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Multicast source redundancy

smalderez
Beginner
Beginner

Hi

I’ve a generic multicast question: I've got 2 sources active/active sending the same multicast group on a network with one receiver receiving the multicast group, without choosing the source (IGMP v2).

In the actual situation, if the client does not choose the source, it receives both streams and it is not OK. So the idea would be to receive only one multicast from only one source and If one source is NOK, the receiver get the multicast from the other source.

What is the best solution to do that?

I've looked at SSM but it's IGMP v3 based and client must specify the source, this is not the case here.
Anycast + PIM or MSDP seems to be the solution but it seems complex for my "simple" need:

http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ip-multicast/prod_white_paper0900aecd8055509e.html

 

Thank you in advance for sharing your ideas!

Best regards,

Sébastien

 

 

8 REPLIES 8

johnd2310
Collaborator
Collaborator

Hi,

How would you determine if one stream is NOK? I think it would be easier if this scenario was handled at the application level.

 

Thanks

John
 

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Hi John2310,

When I say NOK, I mean the stream from the specific source could not be received by the client in the network, something goes wrong on the network. I'm wondering if after a client has subscribed to the stream, a switch or a router could see that at a moment, there is no more stream from that source and so deliver the stream from the other source.

I'm OK with you that it would be easier if handled by application but it is not the case :( so I'd like to know if it could be done by a network protocol.

 

Sébastien

Hi Sébastien,

I have run into same problem.

Could you solved your problem?

 

Thanks,

Laszlo

Hello Laszlo,

the best approach to multicast source redundancy is given by the use of IGMP version3 combined with PIM SSM, source specific multicast.

If your clients do not support IGMPv3, the routers can act on behalf of the client using some interface features that convert an IGMPv2 join in an IGMPv3 join.

see for example SSM mapping here:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_igmp/configuration/15-mt/imc-igmp-15-mt-book/imc_ssm_map.html#GUID-749FCA08-725A-40F8-A14A-67415721CE99

there is also a DNS based ssm mapping that could be helpful.

In recent IOS images there is a also a so called Multicast resiliency that you can find here:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_resil/configuration/15-mt/imc-resil-15-mt-book/imc_live.html#GUID-CC94B6B3-F79C-47F7-8A63-5CC3057516B7

But the examples show the use of ISIS as the IGP with multiple topologies (multicast topology in particular) so I don't know if this can be used by you.

If you are constrained to use PIM SM, with Anycast RP + MSDP between the RPs  you end up receveing two copies of the stream one from each source.

see

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipmulti_pim/configuration/imc-pim-15-mt-book/imc_basic_cfg.html#GUID-FA897FB3-1D16-4096-88C3-8C936FAC7A7C

Hope to help

Giuseppe

When I say NOK, I mean the stream from the specific source could not be received by the client in the network, something goes wrong on the network. I'm wondering if after a client has subscribed to the stream, a switch or a router could see that at a moment, there is no more stream from that source and so deliver the stream from the other source.

How would you determine if one stream is NOK? I think it would be easier if this scenario was handled at the application level.

design1balu1
Beginner
Beginner

When I say NOK, I mean the stream from the specific source could not be received by the client in the network, something goes wrong on the network. I'm wondering if after a client has subscribed to the stream, a switch or a router could see that at a moment, there is no more stream from that source and so deliver the stream from the other source.

I say NOK, I mean the stream from the specific source could not be received by the client in the network, something goes wrong on the network. I'm wondering if after a client has subscribed to the stream, a switch or a router could see that at a moment, there is no more stream from that source and so deliver the stream from the other source.

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