Subject: IGMPv3 QRV and QQI values

From: Todd Hayton <[email-masked]>
Date: Thu, 16 Aug 2001 15:44:16 -0400 (EDT)

Hello,

In IGMPv3 draft it is stated that the QRV and QQI values contain the
[Robustness Value] and [Query Interval] used by the current querier. It
also states that non-queriers should adopt these values as their own.
Once a non-querier adopts these values as its own, when is it going to use
these values (since it's not actually sending out queries)?

It looked as if there were two possible uses:

1) The non-querier uses the received QRV and QQI values to calculate a new
Other Querier Present Interval:

QRV * QQI + [0.5 * Query Response Interval]

And I'm assuming the scenario for this is that because of network latency,
we increase the [Robustness Variable] and [Query Response Interval] on the
current querier, and so we want non-queriers to wait longer as well before
deciding that the current querier has expired.

2) If we adopt these values as our own, and the current querier does in
fact expire, should we use the adopted values (for things such as General
Queries, retransmissions, etc), or should we revert back to the default
values?

Regards,
Todd Hayton

---

From: Bill Fenner <[email-masked]>
Date: Mon, 20 Aug 2001 16:10:14 -0700

>these values (since it's not actually sending out queries)?

It will use them in derived values, e.g. Group Membership Interval,
Other Querier Present Interval, Last Member Query Interval,
Last Member Query Count, Older Host Present Interval.

When a router becomes a Querier, it sends its own configured
values as the QRV and QQI values.

  Bill