Switchmap doesn't show VLANs on some Trunk Ports

[Anonymous]

Hi Pete,

first of all: Thank's for your fantastic tool.
We're currently migrating our voice-VLAN and have the following problem.

Switchmap doesn't show the VLANs on our trunk ports for the following switches:

• Switch A 3750G-Stack with 12.2(58)SE2
• Switch B 3560G-24PS with 12.2(58)SE2
• Switch C 3750G-24TS with 12.2(58)SE2

Example (vlans missing):

Port VLAN State Days
Inactive Speed Duplex Port Label What
(via CDP) MAC Address NIC
Manufacturer IP Address DNS Name
Fa0/1 100 Active 100M full A18 H9-2G-11B, tel-203 trunk port
Fa0/3 100 Active 100M full A23 H9-2G-11B, tel-217 trunk port

Output for our other switches (with vlans showing):

information about the port itself information about what the port is connected to
Port VLAN State Days
Inactive Speed Duplex Port Label What
(via CDP) MAC Address NIC
Manufacturer IP Address DNS Name
Fa2/0/5 100 Active 100M full T129 H6-EG-011, tel-360 trunk port for VLANs 100,205
Fa2/0/6 100 Active 100M full T143 H6-EG-10, tel-214 trunk port for VLANs 100,205
Fa2/0/7 100 Active 100M full H6 H6-EG-007A, tel-198 trunk port for VLANs 100,205

Our Trunk port are all configured with the following template:

macro name tel-h2
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport trunk allowed vlan 100,200
switchport mode trunk
switchport port-security maximum 2
switchport port-security
switchport port-security violation protect
switchport port-security aging time 1
mls qos trust cos
storm-control broadcast level 20.00 5.00
storm-control multicast level 20.00 5.00
storm-control action shutdown
storm-control action trap
spanning-tree portfast trunk

As you can see, all ports are configured with "allowed vlan".

On the other hand, we have 3750G Switches with 12.2(58)SE2, which are showing the VLAN on the trunk port.

Do you have any idea?

[Pete Siemsen]

That is odd. You have 3750G switches running the same software, and some of them show trunks correctly, and some of them don't. My 3750s show trunks correctly. Mine are running 12.2(55)SE6.

This made me go back and look at the SwitchMap code that shows the VLANs on a trunk. The code has several checks that might cause it not to show the VLANs. If you could run SwitchMap.pl with debugging turned on, I might be able to help. Please run the program with this command line:

SwitchMap.pl -d 8 -f <switchname>

...where <switchname> in the name or IP address of one of your 3750s that doesn't show VLANs on trunks. This command will cause SwitchMap to create a file named SwitchMap.log in the current directory. Please email that file to siemsen@ucar.edu.

Note that when you run it this way, SwitchMap will create HTML files as usual, but only for the single switch named <switchname>. You'll want to immediately run SwitchMap again, without command-line options, to create HTML files that represent all your switches.</switchname>