multicast performance measurement on the vbns nanog 20 (washington, dc) october 24, 2000 robert...

Multicast Performance Measurement on the vBNSNANOG 20 (Washington, DC)October 24, 2000

Robert Beverly (rbeverly@mci.net)

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 Packets fr

om 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?