Subject: Re: Another IGMPv3 question

From: [email-masked]
Date: Thu, 26 Apr 2001 18:29:13 -0700

From:  James Huang@MITEL on 04/26/2001 06:29 PM PDT
I understand now.  It works because GMI is larger than (Query Interval + Query
Response Interval).

Thanks,
James Huang

Isidor Kouvelas <[email-masked]> on 04/26/2001 06:24:12 PM

To:   James Huang/USA/Mitel@Mitel
cc:   [email-masked], Isidor Kouvelas <[email-masked]>

Subject:  Re: Another IGMPv3 question

The periodic query / report mechanism of IGMP will make sure that the
INCLUDE hosts get a chance to report before the exclude timer expires
hence the X set will contain the list of sources to use when switching
to include mode.

thanks
I

[email-masked] writes:
>
>
>From:  James Huang@MITEL on 04/26/2001 05:54 PM PDT
>Hi Isidor:
>
>     I found the the following quote from an email you sent back in Aug/2000.
>
>"When the last host in EXCLUDE mode leaves the group, the router sends a group
>specific query. This causes the EXCLUDE group timer on the router to be lowere
>d.
>At this point all hosts in INCLUDE mode respond and update the list X. As ther
>e
>are no hosts left in EXCLUDE mode, no EXCLUDE reports are received to update t
>he
>group timer. Hence the timer expires with all the sources in INCLUDE mode list
>ed
>in X. At this point list X is used as the list of source to forward in INCLUDE
>mode."
>
>     I believe what you described there is about the action to take when
>receiving a TO_IN(A) report when in the EXCLUDE(X,Y) state. My question is
>whether the router should also send a qroup-specific query when the group time
>r
>expires and the router is about to switch from the EXCLUDE mode to the INCLUDE
>mode. When I read section 6.5 "Switching Router Filter-Modes", I can not find
>any description about sending a group specific query when the group timer
>expires.  Without sending a group-sepcific query before switching the filter
>mode of the group, you may end up not forwarding traffics from some sources
>which have interested receivers in the subnet. This may happen, for example,
>when the last EXCLUDE mode host crashes. Of course, the router only have to se
>nd
>the group-specific query if it has not sent such query recently.  Otherwise, t
>he
>router will keep on sending group-specific queries.
>
>
>Thanks,
>-- James Huang
>
>