From: Donny MATEO (donny.mateo@sg.ca-indosuez.com)
Date: Wed Sep 25 2002 - 23:53:21 GMT-3
Beda,
dialer-list is used to clasified which packet allowed to trigger an isdn line (network term
interesting packet). So if you run IP and IPX you need both dialer-list type something like
dialer-list 1 protocol ip permit
dialer-list 1 protocol ipx permit
Ok, now the router knows what is classified as interesting to trigger the ISDN line. but first off
all router needs to know a route to route the packet to the interface. This is L3, you can get away
with floating static. Of course there are other means that could replace this mechanism such as
dialer-watch, backup interface and demand-circuit.
Once the router knows where to route the packet and the packet is interesting it will send the
packet to the interface (BRI / Dialer interface). Now the router needs a way to know how to reach
the next hop of the destination. for this in ISDN you have the command dialer map
dialer map ip <next-hop> name <remote-name> class <class name> <phone-number>
dialer map ipx <next-hop> name <remote-name> class <class name> <phone-number>
So conclusion is packet coming in, router will seek in routing table for next hop path. If the next
hop is a dialer interface, check the dialer-list to see if the packet is classified as packet that
is allowed to make a call to the other site. After this is done send the packet to the interface to
be processed. Router needs a mapping for this next hop packet in layer 2 term (arp in short). when
you do dialer-map you basically define one. Once the router found out the mapping for the next-hop
address it will dial the phone number associated with the correct next hop address. if It can't
find one and you are doing debug ip packet the router will show a encapsulation failed. The same
principal applies to frame-relay, atm, x25 etc that require static mapping. On point to point if
you're to lazy for frame-relay and ATM interface use the LMI and ILMI for dynamic mapping.
hope that helps
Donny
beda jain
<bpjain@cisco.com To: Dong Lin <dlin22@comcast.net>, ccielab@groupstudy.com
> cc:
Sent by: Subject: Re: dialer-group question
nobody@groupstudy
.com
26-09-2002 02:20
Please respond to
beda jain
Hi,
But when i run ipx over isdn i see it also check which traffic can go
through from dailer-list.
Can some body confirm this ????
Thanks,
Beda
At 01:55 PM 9/22/2002 -0400, Dong Lin wrote:
>The dialer-group is ONLY used to select interesting traffic to bring up ISDN
>line, or it is also used to decide which traffic can go through after the
>line is UP ?
>
>In my test, I have the following:
>access-list 104 permit icmp any any log
>dialer-list 1 protocol ip list 104
>
>After the line is up, I see all kinds IP traffic, like BGP, go through the
>line. Looks like dialer-group is ONLY used to bring up the line ?
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