How to route 2 2 ATM interfaces to 2 Fastethernet ports

movielink · ‎08-10-2007

My router: Cisco 1841 with 2 SHDSL modules

My requirement:

Route all traffic from ATM 0/0/0 to FastEthernet 0/0

Route all traffic from ATM 0/1/0 to FastEthernet 0/1

The 2 ATM interfaces are 4 wire point to point links.

There are 2 /29 subnets to route, one on each ATM interface.

How to go about this?

paolo bevilacqua · ‎08-10-2007

You need policy routing for this.

Search PBR on CCO, but in short you make configure 4 route maps, and apply them on the appropriate interface or subinterface:

each route map simply specifies the next hop or interface:

match interface ...

set ip next-hop ...

Thta should do it.

Hope this helps, please rate post if it does!

movielink · ‎08-11-2007

Hi There,

I got the following advice from a Cisco tech:

(Assumptions)

ATM 0/0/0 = client1 PPP link to ISP

ATM 0/0/0 has subnet 203.200.200.0/29 routed to it (By ISP).

Remote end of PPP link = 125.22.33.1

Local end of PPP link = 125.22.33.2

ATM 0/1/0 = client2 PPP link to ISP

ATM 0/1/0 has subnet 203.200.201.0/29 routed to it (by ISP).

Remote end of PPP link = 125.22.33.5

Local end of PPP link = 125.22.33.6

fastethernet 0/0 = For client1

fastethernet 0/1 = For client2

access-list 15 permit any

!

route-map client1 permit 10

match ip add 15

set ip next-hop 125.22.33.1

!

interface fastethernet 0/0

ip policy route-map client1

ip address 203.x.x.1 255.255.255.248

!

route-map client2 permit 10

match ip add 15

set ip next-hop 125.22.33.5

!

interface fastethernet 0/1

ip policy route-map client2

ip address 203.200.201.1 255.255.255.248

This setup fails, it has several problems.

1. If I ping any of the ATM interfaces

125.22.33.2 or 125.22.33.5 from the

router at the other end of the PPP

connection there is a reply but if going

1 hop or more away from the remote end

router, it fails (From Internet).

2. If I ping the 2 fastethernet IP's from

other end of their respective PPP links

there is a reply but moving 1 or more

hops away from the remote end router,

it fails (From Internet).

3. All routing by ISP has been tested and

found to be OK. This was tested by

changing the configuration to

"ip route 0.0.0.0 0.0.0.0 125.22.33.1"

while removing the policy statements.

4. I tested

"ip route 203.200.200.0 255.255.255.248

125.22.33.1", trying to force a route but

that got me nowhere fast.

5. Finally I tested advanced ping by setting

ping source address to 203.200.200.1

(fastethernet 0/0 IP) and pinging the

remote end of the PPP link 125.22.33.1

and this worked but repeating the ping

to a known working IP on Internet fails.

It is as if something is missing. My Cisco

experience is only limited, what to do next.

In Linux it is quite easy to do the above

by simply setting a route rule up to

tell the kernel to route all traffic on one

interface to another. Cisco does not have

that capability (Not directly anyway).

I am now a bit stuck...

Best regards

fida.h · ‎08-11-2007

you can define a light vrf place ATM0/0/0 and F0/0 under that VRF as long as there is no relation ship between ATM0/0/0 and ATM0/1/0

Br,

FH