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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 9 Creating and Maintaining VLANs
Understanding VMPS
Understanding VMPS
The Catalyst 3550 switch acts as a client to the VMPS and communicates with it through the VLAN
Query Protocol (VQP). When the VMPS receives a VQP request from a client switch, it searches its
database for a MAC-address-to-VLAN mapping. The server response is based on this mapping and
whether or not the server is in secure mode. Secure mode determines whether the server shuts down the
port when a VLAN is not allowed on it or just denies the port access to the VLAN.
In response to a request, the VMPS takes one of these actions:
•
If the assigned VLAN is restricted to a group of ports, the VMPS verifies the requesting port against
this group and responds as follows:
–
If the VLAN is allowed on the port, the VMPS sends the VLAN name to the client in response.
–
If the VLAN is not allowed on the port and the VMPS is not in secure mode, the VMPS sends
an access-denied response.
–
If the VLAN is not allowed on the port and the VMPS is in secure mode, the VMPS sends a
port-shutdown response.
•
If the VLAN in the database does not match the current VLAN on the port and active hosts exist on
the port, the VMPS sends an access-denied or a port-shutdown response, depending on the secure
mode of the VMPS.
Step 8
show running-config
Verify your entries.
In the display, make sure that interfaces Fast Ethernet 0/1 and Fast
Ethernet 0/2 are configured as trunk ports.
Step 9
show vlan
When the trunk links come up, Switch 1 receives the VTP information
from the other switches. Verify that Switch 1 has learned the VLAN
configuration.
Step 10
configure terminal
Enter global configuration mode.
Step 11
interface fastethernet 0/1
Enter interface configuration mode, and define Fast Ethernet port 0/1 as
the interface to set the STP cost.
Step 12
spanning-tree vlan 2 cost 30
Set the spanning-tree path cost to 30 for VLAN 2.
Step 13
spanning-tree vlan 3 cost 30
Set the spanning-tree path cost to 30 for VLAN 3.
Step 14
spanning-tree vlan 4 cost 30
Set the spanning-tree path cost to 30 for VLAN 4.
Step 15
end
Return to global configuration mode.
Step 16
Repeat Steps 9 through 11 on Switch 1 interface Fast Ethernet 0/2, and
set the spanning-tree path cost to 30 for VLANs 8, 9, and 10.
Step 17
exit
Return to privileged EXEC mode.
Step 18
show running-config
Verify your entries.
In the display, verify that the path costs are set correctly for interfaces
Fast Ethernet 0/1 and 0/2.
Step 19
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
