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JFrederick29 is correct. I think EIGRP scales up to somewhere around 50,000 networks. Therefore if you have close to 50,000 different network segments inside your company you are reaching the limit which EIGRP can handle and you need something more scalable such as IS-IS.
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JFrederick29 is correct. I think EIGRP scales up to somewhere around 50,000 networks. Therefore if you have close to 50,000 different network segments inside your company you are reaching the limit which EIGRP can handle and you need something more scalable such as IS-IS.

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HI<br />
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my question is why would I use IS-IS protol instead of ospf or eigrp. I know isp's mainly like this protocol but don't know why do they use this instead of bgp and if they use both then again why both? &nbsp;Lot's of why's<br />
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HI

my question is why would I use IS-IS protol instead of ospf or eigrp. I know isp's mainly like this protocol but don't know why do they use this instead of bgp and if they use both then again why both?  Lot's of why's



what exactly is IS-IS protocol and why is it used.

A router is a networking device that forwards data packets between computer networks. Routers perform the "traffic directing" functions on the Internet. The most familiar type of routers are home and small office cable or DSL routers that simply pass data, such as web pages, email, IM, and videos between computers and the Internet. More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, use of software-based routers has grown increasingly common.