In this situation it is best not to characterize BGP as a load-balancing method. BGP is designed to choose the shortest path; the shortest AS path, path vector routing. Therefore if most of your Internet traffic has a shorter path to its destination via ISP A then you will see much higher usage on that link. With BGP you can turn the 'dials' to create an equal traffic load on each link, but it is likely that you would introduce suboptimal routing by forcing traffic down one path and all you will really have done is create an equal load.
Cheers, Dan -----Original Message----- From: Gregg Malcolm [mailto:[EMAIL PROTECTED]] Sent: Wednesday, December 12, 2001 2:09 PM To: [EMAIL PROTECTED] Subject: Re: BGP and ip load-sharing [7:28960] Dave, I have a dumb question regarding multiple defaults. Lets say that you had a multihomed BGP config connected to 2 different providers. Lets say that you had 2 routers below the firewalls sourcing the default. Then take a look at the routing tables below these 2 routers. Wouldn't nearly every routing proto (other than RIP assuming the hop counts were the same) only list 1 default? Wouldn't it be true that outbound traffic patterns would be based upon metrics from the routers sourcing the default? If this is true, then it's not really load balancing. I can think of scenarios were nearly all outbound traffic would be destined for only 1 of the 2 links. I'm sure I'm missing something dumb, but figured it was worth asking anyway. Gregg ""MADMAN"" wrote in message [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > First problem, BGP doesn't load share but with IOS you can source an > interface like a loopback, see BGP and loadsharing. > > If you have two parallel paths to a single provider why are you doing > BGP??? Since you choose BGP I'll assume this is an Internet connection, > set up two default routes, ip cef global command and the configs you > have sent and you will have symetrical outgoing loadsharing. > > Dave > > Alejandro Acosta wrote: > > > > Hi All, > > This is my first message in the list. > > I am running a BGP session with a customer. It has 2 serial links with us > > (Each link of 2 Mbps). The customer and me have selected per-packet sharing > > in order to balanced the link. > > In this moment, the traffic that comes from the customer is very simetric > > in both links, however, the traffic that is sent to the customer from us is > > not simetric. As far as I know (if I am not wrong), if we are using load > > balacing per-packet, the incoming and outgoing traffic should be very very > > similar, right?. Why only the incoming traffic is simetric in this moment. > > > > This is the configuration for both interfaces in my router: > > > > interface Serial2/0 > > description Link 1 > > bandwidth 2048 > > ip address xxx.xxx.xxx.xxx xxx.xxx.xxx.xxx > > no ip directed-broadcast > > ip load-sharing per-packet > > no ip mroute-cache > > load-interval 30 > > no cdp enable > > hold-queue 1024 out > > ! > > > > interface Serial2/4 > > description Link number 2 > > bandwidth 2048 > > ip address xxx.xxx.xxx.xxx xxx.xxx.xxx.xxx > > no ip directed-broadcast > > ip load-sharing per-packet > > no ip mroute-cache > > load-interval 30 > > no fair-queue > > no cdp enable > > > > Any ideas? > > > > Thanks > > > > Alejandro Acosta > > > > P.D. I am using IOS 12.0(7)T > -- > David Madland > Sr. Network Engineer > CCIE# 2016 > Qwest Communications Int. Inc. > [EMAIL PROTECTED] > 612-664-3367 > > "Emotion should reflect reason not guide it" Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=28990&t=28960 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
