Path: utzoo!attcan!uunet!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!ucbarpa.Berkeley.EDU!keshav
From: keshav@ucbarpa.Berkeley.EDU (Keshav)
Newsgroups: comp.protocols.tcp-ip
Subject: Duplicate ping packets on a local area network
Keywords: ping
Message-ID: <32737@ucbvax.BERKELEY.EDU>
Date: 21 Nov 89 22:07:46 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: keshav@ucbarpa.Berkeley.EDU (Keshav)
Organization: University of California, Berkeley
Lines: 11

I get duplicate ping packets over a microwave relay that links
two ethernets. Most, but not all, ICMP ping packets have duplicates,
and the interval between two replies varies from 5 to 60 ms.
The problem occurs between any two machines that are on opposite
ends of the link.
The link itself is rather dumb: it provides a virtual extension 
of the ethernet cable across a distance of about a mile.
Could the problem be due to the CSMA/CD protocol? Or is it some
known bug in TCP? All opinions welcome.

keshav