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IP Bridge over ATM - RFC1483

francisco.rivas
Level 1
Level 1

Hi,

I've got this scenario:

[R1]---ethernet---[Switch/ATM]----ATM------[Cisco7206vxr]

The Switch is a Nortel 8610, and it's bridging the ethernet port with the PVC within the ATM link to the 7206vxr.

I've configured the ethernet of R1 with IP 10.10.20.2, and

the Cisco7206VXR ATM interface with the 10.10.20.1 address.

Well, at first, the routers didn't see the other end. So, I've tried configuring "bridge irb" on the 7206VXR, and did this:

interface ATM1/0.1202 point-to-point

description Test PVC

no ip directed-broadcast

no atm enable-ilmi-trap

pvc 1/202

!

bridge-group 1

interface BVI1

ip address 10.10.20.1 255.255.255.252

no ip directed-broadcast

bridge 1 protocol ieee

bridge 1 route ip

Ok, after this, R1 sees the MAC address of the C7206vxr, but I still can't ping the other side. If I do a "debug arp" in both routers, I see (while I run a "ping 10.10.20.2 from the 7206vxr):

On the 7206vxr side:

d18h: IP ARP: creating incomplete entry for IP address: 10.10.20.2

4d18h: IP ARP: sent req src 10.10.20.1 0000.0c2e.e458,

dst 10.10.20.2 0000.0000.0000 BVI1

4d18h: IP ARP throttled out the ARP Request for 10.10.20.2

4d18h: IP ARP rep filtered src 10.10.20.2 0002.4b5b.1528, dst 10.10.20.1 0000.0c2e.e458 wrong cable, interface ATM1/0.1202

On the R1 side:

06:26:36: IP ARP: rcvd req src 10.10.20.1 0000.0c8b.1db0, dst 10.10.20.2 Ethernet0

06:26:36: IP ARP: sent rep src 10.10.20.2 0002.4b5b.1528,

dst 10.10.20.1 0000.0c8b.1db0 Ethernet0

06:26:38: IP ARP: rcvd req src 10.10.20.1 0000.0c8b.1db0, dst 10.10.20.2 Ethernet0

06:26:38: IP ARP: sent rep src 10.10.20.2 0002.4b5b.1528,

dst 10.10.20.1 0000.0c8b.1db0 Ethernet0

06:26:40: IP ARP: rcvd req src 10.10.20.1 0000.0c8b.1db0, dst 10.10.20.2 Ethernet0

06:26:40: IP ARP: sent rep src 10.10.20.2 0002.4b5b.1528,

dst 10.10.20.1 0000.0c8b.1db0 Ethernet0

In R1:

R1>sh arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 10.10.20.1 4 0000.0c8b.1db0 ARPA Ethernet0

Internet 10.10.20.2 - 0002.4b5b.1528 ARPA Ethernet0

R1>

In C7206VXR:

C7206VXR#sh arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 10.10.20.1 - 0000.0c8b.1db0 ARPA BVI1

Internet 10.10.20.2 0 Incomplete ARPA

So, what I'm doing wrong???

why the C7206vxr insists to put the packet on the ATM interface, and not on the BVI 1 interface???

Regards,

Francisco Rivas C.

1 Reply 1

thomas.chen
Level 6
Level 6

Perhaps the actual “bridge irb” command missed this copy and paste, but it is not here. Also, be aware that spanning tree comes into play under setups such as these, both on the ATM link and from the IEEE protocol being utilized under the bridge group. Make sure you have nothing blocking which shouldn’t be.