[Xorp-users] PIM/SM: Missing Join and Register-Stop from RP

[Holger Kummert]

Please find attached a patch to improve RP's behavior when Register
messages are received (improve_register_receive.patch).
With this patch a JOIN will get sent towards S if there are
Joined receivers present at RP.
Register-Stop messages are sent back to the sender of the Registers
for each received one.
A slight disadvantage is that the Register-Stops are sent immediately
as an answer to the Register messages, not after normal multicast
traffic is received (as stated in RFC4601, sec 3.2).
Therefore a certain amount of packet loss will occur.

The other patches cover improvements for logging:
- flatten log output of TX to look similar to RXs
- Avoid double timestamp in logs.

The latter only applies if logging to syslog (has its own timestamp).
So if there are reasons to leave it as it is the patch could safely
be ignored of course.


Best regards,
Holger

Am 13.03.2014 18:44, schrieb Ben Greear:
> On 03/13/2014 10:31 AM, Holger Kummert wrote:
>>
>> Hello,
>>
>> I do not understand XORP's behavior when running PIM/SM and Register
>> messages (that encapsulate multicast traffic) are received by the
>> RP from S.
>> What I am really missing is the Join msg towards S in order to avoid
>> the encapsulating overhead. Therefore the Register-Stop (in order to
>> stop sending the Register msgs) is also not sent by RP.
>>
>> Shouldn't both messages be sent according to RFC 4601, ch. 3.2?
>>
>> The only situation where I could force the Register-Stop to be sent
>> was by enabling and setting 'switch-to-spt-threshold' to '0'.
>> This sending is independent of any Join'ed receivers and happens
>> immediately after the receive of the first Register message.
>> But this is obviously not the intended usage.
>>
>> Anyhow under no circumstances any Join messages are sent by RP to S.
>>
>> Could someone give more insight on this?
>
> I'm afraid I never knew much about multicast, and what I did learn
> while hacking on xorp mcast logic I have mostly forgotten.
>
> But, if you figure out a patch that makes xorp work better,
> please post it and I will try to review it.
>
> Thanks,
> Ben
>
>>
>>
>> Thanks in advance,
>> Holger
>>
>> _______________________________________________
>> Xorp-users mailing list
>> Xorp-users at xorp.org
>> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-users
>>
>
>
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