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EIGRP Scalability

Which are the limitations of EIGRP?

How many maximun routes supports in each one of the platforms ?

How many AS is convenient to create in EIGRP topology?

How many routers like maximum can I have in every EIGRP SA? And in the backbone SA?

Thanks in advance


Re: EIGRP Scalability

> What are the limitations of EIGRP?

> How many maximum routes supports in each one of the platforms?

Well, there is no "hard limit," nor is there any way of knowing, even on a per platform basis. It's going to be mainly dependant on two things: processor and memory. IF you happen to be running a lot of other processor intensive things on a given router, then the maximu, number of routes the router can handle is going to be much lower. If you are running something that takes up a lot of memory, the same result is true.

I generally get nervous when I see a router with something over 5000 routes. That _doesn't_ mean, however, that you are limited to 5000 routes in a network. If you use summarization properly, you can have 10's of thousands of routes in an EIGRP network. The entire key is SUMMARIZATION. :-) The more you summarize, the bigger your network will get with fewer problems, in all routing protocols.

> How many AS is convenient to create in EIGRP topology?

One. I believe strongly, from years and years of troublesthooting melted EIGRP networks of all sorts of sizes and shapes, that if you are designing an EIGRP network with more than one AS, and redsitributing between those AS', your network is more complex than it needs to be. I've also seen this on the design side--going to one AS resovles a lot of complex design riddles in almost every network I've worked on. I've moved some rather large EIGRP netowrks from multiple AS' to a single, and the result is always a cleaner, more stable network.

Given this, I'll skip the next question. In the best EIGRP network designs, there are no "backbones" or "areas." There is one AS, with summarization at the hierarchical choke points in the network.


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