I have this topology. From R1, show ip bgp result is below. *Every bgp route is coming from 3.3.12.2 or 3.3.14.4.*
[image: bgp.jpg]<https://learningnetwork.cisco.com/servlet/JiveServlet/showImage/2-208950-88940/bgp.jpg> R1#sh ip bgp BGP table version is 14, local router ID is 3.3.1.1 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 *> 3.3.1.0/24 0.0.0.0 0 32768 i * 3.3.2.0/24 3.3.14.4 0 2 i *> 3.3.12.2 0 0 2 i * 3.3.3.0/24 3.3.14.4 0 2 i *> 3.3.12.2 0 2 i * 3.3.4.0/24 3.3.14.4 0 0 2 i *> 3.3.12.2 0 2 i R1# >From R3, it shows same result. For 3.3.1.0, it uses 3.3.4.4 or 3.3.2.2 R3#sh ip bgp BGP table version is 22, local router ID is 3.3.3.3 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 * i3.3.1.0/24 3.3.4.4 0 100 0 1 i *>i 3.3.2.2 0 100 0 1 i r>i3.3.2.0/24 3.3.2.2 0 100 0 i *> 3.3.3.0/24 0.0.0.0 0 32768 i r>i3.3.4.0/24 3.3.4.4 0 100 0 i R3# *However, I have one problem. As you can see below, R2 can only see 3.3.1.0 through 3.3.12.1* R2#show ip bgp BGP table version is 7, local router ID is 3.3.2.2 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 *> 3.3.1.0/24 3.3.12.1 0 0 1 i *> 3.3.2.0/24 0.0.0.0 0 32768 i r>i3.3.3.0/24 3.3.3.3 0 100 0 i r>i3.3.4.0/24 3.3.4.4 0 100 0 i R2# *But, I can see both routes from R4 for 3.3.1.0* R4#sh ip bgp BGP table version is 7, local router ID is 3.3.4.4 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 * i3.3.1.0/24 3.3.2.2 0 100 0 1 i *> 3.3.14.1 0 0 1 i r>i3.3.2.0/24 3.3.2.2 0 100 0 i r>i3.3.3.0/24 3.3.3.3 0 100 0 i *> 3.3.4.0/24 0.0.0.0 0 32768 i R4# R2#show ip bgp 3.3.1.0 BGP routing table entry for 3.3.1.0/24, version 2 Paths: (1 available, best #1, table Default-IP-Routing-Table) Advertised to update-groups: 2 1 3.3.12.1 from 3.3.12.1 (3.3.1.1) Origin IGP, metric 0, localpref 100, valid, external, best R2# R4#sh ip bgp 3.3.1.0 BGP routing table entry for 3.3.1.0/24, version 2 Paths: (2 available, best #2, table Default-IP-Routing-Table) Advertised to update-groups: 2 1 3.3.2.2 (metric 129) from 3.3.3.3 (3.3.3.3) Origin IGP, metric 0, localpref 100, valid, internal Originator: 3.3.2.2, Cluster list: 3.3.3.3 1 3.3.14.1 from 3.3.14.1 (3.3.1.1) Origin IGP, metric 0, localpref 100, valid, external, best R4# (question) *If I shut down interface from R1 which is connected to R2, it shows up right away. Why couldn't i see before 3.3.4.4 from R2 for show ip bgp 3.3.1.0?* R2#show ip bgp 3.3.1.0 BGP routing table entry for 3.3.1.0/24, version 0 Paths: (1 available, no best path) Not advertised to any peer 1 *3.3.4.4 (metric 129) from 3.3.3.3 (3.3.3.3)* Origin IGP, metric 0, localpref 100, valid, internal Originator: 3.3.4.4, Cluster list: 3.3.3.3 R2# R2#show ip bgp BGP table version is 7, local router ID is 3.3.2.2 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 **>i3.3.1.0/24 3.3.4.4 0 100 0 1 i* *> 3.3.2.0/24 0.0.0.0 0 32768 i r>i3.3.3.0/24 3.3.3.3 0 100 0 i r>i3.3.4.0/24 3.3.4.4 0 100 0 i R2# ---------------------- R1 R2 R3 R4 config -------------------------- R1#sh run Building configuration... Current configuration : 1523 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R1 ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 ip cef ! ! ! ! no ip domain lookup ! multilink bundle-name authenticated ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! archive log config hidekeys ! ! ! ! ! ! ! ! interface Loopback0 ip address 3.3.1.1 255.255.255.0 ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address encapsulation frame-relay clock rate 2000000 ! interface Serial0/0.12 point-to-point ip address 3.3.12.1 255.255.255.0 snmp trap link-status frame-relay interface-dlci 102 ! interface Serial0/0.14 point-to-point ip address 3.3.14.1 255.255.255.0 snmp trap link-status frame-relay interface-dlci 104 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface Serial0/3 no ip address shutdown clock rate 2000000 ! router bgp 1 no synchronization bgp log-neighbor-changes network 3.3.1.0 mask 255.255.255.0 neighbor 3.3.12.2 remote-as 2 neighbor 3.3.14.4 remote-as 2 no auto-summary ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! ! ! ! ! ! ! control-plane ! ! ! ! ! ! ! ! ! ! line con 0 exec-timeout 0 0 logging synchronous line aux 0 line vty 0 4 login ! ! end R1# R2#sh run Building configuration... Current configuration : 1765 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R2 ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 ip cef ! ! ! ! no ip domain lookup ! multilink bundle-name authenticated ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! archive log config hidekeys ! ! ! ! ! ! ! ! interface Loopback0 ip address 3.3.2.2 255.255.255.0 ip ospf network point-to-point ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address encapsulation frame-relay clock rate 2000000 ! interface Serial0/0.21 point-to-point ip address 3.3.12.2 255.255.255.0 snmp trap link-status frame-relay interface-dlci 201 ! interface Serial0/0.23 point-to-point ip address 3.3.23.2 255.255.255.0 snmp trap link-status frame-relay interface-dlci 203 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface Serial0/3 no ip address shutdown clock rate 2000000 ! router ospf 1 log-adjacency-changes passive-interface Serial0/0.21 network 3.3.2.2 0.0.0.0 area 0 network 3.3.12.2 0.0.0.0 area 0 network 3.3.23.2 0.0.0.0 area 0 ! router bgp 2 no synchronization bgp log-neighbor-changes network 3.3.2.0 mask 255.255.255.0 neighbor 3.3.3.3 remote-as 2 neighbor 3.3.3.3 update-source Loopback0 neighbor 3.3.12.1 remote-as 1 no auto-summary ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! ! ! ! ! ! ! control-plane ! ! ! ! ! ! ! ! ! ! line con 0 exec-timeout 0 0 logging synchronous line aux 0 line vty 0 4 login ! ! end R2# ---------------- R3#sh run Building configuration... Current configuration : 1856 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R3 ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 ip cef ! ! ! ! no ip domain lookup ! multilink bundle-name authenticated ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! archive log config hidekeys ! ! ! ! ! ! ! ! interface Loopback0 ip address 3.3.3.3 255.255.255.0 ip ospf network point-to-point ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address encapsulation frame-relay clock rate 2000000 ! interface Serial0/0.32 point-to-point ip address 3.3.23.3 255.255.255.0 snmp trap link-status frame-relay interface-dlci 302 ! interface Serial0/0.34 point-to-point ip address 3.3.34.3 255.255.255.0 snmp trap link-status frame-relay interface-dlci 304 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface Serial0/3 no ip address shutdown clock rate 2000000 ! router ospf 1 log-adjacency-changes network 3.3.2.2 0.0.0.0 area 0 network 3.3.23.2 0.0.0.0 area 0 ! router bgp 2 no synchronization bgp log-neighbor-changes network 3.3.2.0 mask 255.255.255.0 neighbor 3.3.3.3 remote-as 2 neighbor 3.3.3.3 update-source Loopback0 neighbor 3.3.3.3 next-hop-self neighbor 3.3.12.1 remote-as 1 no auto-summary ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! ! ! ! ! ! ! control-plane ! ! ! ! ! ! ! ! ! ! line con 0 exec-timeout 0 0 logging synchronous line aux 0 line vty 0 4 login ! ! end -------------------- R4#sh run Building configuration... Current configuration : 1765 bytes ! version 12.4 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname R4 ! boot-start-marker boot-end-marker ! ! no aaa new-model memory-size iomem 5 ip cef ! ! ! ! no ip domain lookup ! multilink bundle-name authenticated ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! archive log config hidekeys ! ! ! ! ! ! ! ! interface Loopback0 ip address 3.3.4.4 255.255.255.0 ip ospf network point-to-point ! interface FastEthernet0/0 no ip address shutdown duplex auto speed auto ! interface Serial0/0 no ip address encapsulation frame-relay clock rate 2000000 ! interface Serial0/0.41 point-to-point ip address 3.3.14.4 255.255.255.0 snmp trap link-status frame-relay interface-dlci 401 ! interface Serial0/0.43 point-to-point ip address 3.3.34.4 255.255.255.0 snmp trap link-status frame-relay interface-dlci 403 ! interface FastEthernet0/1 no ip address shutdown duplex auto speed auto ! interface Serial0/1 no ip address shutdown clock rate 2000000 ! interface Serial0/2 no ip address shutdown clock rate 2000000 ! interface Serial0/3 no ip address shutdown clock rate 2000000 ! router ospf 1 log-adjacency-changes network 3.3.4.4 0.0.0.0 area 0 network 3.3.34.4 0.0.0.0 area 0 ! router bgp 2 no synchronization bgp log-neighbor-changes network 3.3.4.0 mask 255.255.255.0 neighbor 3.3.3.3 remote-as 2 neighbor 3.3.3.3 update-source Loopback0 neighbor 3.3.3.3 next-hop-self neighbor 3.3.14.1 remote-as 1 no auto-summary ! ip forward-protocol nd ! ! no ip http server no ip http secure-server ! ! ! ! ! ! ! control-plane ! ! ! ! ! ! ! ! ! ! line con 0 exec-timeout 0 0 logging synchronous line aux 0 line vty 0 4 login ! ! end R4# _______________________________________________ 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? 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