Which version of RIP supports VLSM and Classless Inter-Domain Routing (CIDR)?

RIP version 2 (RIPv2) is designed to support Variable Length Subnet Masking (VLSM) and Classless Inter-Domain Routing (CIDR). VLSM allows for more efficient use of IP address space by enabling different subnet masks for different subnets within the same network. This flexibility is particularly useful in modern networking environments where address conservation is vital.

CIDR further enhances routing efficiency by allowing for the aggregation of multiple IP addresses into a single routing entry. This capability reduces the size of routing tables, which can be especially beneficial in larger networks.

RIPv2 achieves this by using a more complex routing update format that includes additional information such as subnet masks, whereas earlier versions, like RIPv1, only supported classful routing, which does not accommodate VLSM or CIDR. Therefore, RIPv2's enhancements make it suitable for contemporary networks that require these advanced addressing methodologies.

Aside from RIPv2, other versions do not provide the support for these features. For example, RIPv1 does not support VLSM or CIDR at all, while RIPng, although it supports IPv6, does not directly relate to the requirements stated in the question regarding VLSM and CIDR in an