 1/draftietfbmwgigpdataplaneconvterm00.txt 20060204 22:52:37.000000000 +0100
+++ 2/draftietfbmwgigpdataplaneconvterm01.txt 20060204 22:52:37.000000000 +0100
@@ 1,22 +1,25 @@
Network Working Group
INTERNETDRAFT
 Expires in: December 2003
+ Expires in: April 2004
Scott Poretsky
 Avici Systems
+ Quarry Technologies
 June 2003
+ Brent Imhoff
+ Wiltel Communications
+
+ October 2003
Terminology for Benchmarking
IGP Data Plane Route Convergence

+
Status of this Memo
This document is an InternetDraft and is in full conformance with
all provisions of Section 10 of RFC2026.
InternetDrafts 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.
@@ 30,406 +33,614 @@
The list of current InternetDrafts can be accessed at
http://www.ietf.org/ietf/1idabstracts.txt
The list of InternetDraft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Table of Contents
1. Introduction ...............................................2
2. Existing definitions .......................................2
 3. Term definitions............................................2
 3.1 Network Convergence.....................................2
 3.2 Protocol Convergence....................................3
 3.3 Route Convergence.......................................3
 3.4 Full Route Convergence Time.............................4
 3.5 Route Convergence Packet Loss...........................5
 3.6 Average Route Convergence Time..........................5
 3.7 Route Convergence Event Slope...........................6
 3.8 Route Convergence Recovery Slope........................6
 3.9 Reroute Convergence Time...............................7
 3.10 Local Interface........................................7
 3.11 Neighbor Interface.....................................8
 3.12 Remote Interface.......................................8
 4. Security Considerations.....................................8
 5. References..................................................9
 IGP Route Convergence
+ 3. Term definitions............................................3
+ 3.1 Network Convergence.......................................3
+ 3.2 Protocol Convergence......................................3
+ 3.3 Route Convergence.........................................4
+ 3.4 Convergence Event.........................................4
+ 3.5 Full Convergence..........................................4
+ 3.6 Convergence Packet Loss...................................5
+ 3.7 Convergence Event Instant.................................5
+ 3.8 Convergence Recovery Transition...........................6
+ 3.9 RateDerived Convergence Time.............................6
+ 3.10 Convergence Recovery Instant.............................7
+ 3.11 Convergence Event Transition.............................7
+ 3.12 LossDerived Convergence Time............................8
+ IGP Data Plane Route Convergence
 7. Author's Address............................................9
 8. Full Copyright Statement....................................9
+ 3.13 Route Convergence Time...................................9
+ 3.14 Restoration Convergence Time.............................9
+ 3.15 Packet Sampling Interval.................................10
+ 3.16 Local Interface..........................................10
+ 3.17 Neighbor Interface.......................................10
+ 3.18 Remote Interface.........................................11
+ 3.19 Preferred Egress Interface...............................11
+ 3.20 NextBest Egress Interface...............................12
+ 4. Security Considerations.....................................12
+ 5. References..................................................12
+ 6. Author's Address............................................12
+ 7. Full Copyright Statement....................................13
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 can be
applied to any linkstate IGP such as ISIS [3] and OSPF [4]. The
 data plane is measured to obtain the convergence benchmarking metrics.
 The purpose of this document is to introduce new terms required to
 complete execution of the IGP Route Convergence Methodology [2].
+ data plane is measured to obtain blackbox (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].
 2. Existing definitions
+ 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 Xaxis 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 Convergence Event Time = 0sec
+ Maximum ^ ^ ^
+ Forwarding Rate> \ Packet /
+ \ Loss /<Convergence
+ Convergence>\ / Event Transition
+ Recovery Transition \ /
+ \_____/<100% Packet Loss
+ Xaxis = Time
+ Yaxis = 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.
 3. Term definitions
+ IGP Data Plane Route Convergence
+
+ 3. Term Definitions
3.1 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 only be determined by the occurrence of packet loss or stale
forwarding due to an outofdate FIB.
Measurement Units:
 Converged or Not Converged
+ N/A
Issues:
None
See Also:
Protocol Convergence
Route Convergence
 IGP Data Plane Route Convergence
3.2 Protocol Convergence
Definition:
The completion of updating a router's RIB and the forwarding of
an route update message (LSA for OSPF/LSP for ISIS) to a
neighboring peer.
Discussion:
Protocol Convergence considers only the Control Plane. IGP
messaging is used to verify and measure convergence. Updating
of the FIB, hardware updating, rerouting of traffic, and packet
loss are not considered.
Measurement Units:
 LSA/LSP Transmitted or LSA/LSP Not Transmitted.
+ N/A
Issues:
Protocol Convergence does not consider updating of the FIB,
 hardware updating, rerouting of traffic, and resultant packet
+ hardware updating, rerouting of traffic, and resulting packet
loss. Protocol Convergence is only a partial measurement of
Route Convergence.
See Also:
Network Convergence
Route Convergence
+ IGP Data Plane Route Convergence
3.3 Route Convergence
Definition:
The completion of the router's FIB becoming fully converged.
Discussion:
 All components of the router have been 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.
+ 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:
 Converged or Not Converged
+ N/A
Issues:
None
See Also:
 Route Convergence Time
Network Convergence
Protocol Convergence
 IGP Data Plane Route Convergence
+ Full Convergence
+ Convergence Event
 3.4 Full Route Convergence Time
+ 3.4 Convergence Event
Definition:
 The amount of time it takes for Route Convergence to
 complete as measured by the time to drop from maximum
 forwarding rate and return to maximum forwarding rate
 after occurrence of a network event.
+ The occurrence of a planned or unplanned action in the network
+ that results in a change to an entry in the route table.
Discussion:
 Full Route Convergence Time is a metric applied
 to a single router. Convergence Time could be calculated
 from packet loss. However, this will give a better than
 actual result when converging many routes simultaneously.
 The preferred method to obtain Route Convergence Time is
 to measure the time to drop from maximum forwarding rate
 and return to maximum forwarding rate.
+ Convergence Events include link loss, routing protocol session
+ loss, router failure, and better nexthop.
 Figure 1 shows a graph model of Convergence Time as measured
 from the data plane. IGP Route Convergence Time is the
 amount of time for the Forwarding Rate to begin its downward
 slope upon occurrence of a network event and then fully recover
 to the Maximum Forwarding Rate. This is calculated as
+ Measurement Units:
+ N/A
 (eq 1) Time(Convergence) = Time(Recovery)  Time(Network Event).
+ Issues:
+ None
 Forwarding Rate versus Time
+ See Also:
+ Convergence Packet Loss
+ Convergence Event Instant
 Time=Recovery Time=Network Event Time = 0sec
 Maximum ^ ^ ^
 Forwarding Rate> \ /
 \ /<Route Convergence
 Route Convergence>\ / Event Slope
 Recovery Slope \_______/<100% Packet Loss
+ 3.5 Full Convergence
 Xaxis = Time
 Yaxis = Forwarding Rate
+ Definition:
+ Route Convergence for an entire route table.
 Figure 1. Convergence Graph
+ Discussion:
+ When benchmarking convergence it is useful to measure
+ The time to convergence an entire route table. For example,
+ IGP Data Plane Route Convergence
+
+ A Convergence Event can produced for an OSPF table of 5000
+routes so that the time to converge routes 1 through 5000
+is measured.
Measurement Units:
 seconds/milliseconds
+ N/A
Issues:
None
See Also:
+ Network Convergence
+ Protocol Convergence
Route Convergence
 Route Convergence Packet Loss
 Average Route Convergence Time
 IGP Data Plane Route Convergence
+ Convergence Event
 3.5 Route Convergence Packet Loss
+ 3.6 Convergence Packet Loss
Definition:
 The amount of packet loss until Route Convergence completes.
+ The amount of packet loss produced by a Convergence Event
+ until Route Convergence occurs.
Discussion:
 Route Convergence Packet Loss is used to calculate the
 Route Convergence Time. Packet loss is an externally
 measurable metric.
+ Packet loss can be observed as a reduction of forwarded
+ traffic from the maximum forwarding rate.
Measurement Units:
number of packets
Issues:
None
See Also:
Route Convergence
 Full Route Convergence Time
 Route Convergence Event Slope
 Route Convergence Recovery Slope
+ Convergence Event
+ RateDerived Convergence Time
+ LossDerived Convergence Time
 3.6 Average Route Convergence Time
+ 3.7 Convergence Event Instant
+
+ Definition:
+ The time instant that a Convergence Event occurs.
+
+ 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
+ IGP Data Plane Route Convergence
+
+ Issues:
+ None
+
+ See Also:
+ Route Convergence
+ Convergence Event
+ Convergence Packet Loss
+ Convergence Recovery Instant
+
+ 3.8 Convergence Recovery Instant
+
+ Definition:
+ The time instant that Route Convergence occurs.
+
+ Discussion:
+ Convergence Recovery Instant is observable from the data
+ plane as the precise time that the device under test no
+longer exhibits packet loss.
+
+ Measurement Units:
+ hh:mm:ss:uuu
+
+ Issues:
+ None
+
+ See Also:
+ Route Convergence
+ Convergence Packet Loss
+ Convergence Event Instant
+
+ 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.
+
+ Discussion:
+
+ RateDerived Convergence Time can be measured as the time
+ difference from the Convergence Event Instant to the
+ Convergence Reovery Instant, as shown with Equation 1.
+
+ (eq 1) RateDerived Convergence Time =
+ Convergence Recovery Instant  Convergence Event Instant.
+
+ RateDerived Convergence Time can be measured at the maximum
+ forwarding rate.
+
+Measurement Units:
+ seconds/milliseconds
+ IGP Data Plane Route Convergence
+
+ Issues:
+ None
+
+ See Also:
+ Route Convergence
+ Convergence Packet Loss
+ LossDerived Convergence Time
+
+ 3.10 LossDerived Convergence Time
Definition:
The amount of time it takes for Route Convergence to
complete as calculated from the amount of packet loss
and known forwarding rate.
Discussion:
 Average Route Convergence Time is a metric applied to a
 single router. It can be calculated from packet loss that
 occurs due to a network event and subsequent Route
 Convergence.
+ It can be calculated from packet loss that occurs due
+ to a Convergence Event and Route Convergence, as shown
+ with Equation 2.
+
+ (eq 2) LossDerived Convergence Time =
+ Convergence Packets Loss / Forwarding Rate
+
+ NOTE: Units for this measurement are
+ packets / packets/second = seconds
Measurement Units:
seconds/milliseconds
Issues:
 Use of Packet loss to calculate Route Convergence Time will
 give a better than actual result when converging many routes
 simultaneously. Full Route Convergence Time is
 the preferred benchmark for IGP Route Convergence.
+ LossDerived Convergence time gives a better than
+ actual result when converging many routes simultaneously.
+ Because of this the preferred reporting metric in most
+Cases is RateDerived Convergence Time.
See Also:
Route Convergence
 Route Convergence Packet Loss
 Full Route Convergence Time
 Route Convergence Event Slope
 Route Convergence Recovery Slope
 IGP Data Plane Route Convergence
+ Convergence Packet Loss
+ RateDerived Convergence Time
+ Convergence Event Transition
+ Convergence Recovery Transition
 3.7 Route Convergence Event Slope
+ 3.11 Convergence Event Transition
Definition:
 The characteristic of routers in which forwarding rate
+ The characteristic of A router in which forwarding rate
gradually reaches zero as output queues drain after a
network event.
+ IGP Data Plane Route Convergence
+
Discussion:
 Route Convergence Event Slope is externally observable.
 Full Route Convergence Time ignores the Route
 Convergence Event Slope. Average Route Convergence
 Time based upon the amount of packet loss takes the
 Route Convergence Event Slope into account.
+ RateDerived Convergence Time ignores the Convergence Event
+ Transition. LossDerived Convergence Time based upon the amount
+ of packet loss takes the Convergence Event Transition into
+account. The Convergence Event Transition is best observed for
+Full Convergence.
Measurement Units:
seconds/milliseconds
Issues:
None
See Also:
Route Convergence
 Full Route Convergence Time
 Average Route Convergence Time
 Route Convergence Packet Loss
 Route Convergence Recovery Slope
 3.8 Route Convergence Recovery Slope
+ Convergence Event
+ RateDerived Convergence Time
+ LossDerived Convergence Time
+ Convergence Packet Loss
+ Convergence Recovery Transition
+
+ 3.12 Convergence Recovery Transition
+
Definition:
 The characteristic of routers in which forwarding rate
+ The characteristic of a router in which forwarding rate
gradually rises to the maximum value as many routes
converge to recover from a network event.
Discussion:
 Route Convergence Recovery Slope is externally observable.
 Full Route Convergence Time ignores the Route
 Convergence Recovery Slope. Average Route Convergence
+ RateDerived Convergence Time ignores the Route
+ Convergence Recovery Transition. LossDerived Convergence
Time based upon the amount of packet loss takes the
 Route Convergence Recovery Slope into account.
+Convergence Recovery Transition into account. The
+Convergence Recovery Transition is best observed for Full
+Convergence.
Measurement Units:
seconds/milliseconds
Issues:
None
See Also:
Route Convergence
 Full Route Convergence Time
 Average Route Convergence Time
 Route Convergence Packet Loss
 Route Convergence Event Slope
+ RateDerived Convergence Time
+ LossDerived Convergence Time
+ Convergence Packet Loss
+ Convergence Event Transition
IGP Data Plane Route Convergence
 3.9 Reroute Convergence Time
+ 3.13 Route Convergence Time
+
Definition:
The amount of time it takes for Route Convergence to
 complete as observed from rerouting of traffic to a
 new egress interface.
+ complete as observed from rerouting traffic to a
+ new egress interface due to a change in nexthop without
+packet loss.
Discussion:
 Reroute Convergence Time is the IGP Route Convergence
+ Route Convergence Time is the IGP Route Convergence
benchmark to be used for network events that produce
 a change in nexthop without packet loss. An example
 of this is a cost change in which an backup path becomes
 the preferred path.
+ a change in nexthop without packet loss.
Measurement Units:
seconds/milliseconds
Issues:
None
See Also:
Route Convergence
 Full Route Convergence Time
 Average Route Convergence Time
+ RateDerived Convergence Time
+ LossDerived Convergence Time
+
+ 3.14 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 RateDerived Convergence Time calculation technique,
+ as provided in Equation 1. It is possible, but not desired
+ to have the Restoration Convergence Time differ from the
+ RateDerived Convergence Time.
+
+ Measurement Units:
+ seconds or milliseconds
+
+ Issues:
+ None
+
+ See Also:
+ Convergence Event
+ RateDerived Convegence Time
+ IGP Data Plane Route Convergence
+
+ 3.15 Packet Sampling Interval
+
+ Definition:
+The rate at which the tester (test equipment) polls to make
+measurements for arriving packet flows.
+
+ Discussion:
+ Metrics measured at the Packet Sampling Interval include
+ packets received and Convergence Packet Loss.
+
+ Measurement Units:
+ seconds or milliseconds
+
+ Issues:
+ Packet Sampling Interval can influence the Convergence Graph.
+ This is particularly true as Full Convergence less than 1 second
+ is achieved. 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. Guidelines for use of
+ the Packet Sampling Interval are provided in [2].
+
+ See Also:
+ Convergence Packet Loss
+ Convergence Event Transition
+ Convergence Recovery Transition
+
+ 3.16 Local Interface
 3.10 Local Interface
Definition:
An interface on the DUT.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
Neighbor Interface
Remote interface
 3.11 Neighbor Interface

+ 3.17 Neighbor Interface
Definition:
The interface on the neighbor router or tester that is
directly linked to the DUT's Local Interface.
Discussion:
None
+ IGP Data Plane Route Convergence
Measurement Units:
N/A
 IGP Data Plane Route Convergence
Issues:
None
See Also:
Local Interface
Remote interface
 3.12 Remote Interface
+ 3.18 Remote Interface
Definition:
An interface on a neighboring router that is not directly
linked to any interface on the DUT.
Discussion:
None
Measurement Units:
N/A
Issues:
None
See Also:
Local interface
Neighbor Interface
+ 3.19 Preferred Egress Interface
+
+ Definition:
+ The outbound interface on DUT to the preferred nexthop.
+
+ Discussion:
+ Preferred Egress Interface is the egress interface prior to
+ a Convergence Event
+
+ Measurement Units:
+ N/A
+
+ Issues:
+ None
+
+ See Also:
+ NextBest Egress Interface
+ Convergence Event
+ IGP Data Plane Route Convergence
+
+ 3.20 NextBest Egress Interface
+
+ Definition:
+ The outbound interface on DUT to the secondbest nexthop.
+
+ Discussion:
+ NextBest Egress Interface is the egress interface after to
+ a Convergence Event
+
+ Measurement Units:
+ N/A
+
+ Issues:
+ None
+
+ See Also:
+ Preferred Egress Interface
+ Convergence Event
+
4. 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.
5. References
[1] Poretsky, S., "Benchmarking Applicability for IGP Data Plane
 Route Convergence", draftietfbmwgigpdataplaneconvapp00,
 work in progress, June 2003.
+ Route Convergence", draftietfbmwgigpdataplaneconvapp01,
+ work in progress, October 2003.
 [2] Poretsky, S., "Benchmarking Terminology for IGP Data Plane
 Route Convergence", draftietfbmwgigpdataplaneconvterm00,
 work in progress, June 2003.
+ [2] Poretsky, S., "Benchmarking Methodology for IGP Data Plane
+ Route Convergence", draftietfbmwgigpdataplaneconvmeth01,
+ work in progress, October 2003.
[3] Callon, R., "Use of OSI ISIS for Routing in TCP/IP and Dual
Environments", RFC 1195, December 1990.
[4] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
 IGP Data Plane Route Convergence

6. Author's Address
Scott Poretsky
 Avici Systems
 101 Billerica Avenue
 N. Billerica, MA 01862
+ Quarry Technologies
+ 8 New England Executive Park
+ Burlington, MA 01803
USA
+ Phone: + 1 781 395 5090
+ EMail: sporetsky@quarrytech.com
+ IGP Data Plane Route Convergence
 Phone: + 1 978 964 2287
 EMail: sporetsky@avici.com
+ Brent Imhoff
+ WilTel Communications
+ 3180 Rider Trail South
+ Bridgeton, MO 63045 USA
+ Phone: +1 314 595 6853
+ EMail: brent.imhoff@wcg.com
7. 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