20
Configuring RIP
Hardware compatibility
The A5500 SI Switch Series does not support VPN and BFD related parameters or FRR.
Overview
Routing Information Protocol (RIP) is a distance-vector interior gateway protocol suited to small-sized
networks. It employs UDP to exchange route information through port 520.
The term "router" in this chapter refers to both routers and Layer 3 switches.
RIP route entries
RIP stores routing entries in a database. Each routing entry contains the following elements:
•
Destination address
—IP address of a destination host or a network.
•
Next hop
—IP address of the next hop.
•
Egress interface
—Egress interface of the route.
•
Metric
—Cost from the local router to the destination. RIP uses a hop count to measure the distance
to a destination. The hop count from a router to a directly connected network is 0. The hop count
from a router to a directly connected router is 1. To limit convergence time, RIP restricts the metric
range from 0 to 15. A destination with a metric value of 16 (or greater) is considered unreachable.
For this reason, RIP is not suitable for large-sized networks.
•
Route time
—Time elapsed since the last update. The time is reset to 0 every time the routing entry
is updated.
•
Route tag
—Used for route control. For more information, see "
RIP timers
RIP employs the following timers:
•
Update timer
—Specifies the interval between routing updates.
•
Timeout timer
—Specifies the route aging time. If no update for a route is received within the aging
time, the metric of the route is set to 16.
•
Suppress timer
—Specifies how long a RIP route stays in suppressed state. When the metric of a
route is 16, the route enters the suppressed state. A suppressed route can be replaced by an
updated route that is received from the same neighbor before the suppress timer expires and has a
metric less than 16.
•
Garbage-collect timer
—Specifies the interval from when the metric of a route becomes 16 to when
it is deleted from the routing table. RIP advertises the route with a metric of 16. If no update is
announced for that route before the garbage-collect timer expires, then the route is deleted from the
routing table.