robust internet connection 1/2
Until recently, my overkill home network had two routers with DSL cards in them. An 877W and a 2621XM with a WIC-1ADSL.
The 870 served as the outside router, providing an Internet connection via aDSL to my ISP. I have OSPF running between the two routers, including default route distribution (default-information originate) from the outside router, informing other routers about an Internet access path.
The 870 served as the outside router, providing an Internet connection via aDSL to my ISP. I have OSPF running between the two routers, including default route distribution (default-information originate) from the outside router, informing other routers about an Internet access path.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhcQR-32eg1gKu55Qo4asWgoPvb4f4vfTuYsI-PUVzdlDpIjbqxoCybcTBNtApIN6maxa_OC7AoFYxEvD9F1VYI8ZJ8IbuICg2_HEFkw0s5jimiEWDVm-jqDEV1ANySGjqgRoqBA/s640/r1.png)
Typical setup. Cisco 877W is Internet gateway and responsible for NAT. Traffic is routed via 2621XM.
As I was fiddling with routing protocols and had multiple DSL cards, one question came up: could I have such a setup that if I swap my DSL cable from one router to the other, the user network can keep accessing the Internet without having to configure/reconfigure anything?
I thought so, and I can! What's required?
- A routing protocol to update the routing tables of both routers if such a change would happen. done: OSPF. But now the core router would also have a default route to distribute should it become the Internet uplink (so default-information originate on it too);
- Redundant NAT configurations, so both routers perform address translation in the same way: can do;
So after a little while, I got it going. Sadly, the WIC-1ADSL is far far from being as good as the 877W's DSL chipset, so Internet performance suffers a good bit. However, the exercise here is technological and it is about redundancy and/or robustness (albeit partially manual, as I have to switch the cable between routers).
... to be continued.
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