sj2
router bgp 100
neigh 192.168.1.5 remote-as 100
neigh 172.24.1.18 remote-as 100
sj1
router bgp 100
neigh 192.168.1.6 remote-as 100
sj3
router bgp 100
neigh 172.24.1.17 remote-as 100
sj2#sh ip bgp neigh | incl BGP
BGP neighbor is 172.24.1.18, remote AS 100, internal link
BGP version 4, remote router ID 172.24.1.18
BGP state = Established, up for 00:00:38
BGP table version 1, neighbor version 1/0
BGP neighbor is 192.168.1.5, remote AS 100, internal link
BGP version 4, remote router ID 192.168.1.5
BGP state = Established, up for 00:01:02
BGP table version 1, neighbor version 1/0
there is no connection yet for sj1 to sj3, and flip-flop...
sj2#sh ip route bgp
Gateway of last resort is not set
B 198.133.219.0/24 [200/0] via 172.24.1.18, 00:01:10
sj1#sh ip route bgp
Gateway of last resort is not set
sj1#
nope...
sj1 and sj3 are not peers... they are not fully meshed, and peering is not automatic as a result...
it's why we're doing this...
sj2
router bgp 100
neigh 192.168.1.5 route-reflector-client
neigh 172.24.1.18 route-reflector-client
so we make the neighbors reflector clients of sj2... they like this...
sj2(config-router)#
*Aug 27 16:08:57: %BGP-5-ADJCHANGE: neighbor 192.168.1.5 Down RR client config change
*Aug 27 16:08:57: %BGP_SESSION-5-ADJCHANGE: neighbor 192.168.1.5 IPv4 Unicast topology base removed from session RR client config change
*Aug 27 16:08:57: %BGP-5-ADJCHANGE: neighbor 192.168.1.5 Up
sj2(config-router)#end
*Aug 27 16:08:58: %BGP-5-ADJCHANGE: neighbor 172.24.1.18 Down RR client config change
*Aug 27 16:08:58: %BGP_SESSION-5-ADJCHANGE: neighbor 172.24.1.18 IPv4 Unicast topology base removed from session RR client config change
*Aug 27 16:08:58: %BGP-5-ADJCHANGE: neighbor 172.24.1.18 Up
sj2#sh ip proto | beg "bgp 100"
Routing Protocol is "bgp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Route Reflector for address family IPv4 Unicast, 2 clients
IGP synchronization is disabled
Automatic route summarization is disabled
Neighbor(s):
Address FiltIn FiltOut DistIn DistOut Weight RouteMap
172.24.1.18
192.168.1.5
Maximum path: 1
Routing Information Sources:
Gateway Distance Last Update
172.24.1.18 200 00:05:21
Distance: external 20 internal 200 local 200
there are no references to route reflectors on the clients because, they're clients...
sj1#sh ip route bgp
Gateway of last resort is not set
B 198.133.219.0/24 [200/0] via 172.24.1.18, 00:08:48
sj1#ping 198.133.219.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/12 ms
note the next hop to sj3 for sj1 is not sj2...
The atomic aggregate flag notifies neighbors that traffic sent to this aggregate may not actually follow the advertised AS Path.
make a summary address to inject into bgp on sj3
router bgp 100
aggregate-address 198.0.0.0 255.0.0.0
BGP routing table entry for 198.0.0.0/8, version 5
Paths: (1 available, best #1, table default)
Advertised to update-groups:
2
Refresh Epoch 1
Local, (aggregated by 100 172.24.1.18), (Received from a RR-client)
172.24.1.18 from 172.24.1.18 (172.24.1.18)
Origin IGP, metric 0, localpref 100, valid, internal, atomic-aggregate, best
rx pathid: 0, tx pathid: 0x0
The atomic aggregate flag notifies neighbors that traffic sent to this aggregate may not actually follow the advertised AS Path.
i used to work with a guy years ago who had a band called, atomic johnson...
sj1#sh ip route bgp
Gateway of last resort is not set
B 198.0.0.0/8 [200/0] via 172.24.1.18, 00:04:33
B 198.133.219.0/24 [200/0] via 172.24.1.18, 00:29:38
only send the supernet 198.0.0.0/8 to sj1...
sj2
ip prefix-list superman permit 198.0.0.0/8
router bgp 100
neigh 192.168.1.5 prefix-list superman out
kill it softly first...
sj1#sh ip route bgp
Gateway of last resort is not set
B 198.0.0.0/8 [200/0] via 172.24.1.18, 00:00:17
foreach address {
10.2.2.1
198.133.219.1
192.168.1.5
192.168.1.6
172.24.1.17
172.24.1.18
} { ping $address }
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/8 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.133.219.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/8/8 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.6, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.17, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.24.1.18, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 4/8/12 ms
sj1(tcl)#
very exciting...
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