Partially-Meshed FR Network with One IP Subnet Per VC????

mehdi.saghaei

Hello , I have 3 2501 Router and i want to configure the frame-relay network as Partially-Meshed Network with One IP Subnet Per VC.

How should i can connect them physically? and what about the router's configuration.

I want select Router-A as DCE for remaining anothers.

Thanks.

Netstudent

Well if routerA is the DCE, that will be the switch. You will need to configure the router for frame-relay switching. I'm assuming you have serial 0/0 and serial 0/1 on RouterA

RouterA# Frame-relay switching
#conf t
(config)# int s0/0
(config-if)#encap frame-relay
frame-relay intf-type DCE
clock rate 64000
frame-relay lmi-type ANSI
frame-relay route <input DLCI> output interface <output DCI>
example: "frame-relay route 101 int serial s0/1 102"

Then on the other interface (serial 0/1) you will need to issue the same commands except the frame-relay route will be different.

Now you will be switching the DLCI back the way it came.

So DLCI 101 came in on int s0/0 and then exitied out s0/1 as 102. NOW is will enter on s0/1 as DLCI 102 but exit int s0/0 as 101.

So under serial 0/1 interface config mode.
The route would be "frame-relay route 102 int serial 0/0 101"

This will create the VC in the switch. Now you will need to configure the DTE devices for the right local DLCI, the right LMI type, and correct IP and subnet mask.

RouterB(s0/0)

---

(s0/0)RouterA(frameswitch)(s0/1)

---

(S0/0)RouterC


routerB would have say local DLCI 101
routerC would have local DLCI 102

Anyways read up on these concepts. You will probably need to know this for the CCNA exam and definately will need to know it for the real world.

mysql1988

http://www.techexams.net/techlabs/ccna/lab_fr.shtml


this is a good reference

Netstudent

Also, if you wanted to do a partial mesh config, you are going to need more than 3 routers. You will probably need at least 5 routers to do a true partial mesh. I think.

You could do a full mesh with 4 routers, or a hub-n-spoke with 3 routers. Only way to do a full-mesh with 4 routers is to have one router with at least 3 serial ports.

With 5 routers, Router1 would be the switch, 2,3,4,5 would be the endpoints.

now routers 2,3,4 could create a full mesh with 2 VC's terminating at each router, AND THEN
router5 would be all by it's lonesome with a point-to-point connection back to router2. Router5 would only have a single VC terminating on it's subinterface. This is a true partial-mesh. With point-to-multipoint subinterfaces and point-to-point subinterfaces on Router2. Now there might be some workarounds with turning off keepalives(LMI), but to me that seems more confusing and takes you farther away from simulating real-world.