[NTLUG:Discuss] Cisco Question

[Mark Bickel]

Carter Bennet spake:
>Yo List,
>My company is currently using a MCI frame circuit to connect our 53
Dept.
>stores. Today we are turning up a Sprint circuit and we will be moving
over
>the stores one at a time over the next week or two.
>
>Okay enough setup, we have Cisco 805 routers at the store level. My
question
>is can I put two delci's in the 805 config so when we are ready the
store
>manager can unplug from the MCI jack and plug into the Sprint jack?
>
>The tech. ability at the stores is weak as it should be, they are there
to
>sell goods not program routers. So I would like to do all this remotely
using
>them to move the jack only.

OK the cisco 805 has one high speed-serial port which can provide
synchronous
or asynch connections for your WAN connection. Therefore your connection
to
the FR will be a synchronous serial connection to a FR CSU/DSU.
Encapsulation
on the interface will be frame-relay.  The LMI type will need to be
configured
depending on what LMI signalling variant is used by the provider
(Sprint) so
most likely this will be ANSI, but you should verify this. You already
have a saved
config that is working presently on the router.  It would have been
helpful to post
the pertinent part of the running config for the router but let's assume
that the
interface declaration looks something like this:

interface Serial0
ip address 192.168.1.1 255.255.255.252
no ip directed-broadcast # (default)
encapsulation frame-relay
bandwidth 256 # (or whatever your FR speed is in kbps)
no ip mroute-cache # (default)
frame-relay lmi-type ansi

Now the hard part is how do you map the  IP on the other end of the  FR
circuit
(the default gateway for your Remote Office) to the DLCI? Either you
declare
a map in the serial interface or you call a dialer (which is a sort of
virtual device)
by means of a dialer-map pointing to the dialer  (configured in a
separate section.)

How you declare this depends in part on whether the FR connection is a
PVC or
SVC (you did not specify which method you are using).

Let's assume a PVC connection from Serial0:
Router (config-if) frame-relay map ip 192.168.1.2 99  broadcast ietf
where 99 is the DLCI of your current MCI connection.

So if you are using this most basic way of pointing the next-hop route
via the FR DLCI your solution may be to simply  save the current
running-config:
Router (config) # copy run MCI

edit the running config with the new params
Router (config-if) no ip address
Router (config-if) ip address 192.168.2.1 255.255.255.252
Router (config-if) no frame-relay map ip 192.168.1.2 99 broadcast ietf
Router (config-if) frame-relay map ip 192.168.2.2 111  broadcast ietf

where 111is the DLCI of your new Sprint connection, then:
Router (config) # copy run start

and then revert back to your previous running config:
Router (config) # copy MCI run

then when the switch is to be made have them switch cables and power
cycle router.
Of course you should verify that the new startup-config is correct
first!

Other aproaches involve the delaration of multiple sub-interfaces or
multiple
dialer-maps so that when the old MCI DLCI is swapped to the new Sprint
DLCI
the router switches to the new route-maps when the old ones fail.
These approaches are a bit more involved and depend on what routing
methods
and protocols you use in the configuration, consequently you should have
a knowledgeable cisco resource technician handle this task for you.

-YMMV,
Mark.Bickel at ericsson.com (at work)
now (finally!) mbickel at speakeasy.net (at the house)