RP Address in MULTICAST

[sankarccie]

I have few doubts about Multicast RP address

We have MPLS ISP backbone network, here two P routers are configured as RP address(IN GLOBAL) and MSDP is running between them.

Now, my doubts are

• All the Multicast customer we are giving is under MVPN only, if dense mode no RP concept, if sparse mode MVPN have a separate RP. Then what the use of Global RP and MSDP??
• I come across MSDP for inter domain multicasting, do we need to run MSDP with other ISPs?? if so, is it advisable??

Pls clear my above doubts!!

Thanks in advance!!

[Nagendra Kumar Nainar]

Hi Sankar,

• All the Multicast customer we are giving is under MVPN only, if dense mode no RP concept, if sparse mode MVPN have a separate RP. Then what the use of Global RP and MSDP??

CE multicast (or simply c-multicast) and SP multicast (or simply p-multicast) are totally independent. As you mentioned, even if Customer multicast is sparse mode, the RP should be from VRF. RP from SP global cannot help with VRF multicast (Else you need complex leaking). Global RP is required if the P-multicast is sparse mode, inorder to establish the MDT tunnel. MSDP is required if you provide some inter domain multicast.

• I come across MSDP for inter domain multicasting, do we need to run MSDP with other ISPs?? if so, is it advisable??

MSDP can be iether used for Inter domain or with Anycast RP. Basically MSDP is the protocol used to update any active source details to otehr RP in same domain (in case of Anycast) or different domain.

You may have to check if you have inter-as design or anycast to understand the need for MSDP.

HTH,

Nagendra

[sankarccie]

Hi Nagendra,

Thanks for your notes, actally I am clear abt P-mulicast (sp network) , but c-multicast hw the network design will be? any doc or link plz share.

MDSP, inter-domain what u mention is between to ISPs or something else ??? if so, why both RP need to communicate?? Two ISPs have separate VRF, so why it require??

Global RP is required if the P-multicast is sparse mode, inorder to establish the MDT tunnel

Test case 1, consider we have 2 MVPN running in SPARSE mode, vpn1 and vpn2. Both have seprate RP near to the source. for this setup, what role the GLOBAL RP is doing?? if i shut global RP also both vpns are not affected.

TIA,

Sankar V

[Nagendra Kumar Nainar · Accepted solution]

HI Sankar,

MDSP, inter-domain what u mention is between to ISPs or something else ??? if so, why both RP need to communicate?? Two ISPs have separate VRF, so why it require??

Assuming your query is why you need MSDP on Provider multicast n/w, As mentioned earlier, if you have Inter domain scenario or Anycast RP, you need MSDP to communicate the active source between RP. MSDP between P-RP (not C-RP) is not related to customer multicast streams.

Test case 1, consider we have 2 MVPN running in SPARSE mode, vpn1 and vpn2. Both have seprate RP near to the source. for this setup, what role the GLOBAL RP is doing?? if i shut global RP also both vpns are not affected.

When you mean GLOBAL RP, I assume you are talking about RP configured in Provider multicast n/w. If so, you need GLOBAL RP to build MDT tree. Edge PE where you have MVPN configured should join the MDT tree. If your core Provider n/w is enabled with SSM, you dont need RP, but if it is ASM, you need RP to build the tree.

HTH,

Nagendra

[sankarccie]

Hi Nagendra,

Thanks for your valuble comments.