RE: IGMPV3: Source timer expiration in Exclude Mode

Suresh,

     Following table gives u a more clear picture.

   Mode                      Source Timer

  EXCLUDE             If source timer is running, then there is a=20
                      conflict for the source, i.e., one client wants
                      mcast packets from the source, while another =
doesn't.
                      Hence the result is if source timer is running in=20
                      EXCLUDE mode, the mcast packets from the source =
are
                      forwarded to the n/w. It is the responsibility
                      of the client to filter out unwanted packets.

  EXCLUDE             No source timers are running. The clients in this
                      n/w are in total agreement that they don't need =
packets
                      from this source.

  INCLUDE             Source timer should be running. Because if the =
source
                      timers are not running, there is no point in =
keeping=20
                      the entry as it is obvious that none of the =
clients=20
                      are interested.

    Also, note that in EXCLUDE mode if any igmp packets are received =
which
contains
    sources to be blocked, these are not blocked immediately. A Group =
and
source=20
    specific query is sent to make sure that none of the clients on the =
n/w
wants
    packets from the source. At this point of time, the mode is EXCLUDE =
with=20
    source timer running. If no response is received, the timer expires
blocking=20
    the source. If a client responds, the source timer continues to=20
    run with all mcast packets from the source being forwarded to the
interface.

    Hope this helps.

Thanks,
Srivatsan


----------------------------------------------------------
Srivatsan S
MindTree Consulting, Bangalore.
Ph: 91-80-6711777 Extn:1428
----------------------------------------------------------
                     =20

-----Original Message-----
From: Suresh Boddapati [mailto:[email protected]]
Sent: Wednesday, October 02, 2002 9:55 PM
To: idmr
Subject: IGMPV3: Source timer expiration in Exclude Mode


Hi,
	In the table specified in Section 6.3, when a source timer expires in
EXCLUDE mode, it says "DO NOT Remove Record". I am assuming this means =
the
source record. If so, what is the use of keeping the record and not =
removing
it as is done when the mode is INCLUDE? When the group timer expires and =
the
transition happens to INCLUDE mode, all the source records that have =
expired
timers are removed anyway. Why keep them till the group timer expires?
Thanks.

Suresh