Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.
Showing results for
Search instead for
Did you mean:
Inter-Domain Multicast with MSDP
In this document we will discuss how to send and receive multicast traffic between two different multicast domains reside in two different BGP ASs
using Multicast Source Discovery Protocol (MSDP) to achieve what is known as inter-domain multicasting.
Normally every RP aware about the multicast sources and receivers within the same domain where that RP configured with regard to the multicast groups that Router is RP for. MSDP Peers use TCP sessions and they send Source Active Messages (SA) to inform other peers about any active source within the local domain, Consequently all the MSDP Peers (RPs) will be aware about all sources within the local domain and other domains as well.
The bellow network diagram represents two differnt Multicast domains each domain utilize the multicast range 220.127.116.11/5 locally and they don't send it outside the local domain. each domain has its own RP R10 for AS 100 and R1 for AS 1 and the link between R 10 and R 1 configured as BSR boundary to avoid leaking any RP/BRP information between the two domains. Also MSDP filtering has been applied to both MSDP peers to avoid leak these domain local groups in our example ( 18.104.22.168/5) between the two domains
for more information about the filtering between MSDP peers see the belllow link:
Multicast Source Discovery Protocol SA Filter Recommendations
R3#show ip pim rp mapping PIM Group-to-RP Mappings
Group(s) 22.214.171.124/7 RP 126.96.36.199 (?), v2 Info source: 188.8.131.52 (?), via bootstrap, priority 0, holdtime 150 Uptime: 00:33:35, expires: 00:01:39 Group(s) 184.108.40.206/5 RP 220.127.116.11 (?), v2 Info source: 18.104.22.168 (?), via bootstrap, priority 0, holdtime 150 Uptime: 00:44:16, expires: 00:02:22
as it shown above from the show command in R3, R1 is the RP and the mapping agent (BSR) in AS 200
R3 configured to be receiver for the following groups:
the goal is to have the groups 22.214.171.124 and 126.96.36.199 receive multicast feed from local senders only in AS 200
while group 188.8.131.52.1 can recieve multicast traffic from other Domains in our Example AS 100
R2#show ip pim rp mapping PIM Group-to-RP Mappings
Group(s) 184.108.40.206/7 RP 10.10.10.10 (?), v2 Info source: 10.10.10.10 (?), via bootstrap, priority 0, holdtime 150 Uptime: 00:37:45, expires: 00:01:45 Group(s) 220.127.116.11/5 RP 10.10.10.10 (?), v2 Info source: 10.10.10.10 (?), via bootstrap, priority 0, holdtime 150 Uptime: 00:54:35, expires: 00:02:24
R10 is the RP/BSR for AS 100, bellow is the configuration of R10 ( R1 same configurations)
ip multicast-routing ! interface Loopback0 ip address 10.10.10.10 255.255.255.0 ip pim sparse-mode ip ospf 1 area 0 ! interface FastEthernet1/0 ip address 10.1.1.1 255.255.255.0 ip pim sparse-mode
interface FastEthernet1/1 ip address 192.168.1.10 255.255.255.0 ip pim bsr-border ip pim sparse-mode ! router ospf 1 log-adjacency-changes network 10.1.1.1 0.0.0.0 area 0 default-information originate always ! router bgp 100 no synchronization bgp log-neighbor-changes neighbor 192.168.1.1 remote-as 200 neighbor 192.168.1.1 default-originate no auto-summary ! ip pim bsr-candidate Loopback0 0 ip pim rp-candidate Loopback0 group-list 10 ip msdp peer 192.168.1.1 remote-as 200 ip msdp sa-filter in 192.168.1.1 list 100 ip msdp sa-filter out 192.168.1.1 list 100 ip msdp redistribute list 100 ! access-list 10 permit 18.104.22.168 22.214.171.124 access-list 10 permit 126.96.36.199 188.8.131.52 access-list 100 deny ip any 184.108.40.206 220.127.116.11 access-list 100 permit ip any any
as we can see from the above configurations
R10 and R1 are BGP peers and MSDP peers as well
ACL 10 is for multicast groups
ACL 100 for MSDP SA filtering to make sure 18.104.22.168 rang will not be propagated out side the local domain
lets do some verifcations and pings to simulate a multicast sender from R2 to R3
R10#show ip msdp peer MSDP Peer 192.168.1.1 (?), AS 200 (configured AS) Connection status: State: Up, Resets: 1, Connection source: none configured Uptime(Downtime): 00:00:28, Messages sent/received: 1/1 Output messages discarded: 0 Connection and counters cleared 00:18:49 ago SA Filtering: Input (S,G) filter: 100, route-map: none Input RP filter: none, route-map: none Output (S,G) filter: 100, 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 Input queue size: 0, Output queue size: 0
Type escape sequence to abort. Sending 1, 100-byte ICMP Echos to 22.214.171.124, timeout is 2 seconds: .
this is because of the filtering we put in R10
Type escape sequence to abort. Sending 1, 100-byte ICMP Echos to 126.96.36.199, timeout is 2 seconds:
Reply to request 0 from 188.8.131.52, 504 ms Reply to request 0 from 184.108.40.206, 552 ms
this time we recieved the replay from R3 as this group not part of the filtering and now we have seder in AS 100 and the receiver in AS 200