404
Besides the above mentioned, RIP protocol allows route information discovered by
the other routing protocols to be introduced to the route table. It can also be as the
protocol exchanging route messages with CE on PE routers, and supports the VPN
route/transmitting examples.
The operation of RIP protocol is shown below:
Enable RIP. The switch sends request packets to the neighbor layer3 switches by
broadcasting; on receiving the request, the neighbor devices reply with the packets
containing their local routing information.
The Layer3 switch modifies its local route table on receiving the reply packets and
sends triggered update packets to the neighbor devices to advertise route update
information. On receiving the triggered update package, the neighbor lay3 switches send
triggered update packages to their neighbor lay3 switches. After a sequence of triggered
update package broadcast, all layer3 switches get and maintain the latest route
information.
In addition, RIP layer3 switches will advertise its local route table to their neighbor
devices every 30 seconds. On receiving the packets, neighbor devices maintain their
local route table, select the best route and advertise the updated information to their own
neighbor devices, so that the updated routes are globally valid. Moreover, RIP uses a
timeout mechanism for outdated route, that is, if a switch does not receive regular update
packets from a neighbor within a certain interval (invalid timer interval), it considers the
route from that neighbor invalid, after holding the route fro a certain interval (holddown
timer interval), it will delete that route.
14.4.2 RIP Configuration Task List
1. Enable RIP (required)
(1) Enable/disable RIP module.
(2) Enable interface to send/receive RIP packets
2. Configure RIP protocol parameters (optional)
（
1
）
Configure RIP sending mechanism
1
）
Configure specified RIP packets transmission address
2
）
Configure RIP interface broadcast
（
2
）
Configure the RIP routing parameters
1
）
Configure route introduction (default route metric, configure routes of the other
protocols to be introduced in RIP)
2
）
Configure interface authentication mode and password
3
）
Configure the route deviation
4
）
Configure and apply route filter
5
）
Configure Split Horizon
