Classless Routing Protocols — Identify the True Statements Evaluate the following statements about classless routing protocols: The use of discontiguous networks is not allowed. The use of variable-length subnet masks (VLSM) is permitted. RIPv1 is a classless routing protocol. IGRP supports classless routing within the same autonomous system. RIPv2 supports classless routing. Which combination is correct?

Introduction / Context:
Classless routing protocols carry subnet mask information with each route and support VLSM and discontiguous network designs. Recognizing which protocols are classless helps with address planning and summarization strategies.

Given Data / Assumptions:

• RIPv1 and IGRP are classful and do not include masks in updates.
• RIPv2, EIGRP, OSPF, and IS-IS are classless and include masks.
• VLSM requires classless behavior to function across the network.

Concept / Approach:
Statement 2 is true: classless protocols permit VLSM. Statement 5 is true: RIPv2 is classless and includes mask information in its updates, enabling VLSM and summarization. Statements 1, 3, and 4 are false: classless protocols do allow discontiguous networks, RIPv1 is classful, and IGRP is classful (EIGRP is classless, but the statement cites IGRP).

Step-by-Step Solution:
Mark VLSM permitted (2) as true.Mark RIPv2 classless (5) as true.Mark the rest as false based on classful/classless definitions.Select the combination “2 and 5.”

Verification / Alternative check:
Protocol references confirm that only classless protocols carry masks and support VLSM; lab tests with RIPv1 show mask loss across classful boundaries leading to failures.

Why Other Options Are Wrong:

• A/B/E: Include false assertions about classless capability or wrongly label classful protocols as classless.

Common Pitfalls:
Confusing IGRP (classful) with EIGRP (classless) due to the similar names; always check the “E”.

Final Answer:
2 and 5