Subject: NULL Registers

From: Ravi <[email-masked]>
Date: Wed, 28 Jul 1999 11:02:32 -0700

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: hal sandick <[email-masked]>
Date: Wed, 28 Jul 1999 14:26:21 -0400

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