 1/draftietfbmwgigpdataplaneconvterm13.txt 20071119 19:13:21.000000000 +0100
+++ 2/draftietfbmwgigpdataplaneconvterm14.txt 20071119 19:13:21.000000000 +0100
@@ 1,23 +1,25 @@
Network Working Group
INTERNETDRAFT
 Expires in: January 2008
Intended Status: Informational
Scott Poretsky
Reef Point Systems
Brent Imhoff
Juniper Networks
+
+ November 2007
+
Terminology for Benchmarking
 IGP Data Plane Route Convergence
+ LinkState IGP Data Plane Route Convergence

+
Intellectual Property Rights (IPR) statement:
By submitting this InternetDraft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Status of this Memo
InternetDrafts are working documents of the Internet Engineering
@@ 53,39 +55,41 @@
2. Existing definitions .........................................3
3. Term definitions..............................................4
3.1 Convergence Event.........................................4
3.2 Route Convergence.........................................4
3.3 Network Convergence.......................................5
3.4 Full Convergence..........................................5
3.5 Packet Loss...............................................6
3.6 Convergence Packet Loss...................................6
3.7 Convergence Event Instant.................................7
3.8 Convergence Recovery Instant..............................7
 3.9 RateDerived Convergence Time.............................8
+ 3.9 First Prefix Convergence Instant..........................8
3.10 Convergence Event Transition.............................8
3.11 Convergence Recovery Transition..........................9
 3.12 LossDerived Convergence Time............................9
 3.13 Sustained Forwarding Convergence Time....................10
 3.14 Restoration Convergence Time.............................11
 3.15 Packet Sampling Interval.................................12
 3.16 Local Interface..........................................12
 3.17 Neighbor Interface.......................................13
 3.18 Remote Interface.........................................13
 3.19 Preferred Egress Interface...............................13
 3.20 NextBest Egress Interface...............................14
 3.21 Stale Forwarding.........................................14
 3.22 Nested Convergence Events................................15
 4. IANA Considerations...........................................15
 5. Security Considerations.......................................15
 6. Acknowledgements..............................................15
 7. References....................................................15
 8. Author's Address..............................................16
+ 3.12 RateDerived Convergence Time............................9
+ 3.13 LossDerived Convergence Time............................10
+ 3.14 Sustained Forwarding Convergence Time....................11
+ 3.15 First Prefix Convergence Time............................12
+ 3.16 Reversion Convergence Time...............................12
+ 3.17 Packet Sampling Interval.................................13
+ 3.18 Local Interface..........................................13
+ 3.19 Neighbor Interface.......................................14
+ 3.20 Remote Interface.........................................14
+ 3.21 Preferred Egress Interface...............................15
+ 3.22 NextBest Egress Interface...............................15
+ 3.23 Stale Forwarding.........................................15
+ 3.24 Nested Convergence Events................................16
+ 4. IANA Considerations...........................................16
+ 5. Security Considerations.......................................16
+ 6. Acknowledgements..............................................16
+ 7. References....................................................17
+ 8. Author's Address..............................................18
1. Introduction
This draft describes the terminology for benchmarking Interior
Gateway Protocol (IGP) Route Convergence. The motivation and
applicability for this benchmarking is provided in [Po07a]. The
methodology to be used for this benchmarking is described in [Po07m].
The methodology and terminology to be used for benchmarking Route
Convergence can be applied to any linkstate IGP such as ISIS [Ca90]
and OSPF [Mo98]. The data plane is measured to obtain blackbox
(externally observable) convergence benchmarking metrics. The
@@ 168,47 +172,47 @@
3.2 Route Convergence
Definition:
Route Convergence is the action to update all components of the
router with the most recent route change(s) including the
Routing Information Base (RIB) and Forwarding Information Base
(FIB), along with software and hardware tables, such that
forwarding is successful for one or more destinations.
Discussion:
 Route Convergence is required after a Convergence Event.
+ Route Convergence MUST occur after a Convergence Event.
Route Convergence can be observed externally by the rerouting
 of data traffic to the nextbest egress interface. Also,
+ of data traffic to the Nextbest Egress Interface. Also,
Route Convergence may or may not be sustained over time.
Measurement Units:
N/A
Issues:
None
See Also:
Network Convergence
Full Convergence
Convergence Event
IGP Data Plane Route Convergence
3.3 Network Convergence
Definition:
 The completion of updating of all routing tables, including the
 FIB, in all routers throughout the network.
+ The completion of updating of all routing tables, including
+ distributed FIBs, in all routers throughout the network.
Discussion:
 Network Convergence requires completion of all Route Convergence
 operations for all routers in the network following a
 Convergence Event. Network Convergence can be observed by
+ Network Convergence requires completion of all Route
+ Convergenceoperations for all routers in the network following
+ a Convergence Event. Network Convergence can be observed by
recovery of System Under Test (SUT) Throughput to equal the
offered load, with no Stale Forwarding, and no Blenders
[Ca01][Ci03].
Measurement Units:
N/A
Issues:
None
@@ 229,44 +233,45 @@
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. Full Convergence is externally observable
from the data plane when the Throughput of the data
plane traffic on the NextBest Egress Interface equals the
offered load.
Measurement Units:
N/A
 Issues: None
+ Issues:
+ None
See Also:
Network Convergence
Route Convergence
Convergence Event
IGP Data Plane Route Convergence
3.5 Packet Loss
Definition:
The number of packets that should have been forwarded
 by a DUT under steady state (constant) load that were
+ by a DUT under a constant offered load that were
not forwarded due to lack of resources.
Discussion:
Packet Loss is a modified version of the term "Frame Loss Rate"
as defined in [Ba91]. The term "Frame Loss" is intended for
Ethernet Frames while "Packet Loss" is intended for IP packets.
Packet Loss can be measured as a reduction in forwarded traffic
from the Throughput [Ba91] of the DUT.
Measurement units:
 Number of Noctet offered packets that are not forwarded.
+ Number of offered packets that are not forwarded.
Issues: None
See Also:
Convergence Packet Loss
3.6 Convergence Packet Loss
Definition:
The number of packets lost due to a Convergence Event
@@ 297,21 +302,22 @@
Definition:
The time instant that a Convergence Event 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:nnn, where 'nnn' is milliseconds
+ hh:mm:ss:nnn:uuu,
+ where 'nnn' is milliseconds and 'uuu' is microseconds.
Issues:
None
See Also:
Convergence Event
Convergence Packet Loss
Convergence Recovery Instant
3.8 Convergence Recovery Instant
@@ 320,63 +326,59 @@
The time instant that Full Convergence is measured
and then maintained for an interval of duration equal to
the Sustained Forwarding Convergence Time
Discussion:
Convergence Recovery Instant is measurable from the data
plane as the precise time that the device under test
achieves Full Convergence.
Measurement Units:
 hh:mm:ss:nnn, where 'nnn' is milliseconds
+ hh:mm:ss:nnn:uuu,
+ where 'nnn' is milliseconds and 'uuu' is microseconds.
Issues:
None
See Also:
Sustained Forwarding Convergence Time
Convergence Packet Loss
Convergence Event Instant
IGP Data Plane Route Convergence
 3.9 RateDerived Convergence Time
 Definition:
 The amount of time for Convergence Packet Loss to persist upon
 occurrence of a Convergence Event until occurrence of Route
 Convergence.

 RateDerived Convergence Time can be measured as the time
 difference from the Convergence Event Instant to the
 Convergence Recovery Instant, as shown with Equation 1.
+ 3.9 First Prefix Convergence Instant
 Equation 1 
 RateDerived Convergence Time =
 Convergence Recovery Instant  Convergence Event Instant.
+ Definition:
+ The time instant for convergence of a first route entry
+ following a Convergence Event, as observed by receipt of
+ the first packet from the NextBest Egress Interface.
Discussion:
 RateDerived Convergence Time should be measured at the maximum
 Throughput. Failure to achieve Full Convergence results in
 a RateDerived Convergence Time benchmark of infinity.
+ The First Prefix Convergence Instant is an indication that the
+ process to achieve Full Convergence has begun. Any route may be
+ the first to converge for First Convergence. Measurement on the
+ dataplane enables First Convergence to be observed without any
+ whitebox information from the DUT.
Measurement Units:
 seconds/milliseconds
+ N/A
Issues:
None
See Also:
 Convergence Packet Loss
 Convergence Recovery Instant
 Convergence Event Instant
+ Route Convergence
Full Convergence
+ Stale Forwarding
3.10 Convergence Event Transition
+
Definition:
A time interval observed following a Convergence Event in which
Throughput gradually reduces to zero.
Discussion:
The Convergence Event Transition is best observed for Full
Convergence. The egress packet rate observed during a
Convergence Event Transition may not decrease linearly. Both
the offered load and the Packet Sampling Interval influence the
observations of the Convergence Event Transition. For example,
@@ 382,316 +384,395 @@
observations of the Convergence Event Transition. For example,
even if the Convergence Event were to cause the Throughput
[Ba91] to drop to zero there would be some number of packets
observed, unless the Packet Sampling Interval is exactly
aligned with the Convergence Event. This is further discussed
with the term "Packet Sampling Interval".
IGP Data Plane Route Convergence
Measurement Units:
 seconds/milliseconds
+ seconds
Issues:
None
See Also:
Convergence Event
Full Convergence
Packet Sampling Interval
3.11 Convergence Recovery Transition
Definition:
 The characteristic of a router in which Throughput
 gradually increases to equal the offered load.
+ The characteristic of the DUT in which Throughput gradually
+ increases to equal the offered load.
Discussion:
The Convergence Recovery Transition is best observed for
Full Convergence. The egress packet rate observed during
a Convergence Recovery Transition may not increase linearly.
Both the offered load and the Packet Sampling Interval
influence the observations of the Convergence Recovery
Transition. This is further discussed with the term
"Packet Sampling Interval".
Measurement Units:
 seconds/milliseconds
+ seconds
Issues: None
See Also:
Full Convergence
Packet Sampling Interval
 3.12 LossDerived Convergence Time
+ 3.12 RateDerived Convergence Time
Definition:
 The amount of time it takes for Route Convergence to
 to be achieved as calculated from the Convergence Packet
 Loss. LossDerived Convergence Time can be calculated
 from Convergence Packet Loss that occurs due to a
 Convergence Event and Route Convergence as shown with
 Equation 2.
+ The amount of time for Convergence Packet Loss to persist upon
+ occurrence of a Convergence Event until measurement of Full
+ Convergence.
+
+ RateDerived Convergence Time can be measured as the time
+ difference from the Convergence Event Instant to the
+ Convergence Recovery Instant, as shown with Equation 1.
+
+ (Equation 1)
+ RateDerived Convergence Time =
+ Convergence Recovery Instant  Convergence Event Instant.
+
+ IGP Data Plane Route Convergence
+
+ Discussion:
+ RateDerived Convergence Time should be measured at the maximum
+ Throughput of the DUT. At least one packet per route in the FIB
+ for all routes in the FIB MUST be offered to the DUT per second.
+ Failure to achieve Full Convergence results in a RateDerived
+ Convergence Time benchmark of infinity.
+
+ Measurement Units:
+ seconds
+
+ Issues:
+ None
+
+ See Also:
+ Convergence Packet Loss
+ Convergence Recovery Instant
+ Convergence Event Instant
+ Full Convergence
+
+ 3.13 LossDerived Convergence Time
+
+ Definition:
+ The amount of time it takes for Full Convergence to be
+ achieved as calculated from the amount of Convergence
+ Packet Loss. LossDerived Convergence Time can be
+ calculated from Convergence Packet Loss that occurs due
+ to a Convergence Event and Route Convergence as shown
+ with Equation 2.
Equation 2 
LossDerived Convergence Time =
Convergence Packets Loss / Offered Load
NOTE: Units for this measurement are
packets / packets/second = seconds
 IGP Data Plane Route Convergence
Discussion:
LossDerived Convergence Time gives a better than
actual result when converging many routes simultaneously.
RateDerived Convergence Time takes the Convergence Recovery
Transition into account, but LossDerived 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
Recovery Transition are instantaneous so that the
RateDerived Convergence Time = LossDerived Convergence Time.
However, router implementations are less than ideal.
For these reasons the preferred reporting benchmark for IGP
Route Convergence is the RateDerived Convergence Time.
Guidelines for reporting LossDerived Convergence Time are
provided in [Po07m].
+ IGP Data Plane Route Convergence
+
Measurement Units:
 seconds/milliseconds
+ seconds
Issues:
None
See Also:
Convergence Event
Convergence Packet Loss
RateDerived Convergence Time
Convergence Event Transition
Convergence Recovery Transition
 3.13 Sustained Forwarding Convergence Time
+ 3.14 Sustained Forwarding Convergence Time
Definition:
The amount of time for which Full Convergence is maintained
without additional packet loss.
Discussion:
The purpose of the Sustained Forwarding Convergence Time is to
produce Convergence benchmarks protected against fluctuation
in Throughput after Full Convergence is observed. The
Sustained Forwarding Convergence Time to be used is calculated
as shown in Equation 3.
 IGP Data Plane Route Convergence

Equation 3 
Sustained Forwarding Convergence Time =
C*(Convergence Packet Loss/Offered Load)
where,
a. units are packets/pps = sec and
b. C is a constant. The RECOMMENDED value for C is 5 as
 selected from working group consensus. The value 5 was
 obtained from RFC 2544 [Ba99] which uses 5 seconds as the
 recommended time for residual frames and DUT restabilization.
+ selected from working group consensus. This is similar
+ to RFC 2544 [Ba99] which recommends waiting 2 seconds for
+ residual frames to arrive and 5 seconds for DUT
+ restabilization.
c. at least one packet per route in the FIB for all
routes in the FIB MUST be offered to the DUT per second.
Measurement Units:
 seconds or milliseconds
+ seconds
Issues: None
See Also:
Full Convergence
Convergence Recovery Instant
+ IGP Data Plane Route Convergence
 3.14 Restoration Convergence Time
+ 3.15 First Prefix 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.
+ The amount of time for Convergence Packet Loss until the
+ convergence of a first route entry on the NextBest Egress
+ Interface, as indicated by the First Prefix Convergence
+ Instant.
+
+ First Prefix Convergence Time can be measured as the time
+ difference from the Convergence Event Instant and the First
+ Prefix Convergence Instant, as shown with Equation 4.
+
+ (Equation 4)
+ First Prefix Convergence Time =
+ First Prefix Convergence Instant 
+ Convergence Event Instant.
Discussion:
 Restoration Convergence Time is the amount of time for routes
+ First Prefix Convergence Time should be measured at the maximum
+ Throughput of the DUT. At least one packet per route in the FIB
+ for all routes in the FIB MUST be offered to the DUT per second.
+ Failure to achieve the First Prefix Convergence Instant results
+ in a First Prefix Convergence Time benchmark of infinity.
+
+ Measurement Units:
+ hh:mm:ss:nnn:uuu,
+ where 'nnn' is milliseconds and 'uuu' is microseconds.
+
+ Issues:
+ None
+
+ See Also:
+ Convergence Packet Loss
+ First Prefix Convergence Instant
+
+ 3.16 Reversion Convergence Time
+
+ Definition:
+ The amount of time for the DUT to forward traffic from the
+ Preferred Egress Interface, instead of the NextBest Egress
+ Interface, upon recovery from a Convergence Event.
+
+ Discussion:
+ Reversion Convergence Time is the amount of time for routes
to converge 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
+ the failed link. Reversion Convergence Time is measured
using the RateDerived Convergence Time calculation technique,
as provided in Equation 1. It is possible to have the
 Restoration Convergence Time differ from the RateDerived
+ Reversion Convergence Time differ from the RateDerived
Convergence Time.
+ IGP Data Plane Route Convergence
+
Measurement Units:
 seconds or milliseconds
+ seconds
Issues:
None
See Also:
+ Preferred Egress Interface
Convergence Event
RateDerived Convergence Time
 IGP Data Plane Route Convergence
 3.15 Packet Sampling Interval
+ 3.17 Packet Sampling Interval
Definition:
The interval at which the tester (test equipment) polls to make
measurements for arriving packet flows.
Discussion:
Metrics measured at the Packet Sampling Interval MUST include
Forwarding Rate and Convergence Packet Loss.
Measurement Units:
 seconds or milliseconds
+ seconds
Issues:
Packet Sampling Interval can influence the Convergence Graph.
This is particularly true when 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 RateDerived
Convergence Time. The recommended value for configuration
of the Packet Sampling Interval is provided in [Po07m].
See Also:
Convergence Packet Loss
Convergence Event Transition
Convergence Recovery Transition
 3.16 Local Interface
+ 3.18 Local Interface
Definition:
An interface on the DUT.
Discussion:
 None
+ A failure of the Local Interface indicates that the failure
+ occured directly on the DUT.
+
+ IGP Data Plane Route Convergence
Measurement Units:
N/A
Issues:
None
See Also:
Neighbor Interface
Remote Interface
 IGP Data Plane Route Convergence
 3.17 Neighbor Interface
+ 3.19 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
 3.18 Remote Interface
+ 3.20 Remote Interface
Definition:
An interface on a neighboring router that is not directly
connected to any interface on the DUT.
Discussion:
 None
+ A failure of a Remote Interface indicates that the failure
+ occurred on an interface that is not directly connected
+ to the DUT.
Measurement Units:
N/A
Issues:
None
See Also:
Local Interface
Neighbor Interface
+ IGP Data Plane Route Convergence
 3.19 Preferred Egress Interface
+ 3.21 Preferred Egress Interface
Definition:
The outbound interface from the DUT for traffic routed to the
preferred nexthop.
Discussion:
The Preferred Egress Interface is the egress interface prior
to a Convergence Event.
 IGP Data Plane Route Convergence

Measurement Units:
N/A
Issues:
None
See Also:
NextBest Egress Interface
 3.20 NextBest Egress Interface
+ 3.22 NextBest Egress Interface
Definition:
The outbound interface from the DUT for traffic routed to the
secondbest nexthop. It is the same media type and link speed
as the Preferred Egress Interface
Discussion:
The NextBest Egress Interface becomes the egress interface
after a Convergence Event.
Measurement Units:
N/A
Issues:
None
See Also:
Preferred Egress Interface
 3.21 Stale Forwarding
+ 3.23 Stale Forwarding
Definition:
Forwarding of traffic to route entries that no longer exist
or to route entries with nexthops that are no longer preferred.
Discussion:
Stale Forwarding can be caused by a Convergence Event and is
 also known as a "blackhole" since it may produce packet loss.
 Stale Forwarding exists until Network Convergence is achieved.
+ also known as a "blackhole" or microloop since it may produce
+ packet loss. Stale Forwarding exists until Network Convergence
+ is achieved.
+
+ IGP Data Plane Route Convergence
Measurement Units:
N/A
Issues:
None
See Also:
Network Convergence
 IGP Data Plane Route Convergence
 3.22 Nested Convergence Events
+ 3.24 Nested Convergence Events
Definition:
The occurrence of a Convergence Event while the route
table is converging from a prior Convergence Event.
Discussion:
The Convergence Events for a Nested Convergence Event
MUST occur with different neighbors. A common
observation from a Nested Convergence Event will be
the withdrawal of routes from one neighbor while the
@@ 711,89 +792,89 @@
This document requires no IANA considerations.
5. 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 production
networks.
6. Acknowledgements
 Thanks to Sue Hares, Al Morton, Kevin Dubray, and participants of
 the BMWG for their contributions to this work.
+ Thanks to Sue Hares, Al Morton, Kevin Dubray, Ron Bonica, David Ward,
+ and the BMWG for their contributions to this work.
+
+ IGP Data Plane Route Convergence
7. References
7.1 Normative References
[Ba91] Bradner, S. "Benchmarking Terminology for Network
Interconnection Devices", RFC1242, July 1991.
[Ba99] Bradner, S. and McQuaid, J., "Benchmarking
Methodology for Network Interconnect Devices",
RFC 2544, March 1999.
[Br97] Bradner, S., "Key words for use in RFCs to Indicate
 IGP Data Plane Route Convergence

[Ca90] Callon, R., "Use of OSI ISIS for Routing in TCP/IP and Dual
Environments", RFC 1195, December 1990.
[Ma98] Mandeville, R., "Benchmarking Terminology for LAN
Switching Devices", RFC 2285, February 1998.
[Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
[Mo06] Morton, A., et al, "Packet Reordering Metrics", RFC 4737,
November 2006.
[Po06] Poretsky, S., et al., "Terminology for Benchmarking
Networklayer Traffic Control Mechanisms", RFC 4689,
November 2006.
 [Po07a] Poretsky, S., "Benchmarking Applicability for IGP Data Plane
 Route Convergence", draftietfbmwgigpdataplaneconvapp13,
 work in progress, July 2007.
+ [Po07a] Poretsky, S., "Benchmarking Applicability for LinkState
+ IGP Data Plane Route Convergence",
+ draftietfbmwgigpdataplaneconvapp14, work in progress,
+ November 2007.
[Po07m] Poretsky, S. and Imhoff, B., "Benchmarking Methodology for
 IGP Data Plane Route Convergence",
 draftietfbmwgigpdataplaneconvmeth13, work in progress,
 July 2007.
+ LinkState IGP Data Plane Route Convergence",
+ draftietfbmwgigpdataplaneconvmeth14, work in progress,
+ November 2007.
7.2 Informative References
[Ca01] S. Casner, C. Alaettinoglu, and C. Kuan, "A FineGrained View
of High Performance Networking", NANOG 22, June 2001.
[Ci03] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized
Active Measurements on a Tier 1 IP Backbone", IEEE
Communications Magazine, pp9097, May 2003.
+ IGP Data Plane Route Convergence
+
8. Author's Address
Scott Poretsky
Reef Point Systems
 8 New England Executive Park
 Burlington, MA 01803
+ 3 Federal Street
+ Billerica, MA 01821
USA

Phone: + 1 508 439 9008
EMail: sporetsky@reefpoint.com
Brent Imhoff
Juniper Networks
1194 North Mathilda Ave
Sunnyvale, CA 94089
USA

Phone: + 1 314 378 2571
EMail: bimhoff@planetspork.com
 IGP Data Plane Route Convergence
Full Copyright Statement
Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided
@@ 815,19 +896,21 @@
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+ IGP Data Plane Route Convergence
+
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