10G Core Routing Switch User Manual
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switchC(config-if)#
exit
# Setting static route for switch C
switchC(config)#
ip route 1.1.1.0 255.255.255.0 1.1.2.1
switchC(config)#
ip route 1.1.4.0 255.255.255.0 1.1.3.2
Static Route Fault Diagnosis and Troubleshooting
By default the Switch is not configured with the dynamic routing protocol and both the physical status and the link
layer protocol status of the interface is UP, but the IP packets cannot be forwarded normally.
Troubleshooting:
Use the
show ip route
command to view whether the corresponding static route is correctly configured.
Use the
show ip route
command to view whether the corresponding route is valid.
RIP Configuration
Brief Introduction to RIP
Routing Information Protocol (RIP) is a relatively simple dynamic routing protocol, but it has a wide application. RIP is a
kind of Distance-Vector (D-V) algorithm-based protocol and exchanges routing information via UDP packets. It employs
Hop Count to measure the distance to the destination host, which is called Routing Cost. In RIP, the hop count from a
router to its directly connected network is 0, and that to a network which can be reached through another router is 1,
and so on. To restrict the time to converge, RIP prescribes that the cost value is an integer ranging 0 and 15. The hop
count equal to or exceeding 16 is defined as infinite, that is to say, the destination network or the host is unreachable.
RIP sends routing refreshing message every 30 seconds. If no routing refreshing message is received from one network
neighbor in 180 seconds, RIP will tag all routes of the network neighbor to be unreachable. If no routing refreshing
message is received from one network neighbor in 300 seconds, RIP will finally remove the routes of the network
neighbor from the routing table. To improve the performances and avoid route loop, RIP supports Split Horizon, Poison
Reverse and allows importing the routes discovered by other routing protocols Each router running RIP manages a
route database, which contains routing entries to all the reachable destinations in the network. These routing entries
contain the following information:
Destination address: IP address of a host or network.
Next hop address: The address of the next router that an IP packet will pass through for reaching the destination.
Output interface: The interface through which the IP packet should be forwarded.
Cost: The cost for the router to reach the destination, which should be an integer in the range of 0 to 16.
Timer: Duration from the last time that the routing entry is modified till now. The timer is reset to 0 whenever a
routing entry is modified.
Route tag: Discriminate whether the route is generated by an interior routing protocol or by an exterior routing
protocol.
The whole process of RIP startup and running can be described as follows:
1) If RIP is enabled on a router for the first time, the router will broadcast or multicast the request packet to the
adjacent routers. Upon receiving the request packet, the adjacent routers (on which, RIP should have been
enabled) respond to the request by returning the response packets containing information of their local routing
tables.
2) After receiving the response packets, the router, which has sent the request, will modify its own routing table.
3) At the same time, RIP broadcasts its routing table to the adjacent routers every 30 seconds. The adjacent routers
will maintain their own routing table after receiving the packets and will select an optimal route, and then
