Subject: native multicast with Sun FDDI interface

From: Felix Kugler <[email-masked]>
Date: Wed, 07 Jan 1998 01:16:32 +0100

I got a strange problem with an mrouted installation using
FDDI. Tunnels run fine (except a few days before Xmas where we got
several mrouted and kernel crashes per day), but the communication to
other hosts on the same subnet using native multicast is flawed.

Mrouter setup:

Sun Sparc20 with Solaris 2.6
mrouted3.9b2
Sun Single attached FDDI Sbus card with SunFDDI5.0

Mbone "client" setup:

Sun Sparc20 with SunOS 4.1.4 and mcast kernel patches, running sdr

Right after starting mrouted, session announcements appear on the
client machine and sessions can be opened. After a short time (2..3
minutes) the sessions freeze. Whenever I start tcpdump on the Mrouter
host, the session announcements appear again on the client host and
sessions can be opened. Of course this puts a heavy load on my poor
Mrouter, it sits directly in an exchange point... 
A few minutes after stopping tcpdump, the sessions freeze
again on the client. Looks like setting the FDDI interface into
promiscuous mode has a motivating effect for its multicast
capabilities...

Has anybody made similar experiences ? Are there suggestions how to
deal with this problem ?

Thanks for all useful hints, Felix

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Felix Kugler                                     | email: [email-masked] 
SWITCH - The Swiss Academic and Research Network | Phone: +41 1 268 15 30 
Smail:  Limmatquai 138, 8001 Zurich, Switzerland | FAX:   +41 1 268 15 68