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Two sites, two switches, and issue setting up RIP

Two sites, two switches, and issue setting up RIP

Stephen_Stormon
Contributor
We have two sites with two Summit switches at each. We had a MPLS connection between the two sites and have since added a direct point to point (P2P) connection between the two locations. What we want to do it to configure the network so that all traffic between these sites will default to using the P2P connection and fail over to the MPLS is necessary. We don't believe our license allows for the use of OSPF, so we decided to attempt to implement RIP. We configured RIP to only export "direct routes". Things seem to be going well, but there is a route in each site that for some reason will not become the default and we don't know why:

Related routes at one end (172.22.16.5 is the MPLS router at the site and 172.19.1.1 is the P2P address at the far end of the P2P)
Ori Destination Gateway Mtr Flags VLAN Duration
#s 172.22.62.0/20 172.22.16.5 2 UG---S-um--f- Internal_Appliances 0d:0h:40m:13s
r 172.22.62.0/20 172.19.1.1 2 UG-D---um---- P2P_Express 0d:1h:56m:37s
#s 201.133.58.0/24 172.22.16.5 1 UG---S-um--f- Internal_Appliances 0d:2h:3m:4s
#r 201.133.58.64/26 172.19.1.1 2 UG-D---um--f- P2P_Express 0d:1h:56m:37s

Related routes at the other end (172.22.62.3 is the MPLS router at the site and 172.19.1.14 is the P2P address at the far end of the P2P):
Ori Destination Gateway Mtr Flags VLAN Duration
#s 144.202.234.0/24 172.22.62.3 1 UG---S-um--f- Default 775d:17h:39m:55s
#r 144.202.234.128/25 172.19.1.14 2 UG-D---um--f- P2P_Express 0d:2h:9m:37s
#s 172.22.16.0/20 172.22.62.3 1 UG---S-um--f- Default 0d:1h:55m:38s
r 172.22.16.0/20 172.19.1.14 2 UG-D---um---- P2P_Express 0d:2h:9m:38s
Why is it that the one route acquired by rip became the "Preferred unicast and multicast route" but the other one did not? Is the issue because there is already a statically defined route for that network and static routes take precedence over RIP imported routes?
12 REPLIES 12

Stephen_Stormon
Contributor
So we should not expect to see all routes in the table at once, correct? For instance, using your example, we shouldn't expect to see one entry for a learned RIP route that is preferred and another RIP route waiting in standby?

#r 10.1.0.0/24 192.168.2.1 2 UG-D---um--f- l2 0d:0h:0m:1s
r 10.1.0.0/24 192.168.1.1 3 UG-D---um--f- l1 0d:0h:0m:58s

If we shouldn't see anything like that via "show iproute", should we at least see all of the RIP routes (active or not) when issuing "show rip routes"?

dflouret
Extreme Employee
When you remove the static route you should only see the preferred route. If that preferred route disappears, the secondary route will appear in the routing table.

An example:
Preferred route available
lab9.sw0.2 # sh ipr
Ori Destination Gateway Mtr Flags VLAN Duration
#d 10.0.0.0/24 10.0.0.1 1 U------um--f- r0 0d:0h:2m:29s
#r 10.1.0.0/24 192.168.2.1 2 UG-D---um--f- l2 0d:0h:0m:1s
#d 192.168.1.0/24 192.168.1.2 1 U------um--f- l1 0d:0h:2m:29s
#d 192.168.2.0/24 192.168.2.2 1 U------um--f- l2 0d:0h:2m:29s
Preferred route not available
lab9.sw0.2 # sh ipr
Ori Destination Gateway Mtr Flags VLAN Duration
#d 10.0.0.0/24 10.0.0.1 1 U------um--f- r0 0d:0h:2m:25s
#r 10.1.0.0/24 192.168.1.1 3 UG-D---um--f- l1 0d:0h:0m:58s
#d 192.168.1.0/24 192.168.1.2 1 U------um--f- l1 0d:0h:2m:25s
#d 192.168.2.0/24 192.168.2.2 1 U------um--f- l2 0d:0h:2m:25s

Stephen_Stormon
Contributor
And we would only need to enable RIP on the VLAN connected to the MPLS link and the one connected to the P2P, correct?

If that is the case and I have enabled RIP on those two VLANs, then when I remove the static route listed below, the RIP one should take over and then a new one will also appear that will basically take the place of the existing static but it will be a RIP advertised one?

#s 172.22.62.0/20 172.22.16.5 3 UG---S-um--f- Internal_Appliances 0d:0h:7m:9s
r 172.22.62.0/20 172.19.1.1 2 UG-D---um---- P2P_Express 0d:4h:39m:8s


dflouret
Extreme Employee
Stephen,

You have two vlans through which the networks can be reached: the one that connects to MPLS and the one that connects to P2P. Why don't you simply enable RIP in both of them and forget about static routes?

RIP lets you change the cost of routes received through a vlan with the command:
configure rip vlan [vlan_name | all] cost cost
The cost you configure is added to the cost of the route. So, if your preferred route is through the P2P link, you should increase the cost of the vlan that connects to the MPLS link in both switches. Since the default cost is 1, using 2 should be enough.

GTM-P2G8KFN