From: Scott Morris (swm@emanon.com)
Date: Sat Aug 20 2005 - 13:58:44 GMT-3
Watch the names in the dialer map when using authentication.
If you aren't using authentication, use debug isdn q931 to see if the
incomingcalling number matches your oubound dialer string. Show dialer will
help too.
The thing is that if who you are connected to (inbound traffic) doesn't
match who you THINK you should be connected to (outbound dialer map), then
you'll make another phone call.
This part is true of HDLC or PPP.
HTH,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Arun
Arumuganainar
Sent: Saturday, August 20, 2005 11:57 AM
To: 'Group Study'
Subject: ISDN Dialer Map does not support Bidirectional Traffic !!!
I was working with ISDN !!! I came up on a problem !!!
My Topology looks like this .
R2--------------R5
Bri0/0 Bri0/0
My configurations goes like this
Router 2
isdn switch-type basic-net3
int bri0/0
ip address 150.50.9.2 255.255.255.252
dialer map ip 150.50.9.5 name Router-5 broadcast 5552000 dialer-group 1
dialer-list 1 protocol ip permit
===============================================
Router 5
isdn switch-type basic-net3
int bri0/0
ip address 150.50.9.2 255.255.255.252
dialer map ip 150.50.9.5 name Router-2 broadcast 5551000 dialer-group 1
dialer-list 1 protocol ip permit
===============================================
After configuring like this when I send ping packets from Router 2 to Router
5 . I observe a strange behaviour !!! Forward traffic goes via one BRI
channel and Return traffic goes via another !!!
The behaviour is same when
a) I ping on either directions ( i.e R2-R5 and also From R5 to R2 ) .
b) The behaviour is observed with both HDLC and PPP encapsulaton ( IP Expert
Protor Guide Say with PPP encap. traffic per bri channel should be
bi-directional ) . But I could not notice this !!!
When I removed dialer map on one side !!! Packet from the other side reaches
it . But the return traffic is dropped due to encapsulation failure ( I
observed this with debug ip pack ) !!!
One work around for this : use dialer string instead of dialer maps !!! With
Dialer strings I am able to achive two way traffic using single BRI channel
for both HDLC and also PPP Encapsulations !!!!
I am wondering is this the right behavior ???!!!! It would be great if any
body can clarify !!!
Thanks and Regards
Arun
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