That may be true in some cases, but a /24 will work just fine. Our organization is multihomed and we advertise a /24 to two providers. I have yet to notice any reachability issues. Perhaps there might be portions of the net that filter our address range but I've checked numerous looking glass sites and have yet to see one where our specific prefix didn't appear.
>>> "Eric" 1/15/02 10:36:26 PM >>> IMHO - You will need at least a /21 as some ISP's set policies that will filter anything less. Best bet is to pick up a copy of: Internet Routing Architectures, Second Edition. ISBN# 1-57870-233-X. This book will also introduce you to the third item to consider when connecting to two ISP's: Symmetry. Regards, Eric ----- Original Message ----- From: "John Neiberger" To: Sent: Tuesday, January 15, 2002 7:37 PM Subject: Re: BGP AS Number [7:32107] > To make connections to separate ISPs work, you need to have > some address space assigned to you that is large enough to be > routed successfully. This generally means that you have to > have at least a /24 prefix. > > Once you've successfully gotten that address space from one of > your providers you can apply at www.arin.net to get an ASN. > > If you were only considering multiple connections to the same > ISP one option would be to use a private ASN, or you might not > need to use BGP at all. > > However, to do what you're considering, you need to have your > own ASN and address space. > > Also, for the nitpickers I'm being overly general on > purpose. This can get to be much more complicated if you want > it to be. :-) > > HTH, > John > > > ________________________________________________ > Get your own "800" number > Voicemail, fax, email, and a lot more > http://www.ureach.com/reg/tag > > > ---- On Tue, 15 Jan 2002, Shawn Xu ([EMAIL PROTECTED]) > wrote: > > > As far as we know, when you connect to two ISPs for load > balancing and > > fault > > tolerance, you have to configure BGP, please refer > > > > http://www.cisco.com/warp/public/459/40.html > > > > but from the above examples, you have to have your own AS > number. If I > > don't > > have my own AS number, I can not connect to two ISPs? > > > > Please help, thanks. > > > > Shawn Xu > > > > > ________________________________________________________________ > _ > > MSN Photos is the easiest way to share and print your photos: > > http://photos.msn.com/support/worldwide.aspx > [EMAIL PROTECTED] Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=32165&t=32107 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
