Subject: microsoft ip stack & igmp?

From: Brad Parker <[email-masked]>
Date: Sun, 26 Apr 1998 11:07:41 -0400

[ask long as we're asking ethernet chip questions :-) don't mrouter's
have to receive *all* multicast in order to hear group specific
advertisements?]

On another related topic, does anyone have specific knowledge about
the IGMP in Microsoft Win95 & NT 4.0?

The NT 4.0 stack appears to do IGMP V1 but when using PPP does not seem to 
respond correctly to a "general query" sent after the link has cycled up
& down.

example:
	- bring up PPP link via isdn or modem
	- run SDR
	- bring PPP link down
	- bring PPP link back up

	At this point the NAS sends general query for 0.0.0.0;
	but NT never sends group memberships for SDR's groups...

	my read of draft-ietf-idmr-igmp-v2-06.txt says it should
	set it's time to a random value and eventually advertise
	it's membership...

	If you quit SDR and run it again, the joins come out and 
	everything is fine.

Is this known behavior?  Is it a bug?

-brad

---

From: Steve Deering <[email-masked]>
Date: Sun, 26 Apr 1998 17:58:27 -0700

At 8:07 AM -0700 4/26/98, Brad Parker wrote:
> [as long as we're asking ethernet chip questions :-) don't mrouter's

Yes.  Not only to receive group-specific membership reports, but also to
receive (and potentially forward) multicast data packets sent to any IP
multicast address.

(Technically, it is only necessary for routers to listen to that range of
Ethernet multicast addresses that are used by IP multicast, that is,
01-00-5E-00-00-00 to 01-00-5E-7F-FF-FF.  However, few if any Ethernet
chips support listening to a large subrange of Ethernet addresses and
no others, so one must usually enable reception of all multicasts.)

Steve

---

From: Dave Thaler <[email-masked]>
Date: Mon, 27 Apr 1998 15:05:39 -0400 (EDT)

> respond correctly to a "general query" sent after the link has cycled up

I've forwarded this report to the Microsoft stack people, and
someone will look into this.  If it is a bug, then it should be 
fixed in future releases (e.g. NT5 betas).

-Dave