Question on Multicast VPN

[chintan-shah]

Hi,

In service provider to provide Multicast VPN to customer, they run PIM-SM or PIM-SSM. PIM-SM for default MDT.

PIM-SM require RP and i learnt that best to use Anycast RP.

Now, I have 13 locations having P route connected to form core. Do i need to run Anycast RP on each core local to location and run MSDP between them to exchange SA?

What should be best solution to support PIM-SM in Core for Multicast VPN on MPLS network ?

I guess, Custoemr RP,MSDP would be under VRF instance for each customer.

Please correct me if i am wrong , can suggest any good document.

Regards,

Chintan

[Harold Ritter]

Chintan,

The best option would be to use PIM-SSM for both the default and data MDT. But This might not be possible if you run in a multivendor environment. That being said, I agree that AnycastRP is the best option if you have to run PIM-SM.

You do not need to have an RP per site though. I would select a few sites (maybe 3 or 4) to host an RP. You will need to run MSDP between them as you mentioned.

The solution chosen by the customer is completely independent from what you do in the core. Customer can use any technology they want (AnycastRP, AutoRP, BSR, Static RP) so they don't necessarily need MSDP. But yes, the MSDP configuration would be inside a VRF context if they decided to use AnycastRP.

Regards

[chintan-shah]

Hi Hritter,

As you said it is not require to select all site to host an RP. I can select few sites ( core -Large POP) as an RP. Does it means that othe core/P router which are not configured as RP, I will need to configure ip pim rp-address on those P router along with on all PE.

Regarding PIM SSM, Core will be Cisco, but Edge will be more of Cisco but some of Juniper. IS there any issue you'r already aware of i can use PIM-SSM ?

Thanks agian,

REgards,

Chintan

[shivlu jain]

hi chintan

As per my understanding you are looking for how to announce the rp address to you PEs, correct if I am wrong.

You can use auto-rp or static rp mechanism to advertise you anycast rp. Auro-r runs only on cisco platform if you are using multivendor then you must go with static rp address which is really a hectic job.

regards

shivlu jain

[Harold Ritter]

Shivlu,

Auto-RP is supported in JUNOS (as per URL below) but I would not recommended it in this case. Static RP is much simpler.

http://www.juniper.net/techpubs/software/junos/junos91/swconfig-multicast/configuring-auto-rp.html

Regards

[chintan-shah]

Hi shivlu,

I agree with hriteer. Anycast RP is much simple in terms of optimal routing and redudancy. Auto-RP you will have RP selection again and there are known issue with that...

Regards,

Chintan

[Harold Ritter]

Chintan,

What Shivlu meant is that you could use auto-rp to distribute the AnycastRP address instead of using static RP on all routers. I have seen a few customers doing that but personally I prefer using AnycastRP in conjunction with static RP.

Regards

[chintan-shah]

hritter,

Yeap, i misunderstood. Thanks for clarification...

Regards,

Chintan

[Harold Ritter]

Chintan,

You definitely need to configure "ip pim rp-address " on all routers (Ps and PEs) including the RPs themselves.

You will not be able to use SSM for the default MDT as this is implemented via the MDT SAFI, which is not supported in JUNOS. There is no problem to use SSM for the data MDT though.

Regards

[chintan-shah]

Hi hritter,

Thanks for clarification on SSM. I learnt that MDT SAFI ( IPV4 MDT) you can configure for PIM-SSM default MDT with new SAFI capability in BGP. What is standard for this ?

Regards,

Chintan

[Harold Ritter]

Chintan,

The IOS MDT SAFI implementation is based on the following draft.

http://tools.ietf.org/html/draft-nalawade-idr-mdt-safi-03

Regards

[shivlu jain]

hi hritter

I am not clear from this "You will not be able to use SSM for the default MDT as this is implemented via the MDT SAFI, which is not supported in JUNOS. There is no problem to use SSM for the data MDT though."

Kindly explain or provide a link to document.

regards

shivlu jain

[Harold Ritter · Accepted solution]

Shivlu,

For the PE to use SSM, it needs to somehow learn the source address(es).

For the data MDT, the method to signal the source address is described in draft-rosen-vpn-mcast section 7.2, which is supported by both IOS and JUNOS.

http://www.potaroo.net/ietf/idref/draft-rosen-vpn-mcast/#page-19

For the default MDT, the signaling in IOS is done using draft-nalawade-idr-mdt-safi, which is not supported in JUNOS.

http://tools.ietf.org/html/draft-nalawade-idr-mdt-safi-03

Let me know if I answered your question.

Regards

[chintan-shah]

Hi Hritter,

In case we use SSM for default MDT via MDT SAFI, will this avoid flooding multicast traffic in MD to all PE like PIM-SM default MDT and traffic will be forwarded to only PE who has receiver ? as Here also we use common Multicast group

Regards,

Chintan

[Harold Ritter]

Chintan,

No. Traffic on the default MDT reaches all PEs by definition. This doesn't change whether you use ASM or SSM. The only way to alleviate that is to use a data MDT.

Regards