cat2960 native VLAN1 TAGGED

[fsoffia]

hello

I configured vlan 1,2 and 3 on switch cat2960 ios: C2960 Software (C2960-LANBASE-M), Version 12.2(25)SEE2.

I connected the switch f0/1 port configured like a TRUNK 802.1q, to a cisco2610 router with ios : C2600 Software (C2600-IS-M), Version 12.2(40).

I configured Ethernet SUBINTERFACES on router for 802.1q intervlan routing.

E0/0 subinterface on router has vlan 1 NATIVE encapsulation.

I can't ping the switch from router console and viceversa, intervlan routuing does not work.

THE PROBLEM IS THAT ON CAT2960 THE TRUNK HAS THE VLAN1 TAGGED but the router NO.

Switch#sh interfaces f0/1 switchport

Name: Fa0/1

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Administrative Native VLAN tagging: enabled

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk Native VLAN tagging: enabled

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Unknown unicast blocked: disabled

Unknown multicast blocked: disabled

Appliance trust: none

Switch#

IS THERE A COMMAND THAT CAN DISABLE "ADMINISTRATIVE NATIVE VLAN TAGGING" on CAT2960 ?

best regards

francesco

[fsoffia]

hi amit,

the bug is in cat2960 ios or cisco2610 ios ?

For me it's cat2960 that works wrong !

I think that trunk native vlan tagging "administratively enabled" isn't a good thing.

One would choose if tagging or not the native vlan !

DO you agree

best regards

francesco

[Amit Singh]

Francesco,

The Bug is on the 2610 router end. Cisco's implemetation for native vlan tagging has been the same over a period of time. Its only Cisco's implementation which uses native vlan on the trunkports, IEEE implementation doesnot use that.I think upgrading the IOS on 2610 should resolve the issue. Try uploading it and update us on this.

HTH,Please rate if it does.

-amit singh

[fsoffia]

hi amit

excuse me

It's first time I work with cat2960...

With cat2950 I never had this problem of native vlan tagging on trunk 802.1q with cisco routers.

I never used the tag for native vlan 1 !!!

Or I never saw that thing or it's new on cat2960.

If cisco switches always tag the native vlan by default, do you mean that the tag is negotiated between switch and router on the other end, and if the router does not tag the vlan 1 so the switch disable vlan 1 tagging.

If the router tags vlan 1 on the switch it's the default behaviour.

But in this case the ROUTER does NOT negotiate tagging with cat2960 switch ?

Is it right ?

I don't know that cisco implementation is not like IEEE standard.

I know that ISL is cisco proprietary trunking but not 802.1q.

Could you explain me better or give me a reference doc ?

best regards

francesco