Lab Objective
Configure a switch in VTP transparent mode between an existing VTP server and client, verify it does not apply server-originated VLAN changes to its own database, but still forwards those advertisements onward, and confirm it can independently create its own local VLANs.
Lab Purpose
Transparent mode is often misunderstood: a transparent switch behaves like neither a server nor a client for its own VLAN database, yet it still relays VTP advertisements between other switches physically connected through it. Understanding this dual behavior is essential to correctly diagnosing why a VLAN appears on some switches but not others in a VTP domain.
Lab Topology
SwitchServer ---- SwitchTransparent ---- SwitchClient
All three switches connected via trunk links,
all in VTP domain CorpNet (SwitchServer and
SwitchClient already configured from the
previous lab)Task 1: Configure Transparent Mode
On the middle switch, join the same VTP domain and explicitly set VTP mode to transparent.
Task 2: Create a VLAN on the Server
On SwitchServer, create VLAN 40 named Sales.
Task 3: Verify the Transparent Switch Does Not Apply the VLAN Locally
Check SwitchTransparent's own VLAN database and confirm VLAN 40 is NOT automatically added there.
Task 4: Verify the VLAN Still Reaches the Client
Check SwitchClient's VLAN database and confirm VLAN 40 DID successfully propagate through the transparent switch to reach it.
Task 5: Create a Local VLAN on the Transparent Switch
Create VLAN 50 named LocalOnly directly on SwitchTransparent, and confirm it does NOT appear on either SwitchServer or SwitchClient.
Solution and Verification
SwitchTransparent(config)# vtp domain CorpNet
SwitchTransparent(config)# vtp mode transparent
Setting device to VTP TRANSPARENT modeSwitchServer(config)# vlan 40
SwitchServer(config-vlan)# name Sales
SwitchServer(config-vlan)# exitSwitchTransparent# show vlan brief
VLAN Name Status Ports
---- ---------- --------- -----
1 default active
-- VLAN 40 is absent here -- a transparent
-- switch never applies received VTP changes
-- to its own local databaseSwitchClient# show vlan brief
VLAN Name Status Ports
---- ---------- --------- -----
30 Engineering active
40 Sales active
-- Yet VLAN 40 successfully reached the client,
-- confirming SwitchTransparent forwarded the
-- advertisement onward without applying it locallySwitchTransparent(config)# vlan 50
SwitchTransparent(config-vlan)# name LocalOnly
SwitchTransparent(config-vlan)# exit
SwitchServer# show vlan brief | include 50
-- (no output -- VLAN 50 never appears)
SwitchClient# show vlan brief | include 50
-- (no output -- VLAN 50 never appears)Key Takeaway
A transparent-mode switch is functionally split in two: it acts purely as a pass-through relay for VTP advertisements originating elsewhere in the domain, while simultaneously maintaining a completely independent, locally managed VLAN database that neither sends updates to nor receives updates from any other switch — VLANs created on it stay strictly local, and VLANs created elsewhere pass through it but never take effect on it.