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Is there any way that 2 service providers can pass the multicast traffic without running any sparse or dense pim on the connected link?

i think that in this case you should use multicast address-family under BGP (create EBGP peers under the multicast address-family)

 

john808:

Is there any way that 2 service providers can pass the multicast traffic without running any sparse or dense pim on the connected link?

 

Thank you so much Shai, I was wondering it may takes couple of days to get any respond.

Actualy I have tested all possible senarios including the Multicast BGP but still the join-group messege are not able to pass unless I add "ip pim sparese-mode" on connected link.

 

 

hi

 

can you post here please both router's configurations and me and others will take a look and see if we can locate anything

 

there is a possibilit i am mistaken - but i do not think so

 

anyway post the configurations and others could comment also...

 

Shai

The senario is as follows:

[R1 - R2] - [R3 - R4]

R1 and R2 are SP-1, R3 and R4 are SP-2

OSPF running as IGP protocol between R1 and R2 also same for R3 and R4. (no IGP between R2 and R3)

BGP ipv4 and vpnv4 between R1-R2, R2-R3 and R3-R4. (Using option-B-1 "next-hop-self" approch for inter-AS - link R2-R3 NOT redistributed)

R2 loopback is RP for SP-1 and R3 loopback is RP for SP-2.

There is a Multicast join-group on R1 as well as R4. and "ip pim sparse-mode" configured every where except on R2-R3 link...

MSDP configured between R2 and R3.

Multicast BGP is configured only on R2 and R3.

As RESULT: R1 can ping Multicast group on R4 ONLY on first try !!!!! but if "ip pim sparse-mode" configured on R2-R3 link it works perfect even if I remove Multicast BGP.

The point is, if I need to run "ip pim sparse-mode" on R2-R3 link what could be the reason of using Multicast BGP?

Shai, please let me know if you are still want me to send the configuration! Thanks again.

 

i am not as good as i want to be with multicast - but it seems to be ok to me

we must be missing something - but i am not sure what

 

publish the configurations and let others answer what's wrong...

 

sorry

 

Shai

Multicast BGP doesn't take the place of PIM, it's just used to do the RPF lookup.  When providers run multicast with each other on the Internet they have to run PIM on the link connecting them.  The RP's in the SP clouds then peer with MSDP, allowing each other to know what are the sources/clients.


shai-l wrote:

i am not as good as i want to be with multicast - but it seems to be ok to me

we must be missing something - but i am not sure what

 

publish the configurations and let others answer what's wrong...

 

sorry

 

Shai

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First of all I wish to thank you Brian for your respond,

in this case, Service providers are able to pass Multicast traffics just by 1) running PIM on connected link and 2) running MSDP, therefore what could be the reason for using the Multicast BGP.

I have tried ...

- Multicast BGP and PIM on connected links, no success

- Multicast BGP and MSDP, no success

- MSDP and PIM on connected link, Works perfect (with and without Multicat BGP)

I am still in doubt when we really need to configure Multicast BGP?

John

 

 

Multicast BGP is needed to perform the RPF check on the incoming multicast flow.  Not all peering arrangements will include multicast flow, so you may route back to source X via provider A, while the multicast feed from source X comes in from provider B.  Since this normally is an RPF failure, multicast BGP is run with provider B, which overrides the normal unicast routing table.  Think of multicast BGP like a dynamic "ip mroute" statement.


john808 wrote:

First of all I wish to thank you Brian for your respond,

in this case, Service providers are able to pass Multicast traffics just by 1) running PIM on connected link and 2) running MSDP, therefore what could be the reason for using the Multicast BGP.

I have tried ...

- Multicast BGP and PIM on connected links, no success

- Multicast BGP and MSDP, no success

- MSDP and PIM on connected link, Works perfect (with and without Multicat BGP)

I am still in doubt when we really need to configure Multicast BGP?

John

 

 

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Brian McGahan:

Multicast BGP is needed to perform the RPF check on the incoming multicast flow.  Not all peering arrangements will include multicast flow, so you may route back to source X via provider A, while the multicast feed from source X comes in from provider B.  Since this normally is an RPF failure, multicast BGP is run with provider B, which overrides the normal unicast routing table.  Think of multicast BGP like a dynamic "ip mroute" statement.

Brian McGahan, CCIE #8593 (R&S/SP/Security)
bmcgahan@internetworkexpert.com
 
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john808 wrote:

First of all I wish to thank you Brian for your respond,

in this case, Service providers are able to pass Multicast traffics just by 1) running PIM on connected link and 2) running MSDP, therefore what could be the reason for using the Multicast BGP.

I have tried ...

- Multicast BGP and PIM on connected links, no success

- Multicast BGP and MSDP, no success

- MSDP and PIM on connected link, Works perfect (with and without Multicat BGP)

I am still in doubt when we really need to configure Multicast BGP?

John

 

 

Internetwork Expert - The Industry Leader in CCIE Preparation
http://www.internetworkexpert.com

Subscription information may be found at:
http://www.ieoc.com/forums/ForumSubscriptions.aspx

 

Y! MBGP is common to use Policy control  RPF check ! M-Table is prior U-table!