Cable Guy wrote: > > When you put a hardware loopback plug on a serial to test it, > why does the > router see it as a loopback? With the show int serial command, > you will see > -----serial up, line protocol up (loopback mode)----- It's magic - seriously. http://www.cisco.com/warp/public/471/debug_ppp_negotiation.html says:
MagicNumber: Magic Number support is available on all serial interfaces. When using PPP, PPP always attempts to negotiate for Magic Numbers, which are used to detect looped-back networks. A random string is sent across the link and if the same value is returned, then the router determines that the link is looped back. The link might or might not be taken down upon looped-back detection, depending on the use of the down-when-looped command. Mariusz BTW - does anyone know, how to post to this group via News? I tried twice, with no result. Do I have to give my correct e-mail in From: post headers, or is it enough if Reply-to: field is set correctly? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=56978&t=56883 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
