Owner's Manual

Chapter 23. RIPng | 669

NETGEAR 8800 User Manual

RIPng Versus OSPFv3

The distinction between RIPng and the link-state protocol, OSPFv3, lies in the fundamental

differences between distance-vector protocols (RIPng) and link-state protocols. Using a

distance-vector protocol, each router creates a unique routing table from summarized

information obtained from neighboring routers. Using a link-state protocol, every router

maintains an identical routing table created from information obtained from all routers in the

autonomous system (AS). Each router builds a shortest path tree, using itself as the root. The

link-state protocol ensures that updates sent to neighboring routers are acknowledged by the

neighbors, verifying that all routers have a consistent network map.

Advantages of RIPng and OSPFv3

The biggest advantage of using RIPng is that it is relatively simple to understand and to

implement, and it has been the de facto routing standard for many years.

RIPng has a number of limitations that can cause problems in large networks, including the

following:

• A limit of 15 hops between the source and destination networks

• A large amount of bandwidth taken up by periodic broadcasts of the entire routing table

• Slow convergence

• Routing decisions based on hop count; no concept of link costs or delay

• Flat networks; no concept of areas or boundaries

OSPFv3 offers many advantages over RIPng, including the following:

• No limitation on hop count

• Route updates multicast only when changes occur

• Faster convergence

• Support for load balancing to multiple routers based on the actual cost of the link

• Support for hierarchical topologies where the network is divided into areas

The details of RIPng are explained later in this chapter.

Overview of RIPng

RIPng is primarily intended for use in homogeneous networks of moderate size.

To determine the best path to a distant network, a router using RIPng always selects the path

that has the least number of hops. Each router that data must traverse is considered to be

one hop.