EIGRP vs OSPF
IP Networking NT2640
Travis McCaig
05/07/16
Mr. M. G. Durazo Ed.
EIGRP vs OSPF In this paper we will explore and compare EIGRP and OSPF protocols to determine if one might be better suited to a particular network. First I’ll explore their positive or negative features individually. Then I’ll do a more side-by-side comparison to see if there are more noticeable differences. Finally, I’ll make an informed decision on which protocol to choose based on network’s size, topology and more.
EIGRP
Enhanced Interior Gateway Routing Protocol or (EIGRP) is a protocol that lets routers exchange a copy of its neighbors routing tables. These tables are updated each time a new router comes online and EIGRP can detect changes in routes. It can do this marvelous feat by periodically sending a “hello” packet, that essentially responds an active or inactive result. If a router isn’t available EIGRP changes the route as well as updates the other neighboring routers. Finally, this protocol can consider distance and determine if a path is loop-free thereby determining most efficient route.
OSPF
Open Shortest Path First also called OSPF is a protocol that like EIGRP can exchange routing tables with neighbors with an added bonus. The bonus is that it creates a complete map of all networks and this is dubbed an Autonomous System or AS. This complete picture of the AS is also copied and shared but the advantage lies in the ability to manually manipulate routes for traffic engineering or quality of service requirements. New updates in OSPFv3 include support for IPv6 and protocol processing per-link not per-subnet, making it faster than previous versions. Version three also provides support for multiple instances of OSPF per link as well as removal of opaque LSA’s. If that wasn’t enough they also streamlined the packet format by removing unnecessary addressing semantics.
Comparison It appears that OSPF wins by popularity (it is open source), scalability, speed and support for new technology (IPv6 is fast). Although in today’s environment a smaller network may still want to use EIGRP for its ease of use and stability. Now if your network is expanding and you do need to upgrade to OSPF, there is a way to migrate safely.
Migrating from EIGRP to OSPF Here are some rules to follow which will help keep you from breaking the network when upgrading this protocol stack.
1) Design the OSPF network, like how to divide the areas, what’s the routing policy.
2) Configure OSPF routing protocol on the EIGRP network, make the precedence of OSPF lower than precedence of EIGRP, then put the interfaces into OSPF areas.
3) Complete the configuration followed the second step, because the precedence of EIGRP is higher than OSPF, so only the EIGRP learned routes show up on routing table, OSPF learned routes do not show up on the routing table. So OSPF does not work at this time around.
4) After making sure everything is fine, changes the precedence of EIGRP and OSPF, and makes the precedence of EIGRP lower than OSPF. Because the precedence of OSPF is higher than EIGRP, so the routing table change to OSPF learned routes, EIGRP learned route will disappear, and OSPF will be the working routing protocol.
5) After having made sure the OSPF routing table is perfect, we can delete the EIGRP configuration, and change the precedence of OSPF back to default value. After have done that, the migration is completed.
Conclusion
Choose the protocol that’s right for your network based on size and future needs. If your network is growing, then you can just change from EIGRP to OSPF with confidence. By following the migration steps I provided you can prevent breaking the network and safely revert back to EIGRP if there is a problem.
References
ROUTING PROTOCOL CHOICE OSPF VS EIGRP. (n.d.). Retrieved May 14, 2016, from http://www.h3c.com.hk/products___solutions/products/other_products/routers/quidway_ar18-2x_series_routers/white_paper/200701/194231_57_0.htm#_Toc87242185
What is EIGRP (Enhanced Interior Gateway Routing Protocol)? - Definition from WhatIs.com. (n.d.). Retrieved May 14, 2016, from http://searchnetworking.techtarget.com/definition/EIGRP
What is Open Shortest Path First (OSPF)? (n.d.). Retrieved May 14, 2016, from http://www.metaswitch.com/resources/what-is-open-shortest-path-first-ospf 