4: Multicast Routing 2 Inter-Domain Routing

Transcription

1 4: Multicast outing 2 Inter-Domain outing Typical Intra-Domain Multicast Architecture DATA DATA

2 Connecting Multicast-Domains MB Intra-Domain Intra-Domain Inter-Domain Multicast outing Issues: Address clashes Finding active sources Broadcast/prune vs explicit join M vs AM/FM Parallel paths (Multicast) oute changes upport for distribution tree optimizations 2 different approaches: Create shared tree in multicast border routers Overlay routing architecture (using multicast routing information base)

3 Generic MB Architecture outing logic ( 1,G 1 ) (iif, { oif,... })... hared forwarding cache IGMP DVMP MOPFPIM-M CBT Protocol components Network interfaces Only one routing protocol for each interface Components change forwarding entry for their interface ingle incoming interface per forwarding entry Components typically have separate multicast routing table Event-driven communication between components and routing logic MB routing process On incoming data, the dispatcher determines the iif owner iif owner may drop incoming packet (e.g. not in scope boundaries, PF check failed, etc.) Creation of (,G) entry triggers alert for outgoing interfaces enable flooding Deletion of (,G) entry trigger alert for incoming interface prune/leave Adding outgoing interface to (,G) entry triggers alert for incoming interface join/graft Create (*,*) entries for externally-reached sources towards tree root Owned by routing logic ( interop dispatcher ) Clear state after prunes Create entries for joins Act on component start/shutdown

4 Applicability to Existing Protocols Dense-mode Components are wildcard-receivers for internal sources Wildcard-receivers for external sources if no domain-wide reports available parse-mode MBs need to be on shared distribution tree create wildcard entries for every group at every P/Core Act as D for external sources Example: ender in PIM-M-Domain P DVMP PIM-M

5 Example: ender in PIM-M-Domain P DVMP PIM-M PIM-M outer Operation MB encapsulates data from external sources in egister message Use B-Bit to avoid multiple registrations P sends data downstream Downstream router operation: Look for specific routing state (,G) or (*,G) forward downstream Look for matching (*,*,P) entry forward packets if data arrived on incoming interface Otherwise, drop packets MB treated as group member Gets multicast data from senders within PIM-M-domain Forwards to DVMP-domain P may initiate PT-optimization

6 Example: ender in DVMP-Domain encapsulated data packet sent via unicast to P P DVMP PIM-M Overlay outing Architecture parse-mode approach relies on shared tree low convergence in case of route changes External single point of failure (due to unidirectional tree) BGMP: Border Gateway Multicast Protocol Like BGP-4 for unicast routing Can use any M-IGP (DVMP, MOPF, CBT, PIM, ) Bidirectional routing tree build global multicast IB M only on demand Worse loop prevention (no PF checks) Domain hierarchy to simplify routing decisions

7 eport to border routers Domain Hierarchies in BGMP BGMP join Domain A Domain B Domain C allocated root domain for G IGMP join for group G Domain D Domain Hierarchies in BGMP allocated root domain for G Domain B Domain C Domain A Domain D Multicast data for group G

8 BGMP outing Join/Prune is distributed to allocated root domain BGMP for communication between border routers pecific multicast routing protocol for interior communication Data is sent to multicast group as usual Border routers forward to next hop for specified group Forwarded downstream from root domain Must support specific M-IGP protocols Deal with PF-checks Tree optimizations Domain Hierarchies in BGMP allocated root domain for G Domain B Domain C Domain A encapsulate data to make PF check succeed Domain D Multicast data for group G

9 Domain Hierarchies in BGMP allocated root domain for G Domain B Domain C Domain A source-specific join prune other branches Domain D Multicast data for group G Domain Hierarchies in BGMP allocated root domain for G Domain B Domain C Domain A data sent along optimized PT Domain D Multicast data for group G

10 Address Allocation MALLOC (FC 2908) Overall allocation architecture cope, lifetime, timeliness, resource management, MAC (FC 2909) Claim set of address prefixes CID-like aggregation for routers MZAP (FC 2776) Announce information about local zone hierarchy To be used for address claims MADCAP (FC 2730) Allocate multicast address for instant use support dynamic groups such as ad-hoc-networks imilar to DHCP Current Practice Wide deployment of PIM-M networks Interconnected by MDP (FC 3618) and MBGP egular ource-active-announcements sent to Ps BGMP yet in draft state Tunnels for non-multicast networks Address allocation architecture not ubiquitous guess group addresses (239/8) M simplifies only intra-domain part