Solved

At what point do you need multiple Areas with OSPF?

Posted on 2008-10-26
4
235 Views
Last Modified: 2012-05-05
I have a pretty small network with under 300 people  - six offices - some very small - in the US.  I have read about OSPF setup and design - how Area 0 needs to touch every other area (with exceptions noted), the different LSA types etc.  But it was never clear to me when you really need to move beyond having just Area 0.  For a small network - is it ok to just use area 0 for say a central site and a few spoke sites?
0
Comment
Question by:amigan_99
  • 2
  • 2
4 Comments
 
LVL 50

Expert Comment

by:Don Johnston
ID: 22808416
Sure.

There are a couple primary reasons for multiple areas. One is resources. On a big network, the link state database can become huge. This database takes up memory. And running the SPF algorithm on a large database can take time. Think of all the networks as files on your hard disk... You wouldn't put them all in the root directory, right? :-) By creating multiple areas, you reduce the amount of resources (memory and cpu) required to maintain the routing table.

The other is summarization. In OSPF, you can't hide subnets and only advertise a summary route to an OSPF neighbor in the same area. So if you want to summarize, you need multiple areas.


0
 
LVL 1

Author Comment

by:amigan_99
ID: 22808564
Thanks Don.  So from a design standpoint - where do you draw the line?  I have a mix of 2811s and 3845s at the cores.
0
 
LVL 50

Accepted Solution

by:
Don Johnston earned 250 total points
ID: 22808957
Depends on a few of factors. Number of networks, number of routers, RAM installed, to name a few.

Six offices, probably a dozen networks, 2800 and 3800 series routers... I seriously doubt you need to create multiple areas at this time. I'd say you're fine until your network doubles in size.
0
 
LVL 1

Author Closing Comment

by:amigan_99
ID: 31510111
Thanks Don.
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Building small business network 4 95
exclude a user from a deny permisssion 4 61
How to know if DNS name is  record A or if is ZONE 2 20
ACL not working 11 20
Data center, now-a-days, is referred as the home of all the advanced technologies. In-fact, most of the businesses are now establishing their entire organizational structure around the IT capabilities.
This article will inform Clients about common and important expectations from the freelancers (Experts) who are looking at your Gig.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

821 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question