Cabletron Systems ZX-250 Manual Do Utilizador

SmartCell ZX-250 User Guide   5-5

Troubleshooting

Troubleshooting Congestion  

5.4.3

Port Congestion

s•

Enter the 

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

VCs dropped. Is the difference for cells dropped equal to the difference for VCs dropped?

U

If yes, the switch is improperly set up. Check the switch configuration.

U

If no, this indicates port congestion. Continue.

¢•

Enter the 

command for this port. Note the bandwidth allocated for each Quality of 

Service on this port.

••

For each class of service, enter the 

 command. Set the Max threshold 

to the value recommended in the “Quality of Service Queue Allocation Guidelines” section.

T•

Have you performed step 3 for every class of service for this port?

U

If no, go to step 3.

U

If yes, continue.

Q•

Enter the 

command for this port. Set call admission control for this port 

to a more conservative policy (

 or 

).

–•

Check VC statistics for this port using either the 

 or 

 command, whichever 

is appropriate.

••

If the port belongs to the high virtual channel link (VCL), read the forward stats. If the port belongs 
to the low VCL, read the backward stats. If the port belongs to both high and low VCLs, read both 
stats.

G•

Is the number of cells received increasing?

U

If no, go step 6.

U

If yes, continue.

n•

Convert allocated bandwidth (kb/s) to cells (48 bytes).

Bandwidth in cells = (1024 X Allocated Bandwidth) / 384 
where 384 = 48 cells X 8

s¥

Is the Allocated Bandwidth less than the Cell Reception Rate?

U

If no, go to step 6.

U

If yes, this VC is misbehaving. Take appropriate action, for example, terminate the VC.