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New Member

Cisco 805 bridging config help?

Hopefully someone can shed some light on this problem.

Have two cisco 805 routers connected by a BT kilostream line.(64k)

Both routers have been configured for bridging, and connected together for test purposes with a DTE/DCE back to back test cable, with pcs either side of each router and both pcs can ping each other.

When the routers are put into the BT circuit, they both have a carrier detect light on the front, both ethernet and serial ports and protocols on both routers are up but machines either side of the routers can not ping each other, also no connection....

Any ideas?

Cheers in advance

8 REPLIES
New Member

Re: Cisco 805 bridging config help?

Hi Andrew,

Can you post the router config to have a better view of the setup? It will help also if you can post a 'show int s0' here to see the status of the serial interfaces.

By the way, is it your requirement to do bridging between the 2 locations?

Cheers,

Chris

New Member

Re: Cisco 805 bridging config help?

Here is config. Yes is requirement as they only have two users on link other end which is only used a couple of times a week.

Many Thanks

Current configuration : 522 bytes

!

version 12.2

no service pad

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

!

hostname main

!

boot system flash

!

ip subnet-zero

no ip routing

!

!

!

!

interface Ethernet0

no ip address

no ip route-cache

no ip mroute-cache

bridge-group 1

!

interface Serial0

bandwidth 64

no ip address

no ip route-cache

no ip mroute-cache

bridge-group 1

!

ip classless

ip http server

ip pim bidir-enable

!

!

bridge 1 protocol ieee

!

line con 0

stopbits 1

line vty 0 4

login

!

end

main#sh int

Ethernet0 is up, line protocol is up

Hardware is PQUICC Ethernet, address is 000b.fdf1.fc41 (bia 000b.fdf1.fc41)

MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Half-duplex, 10Mb/s

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue :0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 input packets with dribble condition detected

77060 packets output, 5189970 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

Serial0 is up, line protocol is up

Hardware is PowerQUICC Serial

MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/2/128 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 48 kilobits/sec

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

16230 packets input, 1086228 bytes, 0 no buffer

Received 14220 broadcasts, 0 runts, 0 giants, 0 throttles

4 input errors, 0 CRC, 4 frame, 0 overrun, 0 ignored, 0 abort

75060 packets output, 3303165 bytes, 0 underruns

0 output errors, 0 collisions, 0 interface resets

0 output buffer failures, 0 output buffers swapped out

0 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

main#

New Member

Re: Cisco 805 bridging config help?

Hi Andrew,

From the looks of the config and the 'show int', everything is ok, unless, the remote router has some missing config, such as the 'bridge 1 protocol ieee' or maybe missing 'bridge group 1' on the interfaces.

Would you consider changing the config from bridging to routing so that you will have a granular way of troubleshooting the link?

Cheers,

Chris

New Member

Re: Cisco 805 bridging config help?

Remote router has exactly the same settings other than hostname being different.

Thought about doing the routing way for better diagnostics, and did infact set them up for routing however I could not ping the remote routers. Only ping the local router.

Im convinced the link is at fauly but BT are sure that it is working.

Routers as i say have been linked together in bridge mode and other than adding a manual clock rate to one router on the dce end the config was left the same as above and a pc was put either side of the router. It all worked fine.

Any ideas would be great.

Many Thanks

New Member

Re: Cisco 805 bridging config help?

Hi Andrew,

You've done back-to-back testing on the routers, you've changed it to routing mode and can't ping the remote router serial IP address, it's definitely the BT link that is not working. You can ask them to do a remote loopback on their CSU/DSU, and check if you can see the loopback from your main router. If you can't see the loopback, then there's your proof.

One more thing, what type of router/serial interface are you using? If in case you're using a router with sync/async (A/S) interface, it won't work for a leased line that is faster than 128Kpbs.

cheers,

Chris

New Member

Re: Cisco 805 bridging config help?

Thanks very much for such quick responses from everyone, much appreciated.

Im using a smart serial cable from the back of the router X21 to the BT NTU(CSU/DSU) equipment.

64k leased line.

How do i go about seeing the loopback if I get BT to set on their equipment.

Am i pinging an address or something? or pinging my local router from within the IOS software?

Sorry for sounding dumb on this!

New Member

Re: Cisco 805 bridging config help?

Hi Andrew,

If you ask BT to do a remote loopback on their CSU/DSU, you should see a "Serial0/0 is up, line protocol is up (looped)" from your main router serial interface.

This way, BT can prove to you that their leased circuit is working. If you don't see this, they might have a problem with the circuit.

cheers,

Chris

New Member

Re: Cisco 805 bridging config help?

Ok

Many Thanks for al your help

Am having a joint meeting with BT engineers on monday, they are going to carry out an end to end test using bt equipment. BT engineer each end of the link with testers.

Lets see how it goes!

Thanks again

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