[Xorp-users] IGMP and Multicast question

[admin galerie]

Le 6 févr. 08, à 05:29, Pavlin Radoslavov a écrit :

>>> Juniper has PIM-SM so is there any reason not to configure/use it?
>>> If Juniper won't be running PIM how are you going to get that box
>>> forward the multicast traffic? Are you planning to have it running
>>> IGMP proxy?
>>> If this is the case then XORP needs to run PIM-SM with little
>>> special configuration. I can provide that info to you once I
>>> know what are you going to do on the Juniper side.
>>>
>> The Juniper side is not our responsibility, so we can't make choices
>> for the people who are going to configure it. Between the Juniper and
>> our Xorp router, there is a satellite network, and cypher/decypher
>> devices, where it is necessary to configure security associations for
>> each flow you intend to transmit (unicast and multicast). That is the
>> main reason why we try not to have PIM signalling between the Juniper
>> and us. I asked the person in charge of the Juniper how it was going 
>> to
>> forward the multicast traffic, and he answered there was a simple
>> static configuration, the kind "all MC traffic from interface A shall
>> be directed to interface B". Does it make sense ?
>>
>> To resolve my problem, which seems to be a RFC4605 (thanks Javier) 
>> test
>> case, couldn't I start two instances of Xorp on my Xorp router ?
>
> The simple answer is no.
>
> However, if Juniper forwards all multicast traffic to you, there is
> a way to get it working:
>
> 1. Configure PIM-SM on XORP and configure one of its interfaces as a
>    static RP for the whole 224.0.0.0/4 multicast address range.
>
> 2. Use the "alternative-subnet" configuration statement(s) for the
>    interface/vif on the XORP box toward the Juniper.
>    For example, "alternative subnet 10.0.0.0/8" will tell XORP to
>    consider all multicast traffic from source address in the
>    10.0.0.0/8 range appear like coming from a directly connected
>    subnet, and typically traffic from directly connected subnets
>    will be forwarded if there are downstream receivers.
>    You might need to use more than one such statement to cover all
>    possible sender addresses.
Thanks for your help Pavlin, I did not have time to test today your 
configuration proposition, but I will try it tomorrow and will let you 
know if it does what I need.

Best regards

Vincent