passing VLAN / Spanning-tree between 2960S and 3750X

bberry · ‎10-09-2012

Ok,

Has anything changed in the way of defaults for creating a trunk port and spanning-tree between a 3750x and the newer 2960s? I have one of each I just took out of the box and applied my standard switch configuration template but I cannot get my VLANs that are configured on my 3750X to appear on the 2960S. I find nothing that is blocking and everything seems to be forwarding and I am running out of things to check.

Suggestions???

Brent

Peter Paluch · ‎10-09-2012

Brent,

According to what you write, you expect the new 2960S to learn about existing VLANs automatically. That will work only if the following prerequisities are met:

The link that interconnects the two switches must be configured as a trunk
Both switches must be either in VTP Server or VTP Client mode
The VTP domain name and version must be set identically on both switches
The VTP password (often forgotten) must be identical on both switches

Do you meet these conditions?

Best regards,

Peter

bberry · ‎10-09-2012

yep ... yep ... yep ... not using passwords

I did notice that I now have a MD5 message on the 2960 when I do a sh vtp status

Switch# sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 1
VTP Domain Name                 : Kalamazoo
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 34bd.c808.4800
Configuration last modified by 0.0.0.0 at 10-9-12 18:10:37

Feature VLAN:
--------------
VTP Operating Mode                : Client
Maximum VLANs supported locally   : 255
Number of existing VLANs          : 5
Configuration Revision            : 0
MD5 digest                        : 0xB4 0x77 0xD7 0x96 0x1D 0x11 0xDA 0x4D
                                    0xCB 0x92 0xA2 0x40 0xBB 0xA7 0xCC 0xAB
*** MD5 digest checksum mismatch on trunk: Gi1/0/48 ***

1)Copper port on each switch is configured as trunk ...

3750-x

interface GigabitEthernet1/0/1

switchport trunk encapsulation dot1q

switchport mode trunk

switchport nonegotiate

2960S

interface GigabitEthernet1/0/48
switchport mode trunk
switchport nonegotiate

2) 3750-x is set server and 2960S is set Client

and

3) Domain names are the same

kala_c1#sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 1
VTP Domain Name                 : Kalamazoo
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 6073.5c5e.2c00
Configuration last modified by 192.168.8.1 at 10-9-12 19:47:16
Local updater ID is 192.168.8.1 on interface Vl5 (lowest numbered VLAN interface found)

Feature VLAN:
--------------
VTP Operating Mode                : Server
Maximum VLANs supported locally   : 1005
Number of existing VLANs          : 10
Configuration Revision            : 0
MD5 digest                        : 0x4B 0xCF 0xD5 0xC7 0xB8 0xD9 0x5C 0xE2
                                    0x94 0x8B 0x48 0x5E 0x89 0xDF 0xBF 0x66
kala_c1#

Switch#sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 1
VTP Domain Name                 : Kalamazoo
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 34bd.c808.4800
Configuration last modified by 0.0.0.0 at 10-9-12 18:10:37

Feature VLAN:
--------------
VTP Operating Mode                : Client
Maximum VLANs supported locally   : 255
Number of existing VLANs          : 5
Configuration Revision            : 0
MD5 digest                        : 0xB4 0x77 0xD7 0x96 0x1D 0x11 0xDA 0x4D
                                    0xCB 0x92 0xA2 0x40 0xBB 0xA7 0xCC 0xAB
*** MD5 digest checksum mismatch on trunk: Gi1/0/48 ***
Switch#

Peter Paluch · ‎10-09-2012

Hi Brent,

Both your switches have a configuration revision of 0 so they don't know which one of them is more current. Simply do any change to the VLAN database on the server switch, like creating a dummy VLAN and exit the configuration. Now the configuration revision should jump to 1 and the client switch should accept the complete updated information.

Best regards,

Peter

bberry · ‎10-09-2012

Peter,

That seemed to do the trick. I now have VLANs on the 2960 switch. I also made sure that I have an IP domain-name entry on the 2960 as I saw that on another post for the MD5 issue. I juess it just needed a kick that a simple switch reboot could not do. Onward with the rest of the confg. Thanks...

kala_c1(config)#vlan 5
kala_c1(config-vlan)#name Mgmt
kala_c1(config-vlan)#^Z
kala_c1#
Oct 9 16:12:02.267 est: %SYS-5-CONFIG_I: Configured from console by console
Oct 9 16:12:03 est: Found no corresponding dummy port for instance 5, port_id 128.1
Oct 9 16:12:03 est: Found no corresponding dummy port for instance 7, port_id 128.1
Oct 9 16:12:03 est: Found no corresponding dummy port for instance 8, port_id 128.1
Oct 9 16:12:03 est: Found no corresponding dummy port for instance 9, port_id 128.1
Oct 9 16:12:03 est: Found no corresponding dummy port for instance 10, port_id 128.1
kala_c1#sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 1
VTP Domain Name                 : kalamazoo
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 6073.5c5e.2c00
Configuration last modified by 192.168.8.1 at 10-9-12 21:12:02
Local updater ID is 192.168.8.1 on interface Vl5 (lowest numbered VLAN interface found)

Feature VLAN:
--------------
VTP Operating Mode                : Server
Maximum VLANs supported locally   : 1005
Number of existing VLANs          : 10
Configuration Revision            : 1
MD5 digest                        : 0x87 0x1D 0xF6 0x5F 0x29 0x4F 0xA4 0x0F
                                    0x47 0xF1 0x8C 0xEE 0xFD 0xFF 0x04 0xAD

Switch#sh vtp status
VTP Version capable             : 1 to 3
VTP version running             : 1
VTP Domain Name                 : kalamazoo
VTP Pruning Mode                : Disabled
VTP Traps Generation            : Disabled
Device ID                       : 34bd.c808.4800
Configuration last modified by 192.168.8.1 at 10-9-12 21:12:02

Feature VLAN:
--------------
VTP Operating Mode                : Client
Maximum VLANs supported locally   : 255
Number of existing VLANs          : 10
Configuration Revision            : 1
MD5 digest                        : 0x87 0x1D 0xF6 0x5F 0x29 0x4F 0xA4 0x0F
                                    0x47 0xF1 0x8C 0xEE 0xFD 0xFF 0x04 0xAD
Switch#

Peter Paluch · ‎10-09-2012

Hi Brent,

Well, your problem was definitely caused solely by both switches having the revision number of 0. The VTP domain is always using the VLAN database of the switch having the highest revision number. If there are multiple switches with the same revision number but a different VLAN database (recognized by differing MD5 hashes of the database), VTP does nothing because it does not know which switch is the authoritative source of information.

You simply needed to make one switch have a higher revision than the other, and the other would then gladly replace the VLAN database - which is exactly what you saw. Configuring an IP domain-name entry is, to my experience, irrevelant.

Nevertheless, I am glad you got it working. Take care!

Best regards,

Peter