Solutions

High cpu and high input errors

Solutions ID:    KB4956
Version:    1.0
Status:    Published
Published date:    02/28/2012
 

Problem Description

Seeing a lot of input errors. Have verified cabling, switch ports, duplex settings and have replaced the ssl card (known issue on model 810 whereby the ssl card stops the intel interface card using PCI-X).

Resolution

 

input errors on an interface can also be due to  CPU overload etc. In the case of cpu load the TCP engine in software is not able to keep up with incoming load and as a result, packets are dropped on the receive interface.
 
How to identify if this is a CPU/resource issue:
Under tcp interface information (https://<IP>:8082/tcp/interface), there are two useful counters below for the interface which will be non-zero. They are:
 
- Input errors
- Receive resource errors

Input errors
1368
Output errors
0
Packets received via multicast
84568
Packets sent via multicast
0
Packets received via broadcast
14
Packets sent via broadcast
4
Dropped on input
0
Destined for unsupported protocol
0
Number of receive lockups
0
Receive CRC errors
0
Receive alignment errors
0
Receive resource errors
435

 

 

If you see this then check the sizing. In this case the Wan link was 100Mbps. We were seeing about 70 Mbps of traffic. Now in this case the customer was using ADN. This was the core box in an ADN setup. It was an 810-20 which is designed for a wan link of 40Mbps in an ADN environment so was overloaded. For forward proxy i.e. no ADN then it is designed for a wan link up to 90 Mbps.


Rate this Page

Please take a moment to complete this form to help us better serve you.

Did this document help answer your question?
 
 
If you are finished providing feedback, please click the RATE CONTENT button. Otherwise, please add more detail in the following text box and then click RATE CONTENT.
 
 

Your response will be used to improve our document content.

Ask a Question