*BSD News Article 64012


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From: dherbst@gradin.cis.upenn.edu (Darrel Herbst)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: 3c509 mcast:host is down
Date: 20 Mar 1996 13:57:03 GMT
Organization: University of Pennsylvania
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Message-ID: <4ip2rf$kso@netnews.upenn.edu>
NNTP-Posting-Host: gradin.cis.upenn.edu
X-Newsreader: TIN [version 1.2 PL2-upenn1.3]

I'm having trouble with the ep driver for the 3c509.  I'm opening up a
socket as AF_INET and SOCK_DGRAM and then sending out packets on a
multicast address... after about 100 packets or so, I start getting
sendto errors on my socket that the "host is down".

At first, I thought that by putting in the ether_addmulti calls that
are in the if_ed.c driver would solve my problem, but it hasn't.

I think what's happening is that when I add myself to the mcast group,
the driver should put an entry for the mcast ip in the arp table.
However, when this arp entry times out, it's not getting re-added to
the table.  The system ARP's on the mcast address, and since no one
replies to the mcast ip arp, it complains that the host is down.  Is
this a correct assessment of what's happening?

Am I mistaken in thinking that the ether_addmulti call should add the
mcast ip to the arp table as a mcast ip -- one that shouldn't time-out
really?

Has anyone else encountered this problem?

--dherbst@gradient.cis.upenn.edu