Cabletron Systems 04-0053-01 Manual De Usuario

SmartSwitch ATM User Guide   9-5

Troubleshooting

Troubleshooting Congestion  

*Use the 

 

 command to view bandwidth utilization

Has the congestion subsided?

If yes, you are done.

If no, continue.

Have you changed the EPD threshold (

 command)? 

If yes, replace it to the default setting. If congestion subsides, you are done.

If no, continue.

Enter the 

 and 

 commands for each port. Is the allocated bandwidth 

small and is the traffic mostly UBR?

If no, go back to step 4 and check next port.

If yes, continue.

Enter the 

 command. Is the UBR queue 

 large?

If no, go back to step 4.

If yes, continue.

Reduce the UBR queue 

 by a small amount, then wait a few minutes.

Enter the 

 command, and take the default of 

. Is the number of cells dropped 

increasing for this port, and quickly decreasing for all other ports?

If yes, proceed to the “Port Congestion” section.

If no, continue.

Is the number of cells being dropped by all other ports decreasing somewhat?

If no, go back to step 6.

If yes, continue.

Enter the 

command and set call admission control for this port to a more 

conservative policy (

 or 

).

Go back to step 4 until all ports have been checked.

9.4.3

Port Congestion

Enter the 

 command a few times, noting the value for cells dropped and unknown 

VCs dropped. Is the number of cells dropped equal to the number of VCs dropped?

rt-VBR

Bandwidth* utilization less than 20%: Min = 16, Max = 1024

rt-VBR

Bandwidth* utilization greater than 20%: Min = 128, Max = 4096

Nrt-VBR

Min = 256, Max = 4096

UBR

Min = 256, Max = 8192

ABR

Min = 256, Max = 8192

Table 9-1

Settings for Class of Service Queues (Continued)