convergence as described in Applicability document [1] and
   Methodology document [2].  The methodology and terminology is to
   be used for benchmarking Route Convergence and can be applied to
   any link-state IGP such as ISIS [3] and OSPF [4].  The data plane
   is measured to obtain the convergence benchmarking metrics
   described in [2].

           	      IGP Data Plane Route Convergence

   Table of Contents

     1. Introduction .................................................2
     2. Existing definitions .........................................2 .........................................3
     3. Term definitions..............................................3
	3.1 Convergence Event.........................................3
	3.2 Network Convergence.......................................3
 	3.3 Route Convergence.........................................4
	3.3 Network Convergence.......................................4
	3.4 Full Convergence..........................................4 Convergence..........................................5
	3.5 Convergence Packet Loss...................................5
	3.6 Convergence Event Instant.................................5 Instant.................................6
	3.7 Convergence Recovery Instant..............................6
	3.8 Rate-Derived Convergence Time.............................6 Time.............................7
	3.9 Convergence Event Transition..............................7
	3.10 Convergence Recovery Transition..........................7 Transition..........................8
	3.11 Loss-Derived Convergence Time............................8
	3.12 Sustained Forwarding Convergence Time...................................9
           	      IGP Data Plane Route Convergence Time....................9
	3.13 Restoration Convergence Time.............................9
	3.14 Packet Sampling Interval.................................10
	3.15 Local Interface..........................................10
	3.16 Neighbor Interface.......................................11
	3.17  Remote Interface.........................................11 Interface........................................11
	3.18 Preferred Egress Interface...............................11
	3.19  Next-Best Egress Interface...............................12 Interface..............................12
	3.20 Stale Forwarding.........................................12
     4. Security Considerations.......................................12 Considerations.......................................13
     5. References....................................................13
     6. Author's Address..............................................13
     7. Full Copyright Statement......................................14

   1. Introduction
   This draft describes the terminology for benchmarking IGP Route
   Convergence.  The motivation and applicability for this
   benchmarking is provided in [1].  The methodology to be used for
   this benchmarking is described in [2].  The methodology and
   terminology to be used for benchmarking route convergence Route Convergence can be
   applied to any link-state IGP such as ISIS [3] and OSPF [4].  The
   data plane is measured to obtain black-box (externally observable)
   convergence benchmarking metrics.  The purpose of this document is
   to introduce new terms required to complete execution of the IGP
   Route Convergence Methodology [2].

   An example of Route Convergence as observed and measured from the
   data plane is shown in Figure 1.  The graph in Figure 1 shows
   Forwarding Rate versus Time.  Time 0 on the X-axis is on the far
   right of the graph.  The components of the graph and metrics are
   defined in the Term Definitions section of this document.

		            Recovery section.

           	      IGP Data Plane Route Convergence

                           Convergence    Convergence
                           Recovery         Event
                           Instant         Instant      Time = 0sec
	Maximum		       ^	      ^		    ^
	Forwarding Rate--> ----\    Packet   /---------------
				\    Loss   /<----Convergence
	      Convergence------->\	   /  	  Event Transition
	Recovery Transition	  \	  /
				   \_____/<------100% Packet Loss

	X-axis = Time
	Y-axis = Forwarding Rate
			Figure 1. Convergence Graph

   2.  Existing definitions
   For the sake of clarity and continuity this RFC adopts the template
   for definitions set out in Section 2 of RFC 1242.  Definitions are
   indexed and grouped together in sections for ease of reference.
   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.

           	      IGP Data Plane Route Convergence

   3. Term Definitions

   3.1 Convergence Event

	Definition:
	The occurrence of a planned or unplanned action in the network
	that results in a change to an entry in the route table. egress interface of the DUT for
	routed packets.

	Discussion:
	Convergence Events include link loss, routing protocol session
	loss, router failure, configuration change, and better next-hop. next-hop
	learned via a routing protocol.

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Convergence Packet Loss
	Convergence Event Instant

   3.2 Network Convergence

	Definition:
	The completion of updating of all routing tables, including the
	FIB, in all routers throughout the network.

	Discussion:
	Network Convergence can be approximated to the sum of Route
	Convergence for all routers in the network.  Network Convergence
	can be determined by recovery of the forwarding rate to equal
	the offer load, no stale forwarding, and no blenders[5][6].

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Route Convergence
	Stale Forwarding
           	      IGP Data Plane Route Convergence

   3.3

   3.2 Route Convergence

	Definition:
	Recovery from a Convergence Event indicated by the DUT
	forwarding rate equal to the offered load.

	Discussion:
	Route Convergence is the action of all components of the router
	being updated with the most recent route change(s) including the
	RIB and FIB, along with software and hardware tables. Route
	Convergence can be observed externally by the rerouting of data
	Traffic to a new egress interface.

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Network Convergence
	Full Convergence
  	Convergence Event

   3.4 Full

   3.3 Network Convergence

	Definition:
	Route Convergence for an entire FIB.
	The completion of updating of all routing tables, including the
	FIB, in all routers throughout the network.

	Discussion:
	When benchmarking convergence it
	Network Convergence is useful to measure bounded by the time to converge an entire route sum of Route Convergence
	for all routers in the network.  Network Convergence can be
	determined by recovery of the forwarding rate to equal the offered
	load, no Stale Forwarding, and no blenders[5][6].

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Route Convergence
	Stale Forwarding
           	      IGP Data Plane Route Convergence

   3.4 Full Convergence
	Definition:
	Route Convergence for an entire FIB.

	Discussion:
	When benchmarking convergence it is useful to measure
	the time to converge an entire route table.  For example,

	a Convergence Event can be produced for an OSPF table of 5000
	routes so that the time to converge routes 1 through 5000
	is measured.

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Network Convergence
	Route Convergence
  	Convergence Event
           	      IGP Data Plane Route Convergence

   3.5 Convergence Packet Loss

	Definition:
	The amount of packet loss produced by a Convergence Event
	until Route Convergence occurs.

	Discussion:
	Packet loss can be observed as a reduction of forwarded traffic from
	the maximum forwarding rate.  Convergence Packet Loss include packets
	that were lost and packets that were delayed due to buffering.

	Measurement Units:
	number of packets

	Issues:
	None

	See Also:
	Route Convergence
	Convergence Event
	Rate-Derived Convergence Time
	Loss-Derived Convergence Time
           	      IGP Data Plane Route Convergence

   3.6 Convergence Event Instant

	Definition:
	The time instant that a Convergence Event occurs. becomes observable in the
	data plane.

	Discussion:
	Convergence Event Instant is observable from the data
	plane as the precise time that the device under test begins
	to exhibit packet loss.

	Measurement Units:
	hh:mm:ss:uuu

	Issues:
	None

	See Also:
	Convergence Event
	Convergence Packet Loss
	Convergence Recovery Instant
           	      IGP Data Plane Route Convergence

   3.7 Convergence Recovery Instant

	Definition:
	The time instant that Full Convergence is measured
	and maintained for at least an additional five seconds.

	Discussion:
	Convergence Recovery Instant is measurable from the data
	plane as the precise time that the device under test
	achieves Full Convergence.  Convergence Recovery Instant
	is externally observable from the data plane when the
	forwarding rate on the Next-Best Egress Interface equals
	the offered rate.

	Measurement Units:
	hh:mm:ss:uuu

	Issues:
	None

	See Also:
	Convergence Packet Loss
	Convergence Event Instant
           	      IGP Data Plane Route Convergence

   3.8 Rate-Derived Convergence Time
	Definition:
	The amount of time for Convergence Packet Loss to
	persist upon occurrence of a Convergence Event until
	occurrence of Route Convergence.

	Discussion:

	Rate-Derived Convergence Time can be measured as the time
	difference from the Convergence Event Instant to the
	Convergence Recovery Instant, as shown with Equation 1.

	(eq 1)	Rate-Derived Convergence Time =
		Convergence Recovery Instant - Convergence Event Instant.

	Rate-Derived Convergence Time should be measured at the maximum
	forwarding rate.  Failure to achieve Full Convergence results in
	a Rate-Derived Convergence Time benchmark of infinity.

	Measurement Units:
	seconds/milliseconds

	Issues:
	None

	See Also:
	Convergence Packet Loss
	Convergence Recovery Instant
	Convergence Event Instant
	Full Convergence
           	      IGP Data Plane Route Convergence

   3.9 Convergence Event Transition
	Definition:
	The characteristic of a router in which forwarding rate
	gradually reduces to zero after a Convergence Event.

	Discussion:
	The Convergence Event Transition is best observed for
	Full Convergence.

	Measurement Units:
	seconds/milliseconds

	Issues:
	None

	See Also:
	Convergence Event
	Rate-Derived Convergence Time
	Convergence Packet Loss
	Convergence Recovery Transition
           	      IGP Data Plane Route Convergence

   3.10 Convergence Recovery Transition

	Definition:
	The characteristic of a router in which forwarding rate
	gradually increases to equal the offered load.

	Discussion:
	The Convergence Recovery Transition is best observed for
	Full Convergence.

	Measurement Units:
	seconds/milliseconds

	Issues:
	None

	See Also:
	Full Convergence
	Rate-Derived Convergence Time
	Convergence Packet Loss
	Convergence Event Transition
           	      IGP Data Plane Route Convergence

   3.11 Loss-Derived Convergence Time

	Definition:
	The amount of time it takes for Route Convergence to
	to be achieved as calculated from the Convergence Packet
	Loss.

	Discussion:
	Loss-Derived Convergence Time can be calculated from
	Convergence Packet Loss that occurs due to a Convergence Event
	and Route Convergence, as shown with Equation 2.

	(eq 2) Loss-Derived Convergence Time =
		Convergence Packets Loss / Forwarding Rate

		NOTE: Units for this measurement are
		packets / packets/second = seconds

	Measurement Units:
	seconds/milliseconds

	Issues:
	Loss-Derived Convergence time Time gives a better than
	actual result when converging many routes simultaneously.
	Rate-Derived Convergence Time takes the Convergence Recovery
	Transition into account, but Loss-Derived Convergence Time
	ignores the Route Convergence Recovery Transition because
	it is obtained from the measured Convergence Packet Loss.
	Ideally, the Convergence Event Transition and Convergence
           	      IGP Data Plane Route Convergence

	Recovery Transition are instantaneous so that the
	Rate-Derived Convergence Time = Loss-Derived Convergence Time.
	However, router implementations are less than ideal.
	For these reasons the preferred reporting benchmark for IGP
	Route Convergence is the Rate-Derived Convergence Time.
	Guidelines for reporting Loss-Derived Convergence Time are
	provided in [2].

	See Also:
	Route Convergence
	Convergence Packet Loss
	Rate-Derived Convergence Time
	Convergence Event Transition
	Convergence Recovery Transition
           	      IGP Data Plane Route Convergence

   3.12 Sustained Forwarding Convergence Time

	Definition:
	The amount of time for Route Convergence to be achieved for
	cases in which there is no packet loss.

	Discussion:
	Sustained Forwarding Convergence Time is the IGP Route Convergence
	benchmark to be used for Convergence Events that produce
	a change in next-hop without packet loss.

	Measurement Units:
	seconds/milliseconds

	Issues:
	None

	See Also:
	Route Convergence
	Rate-Derived Convergence Time
	Loss-Derived Convergence Time

   3.13 Restoration Convergence Time

	Definition:
	The amount of time for the router under test to restore
	traffic to the original outbound port after recovery from
	a Convergence Event.

	Discussion:
	Restoration Convergence Time is the amount of time to
	Converge back to the original outbound port.  This is achieved
	by recovering from the Convergence Event, such as restoring
	the failed link.  Restoration Convergence Time is measured
	using the Rate-Derived Convergence Time calculation technique,
	as provided in Equation 1.  It is possible, but not desired
           	      IGP Data Plane Route Convergence

	to have the Restoration Convergence Time differ from the
	Rate-Derived Convergence Time.

	Measurement Units:
	seconds or milliseconds

	Issues:
	None

	See Also:
	Convergence Event
	Rate-Derived Convergence Time
           	      IGP Data Plane Route Convergence

   3.14 Packet Sampling Interval
	Definition:
	The rate interval at which the tester (test equipment) polls to make
	measurements for arriving packet flows.

	Discussion:
	Metrics measured at the Packet Sampling Interval may include
	packets received
	Forwarding Rate and Convergence Packet Loss.

	Measurement Units:
	seconds or milliseconds

	Issues:
	Packet Sampling Interval can influence the Convergence Graph.
	This is particularly true as implementations achieve Full
	Convergence in less than 1 second.  The Convergence Event
	Transition and Convergence Recovery Transition can become
	exaggerated when the Packet Sampling Interval is too long.
	This will produce a larger than actual Rate-Derived
	Convergence Time.  The recommended value for configuration
	of the Packet Sampling Interval is provided in [2].

	See Also:
	Convergence Packet Loss
	Convergence Event Transition
	Convergence Recovery Transition

   3.15 Local Interface
	Definition:
	An interface on the DUT.

	Discussion:
	None

	Measurement Units:
	N/A
           	      IGP Data Plane Route Convergence

	Issues:
	None

	See Also:
	Neighbor Interface
	 Remote interface
           	      IGP Data Plane Route Convergence Interface

   3.16 Neighbor Interface

	Definition:
	The interface on the neighbor router or tester that is
	directly linked to the DUT's Local Interface.

	Discussion:
	None

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Local Interface
	 Remote interface Interface

   3.17  Remote Interface

	Definition:
	An interface on a neighboring router that is not directly
	connected to any interface on the DUT.

	Discussion:
	None

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Local interface Interface
	Neighbor Interface

   3.18 Preferred Egress Interface

	Definition:
	The outbound interface on from the DUT for traffic routed to the
	preferred next-hop.

           	      IGP Data Plane Route Convergence

	Discussion:
	Preferred Egress Interface is the egress interface prior to
	a Convergence Event

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	 Next-Best Egress Interface
           	      IGP Data Plane Route Convergence

   3.19  Next-Best Egress Interface

	Definition:
	The outbound interface on from the DUT for traffic routed to the
	second-best next-hop.

	Discussion:
	 Next-Best Egress Interface is the egress interface after
	a Convergence Event.

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Preferred Egress Interface

   3.20 Stale Forwarding
	Definition:
	Forwarding of traffic to route entries that no longer exist
	or to route entries with next-hops that are no longer preferred.

	Discussion:
	Stale Forwarding can be caused by a Convergence Event and is
	also known as a "black-hole" since it may produce packet loss.
	Stale Forwarding exists until Network Convergence is achieved.

	Measurement Units:
	N/A

	Issues:
	None

	See Also:
	Network Convergence
           	      IGP Data Plane Route Convergence

   4. Security Considerations

        Documents of this type do not directly affect the security of
        Internet or corporate networks as long as benchmarking
        is not performed on devices or systems connected to operating
        networks.

           	      IGP Data Plane Route Convergence

   5. References

   [1]   Poretsky, S., "Benchmarking Applicability for IGP Data Plane
	 Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-02, draft-ietf-bmwg-igp-dataplane-conv-app-03,
	 work in progress, January July 2004.

   [2]   Poretsky, S., "Benchmarking Methodology for IGP Data Plane
	 Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-02, draft-ietf-bmwg-igp-dataplane-conv-meth-03,
	 work in progress, January July 2004.

   [3]   Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
	 Environments", RFC 1195, December 1990.

   [4]   Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.

   [5]   S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View
	 of High Performance Networking", NANOG 22, May 2001.

   [6]   L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized
	 Active Measurements on a Tier 1 IP Backbone", IEEE Communications
	 Magazine, pp90-97, June, 2003.

  6. Author's Address

     	Scott Poretsky
   	Quarry Technologies
  	8 New England Executive Park
   	Burlington, MA 01803
    	USA
    	Phone: + 1 781 395 5090
   	EMail: sporetsky@quarrytech.com

	Brent Imhoff
	WilTel Communications
	3180 Rider Trail South
	Bridgeton, MO 63045
	USA
	Phone: +1 314 595 6853
	EMail: brent.imhoff@wcg.com bimhoff@planetspork.com
           	      IGP Data Plane Route Convergence

   7.  Full Copyright

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   Network Working Group
   INTERNET-DRAFT
   Expires in: July 2004
                                                Scott Poretsky
                                                Quarry Technologies

						Brent Imhoff
						Wiltel Communications

                                       		January 2004

			Benchmarking Methodology for
		      IGP Data Plane Route Convergence

	<draft-ietf-bmwg-igp-dataplane-conv-meth-02.txt>

   Status of this Memo

Copyright Statement

Copyright (C) The Internet Society (2004).  This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of subject to
the Internet Engineering
   Task Force  (IETF), its areas, rights, licenses and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months restrictions contained in BCP 78, 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 except as "work in
   progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   Table of Contents
     1. Introduction ...............................................2
     2. Existing definitions .......................................2
     3. Test Setup..................................................2
     3.1 Test Topologies............................................2
     3.2 Test Considerations........................................4
     3.2.1 IGP Selection............................................4
     3.2.2 BGP Configuration........................................4
     3.2.3 IGP Route Scaling........................................5
     3.2.4 Timers...................................................5
     3.2.5 Convergence Time Metrics.................................5
     3.2.6 Offered Load.............................................5
     3.2.7 Interface Types..........................................5
     3.3 Reporting Format...........................................6
     4. Test Cases..................................................6
           	      IGP Data Plane Route Convergence

     4.1 Convergence Due to Link Failure............................6
     4.1.1 Convergence Due to Local Interface Failure...............6
     4.1.2 Convergence Due to Neighbor Interface Failure............7
     4.1.3 Convergence Due to Remote Interface Failure..............7
     4.2 Convergence Due to PPP Session Failure.....................8
     4.3 Convergence Due to IGP Adjacency Failure...................9
     4.4 Convergence Due to Route Withdrawal........................9
     4.5 Convergence Due to Cost Change.............................10
     4.6 Convergence Due to ECMP Member Interface Failure...........10
     4.7 Convergence Due to Parallel Link Interface Failure.........11
     5. Security Considerations.....................................12
     6. References..................................................12
     7. Author's Address............................................12
     8. Full Copyright Statement....................................13

   1. Introduction
   This draft describes the methodology for benchmarking IGP Route
   Convergence.  The applicability of this testing is described in
   [1] and the new terminology that it introduces is defined in [2].
   Service Providers use IGP Convergence time as a key metric of
   router design and architecture.  Customers of Service Providers
   observe convergence time by packet loss, so IGP Route Convergence
   is considered a Direct Measure of Quality (DMOQ).  The test cases
   in this document are black-box tests that emulate the network
   events that cause route convergence, as described in [1].  The
   black-box test designs benchmark the data plane accounting for
   all of the factors contributing to convergence time, as discussed
   in [1].  The methodology (and terminology) for benchmarking route
   convergence can be applied to any link-state  IGP such as ISIS [3]
   and OSPF [4].

   2.  Existing definitions

   For the sake of clarity and continuity this RFC adopts the template
   for definitions set out in Section 2 of RFC 1242.  Definitions are
   indexed and grouped together in sections for ease of reference.

   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.

   3.  Test Setup
   3.1 Test Topologies

   Figure 1 shows the test topology to measure IGP Route Convergence due
   to local Convergence Events such as SONET Link Failure, PPP Session
   Failure, IGP  Adjacency Failure, Route Withdrawal, and route cost
   change.  These test cases discussed in section 4 provide route
   convergence times that account for the Event Detection time, SPF
   Processing time, and FIB Update time.  These times are measured
   by observing packet loss in the data plane.

           	      IGP Data Plane Route Convergence

	--------- 	Ingress Interface	---------
	|       |<------------------------------|	|
	| 	|				|	|
	|  	| Preferred Egress Interface    |	|
	|  DUT  |------------------------------>|Tester	|
	| 	| 				|	|
	|       |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|	|
	| 	| Next-Best Egress Interface    |	|
	---------				---------

	Figure 1.  IGP Route Convergence Test Topology for Local Changes

   Figure 2 shows the test topology to measure IGP Route Convergence
   time due to remote changes in the network topology.  These times are
   measured by observing packet loss in the data plane.  In this
   topology the three routers are considered a System Under Test (SUT).
   NOTE: All routers in the SUT must be the same model and identically 	configured.

		-----              	    -----------
		|   |	Preferred   	    |         |
	-----	|R2 |---------------------->|	      |
	|   |-->|   | Egress Interface      |	      |
	|   |	-----		     	    |	      |
	|R1 |			     	    |  Tester |
	|   |	-----		     	    |	      |
	|   |-->|   |	Next-Best     	    |	      |
	-----	|R3 |~~~~~~~~~~~~~~~~~~~~~~>|	      |
	  ^	|   |	Egress Interface    |	      |
	  |	-----		     	    -----------
	  |				        |
	  |--------------------------------------
		Ingress Interface

	Figure 2.  IGP Route Convergence Test Topology
			for Remote Changes

   Figure 3 shows the test topology to measure IGP Route Convergence
   time with members of an ECMP Set.  These times are measured by
   observing packet loss in the data plane.  In this topology, the DUT
   is configured with each Egress interface as a member of an ECMP set
   and the Tester emulates multiple next-hop routers (emulates one
   router for each member).

           	      IGP Data Plane Route Convergence

	--------- 	Ingress Interface 	  ---------
	|       |<--------------------------------|	  |
	| 	|				  |	  |
	|  	|	ECMP Set Interface 1	  |	  |
	|  DUT  |-------------------------------->| Tester|
	|	|		.		  |	  |
	|	|		.		  |	  |
	| 	| 		.		  |	  |
	|       |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|	  |
	| 	|	ECMP Set Interface N	  |	  |
	---------				  ---------

	Figure 3.  IGP Route Convergence Test Topology
			for ECMP Convergence

   Figure 4 shows the test topology to measure IGP Route Convergence
   time with members of a Parallel Link.  These times are measured by
   observing packet loss in the data plane.  In this topology, the DUT
   is configured with each Egress interface as a member of a Parallel
   Link and the Tester emulates the single next-hop router.

	--------- 	Ingress Interface 	  ---------
	|       |<--------------------------------|	  |
	| 	|				  |	  |
	|  	|	Parallel Link Interface 1 |	  |
	|  DUT  |-------------------------------->| Tester|
	|	|		.		  |	  |
	|	|		.		  |	  |
	| 	| 		.		  |	  |
	|       |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|	  |
	| 	|	Parallel Link Interface N |	  |
	---------				  ---------

	Figure 4.  IGP Route Convergence Test Topology
		      for Parallel Link Convergence

   3.2 Test Considerations

   3.2.1 IGP Selection
   The test cases described in section 4 can be used for ISIS or
   OSPF.  The Route Convergence test methodology for both is
   identical.  The IGP adjacencies are established on the Preferred
   Egress Interface and Next-Best Egress Interface.

   3.2.2 BGP Configuration
   The obtained results for IGP Route Convergence may vary if
   BGP routes are installed.  It is recommended that the IGP
   Convergence times be benchmarked without BGP routes installed.

           	      IGP Data Plane Route Convergence

   3.2.3 IGP Route Scaling
   The number of IGP routes will impact the measured IGP Route
   Convergence because convergence for the entire IGP route table is
   measured.   For results similar to those that would be observed in
   an operational network it is recommended that the number of
   installed routes closely approximate that for routers in the
   network.

   3.2.4 Timers
   There are some timers that will impact the measured IGP Convergence
   time. The following timers should be configured to the minimum value
   prior to beginning execution of the test cases:

	Timer					Recommended Value
	-----					-----------------
   	SONET Failure Indication Delay		<10milliseconds
   	IGP Hello Timer				1 second
   	IGP Dead-Interval			3 seconds
   	LSA Generation Delay			0
   	LSA Flood Packet Pacing			0
   	LSA Retransmission Packet Pacing	0
   	SPF Delay				0

   3.2.5 Convergence Time Metrics
   The recommended value for the Packet Sampling Interval [2] is
   100 milliseconds.  Rate-Derived Convergence Time [2] is the
   preferred benchmark for IGP Route Convergence.  This benchmark
   must always be reported when the
   Packet Sampling Interval [2] <= 100 milliseconds.
   If the test equipment does not permit the Packet Sampling
   Interval to be set as low as 100 msec, then both the
   Rate-Derived Convergence Time and Loss-Derived Convergence
   Time [2] must be reported.

   3.2.6 Offered Load
   An offered Load of maximum forwarding rate at a fixed packet size
   is recommended for accurate measurement.  The duration of offered
   load must be greater than the convergence time.

   3.2.7 Interface Types
   All test cases in this methodology document may be executed with
   any interface type.  SONET is recommended and specifically
   mentioned in the procedures because it can be configured to have
   no or negligible affect on the measured convergence time.
   Ethernet (10Mb, 100Mb, 1Gb, and 10Gb) is not preferred since
   broadcast media are unable to detect loss of host and rely upon
   IGP Hellos to detect session loss.

           	      IGP Data Plane Route Convergence

   3.3 Reporting Format
   For each test case, it is recommended that the following reporting
   format be completed:

	Parameter					Units
	---------					-----
   	IGP						(ISIS or OSPF)
   	Interface Type					(GigE, POS, ATM, etc.)
   	Packet Size					bytes
   	IGP Routes 					number of IGP routes
   	Packet Sampling Interval			seconds or milliseconds
   	IGP Timer Values
		SONET Failure Indication Delay		seconds or milliseconds
   		IGP Hello Timer				seconds or milliseconds
   		IGP Dead-Interval			seconds or milliseconds
   		LSA Generation Delay			seconds or milliseconds
   		LSA Flood Packet Pacing			seconds or milliseconds
   		LSA Retransmission Packet Pacing	seconds or milliseconds
   		SPF Delay				seconds or milliseconds
      	Benchmarks
		Rate-Derived Convergence Time		seconds or milliseconds
		Loss-Derived Convergence Time		seconds or milliseconds
		Restoration Convergence Time		seconds or milliseconds

   4. Test Cases
   4.1 Convergence Due to Link Failure
   4.1.1 Convergence Due to Local Interface Failure
	Objective
	To obtain the IGP Route Convergence due to a local link
	failure event at the DUT's Local Interface.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
           Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of the
	   routes so that the Preferred Egress Interface is the preferred
   	   next-hop.
	2. Send traffic at maximum forwarding rate to destinations
           matching all IGP routes from Tester to DUT on Ingress Interface
	   [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Remove SONET on DUT's Local Interface [2] by performing an
	   administrative shutdown of the interface.
	5. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   link down event and converges all IGP routes and traffic over
	   the Next-Best Egress Interface.
	6. Restore SONET on DUT's Local Interface by administratively
	   enabling the interface.
	7. Measure Restoration Convergence Time [2] as DUT detects the link
	   up event and converges all IGP routes and traffic back to the
	   Preferred Egress Interface.

           	      IGP Data Plane Route Convergence
	Results
	The measured IGP Convergence time is influenced by the Local
	SONET indication, SPF delay, SPF Holdtime, SPF Execution
	Time, Tree Build Time, and Hardware Update Time.

   4.1.2 Convergence Due to Neighbor Interface Failure
	Objective
	To obtain the IGP Route Convergence due to a local link
	failure event at the Tester's Neighbor Interface.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
           Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of
	   the routes so that the Preferred Egress Interface is the
   	   preferred next-hop.
	2. Send traffic at maximum forwarding rate to destinations
           matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Remove SONET on Tester's Neighbor Interface [2] connected to
   	   DUT' s Preferred Egress Interface.
	5. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   link down event and converges all IGP routes and traffic over
	   the Next-Best Egress Interface.
	6. Restore SONET on Tester's Neighbor Interface connected to
   	   DUT's Preferred Egress Interface.
	7. Measure Restoration Convergence Time [2] as DUT detects the
	   link up event and converges all IGP routes and traffic back to
	   the Preferred Egress Interface.

	Results
	The measured IGP Convergence time is influenced by the Local
	SONET indication, SPF delay, SPF Holdtime, SPF Execution
	Time, Tree Build Time, and Hardware Update Time.

   4.1.3 Convergence Due to Remote Interface Failure
      Objective
	To obtain the IGP Route Convergence due to a Remote
	Interface failure event.

	Procedure
	1. Advertise matching IGP routes from Tester to SUT on
          Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 2.  Set the cost of the
	   routes so that the Preferred Egress Interface is the preferred
   	   next-hop.
	2. Send traffic at maximum forwarding rate to destinations
           matching all IGP routes from Tester to DUT on Ingress Interface
	   [2].
	3. Verify traffic is routed over Preferred Egress Interface.
	4. Remove SONET on Tester's Neighbor Interface [2] connected to
   	   SUT' s Preferred Egress Interface.

           	      IGP Data Plane Route Convergence

	5. Measure Rate-Derived Convergence Time [2] as SUT detects
	   the link down event and converges all IGP routes and traffic
	   over the Next-Best Egress Interface.
	6. Restore SONET on Tester's Neighbor Interface connected to
   	   SUT's Preferred Egress Interface.
	7. Measure Restoration Convergence Time [2] as SUT detects the
	   link up event and converges all IGP routes and traffic over
	   the Preferred Egress Interface.

	Results
	The measured IGP Convergence time is influenced by the
	SONET failure indication, LSA/LSP Flood Packet Pacing,
	LSA/LSP Retransmission Packet Pacing, LSA/LSP Generation
	time, SPF delay, SPF Holdtime, SPF Execution Time, Tree
	Build Time, and Hardware Update Time.  The additional
	convergence time contributed by LSP Propagation can be
	obtained by subtracting the Rate-Derived Convergence Time
	measured in 4.1.2 (Convergence Due to Neighbor Interface
	Failure) from the Rate-Derived Convergence Time measured in
	this test case.

   4.2 Convergence Due to PPP Session Failure
	Objective
	To obtain the IGP Route Convergence due to a Local PPP Session
	failure event.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
           Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of
	   the routes so that the IGP routes along the Preferred Egress
	   Interface is the preferred next-hop.
	2. Send traffic at maximum forwarding rate to destinations
	   matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Remove PPP session from Tester's Neighbor Interface [2]
	   connected to Preferred Egress Interface.
	5. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   PPP session down event and converges all IGP routes and
	   traffic over the Next-Best Egress Interface.
	6. Restore PPP session on DUT's Preferred Egress Interface.
	7. Measure Restoration Convergence Time [2] as DUT detects the
	   session up event and converges all IGP routes and traffic over
	   the Preferred Egress Interface.

	Results
	The measured IGP Convergence time is influenced by the PPP
        failure indication, SPF delay, SPF Holdtime, SPF Execution
        Time, Tree Build Time, and Hardware Update Time.

           	      IGP Data Plane Route Convergence

   4.3 Convergence Due to IGP Adjacency Failure

	Objective
	To obtain the IGP Route Convergence due to a Local IGP Adjacency
	failure event.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
           Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of
	   the routes so that the Preferred Egress Interface is the
	   preferred next-hop.
	2. Send traffic at maximum forwarding rate to destinations
	   matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Remove IGP adjacency from Tester's Neighbor Interface [2]
	   connected to Preferred Egress Interface.
	5. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   IGP session failure event and converges all IGP routes and
	   traffic over the Next-Best Egress Interface.
	6. Restore IGP session on DUT's Preferred Egress Interface.
	7. Measure Restoration Convergence Time [2] as DUT detects the
	   session up event and converges all IGP routes and traffic over
	   the Preferred Egress Interface.

	Results
	The measured IGP Convergence time is influenced by the IGP
	Hello Interval, IGP Dead Interval, SPF delay, SPF Holdtime,
	SPF Execution Time, Tree Build Time, and Hardware Update
	Time.

  4.4 Convergence Due to Route Withdrawal

	Objective
	To obtain the IGP Route Convergence due to Route Withdrawal.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
         Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of
	   the routes so that the Preferred Egress Interface is the
	   preferred next-hop.
	2. Send traffic at maximum forwarding rate to destinations
	   matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Tester withdraws all IGP routes from DUT's Local Interface
	   on Preferred Egress Interface.

           	      IGP Data Plane Route Convergence

	6. Re-advertise IGP routes to DUT's Preferred Egress Interface.
	7. Measure Restoration Convergence Time [2] as DUT converges all
	   IGP routes and traffic over the Preferred Egress Interface.

	Results
	The measured IGP Convergence time is the SPF Processing and FIB
	Update time as influenced by the SPF delay, SPF Holdtime,
	SPF Execution Time, Tree Build Time, and Hardware Update Time.

   4.5 Convergence Due to Cost Change

	Objective
	To obtain the IGP Route Convergence due to route cost change.

	Procedure
	1. Advertise matching IGP routes from Tester to DUT on
           Preferred Egress Interface [2] and Next-Best Egress Interface
	   [2] using the topology shown in Figure 1.  Set the cost of
	   the routes so that the Preferred Egress Interface is the
  	   preferred next-hop.
	2. Send traffic at maximum forwarding rate to destinations
	   matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	3. Verify traffic routed over Preferred Egress Interface.
	4. Tester increases cost for all IGP routes at DUT's Preferred
	   Egress Interface so that the Next-Best Egress Interface
	   has lower cost and becomes preferred path.
	5. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   cost change event and converges all IGP routes and traffic
	   over the Next-Best Egress Interface.
	6. Re-advertise IGP routes to DUT's Preferred Egress Interface
	   with original lower cost metric.
	7. Measure Restoration Convergence Time [2] as DUT converges all
	   IGP routes and traffic over the Preferred Egress Interface.

	Results
	There should be no measured packet loss for this case.

    4.6 Convergence Due to ECMP Member Interface Failure

	Objective
	To obtain the IGP Route Convergence due to a local link
	failure event of an ECMP Member.

	Procedure
	1. Configure ECMP Set as shown in Figure 3.
	2. Advertise matching IGP routes from Tester to DUT on
           each ECMP member.

           	      IGP Data Plane Route Convergence

	3. Send traffic at maximum forwarding rate to destinations
           matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	4. Verify traffic routed over all members of ECMP Set.
	5. Remove SONET on Tester's Neighbor Interface [2] connected to
   	   one of the DUT's ECMP member interfaces.
	6. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   link down event and converges all IGP routes and traffic
	   over the other ECMP members.
	7. Restore SONET on Tester's Neighbor Interface connected to
   	   DUT's ECMP member interface.
	8. Measure Restoration Convergence Time [2] as DUT detects the
	   link up event and converges IGP routes and some distribution
	   of traffic over the restored ECMP member.

	Results
	The measured IGP Convergence time is influenced by the Local
	SONET indication, Tree Build Time, and Hardware Update Time.

   4.7 Convergence Due to Parallel Link Interface Failure

	Objective
	To obtain the IGP Route Convergence due to a local link
	failure event for a Member of a Parallel Link.

	Procedure
	1. Configure Parallel Link as shown in Figure 4.
	2. Advertise matching IGP routes from Tester to DUT on
           each Parallel Link member.
	3. Send traffic at maximum forwarding rate to destinations
           matching all IGP routes from Tester to DUT on Ingress
	   Interface [2].
	4. Verify traffic routed over all members of Parallel Link.
	5. Remove SONET on Tester's Neighbor Interface [2] connected to
   	   one of the DUT's Parallel Link member interfaces.
	6. Measure Rate-Derived Convergence Time [2] as DUT detects the
	   link down event and converges all IGP routes and traffic over
	   the other Parallel Link members.
	7. Restore SONET on Tester's Neighbor Interface connected to
   	   DUT's Parallel Link member interface.
	8. Measure Restoration Convergence Time [2] as DUT detects the
	   link up event and converges IGP routes and some distribution
	   of traffic over the restored Parallel Link member.

	Results
	The measured IGP Convergence time is influenced by the Local
	SONET indication, Tree Build Time, and Hardware Update Time.

           	      IGP Data Plane Route Convergence

   5. Security Considerations

        Documents of this type do not directly affect the security of
        the Internet or corporate networks as long as benchmarking
        is not performed on devices or systems connected to operating
        networks.

   6. References

      [1] Poretsky, S., "Benchmarking Applicability for IGP
	    Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-02, work
	    in progress, January 2004.

      [2] Poretsky, S., Imhoff, B., "Benchmarking Terminology for IGP
	    Convergence", draft-ietf-bmwg-igp-dataplane-conv-term-02, work
	    in progress, January 2004

      [3] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
	    Environments", RFC 1195, December 1990.

      [4] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.

   7. Author's Address

     	Scott Poretsky
   	Quarry Technologies
  	8 New England Executive Park
   	Burlington, MA 01803
    	USA

    	Phone: + 1 781 395 5090
   	EMail: sporetsky@quarrytech.com

	Brent Imhoff
	WilTel Communications
	3180 Rider Trail South
	Bridgeton, MO 63045
	USA

	Phone: +1 314 595 6853
	EMail: brent.imhoff@wcg.com
           	      IGP Data Plane Route Convergence

   8.  Full Copyright Statement
        Copyright (C) The Internet Society (1998).  All Rights
        Reserved.

        This document and translations of it may be copied and
        furnished to others, and derivative works that comment on or
        otherwise explain it or assist in its implementation may be
        prepared, copied, published and distributed, in whole or in
        part, without restriction of any kind, provided that the above
        copyright notice and this paragraph are included on all such
        copies and derivative works.  However, this document itself may
        not be modified in any way, such as by removing the copyright
        notice or references to the Internet Society or other Internet
        organizations, except as needed for the purpose of developing
        Internet standards in which case the procedures for copyrights
        defined in the Internet Standards process must be followed, or
        as required to translate it into languages other than English.

        The limited permissions granted above are perpetual and will
        not be revoked by the Internet Society or its successors or
        assigns.  This document and the information contained herein is
        provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE
        INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES,
        EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY
        THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY
        RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS
        FOR A PARTICULAR PURPOSE.

Poretsky, Imhoff								[Page 13]   Network Working Group
   INTERNET-DRAFT
   Expires in: July 2004
                                                   Scott Poretsky
                                                   Quarry Technologies

                                                   January 2004

        	 Benchmarking Applicability for
		IGP Data Plane Route Convergence

	<draft-ietf-bmwg-igp-dataplane-conv-app-02.txt>

   Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force  (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   ABSTRACT
   This draft describes the applicability of IGP Route Convergence
   benchmarking methodology [1] and IGP Route Convergence benchmarking
   terminology [2].  The methodology and terminology is to be used
   for benchmarking route convergence and can be applied to any
   link-state IGP such as ISIS [3] and OSPF [4].  The data plane is
   measured to obtain the convergence benchmarking metrics described
   in [1].

   Table of Contents
     1. Introduction ...............................................2
     2. Existing definitions .......................................2
     3. Factors for IGP Route Convergence Time......................2
     4. Network Events that Cause Route Convergence.................3
     5. Use of Data Traffic for IGP Route Convergence Benchmarking..3
     6. Security Considerations.....................................4
     7. Acknowledgements............................................4
     8. References..................................................4
           	       IGP Data Plane Route Convergence

     9. Author's Address............................................5
     10. Full Copyright Statement...................................5

   1. Introduction
   IGP Convergence is a critical performance parameter.  Customers
   of Service Providers use packet loss due to IGP Convergence as a
   key metric of their network service quality.  Service Providers
   use IGP Convergence time as a key metric of router design and
   architecture.  Fast network convergence can be optimally achieved
   through deployment of fast converging routers.  The fundamental
   basis by which network users and operators benchmark convergence
   is packet loss, which is an externally observable event having
   direct impact on their application performance.

   IGP Route Convergence is a Direct Measure of Quality (DMOQ) when
   benchmarking the data plane.  For this reason it is important to
   develop a standard router benchmarking methodology and terminology
   for measuring IGP convergence that uses the data plane as described
   in [1] and [2].  This document describes all of the factors that
   influence a convergence measurement and how a purely black box test
   can be designed to account for all of these factors.  This enables
   accurate benchmarking and evaluation for route convergence time.

   2.  Existing definitions

   For the sake of clarity and continuity this RFC adopts the template
   for definitions set out in Section 2 of RFC 1242.  Definitions are
   indexed and grouped together in sections for ease of reference.

   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.

   3. Factors for IGP Route Convergence Time

   There are four major categories of factors contributing to the
   measured Router IGP Convergence Time.   As discussed in [5], [6],
   [7], [8] and [9], these categories are Event Detection, SPF
   Processing, IGP Advertisement, and FIB Update.  These have numerous
   components that influence the convergence time.  These are listed
   as follow:

	-Event Detection-
	SONET failure indication time
	PPP failure indication time
	IGP Hello Dead Interval

	-SPF Processing-
	SPF Delay Time
	SPF Hold time
	SPF Execution time
           	       IGP Data Plane Route Convergence
	-IGP Advertisement-
	LSA/LSP Flood Packet Pacing
	LSA/LSP Retransmission Packet Pacing
	LSA/LSP Generation time

	-FIB Update-
	Tree Build time
	Hardware Update time

   The contribution of each of these factors listed above will vary
   with each router vendors' architecture and IGP implementation.
   It is therefore necessary to design a convergence test that
   considers all of these components, not just one or a few of these
   components.  The additional benefit of designing a test for all
   components is that it enables black-box testing in which knowledge
   of the routers' internal implementations is not required.  It is
   then possible to make valid use of the convergence benchmarking
   metrics when comparing routers from different vendors.

   4. Network Events that Cause Convergence

   There are different types of network events that can cause IGP
   convergence.  These network events are administrative link
   removal, unplanned link failure, line card failure, and route
   changes such as withdrawal, flap, next-hop change, and cost change.
   When benchmarking a router it is important to measure the
   convergence time for local and remote occurrence of these network
   events.  The convergence time measured will vary whether the network
   event occurred locally or remotely due to varying combinations of
   factors listed in the previous sections.  This behavior makes it
   possible to design purely black-box tests that isolate
   measurements for each of the components of convergence time.

   5. Use of Data Plane for IGP Route Convergence Benchmarking

   Customers of service providers use packet loss as the metric to
   calculate convergence time.  Packet loss is an externally observable
   event having direct impact on customers' application performance.
   For this reason it is important to develop a standard router
   benchmarking methodology and terminology that is a Direct Measure
   of Quality (DMOQ)for measuring IGP convergence.  Such a
   methodology uses the data plane as described in [1] and [2].

   An additional benefit of using packet loss for calculation of
   IGP Route Convergence time is that it enables black-box tests to
   be designed.  Data traffic can be offered to the
   device under test (DUT), an emulated network event can be forced
   to occur, and packet loss can be externally measured to calculate
   the convergence time.  Knowledge of the DUT architecture and IGP
   implementation is not required. There is no need to rely on the
   DUT to produce the test results.  There is no need to build
   intrusive test harnesses for the DUT.

           	       IGP Data Plane Route Convergence

   Use of data traffic and measurement of packet loss on the data
   plane also enables Route Convergence methodology test cases that
   consider the time for the Route Controller to update the FIB on
   the forwarding engine of the hardware.  A router is not fully
   converged until all components are updated and traffic is
   rerouted to the correct egress interface.  As long as there is
   packet loss, routes have not converged.  It is possible to send
   diverse traffic flows to destinations matching every route in the
   FIB so that the time it takes for the router to converge an entire
   route table can be benchmarked.

   6. Security Considerations

        Documents of this type do not directly effect the security of
        the Internet or of corporate networks as long as benchmarking
        is not performed on devices or systems connected to operating
        networks.

   7. Acknowledgements
	Thanks to Curtis Villamizar for sharing so much of his
	knowledge and experience through the years. Also, special
	thanks to the many Network Engineers and Network Architects
	at the Service Providers who are always eager to discuss
	Route Convergence.

   8. References

      [1]   Poretsky, S., "Benchmarking Methodology for IGP Data Plane
	    Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-01,
	    work in progress, October 2004.

      [2]   Poretsky, S., "Benchmarking Terminology for IGP Data Plane
	    Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-term-01,
	    work in progress, October 2004.

      [3]   Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
	    Environments", RFC 1195, December 1990.

      [4]   Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.

      [5]   Villamizar, C., "Convergence and Restoration Techniques for
	    ISP Interior Routing", NANOG 25, October 2002.

      [6]   Katz, D., "Why are we Scared of SPF?  IGP Scaling and
	    Stability", NANOG 25, October 2002.

      [7]   Filsfils, C., "Deploying Tight-SLA Services on an Internet
	    Backbone: ISIS Fast Convergence and Differentiated Services
	    Design (tutorial)", NANOG 25, October 2002.

           	       IGP Data Plane Route Convergence

      [8]   Alaettinoglu, C. and Casner, S., "ISIS Routing on the Qwest
	    Backbone: a Recipe for Subsecond ISIS Convergence", NANOG 24,
	    October 2002.

      [9]   Alaettinoglu, C., Jacobson, V., and Yu, H., "Towards
	    Millisecond IGP Convergence", NANOG 20, October 2000.

   9. Author's Address

     	Scott Poretsky
   	Quarry Technologies
  	8 New England Executive Park
   	Burlington, MA 01803
    	USA

    	Phone: + 1 781 395 5090
   	EMail: sporetsky@quarrytech.com

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