In RIP, what is the main difference between classful and classless updates?

• A. Classful updates carry masks; classless updates carry no masks.
• B. Classful updates do not carry subnet masks; classless updates carry subnet masks.
• C. Classful updates carry no masks; classless updates carry masks.
• D. Classful updates propagate more quickly than classless updates.

Answer: (C)

The key distinction is whether RIP updates include subnet mask information. In RIP version 1, updates do not carry subnet masks; routers must apply the default classful mask based on the destination’s IP address class, which means subnets outside the classful boundaries can’t be distinguished and VLSM isn’t supported. In RIP version 2, updates include the 32-bit subnet mask with each route, so routers know the exact subnet size and can support variable-length subnet masks and CIDR. This inclusion of the mask is why classful updates have no masks, while classless updates carry masks. The difference isn’t about speed or propagation, but about the level of subnet detail conveyed in the routing information.