Subject: [dhcwg] Extreme Interest in : IPv4 Address Conflict Detection

From: "Lynn Linse" <[email-masked]>
Date: Sat, 20 Apr 2002 10:45:58 -0700

This draft seems to have been jettisoned - any idea if it's dead or moved or merged or renamed?  Stuart Cheshire had said this was under discussion in both DHC and MobileIP WG.

I'm working with GM (as in cars) and Rockwell Automation.

A severe problems we are hitting in the field with Ethernet+TCP/IP products is wide variation and unpredictable behavior in duplicate IP cases between multiple vendor's devices. Some devices go off-line, some defend, some have a race condition where it depends who sees who first as to what will happen. A device unexpectedly going off-line can cost lots of $$$ to recover, or in rare cases even kill workers or damage hundreds of thousands of $$$ worth of attached equipment. This is part of the reason that Ethernet has taken decades longer to reach the factory floor.

Keep in mind one rarely see PC (either Windows or Linux or Mac) in these plant floor systems, but instead have a wide variety of small devices with diverse in-house (roll-your-own) TCP stacks. Many of these products also use fixed (manually set) IP. DHCP is considered a risk since it creates yet-another critical failure point, so many products even "cheat" and allow using BOOTP to assign an Ip which is then coded into NVRAM and BOOTP is never called again unless a DHCP "FORCERENEW" is issued to in effect unset the old NVRAM IP and cause reissue of BOOTP. Sounds odd, but it gets the job done.

Add these together means we need a documented way (an RFC?) to both predict WHAT happens in duplicate IP cases and to help guide all these roll-your-own TCP stack writers to do it the consistent way. 

best regards

Lynn August Linse, Senior IA Application Engineer
15353 Barranca Parkway, Lantronix Inc, Irvine  CA  92618
[email-masked]   www.lantronix.com
Tel: (949)279-3969  Fax: (949)453-7152

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