>Hi, > >You have tried to post to GroupStudy.com's Professional mailing list. Because >the server does not recognize you as a confirmed poster, you will be required >to authenticate that you are using a valid e-mail address and are not a >spammer. By confirming this e-mail you certify that you are not sending >Unsolicited Bulk Email (UBE). > >By confirming this e-mail you also certify the following: > >1. The message does NOT break Cisco's Non-Disclosure requirements. > >2. The message is NOT designed to advertise a commercial product. > >3. You understand all postings become property of GroupStudy.com > >4. You have searched the archives prior to posting. > >5. The message is NOT inflammatory. > >6. The message is NOT a test message. > >To confirm, simply reply to this message. No editing is necessary. Once >confirmed, you will be able to post without additional confirmations. > > >Welcome to GroupStudy.com! > > >------ORIGINAL MESSAGE--------- > >>From [EMAIL PROTECTED] Wed Jan 30 21:53:29 2002 >Received: from dfw-smtpout2.email.verio.net >(dfw-smtpout2.email.verio.net [129.250.36.42]) > by groupstudy.com (8.9.3/8.9.3) with ESMTP id VAA05947 > GroupStudy Mailer; Wed, 30 Jan 2002 21:53:29 -0500 >Received: from [129.250.38.62] (helo=dfw-mmp2.email.verio.net) > by dfw-smtpout2.email.verio.net with esmtp > id 16W7Mx-00042K-00 > for [EMAIL PROTECTED]; Thu, 31 Jan 2002 02:54:35 +0000 >Received: from [68.49.184.209] (helo=[192.168.0.2]) > by dfw-mmp2.email.verio.net with esmtp > id 16W7O7-0007QD-00 > for [EMAIL PROTECTED]; Thu, 31 Jan 2002 02:55:47 +0000 >Mime-Version: 1.0 >X-Sender: [EMAIL PROTECTED] >Message-Id: >Date: Wed, 30 Jan 2002 21:54:32 -0500 >To: [EMAIL PROTECTED] >From: "Howard C. Berkowitz" >Subject: Re: Default-informatin originate always [7:33729] >Content-Type: text/plain; charset="us-ascii" ; format="flowed" > >>Regarding this command... >>"Default-information originate [always]" >>this is documented as saying... >>this generates the default route into OSPF even if the path to the default >>route goes down... >>and... >>even when the router has no default route, with the magic keyword "always" it >>will create a "default route"...pointing to where?? >>Q: What's the point of advertising a route if it is indeed DOWN? Isn't this >>like saying i know that Exit5 is closed but I'm gona keep directing all >>motorists to go to Exit 5 anyway? >> >>Please clarify this for me. >> >>Elmer > >Imagine you have a fairly large OSPF area. If the default route goes >down, all the topological databases have to be updated and >propagated. While if JUST the default route were involved, the >Dijkstra computation will not have to be run, there still will be >bandwidth and processor utilization. > >If there is only one router generating default, and it goes down, the >traffic is going to fail anyway. To take your traffic analogy, >default-information always is indeed like directing the traffic >LEAVING THE AREA to Exit 5, but not otherwise disturbing those cars >that don't care about Exit 5. > >If there's more than one default router, you definitely don't want >the always keyword. > >Now--as far as where it points: "it depends". All it points to is >the router generating default. That router may or may not have a >default route of its own -- it might be a default-free BGP router as >well as an ASBR. It could have a default route of its own that points >somewhere outside the AS or area. > >AFAIK, if the router was default-free, you couldn't use >default-information originate without always, because the router >would never have a local default to meet the ALWAYS condition. In >that case, you'd have to have BGP or a static route specify it, and >redistribute that route into OSPF.
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