One other thing regarding transit areas in BGP. As a rule, you would not advertise routes received from ISP 1 back to ISP 2 and vice versa. That would bring about the possibility of being a transit area. I have seen this misconfiguration on a live system, but it did not cause a problem because the ISP filtered the received routes anyway. You cannot assume that though, We had a major outage in Australia a year or so ago because two major ISP's did not filter this correctly and caused a traffic loop. You will not become a transit area because of routes you receive, it is the routes you advertise. There are a few different ways to prevent being a transit area in BGP.
On 13/04/13 1:39 PM, "Samir Idris" <[email protected]> wrote: >You can use communities to help your AS not become a transit AS. > >Rest you can use as-path attribute to control your inbound traffic and >local-preference to control your outbound traffic. >On 13/04/2013 4:30 AM, "Robert Beck" <[email protected]> wrote: > >> Hi all, >> >> I have BGP questions. But first the set up. >> >> ISP1 connectected to R1 >> ISP2 connected to R1 >> >> ISP2 connected to R2 >> >> IBGP between R1 and R2 redistributing 0.0.0.0 from EBGP into IGP that is >> received from primary ISP. Which from what I've found on google searches >> that seems to be the norm. >> >> Both routers are receiving the full BGP table. Several Networks >>advertised >> out both ISPs. >> >> Now the questions.. >> 1. Is it a good idea to receive the full BGP table other than the cool >> factor? Also, is there a way to prevent from becoming a transit hop >>while >> receiving the full BGP table? When you receive the full BGP table, isn't >> becoming a transit area automatic? >> >> 2. Is there a good way to load balance outbound traffic to the internet >>in >> this set up? 60/40? If the route goes out ISP1 and network A is >>advertised >> to ISP2 will asymetric routing work in this case? I think not. I would >> assume the best practice method would be to have the path go out which >>ever >> Network is advertised to which ISP. For example, if Network B is >>advertised >> out ISP2 then have them route that way instead of ISP1. >> >> thanks for any info. >> _______________________________________________ >> For more information regarding industry leading CCIE Lab training, >>please >> visit www.ipexpert.com >> >> Are you a CCNP or CCIE and looking for a job? Check out >> www.PlatinumPlacement.com >> >> http://onlinestudylist.com/mailman/listinfo/ccie_rs >> >_______________________________________________ >For more information regarding industry leading CCIE Lab training, please >visit www.ipexpert.com > >Are you a CCNP or CCIE and looking for a job? Check out >www.PlatinumPlacement.com > >http://onlinestudylist.com/mailman/listinfo/ccie_rs _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com http://onlinestudylist.com/mailman/listinfo/ccie_rs
