E1 configuration issue

[Kevin Hart]

Hi

I have an international circuit with the following configuration. Is this correct? Will G.704 at one end and G703 -> X.21 work ok.

A end - 3640 with a E1 G.703 card running in framed mode (G.704, 1984k) connecting onto G.703 International CCT.

B end - International CCT.

G.703 > x.21 conversion

Cisco 3640 with x.21 interface, terminating the cct.

Circuit runs clean, until cct is loaded. We then see high number of input errors / CRC.

Not 100% sure about above configuration. Any help would be appreciated

.Kevin

[dsouzavincent]

Hi Keven,

Could you explain your problem a bit more detailed.

1. Is the ckt up ?

2. Where are the errors seen ?

3. Wht is the error rate / per minute ?

4. Cud u paste the config ?

[Kevin Hart]

Answers to your questions.

1. Yes, the circuit is up.

2. Input errors on cisco router at the A end, which increase with load.

3. unknow at this point. We don't manage the router. we just provide the circuit.

4.

A end Config

!

controller E1 0/1

framing NO-CRC4

channel-group 0 timeslots 1-31

!

!

interface Serial0/1:0

ip address < removed>

ip pim sparse-dense-mode

carrier-delay 15

no fair-queue

serial restart-delay 90

nrzi-encoding

hold-queue 950 in

hold-queue 950 out

!

B end config

!

interface Serial0/1

bandwidth 1984

ip address < removed>

no fair-queue

serial restart-delay 0

hold-queue 950 in

hold-queue 950 out

!

[5mlarsson]

You can not run framed E1 in one end and unframed E1 in the other. Router A expects a sync channel where router B sends data so you will probably see an E1 out of sync error in router A. Incoming data to router B is corrupted by the sync channel so you will probably see CRC errors on a link protocol level.

Try to see if the G.703<->X.21 converter can be set to framed G.704 mode.

[Kevin Hart]

Thanks for your response.

The G.703 -> x.21 converter has now been set to unframed E1 (g.703) and the remote end router configured for unframed E1. Circuit is currently running clean.

I think the problem was related to the remote end modem, which is only capable of running in unframed E1 mode.

Initially the circuit was configured as the following

remote end

router (framed E1)

DSU (unframed E1)

int. circuit.

UK end

DSU (framed)

router (X.21)

What I don't understand is why the circuit came up in the first place, due to the remote end mismatch. Remote Carrier unable to provide any support.

Kevin