1 Deployment of IP Multicast in Campus Infrastructures Kevin Almeroth UC--Santa Barbara

2 Outline multicast protocols overview—see the WWW site –super-brief overview state of deployment getting started with deployment working group activities addendum: router configs—see the WWW site

3 source Unicast performs routing and forwarding at the same time, and in the source-to-receiver direction

4 source Multicast Routing (and Functions) routing (path determination) [but in the reverse direction] packet forwarding and replication handling dynamic membership---path pruning/grafting

5 source Building the Reverse Path

6 source Building an RP Tree

7 source Forwarding Data routing (path determination) [but in the reverse direction] packet forwarding and replication handling dynamic membership---path pruning/grafting

8 source Question for the Ages How to find the source(s)? source

9 How to Find the Sources? broadcast everywhere –receivers decide when they do not want the traffic any source multicast (ASM) [PIM-SM/MBGP/MSDP/IGMPv2] –use a rendezvous point (RP) –receivers send joins along reverse path to RP –sources send traffic to RP source specific multicast (SSM) [PIM/MBGP/IGMPv3] –require receivers to already know source(s) –use some out-of-band mechanism

10 How MSDP works with PIM-SM RP MSDP peer Physical link A B C D Receiver Source PIM message MSDP message SA Join

11 How SSM Works Physical link A B C D Receiver Source PIM message Join

12 State of Deployment

13 Status of the Multicast Pieces (Support for IGMPv2 & PIM-SM/MBGP/MSDP) network: lots of vendors support multicast routing: Cisco & Juniper then Nortel, Foundry, Lucent, others, etc. OSs/kernel: most kernels support functions (IGMPv2) applications: –MBone tools ( –IPTV, Real, MediaPlayer, and now LOTS others…

14 Status of the Multicast Pieces (Support for IGMPv2 & PIM-SM/MBGP/MSDP) content: –UofO ( –GRID ( –ICAIR CSPAN ( –On-the-I ( –Yahoo ( –NASA ( –UCSB ( –All the commodity traffic (sdr)

15 Status of the Multicast Pieces (Support for IGMPv3 & SSM) network: most vendors already support it since functionality in the core has been simplified OSs/kernel: test kernels available – applications: lots of talk, but not much action – content: without supporting software/hardware, content is not there

16 Status of Deployment nice and stable in Abilene (since early 1999) some commercial ISPs… –but typically service is not announced and is not supported –issues are beginning to be only political/financial (layers 8&9) to track multicast deployment and stats… –see –see

17 Latest Multicast Topology

18 The Internet2 (Abilene) Topology

19

20 Site Deployment: Getting Started and Using Multicast

21 Deploying Multicast Locally experiment with multicast on a local network try one- or few-hop multicast topology connect to I2 experiment with advanced applications transition to production service

22 Resources I2 multicast WWW page – I2 multicast mailing list –send to subscribe wg-multicast Your-Name –in the body of the message I2 multicast working group meetings –at Joint Techs meetings (

23 Working Group Activities Continue robust backbone service –track deployment and use –support Source Specific Multicast (SSM) –provide support for gigapop and campus deployment Increase deployment –campuses, international and commodity peering –provide assistance beyond the NOC

24 Working Group Activities Increase use of multicast –encourage campuses to offer events –advertise availability of events to non-geeks –new service to track events Increase variety of applications –create opportunities to use multicast in novel ways –new service to track tools/applications

25 Conclusions Stable backbone –Key first step Deployment in some campuses (low hanging fruit) Working on building a robust service –More than just one-to-many packet delivery applications, support, service, etc. –Lots of issues with legacy infrastructure