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Router on a stick: 2811 with 3750, not propagating VLANs

Hi,

I am trying to configure router on a stick with 2811 and 3750, but I just cannot get it to work - vlans are not getting propagated from 3750 to 2811:

3750:

interface FastEthernet1/0/48

switchport trunk encapsulation dot1q

switchport trunk native vlan 100

switchport mode trunk

speed 100

duplex full

...

3750#sh vtp s

VTP Version                     : running VTP2

Configuration Revision          : 1

Maximum VLANs supported locally : 1005

Number of existing VLANs        : 8

VTP Operating Mode              : Server

VTP Domain Name                 : NULL

VTP Pruning Mode                : Disabled

VTP V2 Mode                     : Enabled

VTP Traps Generation            : Disabled

MD5 digest                      : 0xEC 0x70 0xEB 0x0B 0x7D 0xC0 0xC4 0xDE

Configuration last modified by 192.168.1.205 at 3-2-93 18:33:32

Local updater ID is 192.168.1.205 on interface Vl1 (lowest numbered VLAN interface found)

3750#sh vtp c

VTP statistics:

Summary advertisements received    : 0

Subset advertisements received     : 0

Request advertisements received    : 0

Summary advertisements transmitted : 73

Subset advertisements transmitted  : 7

Request advertisements transmitted : 0

Number of config revision errors   : 0

Number of config digest errors     : 0

Number of V1 summary errors        : 0

VTP pruning statistics:

Trunk            Join Transmitted Join Received    Summary advts received from

                                                   non-pruning-capable device

---------------- ---------------- ---------------- ---------------------------

Fa1/0/46            0                0                0       

Fa1/0/48            0                0                0

3750#sh int fa1/0/48 switchport

Name: Fa1/0/48

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: 100 (SERVER)

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 associations: none

Administrative private-vlan trunk mappings: 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

3750#

2811:

interface FastEthernet0/0

no ip address

duplex full

speed 100

!

interface FastEthernet0/0.1

encapsulation dot1Q 100 native

!

interface FastEthernet0/0.2

encapsulation dot1Q 102

!

interface FastEthernet0/0.3

encapsulation dot1Q 202

2811#sh vtp s

VTP Version                     : 2

Configuration Revision          : 0

Maximum VLANs supported locally : 36

Number of existing VLANs        : 5

VTP Operating Mode              : Client

VTP Domain Name                 : NULL

VTP Pruning Mode                : Disabled

VTP V2 Mode                     : Enabled

VTP Traps Generation            : Disabled

MD5 digest                      : 0x9A 0xC0 0x5E 0x60 0x9B 0xD6 0xE3 0x98

2811#sh vtp c

VTP statistics:

Summary advertisements received    : 0

Subset advertisements received     : 0

Request advertisements received    : 0

Summary advertisements transmitted : 0

Subset advertisements transmitted  : 0

Request advertisements transmitted : 0

Number of config revision errors   : 0

Number of config digest errors     : 0

Number of V1 summary errors        : 0

VTP pruning statistics:

Trunk            Join Transmitted Join Received    Summary advts received from

                                                   non-pruning-capable device

---------------- ---------------- ---------------- ---------------------------

2811#

IOS are 12.4. Tried both VTP1 and VTP2, empty and various domain names, client and transparent modes - all to no avail. I also tried deleting vlan.dat from 2811.

Everyone's tags (5)
1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Router on a stick: 2811 with 3750, not propagating VLANs

John,

The show vtp commands output on the 2811 router would be interesting only if you had a switching module installed into it and created VLANs on that module. Otherwise, the show vlan-switch or show vtp command output is irrelevant. Also, the router does not speak VTP on its routed ports, that is why the VLANs are not propagating.

What you are creating right now are subinterfaces for selected VLANs. You do that on the 2811 without creating the VLANs explicitly - you simply directly refer to them on the individual subinterfaces.

So what you see is absolutely fine and normal. I am sure that the VLANs themselves work. Do not be worried by the VLANs not propagating from the switch to your router - they are not supposed to be propagated.

Best regards,

Peter

1 REPLY
Cisco Employee

Router on a stick: 2811 with 3750, not propagating VLANs

John,

The show vtp commands output on the 2811 router would be interesting only if you had a switching module installed into it and created VLANs on that module. Otherwise, the show vlan-switch or show vtp command output is irrelevant. Also, the router does not speak VTP on its routed ports, that is why the VLANs are not propagating.

What you are creating right now are subinterfaces for selected VLANs. You do that on the 2811 without creating the VLANs explicitly - you simply directly refer to them on the individual subinterfaces.

So what you see is absolutely fine and normal. I am sure that the VLANs themselves work. Do not be worried by the VLANs not propagating from the switch to your router - they are not supposed to be propagated.

Best regards,

Peter

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