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Beginner

No of Routers in OSPF Area

Hi,

could any one please tell me ideally how many routers should be there in a single OSPF area ?

regards

Neo

6 REPLIES 6
Highlighted
Rising star

Re: No of Routers in OSPF Area

My ideal would depend upon the platform/resources available.

I have seen a 60 for Juniper M-series. I dont think similar sized Cisco should have any problems as well.

Thanks.

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Beginner

Re: No of Routers in OSPF Area

Hi,

The maximum number of routers per area depends on several factors, including the following:

What kind of area do you have?

What kind of CPU power do you have in that area?

What kind of media?

Will you be running OSPF in NBMA mode?

Is your NBMA network meshed?

Do you have a lot of external LSAs in the network?

Are other areas well summarized?

For this reason, it's difficult to specify a maximum number of routers per area. Consult your local sales or system engineer for specific network design help.

As per the Self-Study book, the optimal number of routers per area varies based on factors like network stability, but Cisco recommends no more than 50-100 routers per area.

Pls do rate all helpful posts.

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Beginner

Re: No of Routers in OSPF Area

Hi ,

There is huge difference between 50 routers or 100 routers

regards

Neo

Highlighted
Hall of Fame Guru

Re: No of Routers in OSPF Area

Neo

If you had an OSPF area with 100 routers where every router was a 2501 with one LAN interface and two serial interfaces and the area is configured as totally stubby area and you also had another OSPF area with 50 routers and every router had a dozen LAN interfaces and the area is a normal area with several ASBRs, which OSPF area would have a problem of potentially being overloaded?

Counting routers and specifying a maximum number of routers is quite simplistic. You really do need to consider the complexity of the area as a factor in the maximum size.

HTH

Rick

HTH

Rick
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Beginner

Re: No of Routers in OSPF Area

Dear Cisco@learn,

I am aware that there is a huge difference between 50 and 100 routers. The upper limit of 50 to 100 routers depends on the factors stated above in my last post.

I dont think anybody designs the network without taking network traffic types, stabilty and other factors into consideration.

Cheers,

Highlighted
Cisco Employee

Re: No of Routers in OSPF Area

Hi,

depending on the factors like network stability, ideally there should be 50 to 100 routers per area.

Thanks