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ISDN & Async dial-in to PRI on 3845 router

jon.tucker
Level 1
Level 1

We would like to use our 3845 to support dial backup from our remote routers when the main frame line goes down. We will have remote routers that will use ISDN and some will have to use a wic-1am for analog(async) dial. I have two questions:

1. Will my 3845 support such a configuration with a T-1 PRI module installed.

2. Based upon the assumption that it will work, is the following router configuration mock up going to work.

version 12.3

service timestamps debug datetime localtime

service timestamps log datetime localtime

service password-encryption

!

hostname CENTRALPRI

!

username xxxxxxxxxxxxxpassword 7 xxxxxxxxxxxxxxxxxx

username xxxxxxxxxxxxxxpassword 7 xxxxxxxxxxxxxxx

!

aaa new-model

!

aaa authentication login default group tacacs+ line

aaa authentication enable default group tacacs+ enable

aaa authentication ppp default local

aaa authorization exec default group tacacs+ none

aaa authorization commands 15 default group tacacs+ none

aaa accounting update newinfo

aaa accounting exec default start-stop group tacacs+

aaa accounting commands 15 default start-stop group tacacs+

aaa accounting system default start-stop group tacacs+

aaa session-id common

ip subnet-zero

!

ip cef

ip tcp synwait-time 5

!

isdn switch-type primary-ni

!

controller T1 6/0

framing esf

linecode b8zs

pri-group timeslots 1-24

description ISDN PRI CKT#xxxxxxxxxxxx

!

interface FastEthernet0/0

ip address 172.16.1.1 255.255.255.0

duplex full

speed 100

!

interface Serial6/0:23

description ISDN PRI - #xxxxxxxxxxxxx no ip address

encapsulation ppp

dialer pool-member 1

isdn switch-type primary-ni

ppp authentication chap

ppp multilink

!

interface Group-Async0

no ip address

encapsulation ppp

dialer in-band

dialer pool-member 255

async default routing

async mode dedicated

no fair-queue

ppp authentication chap

no group-range

!

interface Dialer2

description Dialer Interface for xxxxxxxxxxxxxx- Remote ISDN Site Dial-in Interface

bandwidth 1

ip address 192.168.66.29 255.255.255.252

encapsulation ppp

dialer pool 1

dialer remote-name xxxxxxxxxxxx

dialer idle-timeout 200

dialer-group 1

ppp authentication chap

ppp multilink

!

interface Dialer40

description Interface for xxxxxxxxxxx- Remote Modem Site Dial-in Interface

bandwidth 1

ip address 192.168.16.21 255.255.255.252

encapsulation ppp

dialer pool 255

dialer remote-name xxxxxxxxxxxx

dialer idle-timeout 200

dialer-group 2

ppp authentication chap

ppp multilink

!

router eigrp 1

network 192.168.16.20 0.0.0.3

network 192.168.66.28 0.0.0.3

network 172.16.1.0 0.0.0.255

no auto-summary

!

ip classless

ip route 0.0.0.0 0.0.0.0 172.16.1.254

!

access-list 101 deny ip any host 224.0.0.10

access-list 101 deny eigrp any any

access-list 101 permit ip any any

!

access-list 102 deny eigrp any any

access-list 102 permit ip any any

!

dialer-list 1 protocol ip list 101

dialer-list 2 protocol ip list 102

2 Replies 2

mwolans1
Level 1
Level 1

Jon, did you ever figure this out? I have the exact same issue.

Here is what I've been able to compile so far:

PRI Modules I'll need:

NM-1CE1T1-PRI 1-port Channelized E1/T1/ISDN-PRI network module

NM-2CE1T1-PRI 2-port Channelized E1/T1/ISDN-PRI network module

We are getting the one port version.

Digital Modems:

NM-6DM 6-digital-modem network module

NM-12DM 12-digital-modem network module

NM-18DM 18-digital-modem network module

NM-24DM 24-digital-modem network module

We will need one of these to terminate the analog (async) calls that come in over the digital PRI circuit. I was told by TAC that the incoming ISDN calls would work just fine with one the PRI module and these digital modems were needed only for the analog calls. Which means we should be able to size our digital modem module according to the ratio of analog calls we think we will be getting on the PRI line. I believe we are getting either the 6 or 12 modem version as these modules aren't cheap. (They also make a 30 modem module - but I'm in the US using a T1 line)

Here are the TAC proposed additions to the posted config:

Serial 0:23

isdn incoming-voice modem

interface Group-Async0

dialer idle-timeout 900

dialer-group 2

ppp multilink

group-range 1 24 (or whatever your modem numbers are)

line 1 24

no flush-at-activation

modem InOut

transport input all

modem autoconfigure type mica

TAC said my individual dialer interfaces with the /30 addresses would work. Which is what I want so I can run EIGRP over the backup lines to support the remote LAN failover.