If you have been living under a rock for the past few weeks you will have no doubt missed that Cisco have made the decision to make EIGRP an open* standard.
They have released an informational RFC (here) on the core workings of the protocol which means that in theory if any other manufacturers wanted they would be able to implement EIGRP into their own NOS (network operating system).
The reason for the Asterisk in the previous statement is due to the fact that whilst on the surface it may look like Cisco have drawn back the secrecy shroud from the previously exclusive protocol they have in-fact only revealed the workings of the basics.
What this means is that Cisco have decided to keep some of the EIGRP special use cases a secret; these include things such as stub networks and DMVPN.
So when can we expect other manufacturers to pick up and start supporting EIGRP? I shouldn’t think it will be anytime soon but I guess we will just have to wait and see.
Why would other people want to use EIGRP I hear you say? Think of it this way, at the moment in open standards we have RIP, OSPF and BGP (yes, IS-IS as well) which means there is a gap that EIGRP fills pretty well.
EIGRP is less complicated than OSPF to set up and scales far better with large topologies (in its default setup anyway) and yet offers far more granularity and control than RIP.
In my day-to-day I can say that the only times I have ever had to come into contact with EIGRP is on the CE’s peering with the customer but even then it is extremely rare, perhaps this will all change, I guess we will just have to wait and find out…