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Multicast Performance Measurement on the vBNS. NANOG 20 (Washington, DC) October 24, 2000. Robert Beverly ([email protected]). Background. End-to-End nightly performance tests run since early 1995 across vBNS Goal: Develop analogous tests for multicast - PowerPoint PPT Presentation
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Multicast Performance Measurement on the vBNSNANOG 20 (Washington, DC)October 24, 2000
Robert Beverly ([email protected])
Background
End-to-End nightly performance tests run since early 1995 across vBNSGoal: Develop analogous tests for multicastNo longer possible to rely on crontab entries for test synchronization (1:N vs 1:1)Developed out-of-band signaling protocol to control tests
Network Details
Tests utilize Sun Ultra2 hosts with OC12c ATM interfaces in each network POPPVC to local Juniper M40Juniper M40s have both POS (OC48c) and ATM (OC12c) links to other backbone network nodesPOS links preferredPIM-SM domain
Signaling Protocol
Signaling protocol designed to allow maximum flexibilityAllows for arbitrary multicast topologiesUses TCP for reliabilityMessages:– Health check– Send N packets of size S on group G at rate R– Receive N packets on group G
Test Operation
1. Coordinator checks health of all daemons2. Coordinator selects one sender and ten
receivers3. Coordinator sends receive control instructions4. Receivers send IGMP membership reports5. Coordinator sends transmit control instruction6. Receivers collect loss and packet misordering
7. Receiver receives last expected packet or times out waiting on final packet
8. Coordinator waits for acknowledgements from all receivers
9. Coordinator gathers loss information, generates graphs and tables
10. Select different transmitter, repeat
Test Operation
Test Details
Addresses selected from GLOP (RFC 2770)Administratively scopedWhy ATM?– Models actual vBNS customer access method– Already deployed across all vBNS POPs– Easily controlled traffic shaping
Control Host (Washington)
Expect 50000 Multicast Packets from Group (G)
Expect 50000 Multicast Packets from Group (G)
Expect 50000 Multicast P
ackets from Group (G
)
Control Host (Washington)
IGMPv2 Membership Report for Group (G)
IGMPv2 Membership Report for Group (G)
IGMPv2 Membership Report for Group (G)
Control Host (Washington)
Send
500
00 to
Gro
up (G
)
Control Host (Washington)
RP Register
Test Traffic to Group G
Control Host (Washington)
(S,G) State Installed
Control Host (Washington)
Traffic
Test Traffic to Group G
Traffic via Shared Tree
Traffic via Shared Tree
Control Host (Washington)
(SPT Built using PIM-SM)
(S,G) State Installed
(S,G) State Installed
Control Host (Washington)
Receivers now see traffic via SPT
Control Host (Washington)
Receiver Report(includes which packetswere lost)
Test Results
Nightly test results available at: http://www.vbns.net/stats/mcastBoth absolute and time relative loss presentedNature of loss (bursty, continuous, etc)Result data validated with OCxMONs
Test Results – Loss ReportMulticast Loss Percentage [Wed Oct 11 00:11:43 EDT 2000]Packets: 49984Pkt Size: 4000 BytesRate: 10 Mbps
ReceiverSRC AST DNG DNJ HAY HSJ NOR PYM RTO SEJ WAE WOR----+-----------------------------------------------------------------ast - 0.074 0.094 0.166 0.016 0.006 0.006 0.016 0.182 0.006 0.006dng 0.046 - 0.006 0.166 0.006 0.008 0.222 0.022 0.132 0.022 0.022dnj 0.098 0.014 - 0.026 0.014 0.010 0.488 0.026 0.116 0.022 0.022hay 0.068 0.036 0.024 - 0.176 0.036 0.070 0.028 0.012 0.048 0.048hsj 0.018 0.010 0.010 0.090 - 0.008 0.018 0.006 0.006 0.018 0.018nor 0.040 0.016 0.016 0.066 0.016 - 0.172 0.016 0.018 0.028 0.028pym 0.024 0.038 0.084 0.172 0.040 0.026 - 0.040 0.236 0.024 0.026rto 0.048 0.046 0.086 0.036 0.016 0.046 0.198 - 0.004 0.048 0.070sej 1.283 0.114 0.086 0.158 0.388 0.114 1.296 0.070 - 1.280 1.280wae 0.016 0.124 0.140 0.184 0.140 0.016 0.016 0.140 0.704 - 0.016wor 0.492 0.480 0.486 0.568 0.504 0.448 0.450 0.504 0.572 0.492 -
Test Results – SNMP PollingROOT: jn1.ast.vbns.net (Null hostent.)
ROOT: 204.147.136.134 (jn1-so7-0-0-0.ast.vbns.net)1: 204.147.136.139 (jn1-so7-0-0-2.mej.vbns.net) [0:04:05] [56142]2: jn1.dng.vbns.net (Null hostent.) [0:04:39] [56142]
ROOT: 204.147.136.134 (jn1-so7-0-0-0.ast.vbns.net)1: 204.147.136.139 (jn1-so7-0-0-2.mej.vbns.net) [0:04:07] [56142]2: 204.147.136.144 (jn1-so7-0-0-2.dng.vbns.net) [0:04:40] [56142]3: jn1.dnj.vbns.net (Null hostent.) [0:04:08] [56096]
ROOT: 204.147.136.129 (jn1-so7-0-0-1.ast.vbns.net)1: 204.147.136.136 (jn1-so7-0-0-0.wae.vbns.net) [0:04:47] [53185]2: 204.147.136.133 (jn1-so7-0-0-0.wor.vbns.net) [0:04:12] [53149]3: jn1.nor.vbns.net (Null hostent.) [0:04:12] [53107]
ROOT: 204.147.136.129 (jn1-so7-0-0-1.ast.vbns.net)1: 204.147.130.162 (jn1-at1-0-0-13.wae.vbns.net) [0:04:50] [53185]2: jn1.pym.vbns.net (Null hostent.) [0:04:13] [50016]
Detected 484 lost pkts (50016 expected)0.968% percent loss
Test Results – Loss Pattern
Detected 72 lost pkts (50016 expected)0.144% percent loss
ast
dng
Test Results – Practical Application
Detect performance problems– Loss– Reordering
Determine vBNS backbone multicast performanceDetect multicast routing anomaliesDetected lost tunnel PIC
Causes of Loss
State initiation delayCongested network path or network elementRouting instabilitiesInherently unreliable protocol (UDP)
Practical Implementation Problems
No way to get OSPF routes into Juniper MRIB (inet.2) in JunOS 4.xForced to export Sun /30 routes into iBGP via a JunOS policy statementIGMP membership reports must be carried in optioned IP packets for the Juniper to recognize them (contrary to RFC)Danger in running native multicast on production routers
Multi-Megabit Multicast
Successfully demonstrated high-date rate multicast from 1 sender to 10 receivers1Million 4k Byte packets at 380MbpsBetween 0.443% and 0.830% lossBackbone M40 routers perform very well, shared memory architectureCurrently trying to scale Sun performance hosts to even higher rates
Other Multicast Measurement Tools
Netcom Systems SmartMulticastIP– http://www.netcomsystems
.com/solutions/products/applications/0300_0025RevE_SmartMulticast.asp
NLANR Multicast Beacon– http://dast.nlanr.net/Projects/Beacon
MRM– http://imj.ucsb.edu/mrm/
Multicast BenchmarkingDocuments
RFC2432: Terminology for IP Multicast BenchmarkingDraft-ietf-bmwg-mcastm-04.txt: Methodology for IP Multicast Benchmarking
Further Research
Full line rate (~580Mbps) testingGroup capacity testingMixed-Class ThroughputLatency/Jitter Measurements
Questions?