OSPF vs EIGRP

What is the different between OSPF & EIGRP? Currently i'm using OSPF but quite difficult to manage & understand the behavior.

Refer the diagram below.



1- If i'm using OSPF routing protocol, which link will the pc1 choose to access the webserver?

2- 1- If i'm using EIGRP routing protocol, which link will the pc1 choose to access the webserver?

My first question is are all these devices cisco hardware? If not you can not use EIGRP since it is cisco proprietary. Next the path that will be taken is dependent on how you configure the routing protocol you pick. Also OSPF is a link state routing protocol and EIGRP is a distance vector protocol which both have pros and cons. There is a little more information needed to answer your question about the routing protocol to use like what does your total network look like and are you running all cisco gear or mixed gear along with what is your private ip address scheme for your vlans?

1- My existing network using mix equipment. We have cisco, 3com and nortel equipment. We are using OSPF as routing protocol. So how will the packet flow in the network?

2- We are planning to upgrade all the equipment using Cisco solution. So what is the best routing protocol?

EIGRP is cisco proprietary. So it is supported only by cisco devices. To use it you have to make sure all your layer 3 (routing) devices are cisco. Otherwise, OSPF should be used.

Back to your questions, If I'm not mistaken, both EIGRP and OSPF will choose the path that passes through "Core Switch 2" given that they are configured correctly. And given that the 10Gbps SM link is not disabled by STP or any thing. Since OSPF uses shortest path routing with link costs (10GBps costs less). And EIGRP also calculates routing metrics according to link "cost + delay" by default. They will probably both choose the same "Core Switch 2" path since hop count in both paths is the same. Thats as far as I know.

Note: check the "bandwidth" command.

That meant OSPF will choose the higher bandwidth link is it?

If not mistaken, OSPF also will do the load balancing between the link. So is it possible both link will be choose to transfer the data?

If you are gonna go all Cisco, can I suggest ISIS. Converges much faster, support for MPLS TE, uses some of the same metric as other link state protocols.