ip subnet-zero ip cef ! interface Ethernet0/0 ip address 10.2.6.2 255.255.255.0 half-duplex ! interface Serial0/0 ip address 10.2.5.1 255.255.255.0 clock rate 64000 ! interface Ethernet0/1 ip address 10.2.2.1 255.255.255.0 half-duplex ! interface Serial0/1 no ip address shutdown ! router bgp 2 no synchronization bgp log-neighbor-changes network 10.2.2.0 mask 255.255.255.0 network 10.2.6.0 mask 255.255.255.0 neighbor 10.2.5.2 remote-as 2 no auto-summary ! ip http server ip classless Tuscon#sh ip bgp BGP table version is 4, local router ID is 10.2.6.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 10.2.2.0/24 0.0.0.0 0 32768 i *> 10.2.6.0/24 0.0.0.0 0 32768 i *>i10.2.8.0/24 10.2.5.2 0 100 0 i Tuscon# Tuscon#sh ip bgp summ BGP router identifier 10.2.6.2, local AS number 2 BGP table version is 10, main routing table version 10 3 network entries using 303 bytes of memory 3 path entries using 144 bytes of memory 2 BGP path attribute entries using 120 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 567 total bytes of memory BGP activity 6/3 prefixes, 6/3 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.2.5.2 4 2 1560 1564 10 0 0 1d01h 1 Tuscon# Tuscon# Tuscon#sh ip int brie Interface IP-Address OK? Method Status Prot ocol Ethernet0/0 10.2.6.2 YES NVRAM up up Serial0/0 10.2.5.1 YES NVRAM up up Ethernet0/1 10.2.2.1 YES NVRAM up up Serial0/1 unassigned YES NVRAM administratively down down Tuscon# +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ version 12.3 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname Dallas ! boot-start-marker boot-end-marker ! enable password *** ! no aaa new-model ip subnet-zero ! ! ! ip cef ! interface Ethernet0/0 ip address 10.2.8.2 255.255.255.0 full-duplex ! interface Serial0/0 ip address 10.2.5.2 255.255.255.0 ! interface BRI0/0 no ip address shutdown ! interface Ethernet0/1 no ip address shutdown half-duplex ! router bgp 2 no synchronization bgp log-neighbor-changes network 10.2.8.0 mask 255.255.255.0 neighbor 10.2.5.1 remote-as 2 no auto-summary ! ip http server ip classless ! ! line con 0 line aux 0 line vty 0 4 password *** Dallas#sh ip bgp summ BGP router identifier 10.2.8.2, local AS number 2 BGP table version is 11, main routing table version 11 3 network entries using 303 bytes of memory 3 path entries using 144 bytes of memory 2 BGP path attribute entries using 120 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 567 total bytes of memory BGP activity 6/3 prefixes, 6/3 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.2.5.1 4 2 1563 1559 11 0 0 1d01h 2 Dallas# Dallas# Dallas#sh ip int brief Interface IP-Address OK? Method Status Prot ocol Ethernet0/0 10.2.8.2 YES manual up up Serial0/0 10.2.5.2 YES manual up up BRI0/0 unassigned YES unset administratively down down BRI0/0:1 unassigned YES unset administratively down down BRI0/0:2 unassigned YES unset administratively down down Ethernet0/1 unassigned YES unset administratively down down Dallas# ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Now take network statements off of Tuscon and look at result on the BGP table in Dallas, the 2 subnets that are the ethernets on Tuscon are gone: Tuscon#conf t Enter configuration commands, one per line. End with CNTL/Z. Tuscon(config)#router bgp 2 Tuscon(config-router)#no network 10.2.6.0 mask 255.255.255.0 Tuscon(config-router)#no network 10.2.2.0 mask 255.255.255.0 Tuscon(config-router)#^Z Tuscon# Tuscon# Tuscon# *Mar 2 04:35:39.049: %SYS-5-CONFIG_I: Configured from console by console Tuscon# Tuscon#telnet 10.2.5.2 Trying 10.2.5.2 ... Open User Access Verification Password: Dallas>en Password: Dallas#sh ip bgp BGP table version is 13, local router ID is 10.2.8.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 10.2.8.0/24 0.0.0.0 0 32768 i Dallas# Dallas#sh ip bgp summ BGP router identifier 10.2.8.2, local AS number 2 BGP table version is 13, main routing table version 13 1 network entries using 101 bytes of memory 1 path entries using 48 bytes of memory 1 BGP path attribute entries using 60 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 209 total bytes of memory BGP activity 6/5 prefixes, 6/5 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 10.2.5.1 4 2 1569 1564 13 0 0 1d01h 0 Dallas#