EIGRP Concepts

Charter 6 of CCNP route EIGRP








We need to ask our self these questions:

So, let's answer some questions:

Why should you consider EIGRP

1. Back Route
2. Simple configuration
3. Flexibility and Summarization
4. Unequal cost balance
5. Combine the best of distance vector and link state (limited routing information but backup path)

Remember that EIGRP is a Distance Vector Routing protocol  that keeps a track of the whole route map protocol

That's difference between OSPF that it's a link vector protocol

EIGRP doesn't need a lot of calculation to get a backup route like ospf:that's why ospf is slower, because it got so much data to converge to..

If you got a router in your network that you want to reach, , EIGRP will know which one is the best path or link, without maintaining the whole topology og the network
It will only maintain the successor and the feasible successor of the current connected link .
Everything else, you don't need it!

EIGRP Tables and terminology

 

 

EIGRP terminology

1. Feasible distance  (FD)
2. Advertize distance (AD)
3. Successor 
4. Feasible successor 
5. Active route( no good active looking  a back up route)
6. Passive route (good)

Dual is the algorithmic to pick the best route

 Remember this:

To be consider a a Feasible successor, the AD must be less than the FD of the successor

 

 

 

 

 Hello is a multicast message that  goes to 224.0.0.10  , only  to EIGRP routers.If it doest have a contact it marks the routes as active

EIGRP it's its own lawyer 4 protocol, it doesn't use tcp or UDP to acknowledge but ACK .

 

 

 

 

 

 

We need to ask these questions as well