Multicast at Interconnects

1
Multicast at Interconnects

• John Meylor ltjmeylor_at_cisco.comgt
• NANOG
• November 8-10, 1998

2
Objectives

• support for native multicast routing
• use of scalable, policy-based routing in
  inter-domain space
• allow for variety of protocols and topologies in
  intra-domain space

3
Design elements

• route exchange
• BGP or BGP4 to provide scalable, policy based
  EGP
• tree building/multicast forwarding protocol
• PIM to allow for (M)BGP interdomain and IGP
  intradomain
• PIM DM initially (to flood s,g state to
  collocated RPs)
• PIM SM eventually (to reduce flood-prune,
  requires MSDP)

4
Design elements

• method for identifying active sources
• dense mode flooding of data to establish s,g
  state
• MSDP to flood only SA packets to MSDP peers
• media
• native broadcast, single packet per source
• fddi concentrator commonly used
• simple, reasonably common denominator
• eliminates variable of switching mechinisms
  initially

5
Topology example Ames MIX
AS10888---R----"MBone"

multicast_interexchange (MIX)
----------------
/ \ /
\ mbgp_peer---R
R---mbgp_peer \
/ \ /
---------------
FIX unicast_exchanges