You are a network administrator and you need to implement a routing protocol on your network that provides:

* Scalability
* VLSM support
* Minimal overhead
* Support for connecting networks using routers of multiple vendors

Which of the following routing protocol would best serve your needs?

A. VTP
B. RIP version 1
C. EIGRP
D. OSPF
E. IGRP
F. CDP

Answer: D

Explanation:
Since one of the requirements is that the routing protocol must support other vendors, our only choices are RIP and OSPF. Since RIP version 1 does not support VLSM, OSPF is the only choice.

Incorrect Answers:
A. VTP is the VLAN Trunking Protocol. This is not a routing protocol.
B. RIP version one does not support VLSM. Note that RIPv2 does support VLSM, and would be a valid choice.
C, E. EIGRP and IGRP are Cisco proprietary routing protocols, and are not supported by other vendors.
F. CDP is the Cisco Discovery Protocol, which is used to exchange information between Cisco devices. It can only be used between Cisco routers and switches, and it is not a routing protocol.