ISDN ( Two sites with ISDN as a backup link connected to HEAD Office)

[Zaheer_Assariya]

Here is the scenario :

Total of three sites as given below

- HeadOffice

- SiteA

- SiteB

Head Office is connected to SiteA and SiteB via Leased line. Isdn is used as a backup link but headoffice got only one ISDN line and siteA and siteB has there own ISDN line.

Q) Its very rare that both the sites (siteA and siteB) will go down simultaneously therefore i wanna know if its possible to use the only isdn line availabe at the headquater for supporting both(siteA and siteB) which has there own isdn lines . If yes then how and what will be a configuration example.

[spremkumar]

Hi

The same can be achieved by configuring different dialer interfaces and configuring the reqd infos to dial out & connect to the respective locations or else try creating simple dial in in the HO to accept the calls from the sites..

Do find the link which can be helpful to achieve the same..

http://www.cisco.com/en/US/tech/tk801/tk133/technologies_configuration_example09186a0080093c2e.shtml

regds

[Zaheer_Assariya]

Dear Spremkumar,

The configuration file (link) was very helpfull and I learned alot from it. The bri configuration is almost done but via this configuration the isdn link will always be up. I wanna use the ISDN link to be up only when the leased line circuit is down, how would i do that ?

And also whats the specific link to on cisco site where i can get configuaration examples (similar to the one u gave me) because that link was a step by step configuration help.

Appriciated

[spremkumar]

hi

to activate the dialer incase of u r LL failure configure backup interface dialer 1 and backup interface dialer 2 under ur respective serial ports where ur site A and site B is getting connected.

also find the link from where u can chekout all the technologies being deployed by cisco..

http://www.cisco.com/pcgi-bin/Support/browse/index.pl?i=Technologies

regds

[Zaheer_Assariya]

Hi spremkumar,

Thanks a million I think i am almost completed the task with ur help. If its possible can u send me a link for configuring backup link via dialer1 and dialer 2 in case LL fails. Thanks

[mohamed-khadr]

To have bri come up ONLY when Serial is down, enter the following config on the serial interface or subinterface:

router(config-if)# backup delay 60 90

backup int bri0

!

end

<< 60 secs to come up & 90 secs to go back down>>

That's -of course- depend on ur network reqs.

hope that help

[Zaheer_Assariya]

Dear Mohammed-khadr,

When my leased line fails i wanna bring up isdn link and that is gonna be done by the command u have told(backup delay 60 90) but i want the isdn link to be up untill the LL comes up and the link must switch from Isdn to LL automatically . R there any commands for that?