Classful vs Classless Routing Protocols

Questions and Answers

What is a Classful Routing Protocol?

This does not send subnet information when sending information to other routers. A class A, B, or C network mask is assumed. Auto-summarization is required at network boundaries. Does not support VLSM.

In classful routing, what does the router do when it receives a packet?

The router auto-summarizes the destination route to the class it belongs to. If it doesn't have that class in its routing table, it will forward the packet to the default route. If it does have the summarized route in the routing table, it will look for a subnet for the classed network. If there is a match, it will forward the packet; if there is no match, it will drop that packet.

What is a Classless Routing Protocol?

This sends subnet information when sending information to other routers. Auto-summarization is not required at network boundaries. Manual summarization is supported. VLSM is supported.

In classless routing, what does the router do when it receives a packet?

The router looks at its routing table for a match to the destination address. If there is a match, it will forward the packet to that address. If there is no match, it forwards the packet to the default route. Signup and view all the answers

Enable Classless Routing command

R1(config)#ip classless Signup and view all the answers

Enable Classful Routing command

R1(config)#no ip classless Signup and view all the answers

Examples of classful routing protocols?

IGRP, RIPv1 Signup and view all the answers

Examples of classless routing protocols?

BGPv4, EIGRP, RIPv2, OSPF Signup and view all the answers

Study Notes

Classful Routing Protocols

Does not transmit subnet information to other routers.
Assumes Class A, B, or C network masks.
Requires auto-summarization at network boundaries.
Does not support Variable Length Subnet Masking (VLSM).

Classful Routing Packet Handling

Auto-summarizes destination route based on its class.
Forwards to the default route if the class is absent in the routing table.
Searches for a matching subnet within the summarized route; drops the packet if no match is found.

Classless Routing Protocols

Sends subnet information between routers, allowing for more detailed routing.
Does not require auto-summarization at network boundaries.
Supports manual summarization and allows for VLSM.

Classless Routing Packet Handling

Checks routing table for a match to the destination address.
Forwards the packet to the matched address; uses the default route if no match exists.

Configuration Commands

To enable Classless Routing:
- R1(config)#ip classless
To enable Classful Routing:
- R1(config)#no ip classless

Examples of Routing Protocols

Classful Routing Protocols: IGRP, RIPv1
Classless Routing Protocols: BGPv4, EIGRP, RIPv2, OSPF

Description

Test your understanding of classful and classless routing protocols with these flashcards. Explore the characteristics, differences, and functions of both types of protocols in networking. Perfect for students and professionals looking to deepen their knowledge in routing concepts.