Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
New Member

Network change from EIGRP to OSPF

Dear Experts,

Currently we are using EIGRP routing protocol in my network.Planning to move to OSPF.

Pls suggest me whether I can go for it and also tell me the basics on IS-IS.

6 REPLIES
Gold

Re: Network change from EIGRP to OSPF

I would ask one question before you leap--why? Why are you switching from EIGRP to OSPF?

It's not that I'm really partial to any specific protocol--they each have their strengths ans weaknesses--but I would not consider switching protocols unless I really really needed to for some specific reason.

For instance, if you're consider a really large scale hub and spoke network, then switching to EIGRP is a valid option. If you're considering switching so you can roll out MPLS/TE, then maybe OSPF or IS-IS is an option. If you're just switching because "EIGRP is dead," or "EIGRP isn't a standard," those aren't really good reasons, in my book, because support is what matters, not standards, IMHO, and EIGRP is definitely NOT dead.

If you want to roll out some sort of MPLS stuff, then I would seriously consider IS-IS instead of OSPF. If it's a matter of being able to install something other than cisco gear, then, well, nevermind..... :-) IMHO, changing routing protocols never solves the problems people think it will (I've seen exceptions, where switching actually provided the opportunity, but those tend to exceptions)--and I've switched a large number of networks in all sorts of directions. Design problems are design problems, no matter what protocol you're dealing with. Fast convergence can be had with any protocol, etc.

Anyway, just consider why you are switching before making radical changes to your network....

:-)

Russ

Hall of Fame Super Gold

Re: Network change from EIGRP to OSPF

Hi, you should be happy with the change. It does all what the proprietary protocol does, and more. Plus is generally more stable and easier to understand.

About IS-IS, when you're a very large and serious SP, consensus is, that is best choice, due to reasons too long to explain here. I do not see any other real application for it.

Gold

Re: Network change from EIGRP to OSPF

Hi, you should be happy with the change. It does all what the proprietary protocol does, and more. Plus is generally more stable and easier to understand.

Sorry to disagree, but I really must. OSPF is not more stable than EIGRP, nor is it easier to understand. As I said above, all routing protocols have their strengths and weaknesses, and it's just this type of generalization any design engineer should avoid at all costs. I've spent some 11 odd years working on really large scale networks using all three protocols--1000+ routers in most cases--and I can tell you from hard experience, and hard learned lessons, that network design is infinitely more important to network stability than the routing protocol is.

About IS-IS, when you're a very large and serious SP, consensus is, that is best choice, due to reasons too long to explain here. I do not see any other real application for it.

I'd guess about 30% of the enterprises in Europe use IS-IS. We've argued almost ceaselessy within Cisco and within the IETF for many years about which is "better," and which is "more suited" to specific networks. The answer is: All of them are better than the others, and all of them are worse than the others.

In the end, you simply cannot make generalizations like: "x is always more stable, and better, than y, and it's simpler to understand."

You'll note that the new CCDE has an equal amount of coverage for all three, EIGRP, OSPF, and IS-IS. This is because the folks on the Team that designed the certification strongly believed that anyone who's going to successfully design networks should know all the tools, and their strengths and weaknesses, rather than one tool. "When the only tool I have is a hammer, every problem looks like a nail."

Sorry to make this such a long post, but I really have fought this sort of the generalization just touches a bit of a raw nerve....

:-)

Russ

Hall of Fame Super Gold

Re: Network change from EIGRP to OSPF

Hi Russ, howdy, I remember you from my time at cisco, I was with the edge bu.

We had our share of large networks to deal with, as well.

I totally agree with almost all you say. Yet I think ospf is a better choice overall and generally is my recommendation for a general purpose protocol.

Regards!

Gold

Re: Network change from EIGRP to OSPF

Yet I think ospf is a better choice overall and generally is my recommendation for a general purpose protocol.

What reasoning would you give? Explain why you think OSPF is a better "general purpose protocol" than EIGRP or IS-IS?

:-)

Russ

Hall of Fame Super Gold

Re: Network change from EIGRP to OSPF

Hi Russ,

Those that read me contributions here, know already that except rare occasions, I'm not very verbose in presenting my arguments.

To my partial excuse, consider that in my professional activity, I have to prepare extensive analysis (that are of course very time consuming) for the clients that I do paid consulting for.

So, think about my laconic attitude as a time-saver for readers, fortunately I can say that people that valued my experience and has been willing to give my recommendations a try, very rarely came back with negative results.

All this introduction to say "why" I'm not going to present a dissertation on why I do recommends the main standard routing protocol over the proprietary one, on that background let me expand a bit more anyway.

I do not work for to cisco anymore, I've no liaison with IETF, and maintaining technological neutrality at all costs is not a objective for me, instead making things run nice and easy, definitely a is primary goal. I have to say that ospf helped in accomplishing this goal.

Finally, in light of all that, I feel that I'm entitled to my opinions for good reasons and I prefer to not going again into an old debate, that I already had many times with people a lot more knowledgeable than me. I've listened to them, then experimented myself, then deployed and delivered to happy clients. And, it wasn't even with ospf all the time :)

Best luck everyone!

190
Views
10
Helpful
6
Replies
CreatePlease to create content