Inter domain multicast

1
Inter- domain multicast

• Domain a set of end-hosts and routers
  implementing a particular multicast protocol.
• Protocol can be app-layer or IP-layer.
• Service end-to-end multicast connectivity across
  these domains
• Motivation audio/video broadcast, software
  updates, etc.

2
A Possible Approach

• Peering between gateways in domains
• Collaborative
• Pre-configured peering relationship
• Method of propagation of routing towards other
  domains
• Overlay (app-level)
• Willingness to carry data towards other domains
• Business model ?? (customer domain provider
  domain style peering)
• What is common among the domains?
• A domain-level routing/multicast protocol
• A session-naming scheme
• Owner-domain.local-session-name

3
Protocol

• Routing
• peers exchange routes to other domains gateways
• path-vector protocol (hop-count/latency/b.w.
  metrics)
• Tree-building soft-state JOIN based protocol.
• Might require session specific egress gateway
  selection at owner domain, since domains might
  overlap geographically
• Data-forwarding
• Between Internal peer gateways
• Requires local (bi-directional) multicast session
  establishment
• Requires internal-peer agreement on injection
  point

Source
Clients
Gateway
4

• In terms of services
• Service Discovery
• By Clients not addressed (configured)
• By Gateways pre-configured peeringroute
  exchange.
• Service Instance (w.r.t. a domain) Gateway
• Service instance selectionredirection done by
  gateways using an internal-peer protocol
• Service replication (w.r.t. a domain) multiple
  injection points within the domain combined with
  scoping, for load-balancing/latency-optimization.
• Policy support
• Based on selective route forwarding
• Is that enough ??
• Tree direction specified by session initiator.
• Data forwarding control required ??
• Data can be injected only along JOIN-paths
• Rate-control required (aggregate /per-session)??
• Then Route-selection would change ??
• QoS - JOINs are like RSVP messages??
• ?? Indicates not implemented, possible future
  work