If Provider 1 is large enough, they should be able to assign you a class C that they do not aggregate when they make their announcements to other providers. I would suggest asking them for one of these, if they want to keep your business they will get it to you one way or the other. Another option would be to ask Provider 2 for a class C out of address space that they DO announce as an aggregate, and announce this class C to Provider 1. In this situation your announcement to Provider 1 would always be more specific and most of your traffic would come through them.
~-----Original Message----- ~From: Robert Fowler [mailto:[EMAIL PROTECTED]] ~Sent: Wednesday, January 15, 2003 9:32 AM ~To: [EMAIL PROTECTED] ~Subject: BGP load balancing questions [7:61095] ~ ~ ~Hello groupstudy, ~ ~I've been banging my head against the wall and figured I would ~defer this ~question to those of you more learned and experienced. Here is the the ~scenario: ~ ~2 routers running BGP ~Router 1 has a connection to ISP 1 and router 2 has a ~connection to ISP 2 ~Each receives full routes. ~Each provider has given us a class C address ~Only the class C from provider 1 is actively used, because ~provider 2 will ~probably be dropped eventually(ssshhh don't tell ARIN) ~ ~ ~The class C is advertised to both ISPs, however ISP 1 aggregates this ~address space so instead of being 1.1.1.x /24 it's 1.1.x.x /16 ~This was checked using various looking glasses. ~ ~What that means is that traffic to my Class C will arrive ~primarily via ISP ~2 because it will see the /24 I advertise though it. That is bad, for ~various reasons. Mainly because we are charged by usage from ~ISP2, but also ~because we are going to upgrade ISP1 to a fractional t3 and use ISP 2 ~primarily as a backup eventually. Also the traffic coming in ~is 90% via ISP ~2 and 10% via ISP 1. ~ ~If I remember from my studying so long ago, even prepending my ~AS number to ~ISP 2 will not work, becuase it doesn't even make it to that ~criteria, but ~rather see the /24 and chooses that route. ~ ~I searched some newsgroups, but amazingly enough nobody seemed ~to have this ~issue. I saw someone who had a larger block than /24 and some ~suggestions ~there but that would not work in this case. ~ ~ ~Options not available: ~Using the Class C from Carrier 2 to load balance using IP ~space and traffic ~types ~Getting a class C independant of a provider from ARIN. (That ~costs money :)) ~ ~ ~Robert ~ ~ ~ ~ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=61099&t=61095 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
