Datasheet

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Release Notes for Cisco IOS Release 12.1E on the Catalyst 6500 and Cisco 7600 Supervisor Engine and MSFC
OL-2310-11
Troubleshooting
To debug STP problems, follow these guidelines:
• The sum of all logical interfaces equals the number of trunks on the switch times the number of
active VLANs on the trunks, plus the number of nontrunking interfaces on the switch.
• The show spanning-tree summary totals command displays the number of logical interfaces in the
STP Active column.
• These maximum numbers of logical interfaces are supported with Release 12.1(13) E and later
releases:
• These maximum numbers of logical interfaces are supported with 12.1 E releases earlier than
Release 12.1(13)E:
Note Cisco IOS software displays a message if you exceed the maximum number of logical interfaces.
• After a switchover from the active to the redundant supervisor engine, the ports on the redundant
supervisor engine take longer to come up than other ports.
• Record all spanning tree-blocked ports in each switch in your network. For each of the spanning
tree-blocked ports, record the output of the show interface command. Check to see if the port has
registered many alignment, FCS, or any other type of line errors. If these errors are incrementing
continuously, the port might drop input BPDUs. If the input queue counter is incrementing
continuously, the port is losing input packets because of a lack of receive buffers. This problem can
also cause the port to drop incoming BPDUs.
• On a blocked spanning tree port, check the duplex configuration to ensure that the port duplex is set
to the same type as the port of its neighboring device.
MST RPVST+ PVST+
Supervisor Engine 2,
MSFC2
50,000 total
6,000
1
per switching module
1. 10 Mbps, 10/100 Mbps, and 100 Mbps switching modules support a maximum of 1,200 logical interfaces per module.
10,000 total
1,800
1
per switching module
13,000 total
1,800
1
per switching module
Supervisor Engine 1,
MSFC or MSFC2
25,000 total
3,000
1
per switching module
6,000 total
1,200
per switching module
6,000 total
1,200
per switching module
PVST+
Supervisor Engine 2,
MSFC2
4,500 total
1,800
1
per switching module
1. 10 Mbps, 10/100 Mbps, and 100 Mbps switching modules
support a maximum of 1,200 logical interfaces per module.
Supervisor Engine 1,
MSFC or MSFC2
4,500 total
1,200
per switching module