#15 Trunk vlan overrides access vlan on older Cisco switches.

[Anonymous]

My issue seems similar to this bug: http://sourceforge.net/tracker/index.php?func=detail&aid=2717452&group_id=110234&atid=655761
But slightly different...

We have some 3550 switches which have 'over configured' ports, they contain access/voice/trunk vlans, but are set to access mode. However, it seems like SM picks up the trunk vlan (and perhaps prioritizes it?), even when the port is in access mode.

Config snip:

interface FastEthernet0/7
switchport access vlan 10
switchport trunk encapsulation dot1q
switchport trunk native vlan 11
switchport mode access
switchport voice vlan 54
spanning-tree portfast
!
interface FastEthernet0/8
switchport access vlan 10
switchport trunk encapsulation dot1q
switchport trunk native vlan 11
switchport mode access
switchport voice vlan 54
spanning-tree portfast

Switchmap html snip:
Fa0/7 11 Active 100M a-full 0021287014da Sun
Fa0/8 11 Active 100M a-full port is active, but no packets have been seen recently
...
This web page was generated by the "SwitchMap" program (version 12.2) on 2010-11-11 at 10:13:39.

This behavior has existed for quite awhile, that I'm aware of, through the 11-12.2 branches.
Thanks for any thoughts.

[Pete Siemsen]

I'm sorry, I don't understand the problem. The SwitchMap HTML snip you provided looks good for port Fa0/7. Is the problem that Fa0/8 has the "port is active..." message instead of MAC addresses?

BTW, I have switches with very similar interface configs, though I don't set the native VLAN explicitly. So I'll probably be able to debug this.

[Petr Čech]

Hi,
i've stumbled upon this also. The problem ist, when the switch doesn't support vlanPortIslOperStatus it will not display correct trunking status as the result of the vlanPortDynamicStatus will never be used. Attached patch fixes this (copy-paste error)

--- GetIsPortTrunking.pm.old 2012-02-22 19:57:33.000000000 +0100
+++ GetIsPortTrunking.pm 2012-05-24 10:27:17.000000000 +0200
@@ -219,7 +219,7 @@
DbgPrintTrunkAdminStatus(\%TrunkAdminStatus, $PortIfIndexRef, $IfToIfNameRef);

my %TrunkOperStatus;
- GetVlanTrunkPortDynamicStatus($Session, $IfToIfNameRef, \%TrunkAdminStatus);
+ GetVlanTrunkPortDynamicStatus($Session, $IfToIfNameRef, \%TrunkOperStatus);
GetVlanPortIslOperStatus($Session, $PortIfIndexRef, $IfToIfNameRef, \%TrunkOperStatus);
if ((keys %TrunkOperStatus) == 0) {
my $SwitchName = GetName $Switch;

[Anonymous]

hi,i dont know how can i config the trunk...please guide me

[Anonymous]

Hi All, just adding an up vote to this request... we have a similar issue in our Cisco environment. Certain Network Engineers like flushing out configs with trunk settings ( just-in-case a port ever got flipped to trunk mode ), but indeed SwitchMap does display the Trunk Vlan rather then the Access Vlan. Likewise, the resultant html pages (e.g. Vlans) don't show all the ports actually on a vlan.

I haven't tried Petr's patch yet, was hoping that if it had been successful it would have been rolled into code trunk by now; i.e. 13.1

Pete any thoughts? And always, extreme thanks for this useful product!