From: Logan, Harold (loganh@mccfl.edu)
Date: Tue Nov 12 2002 - 18:56:02 GMT-3
Good point. Those are the sort of things that have you leaving the lab thinking that you must have passed, because everything worked... as the proctor docks you points for the ISDN section.
FWIW, one of the soap boxes they got on at the power session at networkers was ISDN. Their advice was, unless they specifically forbid you from doing so, ALWAYS use ppp, authentication, and named dialer maps/profiles on your ISDN links.
hth,
Hal
> -----Original Message-----
> From: Sam Munzani [mailto:sam@munzani.com]
> Sent: Tuesday, November 12, 2002 4:34 PM
> To: Logan, Harold; Nathan Chessin
> Cc: ccielab@groupstudy.com
> Subject: Re: Dialer Profiles - remote-name
>
>
> Very good explaination. Usually people define only first B
> channel in dialer string. So when remote router tries to dial
> that number it will fail. If you do debug ip packet,
> encapsulation will fail on packets because the return packet
> does not have a proper dialer map with hostname.
>
> Sam
> > If it works the same as the name option in the dialer map
> command, it simply names the isdn session. Since some ISDN
> switches append an additional digit when calls are dialed,
> you can have both B channels hogged up by a simple ping request:
> >
> > R1----------ISDN-----------R2
> > 5551234 5554321
> >
> > R1 dials R2 using 5554321
> >
> > R2 sees an incoming call from 95551234 (The 9 is appended
> by the isdn switch)
> >
> > R2 receives data from R1, and wants to send a reply. It
> checks to see if it has an ISDN call set up with R1, but
> since R2's dialer maps are pointing to 5551234, it determines
> that it isn't connected to R1.
> >
> > R2 dials R1 using its second B channel.
> >
> > This goes on pretty much ad infinitum... as long as R1 and
> R2 are sending data to each other, both B channels are going
> to stay up.
> >
> > The way to fix this is to use PPP authentication, and use
> the name option in your dialer maps (or dialer remote-name in
> your profiles). The result is that the router tracks its
> incoming calls by the hostname of the calling router, not by
> its LDN. R2 will then correctly determine that it's already
> connected to R1, and the two routers will exchange data on 1
> B channel.
> >
> > Hal Logan CCAI, CCDP, CCNP: Voice
> > Network Specialist / Adjunct Faculty
> > Computing & Engineering Technology
> > Manatee Community College
> >
> >
> > > -----Original Message-----
> > > From: Nathan Chessin [mailto:nchessin@cisco.com]
> > > Sent: Tuesday, November 12, 2002 12:56 AM
> > > To: ccielab@groupstudy.com
> > > Subject: Dialer Profiles - remote-name
> > >
> > >
> > > Hi All,
> > >
> > > What is the reasoning for having a remote-name X with dialer
> > > profiles? I am
> > > doing chap authentication, and no matter what I out as a
> > > string in these, it
> > > seems to work.
> > >
> > >
> > > Nate
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