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Abilene Resiliency Test. John Moore Technical Director Centaur Lab North Carolina ITEC jhm@nc-itec.org. SDSC Kevin Walsh Tom Hutton Abilene NOC Andrew Lee Matt Davy CENIC Erick Sizelove. Spirent Communications Qwest Internet2 Jeff Boote Chris Heermann. Acknowledgements.
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Abilene Resiliency Test John Moore Technical Director Centaur Lab North Carolina ITEC jhm@nc-itec.org
SDSC Kevin Walsh Tom Hutton Abilene NOC Andrew Lee Matt Davy CENIC Erick Sizelove Spirent Communications Qwest Internet2 Jeff Boote Chris Heermann Acknowledgements
Motivations • OC-192 backbone links from Qwest “unprotected” • Previous OC-48 backbone circuits had SONET protection (sub- 50 ms) • Ongoing MPLS investigation requires understanding of various protection options available
Test Objectives • Measure convergence time after a link outage • End-to-end and backbone edge-to-edge • Use longest convenient path • SDSC to NCSU • Examine effect of modifying IGP settings • Chose spf delay value as variable • Examine different MPLS recovery schemes • Soft LSP (loose hop) • Explicit route (strict hops) • Fast re-route
Test Traffic • Spirent Communications AX/4000 tester in CA-ITEC and NC-ITEC Labs • One IPv4 stream • Five MPLS streams • Unidirectional • AMI owamp streams between LOSA and WASH • Actually, we have data for any-any Abilene nodes • IS-IS monitor tool • Not deployed in time
Test Traffic • Owamp traffic • 64 bytes, 10 pps • Increased rate for test, will leave as new default • Measure latency and packet loss (indirectly) • AX/4000 traffic • 1000 bytes frames, 20 Mbps per stream • MPLS tunnel traffic was Ethernet • Used Juniper L2 circuits to get vlan-tagged traffic into LSP • Measure packet rate and packet loss
IS-IS Parameters • Link failure hold time • Delay in declaring link down • Default: zero • LSP interval • Rate limit for LSP flooding (per interface) • Default: 30 LSPs per second • SPF delay • Delay in running spf algorithm • Default: 200 ms • SPF recalculation time • Time required to run spf algorithm • Abilene: usually < 1 ms, some spikes to 2 ms
Observations (so far…) • Decreasing spf delay seems to make convergence time worse • MPLS FRR offers a possible alternative way to minimize convergence time • More analysis needed • More testing needed