VLAN Trunking Protocol (VTP)

VLAN Trunking Protocol (VTP)

  • Cisco Propietary

VTP Domain

  • to exchange information, switches must belong to teh same Domain
  • a Switch can only be  a member of one Management Domain
  • Domain Names are upto 32 Characters
  • Modes:
       * Server; Can add, remove or modify
       * Client; Cannot add, remove or modify
                         listens to advertisments originated by server, installs and passes on

       * Transparent; separate VTP database from the rest of Domain
                                      does not originate advertisments
                                      transparently passes on recieved avertisments without installing
                                      needed for some applications like Private VLANs

VTP message types:
summary advertisement; to make sure every switch is in sync, sent every 300  secs in the management VLAN,
subset advertisement, generated in responce to a request, and contains detailed VLAN configuration information
Request advertisement, to acquire VLAN information


(config)#vtp mode server
(config)#vtp password CISCO01
(config)#vtp domain CISCO


SW01#sh vtp status
VTP Version                     : running VTP2
Configuration Revision          : 89
Maximum VLANs supported locally : 1005
Number of existing VLANs        : 38
VTP Operating Mode              : Server
VTP Domain Name                 : CISCO

VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Enabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0×54 0×86 0×7C 0×5E 0xEE 0×50 0×8F 0xBC
Configuration last modified by at 3-4-93 04:25:36
Local updater ID is on interface Vl99 (preferred interface)
Preferred interface name is vlan99

SW01#sh vtp counters
VTP statistics:
Summary advertisements received    : 88949
Subset advertisements received     : 4
Request advertisements received    : 12
Summary advertisements transmitted : 88841
Subset advertisements transmitted  : 12
Request advertisements transmitted : 0
Number of config revision errors   : 0
Number of config digest errors     : 0
Number of V1 summary errors        : 3
VTP pruning statistics:

Trunk            Join Transmitted Join Received    Summary advts received from
                                                   non-pruning-capable device
—————- —————- —————- —————————
Gi1/0/1             0                0                0       
Gi1/0/2             0                0                0       
Gi1/0/3             0                0                0       
Gi1/0/4             0                0                0       
Gi1/0/6             0                0                0       
Gi1/0/7             0                0                0       
Gi1/0/8             0                0                0       
Gi1/0/9             0                0                0       
Gi1/0/10            0                0                0       
Gi1/0/11            0                0                0       
Gi1/0/12            0                0                0       
Gi2/0/25            0                0                0    

VTP Pruning
Broadcasts and unknown unicasts/ multicast frames are flodded everywhere in the broadcast domain. By Default a trunk link transports traffic from all VLANs unless specific VLANs are removed from the trunk. the following command when enabled on teh server will enable pruning for the entire management domain:

SW01(config)#vtp pruning


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