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Configure dual T-1's ???

Answered Question
Jun 9th, 2010
User Badges:

                          Hello Guys,


                                           I have 2 T1 CSU-DSU WIC on one router and I need to configure both connections to the same service provider? What will the config look like on the T-1 interfaces? I want to load balance accross both T'-1's. Are the routes below correct to do this?



IP Address  for T-1   A


140.8.8.18 255.255.255.0





IP Address  for T-1   B


140.8.8.25  255.255.255.0




ip route 0.0.0.0 0.0.0.0 140.8.8.1


140.8.8.0 255.255.255.0 140.8.8.1

Correct Answer by Giuseppe Larosa about 7 years 2 months ago

Hello Ike,

this is a good question


with

channel-group 0 1-24


we create an object ser0/0:0 that includes all 24 DS0 channels and we use them as a single serial interface without worrying anymore about single B channels


We are using the T1 for data services only in this way.


the same happens also with the alternate command syntax


Hope to help

Giuseppe

Correct Answer by Giuseppe Larosa about 7 years 2 months ago

Hello Ike,

this depends on the exact hardware that you have


on some devices you use something like


controller t1 0/0

channel-group 0 1-24

no shut


this creates interface

serial 0/0:0


you then configure it


int ser0/0:0

enc ppp

ip address x.x.x.x 255.255.255.252

no shut


in other cases the commands for the controller are embedded in the serial interface configuration instead of being under controller object


Hope to help

Giuseppe

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Giuseppe Larosa Wed, 06/09/2010 - 07:47
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Hello Ike,


you will need two default route with different ip next-hops belonging to the two different serial interfaces, also you should avoid to overlap the subnets


140.8.8.16/30

140.8.8.20/30


on the router interfaces



ip route 0.0.0.0 0.0.0.0 140.8.8.17

ip route 0.0.0.0 0.0.0.0 140.8.8.21


this is to perform load balancing, on the other side the SP needs to set two specific static routes like


ip route 140.8.8.128 255.255.255.128 140.8.8.18

ip route 140.8.8.128 255.255.255.128 140.8.8.22


that is given a /24 address space you need to perform appropriate subnetting for getting the IP addresses for the serial links


OR the provider can give one /24 for the LAN and two /30 subnets for the two point-to-point links (this is reasonable too) out of the /24 space


Hope to help

Giuseppe

Charlie Mayes Wed, 06/09/2010 - 08:23
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                        Thanks but, What will the configuration on the T-1 Controller Interfaces look like?

Correct Answer
Giuseppe Larosa Wed, 06/09/2010 - 09:31
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Ike,

this depends on the exact hardware that you have


on some devices you use something like


controller t1 0/0

channel-group 0 1-24

no shut


this creates interface

serial 0/0:0


you then configure it


int ser0/0:0

enc ppp

ip address x.x.x.x 255.255.255.252

no shut


in other cases the commands for the controller are embedded in the serial interface configuration instead of being under controller object


Hope to help

Giuseppe

Charlie Mayes Wed, 06/09/2010 - 09:41
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                      Will this ip address be valid for all 24 channels on the T-1? I mean what about


seria0/0:1


seria0/0:2


seria0/0:3



and the other serial0/0:3 to 23


Or that only for a voice setup like DS0-GROUP or PRI-GROUP

Correct Answer
Giuseppe Larosa Wed, 06/09/2010 - 09:45
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

Hello Ike,

this is a good question


with

channel-group 0 1-24


we create an object ser0/0:0 that includes all 24 DS0 channels and we use them as a single serial interface without worrying anymore about single B channels


We are using the T1 for data services only in this way.


the same happens also with the alternate command syntax


Hope to help

Giuseppe

Charlie Mayes Wed, 06/09/2010 - 10:30
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                                      Thanks Giuseppe,


                                                                I think I am good to go now.

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