Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Increasing input errors and CRCs


This situation is very surprising !

On our 2 mbps point to point link we get perfect ping from one router to another router serial address also a perfect ping from Pc's from either side of link. With no input error's and no CRCS. But when we start our web application suddenly there is increase in input errors and CRCs due to this ( Probably) some web pages are not seen properly. When we directed this traffic via other Link using route-maps application works ok. Is there any relation betwwen applicatin data and input errors and CRC's ? Is there any way to detect that the errors are due to occourance of what event.

Thanks in advance



Re: Increasing input errors and CRCs


Better to check out the physical link for reliability and errors.

You can do the same by asking physical loop from the local telco on both the sides and check for the reliability and errors..

once you are done with the loop test you can move onto troubleshooting next probability of errors..


New Member

Re: Increasing input errors and CRCs

Look, have you checked your webserver, might be some tcp/udp ports are vulnerable, due to this reason whenever you switch on your web server, it generates CRC counts, as soon you disconnect, its OK, either problem in your webserver cable or port level.


Re: Increasing input errors and CRCs


in addition to what have been posted or in more detail check for any speed or duplex mismatch in that interface,check for the MTU also.


New Member

Re: Increasing input errors and CRCs

Could you post a show int for the interface running errors as well as a ping?

When the crc's /errors occur does the link run full?

Does the 2MB run btn you and ISP or you and remote client/ Office? What does the other side look like?

If you clear counters on the interfaces on both sides and check? Do a ping from the other side back and check interface on other side?

It could be a physical layer problem but its best to check this as well.

New Member

Re: Increasing input errors and CRCs

Make troubleshooting steps:

You said 2MB P2P link - fine,

router to router serial address - fine

PC from either side of line = fine

Have you check your notebook on the same cable instead of webserver? = whats the result?

It seems that outside traffic generated CRC due to some open tcp/udp ports in your Webserver.

Could you pls make it design and attach to your msg, it will give us more clear picture.

CreatePlease login to create content