BSR/RP help..
Hey guys. 2 Questions:
1) BSR is one thing that's kind of got me scratching my head. I've head cisco documentation, other sites, the books..the concept isn't clicking. What is the actual use of a BSR in a multicast environment? I understand BSR is an IETF standard, so is the benefit really that it is just an open standard versus AutoRP's cisco proprietary or what??
I guess I just need someone to say "this is why you'd need a BSR", because so far, I'm not seeing many scenario's where I'd need a BSR when I could just use AutoRP.
2) On the BSR subject..I wanted to see it in action, so I got dynamips open, configured all interfaces to be in sparse mode, and used the ip pim bsr-candidate command, with a priority of 100. I do see the BSR with the "show ip pim bsr" command..however when I do a show ip mroute (on routers other than the BSR), I see my <*, 239.1.1.1) RP 0.0.0.0, RPF nbr 0.0.0.0...with the Dense mode flag up..how is this when the interfaces are in sparse-only mode? The BSR is configured so I thought that'd put them in Sparse.
I appreciate the help..this is the last thing that's really jacked me up on multicasting. Once I get my head around this, I'm feeling pretty good.
1) BSR is one thing that's kind of got me scratching my head. I've head cisco documentation, other sites, the books..the concept isn't clicking. What is the actual use of a BSR in a multicast environment? I understand BSR is an IETF standard, so is the benefit really that it is just an open standard versus AutoRP's cisco proprietary or what??
I guess I just need someone to say "this is why you'd need a BSR", because so far, I'm not seeing many scenario's where I'd need a BSR when I could just use AutoRP.
2) On the BSR subject..I wanted to see it in action, so I got dynamips open, configured all interfaces to be in sparse mode, and used the ip pim bsr-candidate command, with a priority of 100. I do see the BSR with the "show ip pim bsr" command..however when I do a show ip mroute (on routers other than the BSR), I see my <*, 239.1.1.1) RP 0.0.0.0, RPF nbr 0.0.0.0...with the Dense mode flag up..how is this when the interfaces are in sparse-only mode? The BSR is configured so I thought that'd put them in Sparse.
I appreciate the help..this is the last thing that's really jacked me up on multicasting. Once I get my head around this, I'm feeling pretty good.
Comments
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Mrock4
Banned Posts: 2,359 ■■■■■■■■□□
Think I kind of found it....
http://www.cisco.com/en/US/docs/ios/11_3/feature/guide/pimv2.html#wp5891
Guidelines for When to Configure a BSR
If there are only Cisco routers in your network (no routers from other vendors), there is no need to configure a BSR. Configure Auto-RP in the mixed PIM Version 1/Version 2 environment.
On the other hand, if you have non-Cisco, PIM Version 2 routers that need to interoperate with Cisco routers running PIM Version 1, both Auto-RP and a BSR are required. We recommend that a Cisco PIM Version 2 router be both the Auto-RP mapping agent and the BSR.
I guess I kind of had the right idea, just wasn't positive. The question now is..I know the routers are in dense mode since I have no RP configured..but shouldn't they operate in sparse if I have a BSR configured?? -
Mrock4
Banned Posts: 2,359 ■■■■■■■■□□
Found my second question. I feel retarded for posting, but maybe in hopes someone else will learn from my mistake, here goes..
My BSR/RP config was as follows:
ip pim bsr-candidate s2/1 32 100
ip pim send-rp-discovery s2/1 scope 5
I didn't realize instead I needed:
ip pim bsr-candidate s2/1 32 100
ip pim rp-candidate s2/1 group-list 5
As soon as fixing that, the interfaces are all operating in Sparse mode correctly, and things are back to normal. Live and learn. Multicast killed me on my last attempt.