TMS zl Management and Configuration Guide ST.1.1.100226

9-15
Routing
RIP
RIP
RIP is a well-known and commonly used distance-vector routing protocol. RIP
is simple to configure but can be slow to converge.
Because route selection relies purely on hop count, RIP may not always
generate the best routes. For example, WANs usually include links of varying
bandwidth, so the lowest hop count is not always the fastest or best route.
RIP Overview
Read this section if you are interested in learning more about how RIP
functions on the TMS zl Module. If you are interested only in setting up RIP
on your module, move to “RIP Configuration” on page 9-19.
RIP Process
On the TMS zl Module, RIP interfaces transmit:
■ All RIP routes
■ All routes manually redistributed into RIP, which can include OSPF and
static routes as well as routes to connected networks (VLANs that exist
on the module)
Note By default, the TMS zl Module does not redistribute any routes, including
connected routes.
Each route includes a metric that specifies how many hops the advertising
interface is from the destination.
When the module receives a route that it does not know from a neighbor, it
adds the route to its routing table. The source of the update becomes the next-
hop address for the destination, and the metric is the advertised metric plus
one. That is, because the module is one hop from the source of the update, the
module is one more hop from the destination. After the module adds the route
to its table, it can advertise this route itself, with the incremented metric.
The module will change entries in its routing table for several reasons:
■ The neighbor listed as the next-hop address changes the metric for the
route. The module then changes the metric for the route in its own table
to the new metric plus one.