Introduction / Context:
VLAN Trunking Protocol (VTP) allows Cisco switches to share VLAN configuration within a VTP domain. Knowing the minimal requirements for VTP to work is essential for quick deployments and troubleshooting.
Given Data / Assumptions:
- Candidate requirements include same VTP domain name, VTP server presence, encapsulation types, access-port settings, cabling, and router involvement.
Concept / Approach:
For two switches to exchange VLAN information via VTP, they must share the same VTP management domain name and at least one device in that domain must be a VTP server to originate and propagate VLAN database updates.
Step-by-Step Solution:
Requirement 2: “The VTP management domain name of both switches must be set the same.” This is mandatory. ✔Requirement 4: “One of the two switches must be configured as a VTP server.” At least one server is required to advertise VLAN changes. ✔Requirement 1: “Each end of the trunk link must be set to the IEEE 802.1e encapsulation.” Invalid; Cisco uses 802.1Q (dot1q) or ISL (legacy), not “802.1e.” ✖Requirement 3: “All ports … must be set as access ports.” Incorrect; trunk ports are needed for VTP advertisements to pass. ✖Requirement 5: “A rollover cable is required …” Not required; standard switch-to-switch cabling (typically straight-through on modern devices) is used. ✖Requirement 6: “A router must be used to forward VTP traffic …” VTP is Layer 2 and does not require a router within the same domain. ✖
Verification / Alternative check:
Use show vtp status on both switches to confirm the same VTP domain and verify at least one device is in server mode.
Why Other Options Are Wrong:
- 1, 2 and 4: Includes item 1, which is invalid.
- 3, 5 and 6: None of these are required for VTP operation.
- 1 and 6: Both are incorrect requirements.
- 1, 2 and 6: Contains invalid items 1 and 6.
Common Pitfalls:
Forgetting to set a common VTP domain and neglecting to ensure at least one VTP server; confusing 802.1Q trunking with nonexistent “802.1e.”
Final Answer:
2 and 4
Discussion & Comments