draft-ietf-bmwg-igp-dataplane-conv-app-07.txt   draft-ietf-bmwg-igp-dataplane-conv-app-08.txt 
Network Working Group Network Working Group
INTERNET-DRAFT INTERNET-DRAFT
Expires in: January 2006 Expires in: April 2006
Scott Poretsky Scott Poretsky
Reef Point Systems Reef Point Systems
July 2005 October 2005
Considerations for Benchmarking Considerations for Benchmarking
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
<draft-ietf-bmwg-igp-dataplane-conv-app-07.txt> <draft-ietf-bmwg-igp-dataplane-conv-app-08.txt>
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ABSTRACT ABSTRACT
This draft provides considerations for IGP Route Convergence This draft provides considerations for IGP Route Convergence
benchmarking methodology [1] and IGP Route Convergence benchmarking benchmarking methodology [1] and IGP Route Convergence benchmarking
terminology [2]. The methodology and terminology is to be used terminology [2]. The methodology and terminology is to be used
for benchmarking route convergence and can be applied to any for benchmarking route convergence and can be applied to any
link-state IGP such as ISIS [3] and OSPF [4]. The data plane is link-state IGP such as ISIS [3] and OSPF [4]. The data plane is
measured to obtain the convergence benchmarking metrics described measured to obtain the convergence benchmarking metrics described
in [1]. in [1].
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....3
6. Security Considerations.....................................4 6. IANA Considerations.........................................4
7. Acknowledgements............................................4 7. Security Considerations.....................................4
8. Normative References........................................5 8. Acknowledgements............................................4
9. Author's Address............................................5 9. Normative References........................................5
10. Author's Address...........................................5
1. Introduction 1. Introduction
IGP Convergence is a critical performance parameter. Customers IGP Convergence is a critical performance parameter. Customers
of Service Providers use packet loss due to IGP Convergence as a of Service Providers use packet loss due to IGP Convergence as a
key metric of their network service quality. Service Providers key metric of their network service quality. Service Providers
use IGP Convergence time as a key metric of router design and use IGP Convergence time as a key metric of router design and
architecture. Fast network convergence can be optimally achieved architecture. Fast network convergence can be optimally achieved
through deployment of fast converging routers. The fundamental through deployment of fast converging routers. The fundamental
basis by which network users and operators benchmark convergence basis by which network users and operators benchmark convergence
is packet loss, which is an externally observable event having is packet loss, which is an externally observable event having
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benchmarking the data plane. For this reason it is important to benchmarking the data plane. For this reason it is important to
develop a standard router benchmarking methodology and terminology develop a standard router benchmarking methodology and terminology
for measuring IGP convergence that uses the data plane as described for measuring IGP convergence that uses the data plane as described
in [1] and [2]. This document describes all of the factors that in [1] and [2]. This document describes all of the factors that
influence a convergence measurement and how a purely black box test influence a convergence measurement and how a purely black box test
can be designed to account for all of these factors. This enables can be designed to account for all of these factors. This enables
accurate benchmarking and evaluation for route convergence time. accurate benchmarking and evaluation for route convergence time.
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
document are to be interpreted as described in BCP 14, RFC 2119 this document are to be interpreted as described in BCP 14, RFC
[Br97]. RFC 2119 defines the use of these key words to help make the 2119. 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
document uses these keywords, this document is not a standards track this document uses these keywords, this document is not a standards
document. track document.
3. Factors for IGP Route Convergence Time 3. Factors for IGP Route Convergence Time
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 [5], [6], measured Router IGP Convergence Time. As discussed in [5], [6],
[7], [8] and [9], these categories are Event Detection, SPF [7], [8] and [9], these categories are Event Detection, SPF
Processing, IGP Advertisement, and FIB Update. These have numerous Processing, IGP Advertisement, and FIB Update. These have
components that influence the convergence time. These are listed numerous components that influence the convergence time. These
as follow: are listed as follow:
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
-Event Detection- -Event Detection-
SONET failure indication time SONET failure indication time
PPP failure indication time PPP failure indication time
IGP Hello Dead Interval IGP Hello Dead Interval
-SPF Processing- -SPF Processing-
SPF Delay Time SPF Delay Time
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components. The additional benefit of designing a test for all components. The additional benefit of designing a test for all
components is that it enables black-box testing in which knowledge components is that it enables black-box testing in which knowledge
of the routers' internal implementations is not required. It is of the routers' internal implementations is not required. It is
then possible to make valid use of the convergence benchmarking then possible to make valid use of the convergence benchmarking
metrics when comparing routers from different vendors. 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 administrative link convergence. These network events are administrative link
removal, unplanned link failure, line card failure, and route removal, unplanned link failure, line card failure, and route
changes such as withdrawal, flap, next-hop change, and cost change. changes such as withdrawal, flap, next-hop change, and cost
When benchmarking a router it is important to measure the change. When benchmarking a router it is important to measure
convergence time for local and remote occurrence of these network convergence time for local and remote occurrence of these network
events. The convergence time measured will vary whether the network events. The convergence time measured will vary whether the
event occurred locally or remotely due to varying combinations of network event occurred locally or remotely due to varying
factors listed in the previous sections. This behavior makes it combinations of factors listed in the previous sections. This
possible to design purely black-box tests that isolate behavior makes it possible to design purely black-box tests that
measurements for each of the components of convergence time. isolate measurements for each of the components of convergence
time.
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 observable calculate convergence time. Packet loss is an externally
event having direct impact on customers' application performance. observable event having direct impact on customers' application
For this reason it is important to develop a standard router performance. For this reason it is important to develop a
benchmarking methodology and terminology that is a Direct Measure standard router benchmarking methodology and terminology that is
of Quality (DMOQ) for measuring IGP convergence. Such a a Direct Measure of Quality (DMOQ) for measuring IGP convergence.
methodology uses the data plane as described in [1] and [2]. Such a methodology uses the data plane as described in [1] and [2].
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
An additional benefit of using packet loss for calculation of An additional benefit of using packet loss for calculation of
IGP Route Convergence time is that it enables black-box tests to IGP Route Convergence time is that it enables black-box tests to
be designed. Data traffic can be offered to the be designed. Data traffic can be offered to the
device under test (DUT), an emulated network event can be forced device under test (DUT), an emulated network event can be forced
to occur, and packet loss can be externally measured to calculate to occur, and packet loss can be externally measured to calculate
the convergence time. Knowledge of the DUT architecture and IGP the convergence time. Knowledge of the DUT architecture and IGP
implementation is not required. There is no need to rely on the implementation is not required. There is no need to rely on the
DUT to produce the test results. There is no need to build DUT to produce the test results. There is no need to build
intrusive test harnesses for the DUT. intrusive test harnesses for the DUT.
Use of data traffic and measurement of packet loss on the data Use of data traffic and measurement of packet loss on the data
plane also enables Route Convergence methodology test cases that plane also enables Route Convergence methodology test cases that
consider the time for the Route Controller to update the FIB on consider the time for the Route Controller to update the FIB on
the forwarding engine of the hardware. A router is not fully the forwarding engine of the hardware. A router is not fully
converged until all components are updated and traffic is converged until all components are updated and traffic is
rerouted to the correct egress interface. As long as there is rerouted to the correct egress interface. As long as there is
packet loss, routes have not converged. It is possible to send packet loss, routes have not converged. It is possible to send
diverse traffic flows to destinations matching every route in the diverse traffic flows to destinations matching every route in
FIB so that the time it takes for the router to converge an entire the FIB so that the time it takes for the router to converge an
route table can be benchmarked. entire route table can be benchmarked.
6. Security Considerations 6. IANA Considerations
Documents of this type do not directly effect the security of This document requires no IANA considerations.
the Internet or of corporate networks as long as benchmarking
is not performed on devices or systems connected to operating
networks.
7. Acknowledgements 7. 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 production networks.
8. Acknowledgements
Thanks to Curtis Villamizar for sharing so much of his Thanks to Curtis Villamizar for sharing so much of his
knowledge and experience through the years. Also, special knowledge and experience through the years. Also, special
thanks to the many Network Engineers and Network Architects thanks to the many Network Engineers and Network Architects
at the Service Providers who are always eager to discuss at the Service Providers who are always eager to discuss
Route Convergence benchmarking. Route Convergence benchmarking.
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
8. Normative References 9. Normative References
[1] Poretsky, S., "Benchmarking Methodology for IGP Data Plane [1] Poretsky, S., "Benchmarking Methodology for IGP Data Plane
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-07, Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-meth-08,
work in progress, July 2005. work in progress, October 2005.
[2] Poretsky, S., "Benchmarking Terminology for IGP Data Plane [2] Poretsky, S., "Benchmarking Terminology for IGP Data Plane
Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-term-07, Route Convergence", draft-ietf-bmwg-igp-dataplane-conv-term-08,
work in progress, July 2005. work in progress, October 2005.
[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.
[5] Villamizar, C., "Convergence and Restoration Techniques for [5] Villamizar, C., "Convergence and Restoration Techniques for
ISP Interior Routing", NANOG 25, October 2002. ISP Interior Routing", NANOG 25, October 2002.
[6] Katz, D., "Why are we Scared of SPF? IGP Scaling and [6] Katz, D., "Why are we Scared of SPF? IGP Scaling and
skipping to change at page 5, line 38 skipping to change at page 5, line 38
Backbone: ISIS Fast Convergence and Differentiated Services Backbone: ISIS Fast Convergence and Differentiated Services
Design (tutorial)", NANOG 25, October 2002. Design (tutorial)", NANOG 25, October 2002.
[8] Alaettinoglu, C. and Casner, S., "ISIS Routing on the Qwest [8] Alaettinoglu, C. and Casner, S., "ISIS Routing on the Qwest
Backbone: a Recipe for Subsecond ISIS Convergence", NANOG 24, Backbone: a Recipe for Subsecond ISIS Convergence", NANOG 24,
October 2002. October 2002.
[9] Alaettinoglu, C., Jacobson, V., and Yu, H., "Towards [9] Alaettinoglu, C., Jacobson, V., and Yu, H., "Towards
Millisecond IGP Convergence", NANOG 20, October 2000. Millisecond IGP Convergence", NANOG 20, October 2000.
9. Author's Address 10. 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: + 1 781 395 5090 Phone: + 1 508 439 9008
EMail: sporetsky@quarrytech.com EMail: sporetsky@reefpoint.com
IGP Data Plane Route Convergence IGP Data Plane Route Convergence
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
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.
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