- Any cast is a method to create redundancy
- Traffic from source to destination reaches closest destination in the topology
- Multiple destinations share the same address and route to the closest one based on the IGP/BGP table
Any Cast RP
- Use any cast load balancing to decentralize the placement of PIM spare mode RPs
- All RPs must share the same information about senders and receivers
- PIM register and join messages go to the closest RP in the topology
- If one RP goes down, convergence is up to IGP
- As long as one RP is up, new trees will be built up
MSDP
- MSDP uses to advertise (S,G) pair between RPs
- MSDP will make sure that PIM register is sent to one of the any cast RPs
- Another RP will not get PIM join message
- MSDP will telll other RPs about (S,G) through an MSDP source active (SA) message
- Allow PIM domain to use independent RPs
- Any cast RPs are MSDP peers using unique address
- Router (config) # ip msdp peer x.x.x.x connect-source loopback xx
- Router (config) # ip msdp originator-id loopback xx
Where is going to use for?
- It is useful when multicast goes on internet and we have many sources and want closet source to your region will send you the stream
ANYCAST LAB
R2 CONFIGURATION
R2#show run | section msdp
ip msdp peer 3.3.3.3 connect-source Loopback0
ip msdp cache-sa-state
ip msdp originator-id Loopback0
This is rp address and any cast address ( This address will be shared with R3)
ip pim rp-address 23.23.23.23
R2#show ip int brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 10.12.12.2 YES NVRAM up up
GigabitEthernet1/0 10.23.23.2 YES NVRAM up up
Loopback0 2.2.2.2 YES NVRAM up up
Loopback23 23.23.23.23 YES NVRAM up up ( any cast)
Tunnel0 23.23.23.23 YES unset up up
Tunnel1 23.23.23.23 YES unset up up
R2#show ip pim nei
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.12.12.1 GigabitEthernet0/0 01:02:29/00:01:30 v2 1 / S P G
10.23.23.3 GigabitEthernet1/0 01:02:29/00:01:15 v2 1 / DR S P G
R2#
R2#show ip msdp peer
MSDP Peer 3.3.3.3 (?), AS ?
Connection status:
State: Up, Resets: 16, Connection source: Loopback0 (2.2.2.2)
Uptime(Downtime): 00:00:29, Messages sent/received: 1/1
Output messages discarded: 0
Connection and counters cleared 01:04:59 ago
SA Filtering:
Input (S,G) filter: none, route-map: none
Input RP filter: none, route-map: none
Output (S,G) filter: none, route-map: none
Output RP filter: none, route-map: none
SA-Requests:
Input filter: none
Peer ttl threshold: 0
SAs learned from this peer: 0
Number of connection transitions to Established state: 17
Input queue size: 0, Output queue size: 0
MD5 signature protection on MSDP TCP connection: not enabled
Message counters:
RPF Failure count: 0
SA Messages in/out: 0/0
SA Requests in: 0
SA Responses out: 0
Data Packets in/out: 0/0
R3 CONFIGURATION
should be the same as R2
Useful "SHOW" commands
- show ip msdp peer
- show ip msdp sa cache
- show ip pim neighbor
- show ip pim interface
- show ip pim rp mapping
- show ip mroute
Useful "DEBUG" commands
- debug ip pim
- debug ip msdp detail
- mtrace x.x.x
REFERENCE
- https://ine.com/
- https://tools.ietf.org/html/rfc4610
- https://www.cisco.com/c/en/us/td/docs/ios/solutions_docs/ip_multicast/White_papers/anycast.html
- https://community.cisco.com/t5/network-architecture-documents/rp-redundancy-with-pim-sm-anycast-rp/ta-p/3116911
