Re: Off Subject - OPSF best practice

Another advantage to multiple areas would be the ability to do inter-area filtering at the ABR, or even make remote sites stub/total stub if necessary so they essentially get only the default route (total stub).

In short multiple areas gives you more control over your resources and isolates off pieces of your network. This can be good or bad depending on if you have network people that understand the added complexity : )

Regards,

Joe Astorino - CCIE #24347 R&S
Technical Instructor - IPexpert, Inc.
Cell: +1.586.212.6107
Fax: +1.810.454.0130
Mailto: jastorino_at_ipexpert.com

-----Original Message-----
From: ALL From_NJ <all.from.nj_at_gmail.com>
Date: Tue, 19 Jan 2010 22:33:07
To: Joe Astorino<jastorino_at_ipexpert.com>
Cc: Dufour, Andre<Andre.Dufour_at_paetec.com>; Nish Vamadevan<ipnish_at_gmail.com>; Charles T. Alexander<charles.t.alexander_at_verizon.net>; ccielab_at_groupstudy.com<ccielab_at_groupstudy.com>; David Clark<dclark_at_ccbootcamp.com>
Subject: Re: Off Subject - OPSF best practice

This sounds like a small network ... not sure you need to have many areas
...other than area 0 at this time. You might look at this decision with a
bit more 'detailed' analysis. You will need to do the homework ...

Multiple areas can help you with summarizing routes, using less CPU and
bandwidth for updates / SPF processing. Do you have unstable links, low
bandwidth, etc ...

Likely you will decide to use areas to separate different portions of your
network ... for example, the data center from the core, and from the core
the WAN / branch offices might be in separate areas.

As David Clark says when speaking of network design, "separate complexity
from complexity ..." words to live by says I. ;-)

Charles, I think it really depends on your particular network. ;-)

Charles - have you also been through the OSPF design guide? Just a thought
and this is an awesome read if you have not done so yet or if anyone on this
mailer wants to learn more of OSPF. Please ask questions if any of this is
unclear. Some folks on this list have also suggested Russ White's large
scale network design book (can't think of the name of it).

Charles - some additional concerns might include the CPU and memory of each
router ... think in terms of peak resource usage, and always design with the
ability to perform more that what could be needed. What happens today if
you design your network and then next year you roll out a new application?
A network like yours will need flexibility and you do not want to put
yourself in a box, ... this relates to OSPF design since OSPF requires
control plane resources (like any other control protocol... another example
might be QoS configs / NBAR, and IGMP/PIM etc...)

Oh ... before I forget. Also include the possibility of changing your
design slightly after live testing. You will want to test several points in
your network for resource usage and convergence times. Make sure this is
put into your plan.

HTH Charles and have a great night!

Andrew

On Tue, Jan 19, 2010 at 8:02 PM, Joe Astorino <jastorino_at_ipexpert.com>wrote:

> I can see both ways here -- Right NOW it might not be all that useful
> if you only have 16 remote sites, each with say an edge router back to
> HQ.
>
> However, if you design correctly now you can always expand later and
> not have to worry about redesigning your network
>
> On Tue, Jan 19, 2010 at 7:39 PM, Dufour, Andre <Andre.Dufour_at_paetec.com>
> wrote:
> > Number of users really does not matter too much. Subnets matter.
> >
> > If it's only 16 sites and 1-2 subnets per site, that's 32 routes which
> really is fine. Also, how many routers are running OSPF matters if there's
> going to be a ton.....
> >
> > Andre
> >
> > -----Original Message-----
> > From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of
> Nish Vamadevan
> > Sent: Tuesday, January 19, 2010 7:32 PM
> > To: Charles T. Alexander; ccielab_at_groupstudy.com
> > Subject: Re: Off Subject - OPSF best practice
> >
> > In my opinion, you will have more control and better performance if you
> have them in separate areas...
> >
> > ------Original Message------
> > From: Charles T. Alexander
> > Sender: nobody_at_groupstudy.com
> > To: ccielab_at_groupstudy.com
> > ReplyTo: Charles T. Alexander
> > Subject: Off Subject - OPSF best practice
> > Sent: 20 Jan 2010 00:11
> >
> > B
> >
> > Does it make sense in OSPF from performance for, a firm of 1000 users in
> > 16 WAN locations to have different OSPF areas for each office rather than
> putting everyone in Area 0?
> >
> >
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> Regards,
>
> Joe Astorino CCIE #24347 (R&S)
> Sr. Technical Instructor - IPexpert
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-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net