Received: from dymwsm13.mailwatch.com by fsutil01; Wed, 28 Feb 2001 15: 02:07 -0700 Received: from dymw0122.allegro.net (dymw0122.allegro.net [204.253.83.46]) by dymwsm13.mailwatch.com (8.11.0/8.11.0) with SMTP id f1SM2fR13715 for <[EMAIL PROTECTED]>; Wed, 28 Feb 2001 17: 02:41 -0500 Received: from 204.253.83.71 by dymw0122.allegro.net with SMTP ( WorldSecure Server SMTP Relay(WSS) v4.3); Wed, 28 Feb 01 17:02:04 -0500 X-Server-Uuid: e51863a8-8a79-11d4-9674-00508be1352e Received: from ren-1.cais.net (ren-1.cais.net [205.252.14.76]) by dymwsm09.mailwatch.com (8.11.0/8.11.0) with ESMTP id f1SM2gU13848 for <[EMAIL PROTECTED]>; Wed, 28 Feb 2001 17:02:42 -0500 Received: from [63.216.127.100] (63-216-127-100.sdsl.cais.net [63.216.127.100]) by ren-1.cais.net (8.11.1/8.11.1) with ESMTP id f1SM23t84795; Wed, 28 Feb 2001 17:02:03 -0500 (EST) MIME-Version: 1.0 X-Sender: [EMAIL PROTECTED] Message-ID: <p05001928b6c308ad83a9@[63.216.127.100]> In-Reply-To: <sa9cd0d2.073@fsutil01> References: <sa9cd0d2.073@fsutil01> Date: Wed, 28 Feb 2001 17:01:58 -0500 To: "John Neiberger" <[EMAIL PROTECTED]> From: "Howard C. Berkowitz" <[EMAIL PROTECTED]> Subject: Re: OSPF design question re: location of Area Border Router cc: [EMAIL PROTECTED] X-WSS-ID: 1683AAD6500-01-01 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit I haven't seen any of my posts show up for about a day or two -- not sure they are getting through. Feel free to post this since yours, clearly are! I'll copy to groupstudy just in case my posts start to work. >I think I must be missing something here, or I don't understand the >concept of ABR. > >If you have a 7513 in area 0 connected to a 4500 in area 1, for >instance, then the 4500 will have one interface in area0 and the rest >presumably in area 1. By definition, that makes the 4500 an ABR, >doesn't it? Yes. >I don't see how you have any choice in this matter at all, >but since I've never actually configured OSPF perhaps someone will >enlighten me. In the situation described, the choice -- which I often like to do -- is not to put any area interfaces on the 4500. Assume the 4500 is in area 0.0.0.1, and the WAN link to the core is 192.168.0.0/30. There's another 4500 in area 0.0.0.2, with a WAN link, 192.168.1.0/30. Then, a configuration snippet for the 7513 might be: int s0.1 ip addr 192.168.0.1 255.255.255.252 int s0.2 ip addr 192.168.1.1 255.255.255.252 int fe0 ip addr 172.16.0.1 255.255.255.0 router ospf 1 network 192.168.0.1 0.0.0.0 area 0.0.0.1 network 192.168.1.1 0.0.0.0 area 0.0.0.2 network 172.16.0.1 0.0.0.0 area 0.0.0.0 In this example, I deliberately put area 0.0.0.0 on a Fast Ethernet. Often, I keep 0.0.0.0 very small. If I have redundant core routers, I'll connect them to switch ports on a common subnet. I'll usually connect infrastructure servers such as SNMP, DNS, and DHCP to that subnet, but I avoid putting any application servers into it. Even if the core routers are colocated at the same site as the application servers, I'm quite prone to put the servers in their own area. One of the advantages of doing so is keeping server-to-server traffic, such as synchronization and backup, out of the core. > >>>> "Hennen, David" <[EMAIL PROTECTED]> 2/28/01 9:32:59 AM >>> >Hi, I am preparing to bring up a new site in an ospf network. The new >site >will be a training facility connected back to the main office by a t1. >Currently we use OSPF and have everything in area 0, around 100 >routers. > >I want to make this new site a different area and to make the new area >a >Totally Stubby Area. We have two 7513 routers at the main office that >handle all the wan traffic, the new remote office would connect to one >of >these. The remote training office will have a 4500. > >One of my coworkers suggested that the 7513 at the main office should >be the >Area Border Router, because we should keep area 0 from being spread out >over >a bunch of wan links. I had it in mind that the remote 4500 should be >the >ABR. I don't have a strong reason for thinking that way. The cpu of >the >7513 runs between 20-30 % utilization according to snmp info. > >Are there any rules of thumb regarding this? I looked through the >Cisco >OSPF network design book and can see some examples that support having >the >ABR at the main office. Is that the accepted practice? Are there any >gotcha's to look out for? > >Thanks if you can help >dave h > >_________________________________ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > > > >_________________________________ >FAQ, list archives, and subscription info: >http://www.groupstudy.com/list/cisco.html >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
