draft-ietf-bmwg-igp-dataplane-conv-term-08.txt   draft-ietf-bmwg-igp-dataplane-conv-term-09.txt 
Network Working Group Network Working Group
INTERNET-DRAFT INTERNET-DRAFT
Expires in: April 2006 Expires in: June 2006
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
Brent Imhoff Brent Imhoff
Juniper Networks
October 2005 January 2006
Terminology for Benchmarking Terminology for Benchmarking
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
<draft-ietf-bmwg-igp-dataplane-conv-term-08.txt> <draft-ietf-bmwg-igp-dataplane-conv-term-09.txt>
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). All Rights Reserved. Copyright (C) The Internet Society (2006).
ABSTRACT ABSTRACT
This draft describes the terminology for benchmarking IGP Route This document describes the terminology for benchmarking IGP
Convergence as described in Applicability document [1] and Route Convergence as described in Applicability document [1] and
Methodology document [2]. The methodology and terminology is to Methodology document [2]. The methodology and terminology are to
be used for benchmarking Route Convergence and can be applied to be used for benchmarking Convergence Time and can be applied to
any link-state IGP such as ISIS [3] and OSPF [4]. The data plane any link-state IGP such as ISIS [3] and OSPF [4]. The data plane
is measured to obtain the convergence benchmarking metrics is measured to obtain the convergence benchmarking metrics
described in [2]. described in [2].
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
Table of Contents Table of Contents
1. Introduction .................................................2 1. Introduction .................................................2
2. Existing definitions .........................................3 2. Existing definitions .........................................3
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terminology to be used for benchmarking Route Convergence can be terminology to be used for benchmarking Route Convergence can be
applied to any link-state IGP such as ISIS [3] and OSPF [4]. The applied to any link-state IGP such as ISIS [3] and OSPF [4]. The
data plane is measured to obtain black-box (externally observable) data plane is measured to obtain black-box (externally observable)
convergence benchmarking metrics. The purpose of this document is convergence benchmarking metrics. The purpose of this document is
to introduce new terms required to complete execution of the IGP to introduce new terms required to complete execution of the IGP
Route Convergence Methodology [2]. These terms apply to IPv4 and Route Convergence Methodology [2]. These terms apply to IPv4 and
IPv6 traffic as well as IPv4 and IPv6 IGPs. IPv6 traffic as well as IPv4 and IPv6 IGPs.
An example of Route Convergence as observed and measured from the An example of Route Convergence as observed and measured from the
data plane is shown in Figure 1. The graph in Figure 1 shows 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 Throughput versus Time. Time 0 on the X-axis is on the far
right of the graph. The components of the graph and metrics are right of the graph. The components of the graph and metrics are
defined in the Term Definitions section. defined in the Term Definitions section.
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
Convergence Convergence Convergence Convergence
Recovery Event Recovery Event
Instant Instant Time = 0sec Instant Instant Time = 0sec
Maximum ^ ^ ^ Maximum ^ ^ ^
Forwarding Rate--> ------\ Packet /--------------- Throughput--> ------\ Packet /---------------
\ Loss /<----Convergence \ Loss /<----Convergence
Convergence------->\ / Event Transition Convergence------->\ / Event Transition
Recovery Transition \ / Recovery Transition \ /
\_____/<------Maximum Packet Loss \_____/<------Maximum Packet Loss
X-axis = Time X-axis = Time
Y-axis = Forwarding Rate Y-axis = Throughput
Figure 1. Convergence Graph Figure 1. Convergence Graph
2. Existing definitions 2. Existing definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in BCP 14, RFC 2119. document are to be interpreted as described in BCP 14, RFC 2119.
RFC 2119 defines the use of these key words to help make the RFC 2119 defines the use of these key words to help make the
intent of standards track documents as clear as possible. While this intent of standards track documents as clear as possible. While this
document uses these keywords, this document is not a standards track document uses these keywords, this document is not a standards track
document. document. The term Throughput is defined in RFC 2544.
3. Term Definitions 3. Term Definitions
3.1 Convergence Event 3.1 Convergence Event
Definition: Definition:
The occurrence of a planned or unplanned action in the network The occurrence of a planned or unplanned action in the network
that results in a change in the egress interface of the DUT for that results in a change in the egress interface of the Device
Under Test (DUT) for
routed packets. routed packets.
Discussion: Discussion:
Convergence Events include link loss, routing protocol session Convergence Events include link loss, routing protocol session
loss, router failure, configuration change, and better next-hop loss, router failure, configuration change, and better next-hop
learned via a routing protocol. learned via a routing protocol.
Measurement Units: Measurement Units:
N/A N/A
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See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Event Instant Convergence Event Instant
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.2 Route Convergence 3.2 Route Convergence
Definition: Definition:
Recovery from a Convergence Event indicated by the DUT Recovery from a Convergence Event indicated by the DUT
forwarding rate equal to the offered load. Throughput equal to the offered load.
Discussion: Discussion:
Route Convergence is the action of all components of the router Route Convergence is the action of all components of the router
being updated with the most recent route change(s) including the being updated with the most recent route change(s) including the
RIB and FIB, along with software and hardware tables. Route Routing Information Base (RIB) and Forwaridng Information Base
(FIB), along with software and hardware tables. Route
Convergence can be observed externally by the rerouting of data Convergence can be observed externally by the rerouting of data
Traffic to a new egress interface. Traffic to a new egress interface.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
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3.3 Network Convergence 3.3 Network Convergence
Definition: Definition:
The completion of updating of all routing tables, including the The completion of updating of all routing tables, including the
FIB, in all routers throughout the network. FIB, in all routers throughout the network.
Discussion: Discussion:
Network Convergence is bounded by the sum of Route Convergence Network Convergence is bounded by the sum of Route Convergence
for all routers in the network. Network Convergence can be for all routers in the network. Network Convergence can be
determined by recovery of the forwarding rate to equal the offered determined by recovery of the Throughput to equal the
load, no Stale Forwarding, and no blenders[5][6]. offered load, with no Stale Forwarding, and no blenders[5][6].
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Route Convergence Route Convergence
Stale Forwarding Stale Forwarding
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.4 Full Convergence 3.4 Full Convergence
Definition: Definition:
Route Convergence for an entire FIB. Route Convergence for an entire FIB.
Discussion: Discussion:
When benchmarking convergence it is useful to measure When benchmarking convergence, it is useful to measure
the time to converge an entire FIB. For example, the time to converge an entire FIB. For example,
a Convergence Event can be produced for an OSPF table of a Convergence Event can be produced for an OSPF table of
5000 routes so that the time to converge routes 1 through 5000 routes so that the time to converge routes 1 through
5000 is measured. Full Convergence is externally observable 5000 is measured. Full Convergence is externally observable
from the data plane when the forwarding rate of the data from the data plane when the Throughput of the data
plane traffic on the Next-Best Egress Interface equals the plane traffic on the Next-Best Egress Interface equals the
offered load. offered load.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues: None
None
See Also: See Also:
Network Convergence Network Convergence
Route Convergence Route Convergence
Convergence Event Convergence Event
3.5 Convergence Packet Loss 3.5 Convergence Packet Loss
Definition: Definition:
The amount of packet loss produced by a Convergence Event The amount of packet loss produced by a Convergence Event
until Route Convergence occurs. until Route Convergence occurs.
Discussion: Discussion:
Packet loss can be observed as a reduction of forwarded traffic from Packet loss can be observed as a reduction of forwarded traffic
the maximum forwarding rate. Convergence Packet Loss include packets from the maximum Throughput. Convergence Packet Loss
that were lost and packets that were delayed due to buffering. includes packets that were lost and packets that were delayed
Convergence Packet Loss may or may not reach 100%. due to buffering. The maximum Convergence Packet Loss observed
in a Packet Sampling Interval may or may not reach 100% during
Route Convergence (see Figure 1).
Measurement Units: Measurement Units:
number of packets number of packets
Issues: Issues: None
None
See Also: See Also:
Route Convergence Route Convergence
Convergence Event Convergence Event
Rate-Derived Convergence Time Rate-Derived Convergence Time
Loss-Derived Convergence Time Loss-Derived Convergence Time
Packet Sampling Interval
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.6 Convergence Event Instant 3.6 Convergence Event Instant
Definition: Definition:
The time instant that a Convergence Event becomes observable in the The time instant that a Convergence Event becomes observable in
data plane. the data plane.
Discussion: Discussion:
Convergence Event Instant is observable from the data Convergence Event Instant is observable from the data
plane as the precise time that the device under test begins plane as the precise time that the device under test begins
to exhibit packet loss. to exhibit packet loss.
Measurement Units: Measurement Units:
hh:mm:ss:uuu hh:mm:ss:nnn, where 'nnn' is milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
Convergence Packet Loss Convergence Packet Loss
Convergence Recovery Instant Convergence Recovery Instant
3.7 Convergence Recovery Instant 3.7 Convergence Recovery Instant
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Rate-Derived Convergence Time can be measured as the time Rate-Derived Convergence Time can be measured as the time
difference from the Convergence Event Instant to the difference from the Convergence Event Instant to the
Convergence Recovery Instant, as shown with Equation 1. Convergence Recovery Instant, as shown with Equation 1.
(eq 1) Rate-Derived Convergence Time = (eq 1) Rate-Derived Convergence Time =
Convergence Recovery Instant - Convergence Event Instant. Convergence Recovery Instant - Convergence Event Instant.
Discussion: Discussion:
Rate-Derived Convergence Time should be measured at the maximum Rate-Derived Convergence Time should be measured at the maximum
forwarding rate. Failure to achieve Full Convergence results in Throughput. Failure to achieve Full Convergence results in
a Rate-Derived Convergence Time benchmark of infinity. a Rate-Derived Convergence Time benchmark of infinity.
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Recovery Instant Convergence Recovery Instant
Convergence Event Instant Convergence Event Instant
Full Convergence Full Convergence
3.9 Convergence Event Transition 3.9 Convergence Event Transition
Definition: Definition:
The characteristic of a router in which forwarding rate The characteristic of a router in which Throughput
gradually reduces to zero after a Convergence Event. gradually reduces to zero after a Convergence Event.
Discussion: Discussion:
The Convergence Event Transition is best observed for The Convergence Event Transition is best observed for
Full Convergence. The Convergence Event Transition may Full Convergence. The Convergence Event Transition may
not be linear. not be linear.
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
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See Also: See Also:
Convergence Event Convergence Event
Rate-Derived Convergence Time Rate-Derived Convergence Time
Convergence Packet Loss Convergence Packet Loss
Convergence Recovery Transition Convergence Recovery Transition
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
3.10 Convergence Recovery Transition 3.10 Convergence Recovery Transition
Definition: Definition:
The characteristic of a router in which forwarding rate The characteristic of a router in which Throughput
gradually increases to equal the offered load. gradually increases to equal the offered load.
Discussion: Discussion:
The Convergence Recovery Transition is best observed for The Convergence Recovery Transition is best observed for
Full Convergence. The Convergence Event Transition may Full Convergence. The Convergence Event Transition may
not be linear. not be linear.
Measurement Units: Measurement Units:
seconds/milliseconds seconds/milliseconds
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Convergence Recovery Transition Convergence Recovery Transition
3.12 Sustained Forwarding Convergence Time 3.12 Sustained Forwarding Convergence Time
Definition: Definition:
The amount of time for which Full Convergence is maintained The amount of time for which Full Convergence is maintained
without additional packet loss. without additional packet loss.
Discussion: Discussion:
The purpose of the Sustained Forwarding Convergence Time is to The purpose of the Sustained Forwarding Convergence Time is to
produce Convergence Time benchmarks protected against fluctuation produce Convergence benchmarks protected against fluctuation
in Forwarding Rate after Full Convergence is observed. The in Throughput after Full Convergence is observed. The
Sustained Forwarding Convergence Time to be used is calculated Sustained Forwarding Convergence Time to be used is calculated
as shown in Equation 3. as shown in Equation 3.
(eq 3) (eq 3)
Sustained Forwarding Convergence Time = Sustained Forwarding Convergence Time = 5 packets/Offered Load
5 x (# routes in FIB) / (Offered Load) units are packets/pps = sec
for which at least one packet per destination MUST be received for which at least one packet per route in the FIB for all
at the DUT. routes in the FIB MUST be offered to the DUT per second.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
Issues: None Issues: None
See Also: See Also:
Full Convergence Full Convergence
Convergence Recovery Instant Convergence Recovery Instant
3.13 Restoration Convergence Time 3.13 Restoration Convergence Time
Definition: Definition:
The amount of time for the router under test to restore The amount of time for the router under test to restore
traffic to the original outbound port after recovery from traffic to the original outbound port after recovery from
a Convergence Event. a Convergence Event.
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
Discussion: Discussion:
Restoration Convergence Time is the amount of time to Restoration Convergence Time is the amount of time for routes
Converge back to the original outbound port. This is achieved to converge to the original outbound port. This is achieved
by recovering from the Convergence Event, such as restoring by recovering from the Convergence Event, such as restoring
the failed link. Restoration Convergence Time is measured the failed link. Restoration Convergence Time is measured
using the Rate-Derived Convergence Time calculation technique, using the Rate-Derived Convergence Time calculation technique,
as provided in Equation 1. It is possible, but not desired as provided in Equation 1. It is possible to have the
to have the Restoration Convergence Time differ from the Restoration Convergence Time differ from the Rate-Derived
Rate-Derived Convergence Time. Convergence Time.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
Issues: Issues:
None None
See Also: See Also:
Convergence Event Convergence Event
Rate-Derived Convergence Time Rate-Derived Convergence Time
3.14 Packet Sampling Interval 3.14 Packet Sampling Interval
Definition: Definition:
The interval at which the tester (test equipment) polls to make The interval at which the tester (test equipment) polls to make
measurements for arriving packet flows. measurements for arriving packet flows.
Discussion: Discussion:
Metrics measured at the Packet Sampling Interval may include Metrics measured at the Packet Sampling Interval may include
Forwarding Rate and Convergence Packet Loss. Throughput and Convergence Packet Loss.
Measurement Units: Measurement Units:
seconds or milliseconds seconds or milliseconds
Issues: Issues:
Packet Sampling Interval can influence the Convergence Graph. Packet Sampling Interval can influence the Convergence Graph.
This is particularly true as implementations achieve Full This is particularly true when implementations achieve Full
Convergence in less than 1 second. The Convergence Event Convergence in less than 1 second. The Convergence Event
Transition and Convergence Recovery Transition can become Transition and Convergence Recovery Transition can become
exaggerated when the Packet Sampling Interval is too long. exaggerated when the Packet Sampling Interval is too long.
This will produce a larger than actual Rate-Derived This will produce a larger than actual Rate-Derived
Convergence Time. The recommended value for configuration Convergence Time. The recommended value for configuration
of the Packet Sampling Interval is provided in [2]. of the Packet Sampling Interval is provided in [2].
See Also: See Also:
Convergence Packet Loss Convergence Packet Loss
Convergence Event Transition Convergence Event Transition
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Local Interface Local Interface
Neighbor Interface Neighbor Interface
3.18 Preferred Egress Interface 3.18 Preferred Egress Interface
Definition: Definition:
The outbound interface from the DUT for traffic routed to the The outbound interface from the DUT for traffic routed to the
preferred next-hop. preferred next-hop.
Discussion: Discussion:
Preferred Egress Interface is the egress interface prior to The Preferred Egress Interface is the egress interface prior
a Convergence Event to a Convergence Event.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Next-Best Egress Interface Next-Best Egress Interface
3.19 Next-Best Egress Interface 3.19 Next-Best Egress Interface
Definition: Definition:
The outbound interface from the DUT for traffic routed to the The outbound interface from the DUT for traffic routed to the
second-best next-hop. It is the same media type and link speed second-best next-hop. It is the same media type and link speed
as the Preferred Egress Interface as the Preferred Egress Interface
Discussion: Discussion:
Next-Best Egress Interface is the egress interface after The Next-Best Egress Interface becomes the egress interface
a Convergence Event. after a Convergence Event.
Measurement Units: Measurement Units:
N/A N/A
Issues: Issues:
None None
See Also: See Also:
Preferred Egress Interface Preferred Egress Interface
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
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IGP Data Plane Route Convergence IGP Data Plane Route Convergence
5. Security Considerations 5. Security Considerations
Documents of this type do not directly affect the security of Documents of this type do not directly affect the security of
Internet or corporate networks as long as benchmarking Internet or corporate networks as long as benchmarking
is not performed on devices or systems connected to production is not performed on devices or systems connected to production
networks. networks.
6. Normative References 6. References
6.1 Normative References
[1] Poretsky, S., "Benchmarking Applicability for IGP Data Plane [1] Poretsky, S., "Benchmarking Applicability for IGP Data Plane
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-08, Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-app-09,
work in progress, October 2005. work in progress, January 2006.
[2] Poretsky, S., "Benchmarking Methodology for IGP Data Plane [2] Poretsky, S., "Benchmarking Methodology for IGP Data Plane
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-08, Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-09,
work in progress, October 2005. work in progress, January 2006.
[3] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual [3] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual
Environments", RFC 1195, December 1990. Environments", RFC 1195, December 1990.
[4] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. [4] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
6.2 Informative References
[5] S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View [5] S. Casner, C. Alaettinoglu, and C. Kuan, "A Fine-Grained View
of High Performance Networking", NANOG 22, June 2001. of High Performance Networking", NANOG 22, June 2001.
[6] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized [6] L. Ciavattone, A. Morton, and G. Ramachandran, "Standardized
Active Measurements on a Tier 1 IP Backbone", IEEE Active Measurements on a Tier 1 IP Backbone", IEEE
Communications Magazine, pp90-97, May 2003. Communications Magazine, pp90-97, May 2003.
7. Author's Address 7. Author's Address
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
8 New England Executive Park 8 New England Executive Park
Burlington, MA 01803 Burlington, MA 01803
USA USA
Phone: + 1 508 439 9008 Phone: + 1 508 439 9008
EMail: sporetsky@reefpoint.com EMail: sporetsky@reefpoint.com
IGP Data Plane Route Convergence
Brent Imhoff Brent Imhoff
Juniper Networks
1194 North Mathilda Ave
Sunnyvale, CA 94089
USA USA
Phone: + 1 314 378 2571
EMail: bimhoff@planetspork.com EMail: bimhoff@planetspork.com
IGP Data Plane Route Convergence
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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