Port Congestion - Cabletron Systems SmartSwitch 6500 User Manual

Troubleshooting
Table 9-1
Service Class Recommended Settings
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
*Use the
show portconfig
3. Has the congestion subsided?
•
If yes, you are done.
•
If no, continue.
4. Have you changed the EPD threshold (
•
If yes, replace it to the default setting. If congestion subsides, you are done.
•
If no, continue.
Enter the
5.
show cacinfo
small and is the traffic mostly UBR?
•
If no, go back to step 4 and check next port.
•
If yes, continue.
6. Enter the
show porttrafficcongestion
•
If no, go back to step 4.
•
If yes, continue.
Reduce the UBR queue
7.
Enter the
8.
show portstats
increasing for this port, and quickly decreasing for all other ports?
•
If yes, proceed to the "Port Congestion" section.
•
If no, continue.
9. 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
10.
set caceqbwallocscheme
conservative policy (
moderate
Go back to step 4 until all ports have been checked.
11.
9.4.3

Port Congestion

Enter the
1.
show portstats
VCs dropped. Is the number of cells dropped equal to the number of VCs dropped?
Settings for Class of Service Queues (Continued)
command to view bandwidth utilization
set switchtrafficcongestion
and commands for each port. Is the allocated bandwidth
show portconfig
command. Is the UBR queue
by a small amount, then wait a few minutes.
MaxValue
command, and take the default of
command and set call admission control for this port to a more
or ).
conservative
command a few times, noting the value for cells dropped and unknown
command)?
large?
MaxValue
. Is the number of cells dropped
all
SmartSwitch 6500 User Guide 9-5
Troubleshooting Congestion