E1 Controller Framing mismatch

[wanhwai]

Hi all,

What will happen if i configure a router with E1 controller framing CRC4 and the other router with framing no-CRC4.

This lease line is from Singapore to Shanghai.

Thank you

[pkhatri · Accepted solution]

Hi,

The router configured with framing CRC4 will perceive the signal as having CRC errors and drop the frames. YOu need to have this match on both sides.

Paresh

[mheusinger · Accepted solution]

Hi,

the CRC4 settings have to match your local telco settings. It could be different at both ends f.e. with two different telcos providing the local loop at each end.

Regards, Martin

[wanhwai]

Hi,

1.How if i ask my local ISP about the framing format for oversea site?

DO you think they know?

2.Now the connection is up but there are a lot of error for both end router serial interface.

3. If i change the oversea framing format CRC4, do you think the connection would down?

4. For oversea lease line is E1 line. So does it mean it necessary to use CRC4?

Thank you

Regards,

Steven Hoo

[tdrais · Accepted solution]

1. the provider of the circuit is always suppose to know this. They may buy the last mile circuit from another local provider but it is still the person you pay the money to that is responsible for all this.

3. You have to assume it will if you are going to change it remotely. Just make sure you save your configuration and then do a reload in 5 minutes. Change the crc setting. If you lose connectivity the router will reboot and load your saved confige and the line will come back up. If you do not lose connectivity just cancel the reload. This is more than likely you best bet. You can never 100% trust your provider has the correct information.

4. Most e1 use crc4 if the are not unframed. This varies from country to country but in a lot of cases the provider will change it to whatever you want if their default does not work.