Work ordered the trainsignal CCNP bundle i have been nagging them about :o)
So lets get started:

TRAINSIGNAL

Lecture 1 - Routing fundamentals

Lets start with a quick recap of RIP



RIP v1
Broadcasts every 30 seconds
Classful, does not recognise VLSM, update carries FULL routing table
Equal-cost load sharing by default
Max hop count 15
No routing authentication
Uses Bellman-Ford algorithm
updates carry 25 routes MAX


RIP v2
Multicast every 30 seconds to 224.0.0.9
Classless, Supports VLSM, update carries FULL routing table
Equal-cost load sharing by default
Max hop count 15
Supports routing authentication (clear text & MD5)
Uses Bellman-Ford algorithm
updates carry 25 routes MAX



In a larger network, another problem arises. RIP routing updates can hold a max of 25 routes, so if there are 105 routes in your, network, that is 5 update packets would be needed! since they go out every 30 secs, whether anything had actually changed in the network, RIP is generally a poor choice for a WAN protocol!

Another reason you dont see DV (Distance Vector) protocols used on WANs very often is their method of determining the best path.  Both versions of RIP only understand hop count .... On a LAN this hop count is not too much of an issue, but RIPs limiatations quickly become a problem on a WAN

RIP see's these as all equal links and will begin equal-cost load balancing over them ..... :0(, not good for todays delay sensitive networks!

EIGRP

Multicasts to 224.0.0.10
Sends entire routing table only when the adjacency is first formed
Sends only routing update after that when necessary, update reflects only the changes
Uses DUAL routing algorithm
Equal-cost load sharing by default, unequal-cost load sharinh configured with the variance command

Recap of AD Values:

Directly Connected route / Static route: 0
Static route with next-hop IP address: 1
EIGRP-Summary: 5
External BGP: 20
Internal EIGRP: 90
OSPF: 110
RIP: 120
External EIGRP: 170
Internal BGP: 200
unknown network: 255