That is because 172.17.1.0 is a connected network on RTA. To illustrate your point, create some loopbacks either on RTB or RTC then advertise them with the network command. Then you'll see those routes show up on RTD with the next hop unchanged.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Hunt Lee Sent: Saturday, June 22, 2002 6:25 PM To: [EMAIL PROTECTED] Subject: BGP Next-hop [7:47219] Sorry, the bgp output stuffs up before, so here's a repost ;) Hey all, I'm probably missing some fairly simple concept here. I have setup 4 routers as follows:- RTB / RTD --- RTA \ RTC Both RTB & RTC are connected (via Eth) to a network called 172.17.1.0 /24. RTA & RTD are both in AS2 RTB & RTC are both in AS1 The connection between RTA & RTD is via Ethernet RouterA#sh ip bgp BGP table version is 9, local router ID is 25.25.25.2 Status codes: s suppressed, d damped, h history, * valid, > best,i -internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 10.1.1.0/30 10.1.1.2 0 0 1 i * 10.1.2.2 0 1 i *> 10.1.2.0/30 10.1.1.2 0 1 i * 10.1.2.2 0 0 1 i *> 25.25.25.0/24 0.0.0.0 0 32768 i *> 172.17.1.0/24 10.1.1.2 0 0 1 i * 10.1.2.2 0 0 1 i RouterA#sh running-config router bgp 2 network 25.25.25.0 mask 255.255.255.0 neighbor 10.1.1.2 remote-as 1 neighbor 10.1.2.2 remote-as 1 neighbor 25.25.25.1 remote-as 2 maximum-paths 6 When I lookup RTD's BGP table (shown below), for the route 172.17.1.0/24, instead of via 10.1.1.2 or 10.1.2.2, it is 25.25.25.2. Ok - here's what I'm confused about. Since I thought that in EBGP peering, the next hop is usually the IP address of the neighbor that announced the route, but IBGP peering preserve the Next-hop attribute learned from EBGP peers. So in the case, if I haven't use next-hop-self on RTA, I would think the EBGP next hop in RTD's BGP table would be either 10.1.1.2 or 10.1.2.2, but why is the EBGP next-hop is 25.25.25.2? RouterD#sh ip bgp BGP table version is 6, local router ID is 172.16.0.2 Status codes: s suppressed, d damped, h history, * valid, > best,i -internal Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *>i10.1.1.0/30 25.25.25.2 0 100 0 1 i*>i10.1.2.0/30 25.25.25.2 100 0 1 i*>i25.25.25.0/24 25.25.25.2 0 100 0 1 i *>i172.17.1.0/24 25.25.25.2 0 100 0 1 i Thanks, H. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=47253&t=47219 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
