[nsp] OSPF Area Design

[Matthew Crocker]

On Feb 25, 2004, at 7:34 PM, Vandy Hamidi wrote:

> Matt, thanks for the great reply, that's what I was thinking too.
> The dedicated internet connections at our remote offices are not on 
> the same routers as the frame relay.  It's typically:
>    ISP-----Router----FW-----Router----Frame-Relay full mesh
>                               |
>                           Office LAN
>
> Couple other considerations:
> the 4 remote offices are on the east coast and the main is on the west 
> with the 2 data centers.
> 1) I want the default routes needed by the east coast offices routed 
> to internet capable sites on the east coast.  Because I have fully 
> meshed 1.5Mbps, OSPF may consider our New York site as close to our 
> San Francisco office as it is to the Chicago office (same hop-count 
> and bandwidth).  NY's internet traffic may be routed across a 70ms 
> link to exit at SF instead of the 20ms link to CH.  How do I keep the 
> internet traffic going over closest link.
>

You can handle that with some local preference settings so the CH link 
is favored over the SF link so long as both are up.

> 2) We want the DC's IP's to be routable from the offices as well, but 
> it isn't directly connected to the WAN Cloud/FR Net.  I want to avoid 
> using virtual OSPF links if possible.  How can I accomplish that?

How is the DC office connected to your network?  Does it VPN in?  If 
so, can the VPN device run OSPF to announce routes from connected 
clients?

> Can I have two separate instances of OSPF and inject the DC's routes 
> into the other?

You can have separate OSPF areas on the same router

>
> 	-=Vandy=-
>
>
> -----Original Message-----
> From: Matthew Crocker [mailto:matthew at crocker.com]
> Sent: Wednesday, February 25, 2004 3:21 PM
> To: Vandy Hamidi
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [nsp] OSPF Area Design
>
>
>
> Are the routers that connect the frame network to the offices also the
> ones that handle the direct Inet links?  Or, do you have 2 routers in
> each office?  I would set the frame-relay network as area 0 and create
> a different area for each office.
>
> Example,
>
>   Office A:
>    has internet connection on router R.A1
>    has frame connection on router R.A2
>    has LAN segment 192.168.1.0/24
>
> Office B:
>    has internet connection on R.B2
>    has frame connection on router R.B2
>    has LAN segment 192.168.2.0/24
>
>   Main Office
>    has Internet connection on R.M1
>    has frame connection on route R.M2
>    has T1 to data center 1 on router R.M3
>    has T1 to data center 2 on router R.M4
>    has LAN segment 192.168.0.0/24
>
>   Datacenter 1
>     has T1 to main office on router R.D1
>     has T1 to datacenter 2 on router R.D2
>     has LAN segment 192.168.100.0/24
>
> OSPF area 0 contains R.A2, R.B2, R.M2,   PVCs interfaces on all routers
> listen for OSPF from all other routers (full mesh)
> OSPF area 192.168.1.0 contains R.A1, R.A2
> OSPF area 192.168.2.0 contains R.B1, R.B2
> OSPF area 192.168.0.0 contains R.M1, R.M2, R.M3, R.M4
> OSPF area 192.168.100.0 contains R.D1, R.D2
>
> router R.A1 originates default 0/0
> router R.B1 originates default 0/0
> router R.M1 originates default 0/0
>
>
>
>
> On Feb 25, 2004, at 5:15 PM, Vandy Hamidi wrote:
>
>> Current State:
>>  -4 Remote offices
>> 	-3 have dedicated Internet
>>  -1 Main Office
>> 	-Offices fully meshed through Frame-Relay
>> 	-Has dedicated INet
>>  -2 Remote Data Centers
>> 	-Data Centers fully meshed with Main office
>>
>> We're Configuring OSPF for our 4 remote and Main offices using
>> Frame-Relay to fully mesh all locations.
>> Our main office also has a fully meshed point-to-point network with
>> our 2 data centers.
>> We'll have 4 connections to the internet from our 5 offices and we'd
>> like to be able to provide (originate 0/0) internet access to all
>> offices (current and new) as a backup for those that have dedicated
>> Inet and primary for offices w/o dedicated Inet.
>>
>> All offices need to communicate directly with each other over the WAN.
>>
>> We're currently using Static routes, but want to move to dynamic
>> routing for resiliency and ease of scalability.  We chose OSPF because
>> it's compatible with our Cisco and non-Cisco equipment.
>>
>> What's the best way to design the OSPF Areas that will give us the
>> most effective routing and resiliency to failures while still
>> maintaining a simple configuration?
>>
>> 	-=Vandy=-
>>
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>