Subject: RE: NULL Registers

From: Desikan Saravanan <[email-masked]>
Date: Wed, 28 Jul 1999 11:16:12 -0700

Yes. The spec is not clear about this.
I feel it should not be used to refresh the (s, g) state at RP.

Desikan

-----Original Message-----
From: Ravi [mailto:[email-masked]]
Sent: Wednesday, July 28, 1999 11:03 AM
To: [email-masked]
Subject: NULL Registers

If it is used as a probe from the DR to the RP, is it used to refresh 
the <*, G> or <S, G> state at the RP. The spec is not clear on how
an RP processes the NULL register packets.

Ravi

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From: Desikan Saravanan <[email-masked]>
Date: Wed, 28 Jul 1999 11:44:56 -0700

Hal,

What you have said is completely understood. no ambiguity in that.
But Ravi's question was specifically about NULL registers.
NULL registers do not carry any data and they are sent even when
the register-supppression-timer is runnig, to probe and extend the
register-suppression if possible.

Desikan

-----Original Message-----
From: hal sandick [mailto:[email-masked]]
Sent: Wednesday, July 28, 1999 11:26 AM
To: Ravi; [email-masked]
Subject: Re: NULL Registers

Ravi,

from section 3.8.1

    *    [Register-Suppression-Timer (kept per (S,G) route entry)]
          An (S,G) route entry's Register-Suppression-Timer is used to
          suppress registers when the RP is receiving data packets
          natively. When a Register-Stop message for the entry is
          received from the RP, the timer is set to a random value in
          the range 0.5 * [Register-Suppression-Timeout] to 1.5 *
          [Register-Suppression-Timeout]. While the timer is running,
          Registers for that entry will be suppressed.  If null
          registers are used, a null register is sent [Probe-Time]
          seconds before the timer expires.

This avoids sending encapsulated data to an RP which either has no
downstream users or is using an SPT to the source.

regards,

hal

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From: Bill Fenner <[email-masked]>
Date: Wed, 28 Jul 1999 18:08:25 -0700

>an RP processes the NULL register packets.

I think you use the rules in section 3.3.2, skipping the part about
forwarding the encapsulated packet.  (i.e. you refresh the (S,G) state,
if any.)  (*,G) state should only get refreshed by Joins, right?

  Bill