PPP uses magic numbers to detect loops. You'll see warnings about receiving your magic #, etc if it detects a loop. The magic number is a optional feature though and every vendor doesn't use it or have it enabled by default. If using BayRS's 'Wellfleet Standard' which is their implementation of HDLC - IP will come up if the circuit/line is looped somewhere. Setting it to HDLC on Cisco or Bay is a good test for pointing problem to carrier when they've tested the line and swear its ok and tests clean. It's also a good way to make sure the cables between the router interface and the CSU/DSU config are good. To prove it's not your equipment you unplug the circuit from the CSU/DSU and IP will go down if your local equipment is functioning/configured fine. Also, HDLC is less picky then PPP usually. Changing the encaps to HDLC may be useful in troubleshooting either a PPP configuration problem or line/circuit issue. If IP comes up and you can ping other end then you have connectivity to the other site - but how good? :) Time to look at the interface stats to see what errors your getting. --- "Howard C. Berkowitz" <[EMAIL PROTECTED]> wrote: > > I wasn't aware of that! Thanks. > > But isn't loop detection also a PPP option? > > At 10:16 PM 2/19/2001 -0500, Marty Adkins wrote: > >"Howard C. Berkowitz" wrote: > > > > > > HDLC really doesn't offer any advantages over > PPP, so it really > > > reflects someone who doesn't want to do minimum > reconfiguration of > > > their Ciscos to worry about using PPP for > multivendor compatibility. > > > > >Well, one small advantage is that Cisco's > proprietary HDLC keepalive > >will report a loop condition on the layer 1. And > it will also, by > >default, treat a looped interface as "line protocol > up", which is > >great for testing, using just the router. __________________________________________________ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/ _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
