draft-ietf-bmwg-igp-dataplane-conv-app-13.txt   draft-ietf-bmwg-igp-dataplane-conv-app-14.txt 
Network Working Group Network Working Group
INTERNET-DRAFT INTERNET-DRAFT
Expires in: January 2008
Intended Status: Informational Intended Status: Informational
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
November 2007
Considerations for Benchmarking Considerations for Benchmarking
IGP Data Plane Route Convergence Link-State IGP Data Plane Route Convergence
<draft-ietf-bmwg-igp-dataplane-conv-app-13.txt> <draft-ietf-bmwg-igp-dataplane-conv-app-14.txt>
Intellectual Property Rights (IPR) statement: Intellectual Property Rights (IPR) statement:
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware 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 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. aware will be disclosed, in accordance with Section 6 of BCP 79.
Status of this Memo Status of this Memo
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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observable (black box) data plane measurements. A companion observable (black box) data plane measurements. A companion
terminology document is to be referenced to support the benchmarking. terminology document is to be referenced to support the benchmarking.
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 .......................................2 2. Existing definitions .......................................2
3. Factors for IGP Route Convergence Time......................2 3. Factors for IGP Route Convergence Time......................2
4. Network Events that Cause Route Convergence.................3 4. Network Events that Cause Route Convergence.................3
5. Use of Data Plane for IGP Route Convergence Benchmarking....3 5. Use of Data Plane for IGP Route Convergence Benchmarking....4
6. IANA Considerations.........................................4 6. IANA Considerations.........................................4
7. Security Considerations.....................................4 7. Security Considerations.....................................4
8. Acknowledgements............................................4 8. Acknowledgements............................................5
9. Normative References........................................5 9. Normative References........................................5
10. Author's Address...........................................5 10. Author's Address...........................................6
1. Introduction 1. Introduction
Convergence Time is a critical performance parameter. Customers Convergence Time is a critical performance parameter. Customers
of Service Providers use convergence packet loss [Po07t] due to of Service Providers use convergence packet loss [Po07t] due to
Interior Gateway Protocol (IGP) Convergence as a key metric of Interior Gateway Protocol (IGP) convergence as a key metric of
their network service quality. Service Providers use IGP their network service quality. Service Providers use IGP
Convergence time as a key metric of router design and architecture Convergence time as a key metric of router design and architecture
for any IGP such as Intermediate System - Intermediate System for any IGP such as Intermediate System - Intermediate System
(ISIS) [Ca90] and Open-Shorted Path first (OSPF) [Mo98]. Fast (ISIS) [Ca90] and Open-Shorted Path first (OSPF) [Mo98]. Fast
network convergence can be optimally achieved through deployment network convergence can be optimally achieved through deployment
of fast converging routers. The fundamental basis by which network of fast converging routers. The fundamental basis by which network
users and operators benchmark convergence is packet loss, which is users and operators benchmark convergence is packet loss, which is
an externally observable event having direct impact on their an externally observable event having direct impact on their
application performance. application performance.
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There are four major categories of factors contributing to the There are four major categories of factors contributing to the
measured Router IGP Convergence Time. As discussed in [Vi02], measured Router IGP Convergence Time. As discussed in [Vi02],
[Ka02], [Fi02], [Al02] and [Al00], these categories are Event [Ka02], [Fi02], [Al02] and [Al00], these categories are Event
Detection, Shortest Path First (SPF) Processing, IGP Advertisement, Detection, Shortest Path First (SPF) Processing, IGP Advertisement,
and Forwarding Information Base (FIB) Update. These have numerous and Forwarding Information Base (FIB) Update. These have numerous
components that influence the convergence time, as listed below: components that influence the convergence time, as listed below:
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
-Event Detection- -Event Detection-
Physical Layer failure indication time Physical Layer failure/recovery indication time
Layer 2 failure indication time Layer 2 failure/recovery indication time
IGP Hello Dead Interval IGP Hello Dead Interval
-SPF Processing- -SPF Processing-
SPF Delay Time SPF Delay Time
SPF Hold time SPF Hold time
SPF Execution time SPF Execution time
-IGP Advertisement- -IGP Advertisement-
LSA/LSP Flood Packet Pacing LSA/LSP Flood Packet Pacing
LSA/LSP Retransmission Packet Pacing LSA/LSP Retransmission Packet Pacing
LSA/LSP Generation time LSA/LSP Generation time
-FIB Update- -FIB Update-
Tree Build time Tree Build time
Hardware Update time Hardware Update time
-Increased Forwarding Delay due to Queueing
The contribution of each of these factors listed above will vary The contribution of each of these factors listed above will vary
with each router vendors' architecture and IGP implementation. with each router vendors' architecture and IGP implementation.
Routers may have a centralized forwarding architecture, in which
one route table is calculated and referenced for all arriving
packets, or a distributed forwarding architecture, in which the
central route table is calculated and distributed to the
interfaces for local look-up as packets arrive. The distributed
route tables are typically maintained in hardware.
It is therefore necessary to design a convergence test that It is therefore necessary to design a convergence test that
considers all of these components, not just one or a few of these considers all of these components contributing to convergence time
components. The additional benefit of designing a test for all and is independent of the Device Under Test (DUT) architecture,
components is that it enables black-box testing in which knowledge The benefit of designing a test for these considerations is that
of the routers' internal implementations is not required. It is it enables black-box testing in which knowledge of the routers'
then possible to make valid use of the convergence benchmarking internal implementations is not required. It is then possible
metrics when comparing routers from different vendors. to make valid use of the convergence benchmarking metrics when
comparing routers from different vendors.
4. Network Events that Cause Convergence 4. Network Events that Cause Convergence
There are different types of network events that can cause IGP There are different types of network events that can cause IGP
convergence. These network events are as follow: convergence. These network events are as follow:
* administrative link removal * administrative link removal
* unplanned link failure * unplanned link failure
* line card failure * line card failure
* route changes such as withdrawal, flap, next-hop change, * route changes such as withdrawal, flap, next-hop change,
and cost change. and cost change.
* session loss due to loss of peer or adjancency
* link recovery
* link insertion
IGP Data Plane Route Convergence
When benchmarking a router it is important to measure convergence When benchmarking a router it is important to measure convergence
time for local and remote occurrence of these network events. time for local and remote occurrence of these network events.
The convergence time measured will vary whether the network event The convergence time measured will vary whether the network event
occurred locally or remotely due to varying combinations of occurred locally or remotely due to varying combinations of
factors listed in the previous sections. This behavior makes it factors listed in the previous sections. This behavior makes it
possible to design purely black-box tests that isolate possible to design purely black-box tests that isolate
measurements for each of the components of convergence time. measurements for each of the components of convergence time.
IGP Data Plane Route Convergence
5. Use of Data Plane for IGP Route Convergence Benchmarking 5. Use of Data Plane for IGP Route Convergence Benchmarking
Customers of service providers use packet loss as the metric to Customers of service providers use packet loss as the metric to
calculate convergence time. Packet loss is an externally calculate convergence time. Packet loss is an externally
observable event having direct impact on customers' application observable event having direct impact on customers' application
performance. For this reason it is important to develop a performance. For this reason it is important to develop a
standard router benchmarking methodology and terminology that is standard router benchmarking methodology and terminology that is
a Direct Measure of Quality (DMOQ) for measuring IGP convergence. a Direct Measure of Quality (DMOQ) for measuring IGP convergence.
Such a methodology uses the data plane as described in [Po07m] Such a methodology uses the data plane as described in [Po07m]
using the terminology provided in [Po07t]. using the terminology provided in [Po07t].
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This document requires no IANA considerations. This document requires no IANA considerations.
7. Security Considerations 7. Security Considerations
Documents of this type do not directly effect the security Documents of this type do not directly effect the security
of the Internet or of corporate networks as long as of the Internet or of corporate networks as long as
benchmarking is not performed on devices or systems benchmarking is not performed on devices or systems
connected to production networks. connected to production networks.
8. 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 benchmarking.
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
8. Acknowledgements
Thanks to Curtis Villamizar for sharing so much of his knowledge
and experience through the years. Thanks to Ron Bonica, Al Morton,
David Ward, and the BMWG for their reviews and comments.
9. References 9. References
9.1 Normative References 9.1 Normative References
[Br97] Bradner, S., "Key words for use in RFCs to Indicate [Br97] Bradner, S., "Key words for use in RFCs to Indicate
[Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP [Ca90] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP
and Dual Environments", RFC 1195, December 1990. and Dual Environments", RFC 1195, December 1990.
[Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998. [Mo98] Moy, J., "OSPF Version 2", RFC 2328, IETF, April 1998.
[Po07m] Poretsky, S., "Benchmarking Methodology for IGP Data [Po07m] Poretsky, S., "Benchmarking Methodology for
Plane Route Convergence", Link-State IGP Data Plane Route Convergence",
draft-ietf-bmwg-igp-dataplane-conv-meth-13, work in draft-ietf-bmwg-igp-dataplane-conv-meth-14, work in
progress, July 2007. progress, November 2007.
[Po07t] Poretsky, S., "Benchmarking Terminology for IGP Data [Po07t] Poretsky, S., "Benchmarking Terminology for
Plane Route Convergence", Link-State IGP Data Plane Route Convergence",
draft-ietf-bmwg-igp-dataplane-conv-term-13, work in draft-ietf-bmwg-igp-dataplane-conv-term-14, work in
progress, July 2007. progress, November 2007.
9.2 Informative References 9.2 Informative References
[Al00] Alaettinoglu, C., Jacobson, V., and Yu, H., "Towards [Al00] Alaettinoglu, C., Jacobson, V., and Yu, H., "Towards
Millisecond IGP Convergence", NANOG 20, March 2000. Millisecond IGP Convergence", NANOG 20, March 2000.
[Al02] Alaettinoglu, C. and Casner, S., "ISIS Routing on the [Al02] Alaettinoglu, C. and Casner, S., "ISIS Routing on the
Qwest Backbone: a Recipe for Subsecond ISIS Convergence", Qwest Backbone: a Recipe for Subsecond ISIS Convergence",
NANOG 24, March 2002. NANOG 24, March 2002.
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Internet Backbone: ISIS Fast Convergence and Internet Backbone: ISIS Fast Convergence and
Differentiated Services Design (tutorial)", NANOG 25, Differentiated Services Design (tutorial)", NANOG 25,
March 2002. March 2002.
[Ka02] Katz, D., "Why are we Scared of SPF? IGP Scaling and [Ka02] Katz, D., "Why are we Scared of SPF? IGP Scaling and
Stability", NANOG 25, March 2002. Stability", NANOG 25, March 2002.
[Vi02] Villamizar, C., "Convergence and Restoration Techniques [Vi02] Villamizar, C., "Convergence and Restoration Techniques
for ISP Interior Routing", NANOG 25, March 2002. for ISP Interior Routing", NANOG 25, March 2002.
10. Author's Address IGP Data Plane Route Convergence
10. Author's Address
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
8 New England Executive Park 3 Federal Street
Burlington, MA 01803 Billerica, MA 01821 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
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
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 This document and the information contained herein are provided
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