JUNOS_BGP_その１(timer)

JUNOSのBGP
まずか簡単なところから構成は↓

R4はR6のConfigはR3とR5と似た内容なので、省略

R3

 R3#show run | sec router bgp 100
router bgp 100
　bgp router-id 1.1.1.3
　bgp log-neighbor-changes
　neighbor 172.16.4.254 remote-as 100
　neighbor 172.16.5.254 remote-as 200
　!
　address-family ipv4
　 network 1.1.1.3 mask 255.255.255.255
　 neighbor 172.16.4.254 activate
　 neighbor 172.16.4.254 next-hop-self
　 neighbor 172.16.4.254 soft-reconfiguration inbound
　 neighbor 172.16.5.254 activate
　 neighbor 172.16.5.254 soft-reconfiguration inbound
　exit-address-family

R5

router-id 2.1.1.5;
autonomous-system 200;
set policy-options prefix-list LOCAL 2.1.1.5/32
set policy-options policy-statement EXT term 1 from protocol bgp
set policy-options policy-statement EXT term 1 then next-hop self
set policy-options policy-statement EXT term 2 from prefix-list LOCAL
set policy-options policy-statement EXT term 2 then accept
set policy-options policy-statement INT term 1 from protocol bgp
set policy-options policy-statement INT term 1 then next-hop self
set policy-options policy-statement INT term 1 then accept
set policy-options policy-statement INT term 2 from prefix-list LOCAL
set policy-options policy-statement INT term 2 then next-hop self
set protocols bgp group external type external
set protocols bgp group external local-address 172.16.5.254
set protocols bgp group external neighbor 172.16.5.1 export EXT
set protocols bgp group external neighbor 172.16.5.1 peer-as 100
set protocols bgp group internal type internal
set protocols bgp group internal local-address 172.16.7.1
set protocols bgp group internal neighbor 172.16.7.254 export INT

R5でR6とのpeer確認

admin@R5# run show bgp neighbor 172.16.7.254
Peer: 172.16.7.254+54497 AS 200 Local: 172.16.7.1+179 AS 200
　 Group: internal Routing-Instance: master
　 Forwarding routing-instance: master
　 Type: Internal State: Established Flags: <Sync>
　 Last State: OpenConfirm Last Event: RecvKeepAlive
　 Last Error: Cease
　 Export: [ INT ]
　 Options: <Preference LocalAddress GracefulRestart Refresh>
　 Local Address: 172.16.7.1 Holdtime: 90 Preference: 170
　 Number of flaps: 9
　 Last flap event: Stop
　 Error: 'Cease' Sent: 7 Recv: 2
　 Peer ID: 2.1.1.6 Local ID: 2.1.1.5 Active Holdtime: 90
　 Keepalive Interval: 30 Group index: 1 Peer index: 0 SNMP index: 3

 R5でR3とのpeer確認

admin@R5# run show bgp neighbor 172.16.5.1
Peer: 172.16.5.1+36571 AS 100 Local: 172.16.5.254+179 AS 200
　 Group: external Routing-Instance: master
　 Forwarding routing-instance: master
　 Type: External State: Established Flags: <Sync>
　 Last State: OpenConfirm Last Event: RecvKeepAlive
　 Last Error: Cease
　 Export: [ EXT ]
　 Options: <Preference LocalAddress GracefulRestart PeerAS Refresh>
　 Local Address: 172.16.5.254 Holdtime: 90 Preference: 170
　 Number of flaps: 6
　 Last flap event: Stop
　 Error: 'Cease' Sent: 6 Recv: 0
　 Peer ID: 1.1.1.3 Local ID: 2.1.1.5 Active Holdtime: 90
　 Keepalive Interval: 30 Group index: 0 Peer index: 0 SNMP index: 2

JUNOSのinterval / holdtime は30/90
Ciscoのinterval / holdtime は60/180

BGPのtimer不一致時は小さいほうに従うので、このR3-R5はJUNOSに従っている。
R3側でも確認

 R3#show bgp ipv4 unicast neighbors 172.16.5.254
BGP neighbor is 172.16.5.254, remote AS 200, external link
　 BGP version 4, remote router ID 2.1.1.5
　 BGP state = Established, up for 00:57:07
　 Last read 00:00:13, last write 00:00:16, hold time is 90, keepalive interval is 30 seconds
　 Neighbor sessions:
　 1 active, is not multisession capable (disabled)

 念のため、R5との接続はデフォルト60/180になっている事を確認

 R3#show bgp ipv4 unicast neighbors 172.16.4.254
BGP neighbor is 172.16.4.254, remote AS 100, internal link
　 BGP version 4, remote router ID 1.1.1.4
　 BGP state = Established, up for 00:29:41
　 Last read 00:00:14, last write 00:00:18, hold time is 180, keepalive interval is 60 seconds
　 Neighbor sessions:
　 1 active, is not multisession capable (disabled)
　 Neighbor capabilities:

こっから本題

この状態でR3をtimer 10/30、R5を15/45に変更してみる。
この場合、R3-R5は10/30　R5-R6は15/45になると思われる。

変更後、R5でR3とのpeer確認

 admin@R5# run show bgp neighbor 172.16.5.1
Peer: 172.16.5.1+56976 AS 100 Local: 172.16.5.254+179 AS 200
　 Group: external Routing-Instance: master
　 Forwarding routing-instance: master
　 Type: External State: Established Flags: <Sync>
　 Last State: OpenConfirm Last Event: RecvKeepAlive
　 Last Error: None
　 Export: [ EXT ]
　 Options: <Preference LocalAddress HoldTime GracefulRestart PeerAS Refresh>
　 Local Address: 172.16.5.254 Holdtime: 45 Preference: 170
　 Number of flaps: 1
　 Last flap event: TransportError
　 Peer ID: 1.1.1.3 Local ID: 2.1.1.5 Active Holdtime: 30
　 Keepalive Interval: 10 Group index: 0 Peer index: 0 SNMP index: 2
　 I/O Session Thread: bgpio-0 State: Enabled

 変更後、R6でR5とのpeer確認

 admin@R6# run show bgp neighbor 172.16.7.1
Peer: 172.16.7.1+179 AS 200 Local: 172.16.7.254+64962 AS 200
　 Group: internal Routing-Instance: master
　 Forwarding routing-instance: master
　 Type: Internal State: Established Flags: <Sync>
　 Last State: OpenConfirm Last Event: RecvKeepAlive
　 Last Error: Cease
　 Export: [ INT ]
　 Options: <Preference LocalAddress GracefulRestart Refresh>
　 Local Address: 172.16.7.254 Holdtime: 90 Preference: 170
　 Number of flaps: 9
　 Last flap event: RecvNotify
　 Error: 'Cease' Sent: 1 Recv: 8
　 Peer ID: 2.1.1.5 Local ID: 2.1.1.6 Active Holdtime: 45
　 Keepalive Interval: 15 Group index: 1 Peer index: 0 SNMP index: 3