The RIP Protocol makes horizontal segmentation valid or invalid.

Generally, a router connected to a broadcast-type IP network and a distance vector routing protocol uses a horizontal partitioning mechanism to avoid loops. Horizontal segmentation prohibits routers outside the information source interface from broadcasting route information. This usually optimizes communication between multiple routers, especially when the link is interrupted. However, for non-broadcast networks (such as frame relay and high-speed exchange data services), horizontal segmentation results are not ideal. Therefore, horizontal segmentation does not work. This applies to both IGRP and RIP.

If the interface is configured with a secondary IP address and the horizontal segmentation is valid, the update does not come from each secondary IP address. Route updates are sourced from each network number unless the horizontal segmentation is invalid. To make horizontal segmentation valid or invalid, perform the following tasks in Interface Configuration Mode:

The default horizontal split is invalid for Frame Relay and high-speed exchange data services, and is effective by any interface encapsulated by X.25 by default. Other packages are also effective by default for horizontal segmentation.

For examples of horizontal segmentation, see the examples at the end of this chapter.
Note: in short, it is not recommended to change the default status, unless you must make these changes to properly advertise the route. Note: If the horizontal segmentation on a serial interface is invalid (and the interface is attached to the group conversion network), all routers in multiple packets on the network should make the horizontal segmentation invalid.

Related Articles]

• RIP Protocol Processing

• RIP Protocol Update route table

• RIP Route Protocol Configuration