Multicast BootStrap Router (BSR

BSR Bootstrap Router

• Open newer standard alternative to Auto RP
• Allows dynamic learning of RP address
• Standard for PIMV2 and inbuilt to the protocol so no need for dense mode for certain groups like AutoRP
• 224.0.0.13
• BSR Router- which would be similar to mapping agent in autorp picks rp for groups
• RP Candidate - similart to candidate RP in autorp it use unicast to advertise it self to the BSR router
• So the first thing that happens is that every router configured as BSR floods and listens for candidate BSR messages the BSR with the highest priority wins if equal priority highest ip wins. Eventually there is only 1 BSR in the multicasting domain and all routers learn about this BSR
• Then RP candidates will unicast to the BSR saying what groups it would like to be candidate RP for . This is down to priority again (lowest priority wins) if equal it is random hash value will decide . When the BSR has worked out the rp for each of the groups it advertises this out to all routers in the networks
• This is ideal for hub and spoke topologies to get around limits of Autorp
• We can not define the scope or intervals like we can in Auto RP though

Commands

ip pim bsr-candidate lo0

ip pim rp-candidate lo0
LAB


OK for the Lab i am going to configure BSR candidate and rp on r5. I will not configure on r2 as we will have similar problems as the previous lab the split horizon behaviour where r5 will not readvertise out to the rest of the frame-relay on interface it recieved on we saw a solution using gre. In BSR we will not be using pim dense mode for any groups the BSR information is carried in the pimv2 packets

R5
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We will first configure r5 as bsr canidate the bsr part is the equivlant to the mapping agent in auto rp

r5(config)#ip pim bsr-candidate lo0
Warning: PIMv2 not configured on Loopback0, BSR messages not originated
r5(config)#

Straigtht away it reminds me i need to enable pim on lo0 in order to be used for BSR

r5(config)#int lo0
r5(config-if)#ip pim sparse
r5(config-if)#
*Feb 13 18:59:57.747: %PIM-5-DRCHG: DR change from neighbor 0.0.0.0 to 5.5.5.5 on interface Loopback0 (vrf default)exit
r5(config)#ip pim bsr-candidate lo0
r5(config)#

ok now we will set the rp canidate also on r5
r5(config)#ip pim rp-candidate lo0

r5#sh ip pim rp mapp
PIM Group-to-RP Mappings
This system is a candidate RP (v2)
This system is the Bootstrap Router (v2)
Group(s) 224.0.0.0/4
  RP 5.5.5.5 (?), v2
    Info source: 5.5.5.5 (?), via bootstrap, priority 0, holdtime 150
         Uptime: 00:01:23, expires: 00:02:06
r5#

r1 is getting it also
r1#sh ip pim rp mapp
PIM Group-to-RP Mappings
Group(s) 224.0.0.0/4
  RP 5.5.5.5 (?), v2
    Info source: 5.5.5.5 (?), via bootstrap, priority 0, holdtime 150
         Uptime: 00:02:33, expires: 00:02:05
r1#
notice no additional mroutes
r1#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.0.1.40), 00:18:24/00:02:21, RP 0.0.0.0, flags: DPL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list: Null