Redundant Internet Connections in two cities 1

[hrwilliams99]

Internet---R1---R2----------------------R3---R4---Internet

Simplified Setup:
R1 and R2 are routers in City A.
R3 and R4 are routers in City B.
Users are in subnet off of routers R2 and R3.

My question: How can I set up the routers to allow users in CityA to be automatically routed to the Internet thru CityB if the Internet connection for CityA is down?

 

[dk87]

You should supply more info on your connections, re:NAT/PAT or dual ethernet interfaces, etc. I will assume for now...

Set up secondary routes in each router. For example:

R1 has an IP address of 192.168.1.1
R2 has an IP address of 192.168.2.1
R3 has an IP address of 192.168.3.1
R4 has an IP address of 192.168.4.1

R2:
ip route 0.0.0.0 0.0.0.0 192.168.1.1
ip route 0.0.0.0 0.0.0.0 192.168.4.1 500

R3
ip route 0.0.0.0 0.0.0.0 192.168.4.1
ip route 0.0.0.0 0.0.0.0 192.168.1.1 500

If you post some more info, it might be easier...

 

[hrwilliams99]

Thanks dk87 for your reply!

Maybe it is that simple! That would be great!

Using your example, if R1 is up, but its connection to the Internet is down, will R2 still use the default route to 192.168.1.1 or will it be able to determine that it can't make it to its final destination and then attempt the secondary route to 192.168.4.1?

Thanks for your reply.

 

[dk87]

It will try to route the traffic. If R1 is up but the connection is down, the traffic will not route and be sent to R4. If you notice, I placed a metric of 500 on your secondary routes. Depending on your actual network config, you may need to tweak that to keep performance optimal.

 

[hrwilliams99]

Thanks!

I am just in the process of ordering the second internet connection, so I will try that when I get to that point.

 

[Liaquat]

You should look into setting up HSRP for your routers, which is the recommended solution for redundant connectivity.
Only relying on static routes or other would not accomplish what you are looking for as there is no WAIT mechanism to decide whether this line is down, without using HSRP.

 

[chrismccatgmail]

hrwilliams99 stated:
> Maybe it is that simple! That would be great!


hrwilliams99 stated:
>I am just in the process of ordering the second internet connection, so I will try that when I get to that point.


Your original post didn't include the Internet in between the two cities. vastly different scenerios.

 

[hrwilliams99]

Our current setup is ...

Internet---R1---R2----------------------R3
with a frame connection between R2 and R3, so CityB is using the internet from CityA.

I am just trying to figure out how I could provide redundancy for CityA by setting up another internet connection in CityB.

If I can do it with secondary routes, then great!
If I need to investigate HSRP, which I know nothing about, then I'll start looking into that.

Thanks for the feedback!