Path: utzoo!utgpu!watserv1!watmath!att!bellcore!uunet!samsung!crackers!m2c!umvlsi!dime!process.com
From: VOLZ@process.com (Bernard E. Volz)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Timeout mechanism to invalidate ARP cache entries
Message-ID: <27094@dime.cs.umass.edu>
Date: 23 Feb 91 18:12:20 GMT
References: <2669@inews.intel.com>
Sender: news@dime.cs.umass.edu
Organization: Process Software Corporation
Lines: 25
X-News-Reader: VMS NEWS 1.04
In-Reply-To: echan@cadev6.intel.com's message of 23 Feb 91 03:38:31 GMT

In <2669@inews.intel.com> echan@cadev6.intel.com writes:

> On page 23 of RFC1122 (Requirements for Internet Hosts--Communication
> Layers) under the DISCUSSION paragraph said this:
> 
>    " The ARP specification [LINK:2} suggests but "DOES NOT" require a
> timeout mechanism to invalidate cache entries when hosts change their
> Ethernet addresses "
> 
> Would someone tell me what are implemented and how it is done on SunOS,
> Ultrix and other UNIX machines ?
> 
> The RFC mentioned four mechanisms-- timeout, unicast poll, link-layer
> advise and high-layer advice. So, which OS is using which mechanisms ?
> 
> Thanks in advance for your input.
> 
> Eldon Chan
> Design Technology
> Intel Corporation
> echan@scdt.intel.com

For Process Software Corporation's TCPware for VMS we flush an ARP cache
entry if we haven't RECEIVED a packet from the <Internet-Address>,<Ethernet-
Physical-Address> pair within a reasonable time period (typically 10 minutes).


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