kita menggunakan RIP routing protocol di ketiga router ini, dan pastikan semua router dapat ping ke masing-masing loopback router via RIP...
R1
inter lo0
ip add 192.168.1.1 255.255.255.0
inter fa0/0
no shu
ip add 12.12.12.1 255.255.255.0
router rip
ver 2
net 0.0.0.0
no auto
R2
inter lo0
ip add 192.168.2.1 255.255.255.0
inter fa0/0
no shu
ip add 12.12.12.2 255.255.255.0
inter fa0/1
no shu
ip add 23.23.23.2 255.255.255.0
router rip
ver 2
net 0.0.0.0
no auto
R3
inter lo0
ip add 192.168.3.1 255.255.255.0
inter fa0/1
no shu
ip add 23.23.23.3 255.255.255.0
router rip
ver 2
net 0.0.0.0
no auto
lalu sekarang kita akan mencoba EBGP peeringnya
untuk EBGP peeringnya, berikut confignya :
*** pada R1router bgp 100 no auto no sync nei 192.168.2.1 remote 200 nei 192.168.2.1 update lo0 nei 192.168.2.1 ebgp 2 network 192.168.1.0 *** pada R2router bgp 200 no auto no sync nei 192.168.1.1 remote 100 nei 192.168.1.1 update lo0 nei 192.168.1.1 ebgp 2 nei 192.168.3.1 remote 300 nei 192.168.3.1 update lo0 nei 192.168.3.1 ebgp 2 network 192.168.2.0 *** pada R3router bgp 300 no auto no sync nei 192.168.2.1 remote 200 nei 192.168.2.1 update lo0 nei 192.168.2.1 ebgp 2 network 192.168.3.0
kalau kita lihat ini, sepertinya semua lancar...
R2(config-router)#do sh ip bgp sum BGP router identifier 192.168.2.1, local AS number 200 BGP table version is 4, main routing table version 4 3 network entries using 360 bytes of memory 3 path entries using 156 bytes of memory 4/3 BGP path/bestpath attribute entries using 496 bytes of memory 2 BGP AS-PATH entries using 48 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 Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory BGP using 1092 total bytes of memory BGP activity 3/0 prefixes, 3/0 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 192.168.1.1 4 100 4 7 4 0 0 00:01:53 1 192.168.3.1 4 300 4 7 4 0 0 00:01:39 1 R2(config-router)#do sh ip bgp BGP table version is 4, local router ID is 192.168.2.1 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*> 192.168.1.0 192.168.1.1 0 0 100 i *> 192.168.2.0 0.0.0.0 0 32768 i *> 192.168.3.0 192.168.3.1 0 0 300 i
tapi kalo kita lihat ada yang aneh...kenapa network 192.168.1.0 next-hopnya 192.168.1.1
R2(config-router)#do sh ip route | inc 192.168.1.0 B 192.168.1.0/24 [20/0] via 192.168.1.1, 00:02:58 R2(config-router)#do sh ip route 192.168.1.0 Routing entry for 192.168.1.0/24 Known via "bgp 200", distance 20, metric 0 Tag 100, type external Last update from 192.168.1.1 00:00:09 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:09 ago Route metric is 0, traffic share count is 1 AS Hops 1 Route tag 100
lalu kita juga tidak bisa ping dari R2 ke loopback R1
R2(config-router)#do sh ip route 192.168.1.0 Routing entry for 192.168.1.0/24 Known via "bgp 200", distance 20, metric 0 Tag 100, type external Last update from 192.168.1.1 00:00:06 ago Routing Descriptor Blocks: * 192.168.1.1, from 192.168.1.1, 00:00:06 ago Route metric is 0, traffic share count is 1 AS Hops 1 Route tag 100 R2(config-router)#R2(config-router)#do ping 192.168.1.1 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds: ..... Success rate is 0 percent (0/5) R2(config-router)#
show status BGPnya juga up down up down selalu....
*Mar 1 00:49:43.299: %BGP-3-NOTIFICATION: sent to neighbor 192.168.2.1 4/0 (hold time expired) 0 bytes
*Mar 1 00:50:09.743: %BGP-5-ADJCHANGE: neighbor 192.168.2.1 Up
*Mar 1 00:53:09.859: %BGP-5-ADJCHANGE: neighbor 192.168.2.1 Down BGP Notification sent
*Mar 1 00:53:09.859: %BGP-3-NOTIFICATION: sent to neighbor 192.168.2.1 4/0 (hold time expired) 0 bytes
*Mar 1 00:53:45.243: %BGP-5-ADJCHANGE: neighbor 192.168.2.1 Up
*Mar 1 00:59:45.675: %BGP-5-ADJCHANGE: neighbor 192.168.2.1 Down BGP Notification sent
*Mar 1 00:59:45.675: %BGP-3-NOTIFICATION: sent to neighbor 192.168.2.1 4/0 (hold time expired) 0 bytes
untuk solve problem ini, agar BGP up dan bisa ping ke semua loopbacknya, kita menggunakan Backdoor..
dari sisi R3 confignya seperti ini:
router bgp 300
no synchronization
bgp log-neighbor-changes
network 192.168.2.0 backdoor
neighbor 192.168.2.1 remote-as 200
neighbor 192.168.2.1 ebgp-multihop 2
neighbor 192.168.2.1 update-source Loopback0
no auto-summary
R1 confignya seperti ini :
router bgp 100
no synchronization
bgp log-neighbor-changes
network 192.168.1.1 mask 255.255.255.255
network 192.168.2.0 backdoor
neighbor 192.168.2.1 remote-as 200
neighbor 192.168.2.1 ebgp-multihop 2
neighbor 192.168.2.1 update-source Loopback0
no auto-summary
lalu R2
router bgp 200
no synchronization
bgp log-neighbor-changes
network 192.168.1.0 backdoor
network 192.168.3.0 backdoor
neighbor 192.168.1.1 remote-as 100
neighbor 192.168.1.1 ebgp-multihop 2
neighbor 192.168.1.1 update-source Loopback0
neighbor 192.168.3.1 remote-as 300
neighbor 192.168.3.1 ebgp-multihop 2
neighbor 192.168.3.1 update-source Loopback0
no auto-summary
kalo kita ping dari R3 ke loopback R1, maka hasilnya 100% success
R3(config-router)#do ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/69/108 ms
begitu juga sebaliknya
R1#ping 192.168.3.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 52/77/104 ms
sekarang kalau kita lihat, R3 mengenal R1 loopback via BGP
R3(config-router)#do sh ip route | beg Gate Gateway of last resort is not set 10.0.0.0/26 is subnetted, 2 subnets C 10.23.23.0 is directly connected, Serial1/1 O 10.12.12.0 [110/128] via 10.23.23.2, 00:23:30, Serial1/1B 192.168.1.0/24 [20/0] via 192.168.2.1, 00:18:39 O 192.168.2.0/24 [110/65] via 10.23.23.2, 00:06:35, Serial1/1 C 192.168.3.0/24 is directly connected, Loopback0 R3(config-router)#
cukup sekian dulu..see u in the next post.....
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