OSPF and RIP Advanced Routing Services

In addition to Policy-based Routing and RIP advertising, SonicOS offers the option of enabling Advanced Routing Services (ARS). Advanced Routing Services provides full advertising and listening support for the Routing Information Protocol (RIPv1 - RFC1058) and (RIPv2 - RFC2453), and Open Shortest Path First (OSPFv2 – RFC2328). Advanced Routing Service should only be enabled by those environments requiring support for either or both of these dynamic routing protocols.

RIP and OSPF are Interior Gateway Protocols (IGP) that are both widely used by networks of various sizes to automate the process of route distribution. RIP is commonly used within smaller networks, while OSPF is used by larger networks, although network size should not be the only factor used to determine the appropriateness of one protocol over the other – network speed, interoperability requirements, and relative overall complexity, for example, should also be considered. RIPv1 and RIPv2 are both supported by ARS, the largest differences between the two being that RIPv2 supports VLSM (Variable Length Subnet Masks), authentication, and routing updates. Routing Information Protocol Differences illustrates the major differences between RIPv1, RIPv2, and OSPFv2/OSPFv3:

Routing Information Protocol Differences

	RIPv1	RIPv2	OSPFv2/OSPFv3
Protocol metrics	Distance Vector	Distance Vector	Link State
Maximum Hops	15	15	Unlimited
Routing table updates	Full table broadcast periodically, slower convergence	Full table broadcast or multicast periodically, slower convergence	Link state advertisement multicasts, triggered by changes, fast convergence
Subnet Sizes Supported	Only class-based (a/b/c) subnets support	Class-based only	VLSM
Autonomous system topology	Indivisible and flat	Indivisible and flat	Area-based, allowing for segmentation and aggregation

 

• About Routing Services

• OSPF Terms