➡
BGP の練習
本エントリについて
Dynagen、Dynamips を使って、BGP を練習します。
Dynagen、Dynamips の利用環境はすでに整っているものとします。
[[ROUTER r1]]
model = 3725
console = 2001
f0/0 = NIO_tap:tap0
s1/2 = r2 s1/2
s1/3 = r3 s1/2
[[ROUTER r2]]
model = 3725
console = 2002
f0/0 = NIO_udp:30000:127.0.0.1:20000
s1/0 = r4 s1/1
[[ROUTER r3]]
model = 3725
console = 2003
f0/0 = NIO_udp:30001:127.0.0.1:20001
s1/0 = r2 s1/1
[[ROUTER r4]]
model = 3725
console = 2004
f0/0 = NIO_udp:30002:127.0.0.1:20002
s1/0 = r3 s1/1
事前設定
事前設定として、各ルータで以下のように設定します。
手順については割愛します。
r1#show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.2.0.254 YES NVRAM up up
FastEthernet0/1 unassigned YES NVRAM administratively down down
Serial1/0 unassigned YES NVRAM administratively down down
Serial1/1 unassigned YES NVRAM administratively down down
Serial1/2 172.16.0.253 YES NVRAM up up
Serial1/3 172.16.0.249 YES NVRAM up up
Loopback0 1.1.1.1 YES NVRAM up up
r1#show cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Device ID Local Intrfce Holdtme Capability Platform Port ID
r2 Ser 1/2 145 R S I 3725 Ser 1/2
r3 Ser 1/3 173 R S I 3725 Ser 1/2
r1#show ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
1.1.1.1 0.0.0.0 area 0
10.2.0.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Passive Interface(s):
FastEthernet0/0
Routing Information Sources:
Gateway Distance Last Update
Distance: (default is 110)
r2#show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.2.1.254 YES NVRAM up up
FastEthernet0/1 unassigned YES NVRAM administratively down down
Serial1/0 172.16.1.253 YES NVRAM up up
Serial1/1 172.16.3.254 YES NVRAM up up
Serial1/2 172.16.0.254 YES NVRAM up up
Serial1/3 unassigned YES NVRAM administratively down down
Loopback0 2.2.2.2 YES NVRAM up up
r2#show cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Device ID Local Intrfce Holdtme Capability Platform Port ID
r3 Ser 1/1 134 R S I 3725 Ser 1/0
r1 Ser 1/2 120 R S I 3725 Ser 1/2
r4 Ser 1/0 162 R S I 3725 Ser 1/1
r2#show ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 2.2.2.2
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
2.2.2.2 0.0.0.0 area 0
10.2.1.0 0.0.0.255 area 0
172.16.1.0 0.0.0.255 area 0
172.16.3.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Passive Interface(s):
FastEthernet0/0
Routing Information Sources:
Gateway Distance Last Update
4.4.4.4 110 00:00:46
3.3.3.3 110 00:01:30
Distance: (default is 110)
r3#show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.2.2.254 YES NVRAM up up
FastEthernet0/1 unassigned YES NVRAM administratively down down
Serial1/0 172.16.3.253 YES NVRAM up up
Serial1/1 172.16.2.254 YES NVRAM up up
Serial1/2 172.16.0.250 YES NVRAM up up
Serial1/3 unassigned YES NVRAM administratively down down
Loopback0 3.3.3.3 YES NVRAM up up
r3#show cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Device ID Local Intrfce Holdtme Capability Platform Port ID
r2 Ser 1/0 151 R S I 3725 Ser 1/1
r1 Ser 1/2 154 R S I 3725 Ser 1/3
r4 Ser 1/1 166 R S I 3725 Ser 1/0
r3#show ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 3.3.3.3
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
3.3.3.3 0.0.0.0 area 0
10.2.2.0 0.0.0.255 area 0
172.16.2.0 0.0.0.255 area 0
172.16.3.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Passive Interface(s):
FastEthernet0/0
Routing Information Sources:
Gateway Distance Last Update
4.4.4.4 110 00:02:13
2.2.2.2 110 00:02:50
Distance: (default is 110)
r4#show ip int bri
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 10.2.3.254 YES NVRAM up up
FastEthernet0/1 unassigned YES NVRAM administratively down down
Serial1/0 172.16.2.253 YES NVRAM up up
Serial1/1 172.16.1.254 YES NVRAM up up
Serial1/2 unassigned YES NVRAM administratively down down
Serial1/3 unassigned YES NVRAM administratively down down
Loopback0 4.4.4.4 YES NVRAM up up
r4#show cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater
Device ID Local Intrfce Holdtme Capability Platform Port ID
r2 Ser 1/1 128 R S I 3725 Ser 1/0
r3 Ser 1/0 126 R S I 3725 Ser 1/1
r4#show ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 4.4.4.4
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
4.4.4.4 0.0.0.0 area 0
10.2.3.0 0.0.0.255 area 0
172.16.1.0 0.0.0.255 area 0
172.16.2.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Passive Interface(s):
FastEthernet0/0
Routing Information Sources:
Gateway Distance Last Update
2.2.2.2 110 00:02:47
3.3.3.3 110 00:02:57
Distance: (default is 110)
BGP の有効化
eBGP は異なるAS間、iBGP は同じAS内の接続です。
eBGP
r1 で BGPを有効化します。
BGPでは明示的にピアルータを指定します。
r1(config)#router bgp 65001
r1(config-router)#neigh 172.16.0.254 remote-as 65002
r1(config-router)#network 10.2.0.0 mask 255.255.255.0
状態を確認します。
r1#show ip bgp summary
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 1, main routing table version 1
1 network entries using 120 bytes of memory
1 path entries using 52 bytes of memory
2/0 BGP path/bestpath attribute entries using 248 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 420 total bytes of memory
BGP activity 1/0 prefixes, 1/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.254 4 65002 0 0 0 0 0 never Idle
r1#show ip bgp
BGP table version is 1, local router ID is 1.1.1.1
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
* 10.2.0.0/24 0.0.0.0 0 32768 i
r2 で BGPを有効化します。
r2(config)#router bgp 65002
r2(config-router)#neighbor 172.16.0.253 remote-as 65001
r2(config-router)#network 10.2.1.0 mask 255.255.255.0
状態を確認します。
r2#show ip bgp summary
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 1, main routing table version 1
1 network entries using 120 bytes of memory
1 path entries using 52 bytes of memory
2/0 BGP path/bestpath attribute entries using 248 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 420 total bytes of memory
BGP activity 1/0 prefixes, 1/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.253 4 65001 0 0 0 0 0 never Idle
r2#show ip bgp summary
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 3, main routing table version 3
2 network entries using 240 bytes of memory
2 path entries using 104 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 bytes of memory
1 BGP AS-PATH entries using 24 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 772 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.253 4 65001 4 4 3 0 0 00:00:48 1
r2#show ip bgp
BGP table version is 3, local router ID is 2.2.2.2
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
*> 10.2.0.0/24 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 00:00:34
r1でも確認します。
r1#show ip bgp summary
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 3, main routing table version 3
2 network entries using 240 bytes of memory
2 path entries using 104 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 bytes of memory
1 BGP AS-PATH entries using 24 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 772 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.254 4 65002 6 6 3 0 0 00:02:51 1
r1#show ip bgp
BGP table version is 3, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
*> 10.2.1.0/24 172.16.0.254 0 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 2 subnets
B 10.2.1.0 [20/0] via 172.16.0.254, 00:02:36
iBGP
r2 でピア設定を追加します。MD5認証についても設定しています。
r2(config)#router bgp 65002
r2(config-router)#neighbor 172.16.3.253 remote-as 65002
r2(config-router)#neighbor 172.16.3.253 password cisco
r3 でBGPを有効化します。r2 と同様に、MD5認証についても設定しています。
r3(config)#router bgp 65002
r3(config-router)#neighbor 172.16.3.254 remote-as 65002
r3(config-router)#neighbor 172.16.3.254 password cisco
r3(config-router)#network 10.2.2.0 mask 255.255.255.0
状態を確認します。
トポロジーテーブルの r(RIB-failure) は、他のルーティングプロトコル(ここではospf)で学習した経路を表します。
r3#show ip bgp summ
BGP router identifier 3.3.3.3, local AS number 65002
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
4/2 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1068 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
172.16.3.254 4 65002 9 8 4 0 0 00:03:42 2
r3#show ip bgp
BGP table version is 4, 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
* i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r3#show ip route bgp
r2でも状態を確認します。
r2#show ip bgp summary
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 5, main routing table version 5
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
1 BGP AS-PATH entries using 24 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 3 (at peak 3) using 96 bytes of memory
BGP using 1132 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
172.16.0.253 4 65001 13 14 5 0 0 00:09:43 1
172.16.3.253 4 65002 9 10 5 0 0 00:04:55 1
r2#show ip bgp
BGP table version is 5, local router ID is 2.2.2.2
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
*> 10.2.0.0/24 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 00:09:23
r1 で状態を確認します。
r1#show ip bgp summary
BGP router identifier 1.1.1.1, local AS number 65001
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
1 BGP AS-PATH entries using 24 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 1068 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
172.16.0.254 4 65002 15 14 4 0 0 00:10:31 2
r1#show ip bgp
BGP table version is 4, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
*> 10.2.1.0/24 172.16.0.254 0 0 65002 i
*> 10.2.2.0/24 172.16.0.254 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 3 subnets
B 10.2.1.0 [20/0] via 172.16.0.254, 00:10:11
B 10.2.2.0 [20/0] via 172.16.0.254, 00:05:47
loopback インタフェースの利用
ピアルータのloopbackインタフェースのアドレスを、ピアルータのアドレスとして指定します。
送信元アドレスとして、自身のloopbackインタフェースのアドレスを利用します。
r3(config)#router bgp 65002
r3(config-router)#neighbor 4.4.4.4 remote-as 65002
r3(config-router)#neighbor 4.4.4.4 update-source loopback 0
r4 でも同様に設定します。
r4(config)#router bgp 65002
r4(config-router)#neighbor 3.3.3.3 remote-as 65002
r4(config-router)#neighbor 3.3.3.3 update-source loopback 0
r4(config-router)#network 10.2.3.0 mask 255.255.255.0
r4 で状態を確認します。
r4#show ip bgp summ
BGP router identifier 4.4.4.4, local AS number 65002
BGP table version is 4, main routing table version 4
2 network entries using 240 bytes of memory
2 path entries using 104 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 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 748 total bytes of memory
BGP activity 2/0 prefixes, 2/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3.3 4 65002 5 5 4 0 0 00:00:57 1
r4#show ip bgp
BGP table version is 4, local router ID is 4.4.4.4
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
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
r3 で状態を確認します。
r3#show ip bgp summ
BGP router identifier 3.3.3.3, local AS number 65002
BGP table version is 6, main routing table version 6
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/2 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1240 total bytes of memory
BGP activity 4/0 prefixes, 4/0 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 6 6 6 0 0 00:01:33 1
172.16.3.254 4 65002 16 15 6 0 0 00:10:12 2
r3#show ip bgp
BGP table version is 6, 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
* i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
r2 で状態を確認します。
r2#show ip bgp
BGP table version is 5, local router ID is 2.2.2.2
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
*> 10.2.0.0/24 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 00:15:23
r1 で状態を確認します。
r1#show ip bgp
BGP table version is 4, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
*> 10.2.1.0/24 172.16.0.254 0 0 65002 i
*> 10.2.2.0/24 172.16.0.254 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 3 subnets
B 10.2.1.0 [20/0] via 172.16.0.254, 00:16:05
B 10.2.2.0 [20/0] via 172.16.0.254, 00:11:40
ルートリフレクタ
iBGPでは、iGBPスプリットホライズンにより、ピアから入手した経路を他のピアにアドバタイズしません。
ルートリフレクタを利用することで、アドバタイズを他のピアへ転送するようになります。
フルメッシュのピアを張らなくても、ルートリフレクタとのピア設定だけですむようになります。
r3(config)#router bgp 65002
r3(config-router)#neighbor 172.16.3.254 route-reflector-client
r3(config-router)#neighbor 4.4.4.4 route-reflector-client
状態を確認します。
r3#show ip bgp summ
BGP router identifier 3.3.3.3, local AS number 65002
BGP table version is 12, main routing table version 12
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/2 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 2) using 32 bytes of memory
BGP using 1240 total bytes of memory
BGP activity 4/0 prefixes, 7/3 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 16 18 12 0 0 00:01:51 1
172.16.3.254 4 65002 27 28 12 0 0 00:01:55 2
r3#show ip bgp
BGP table version is 12, 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
* i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
r4 で状態を確認します。
r4#show ip bgp summ
BGP router identifier 4.4.4.4, local AS number 65002
BGP table version is 9, main routing table version 9
3 network entries using 360 bytes of memory
3 path entries using 156 bytes of memory
3/2 BGP path/bestpath attribute entries using 372 bytes of memory
1 BGP rrinfo entries using 24 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 2) using 32 bytes of memory
BGP using 944 total bytes of memory
BGP activity 4/1 prefixes, 4/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
3.3.3.3 4 65002 19 17 9 0 0 00:02:43 2
r4#show ip bgp
BGP table version is 9, local router ID is 4.4.4.4
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
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
r2 で状態を確認します。
r2#show ip bgp summary
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 10, main routing table version 10
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP rrinfo entries using 24 bytes of memory
1 BGP AS-PATH entries using 24 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 3 (at peak 4) using 96 bytes of memory
BGP using 1328 total bytes of memory
BGP activity 4/0 prefixes, 5/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.253 4 65001 26 30 10 0 0 00:22:47 1
172.16.3.253 4 65002 30 29 10 0 0 00:03:19 2
r2#show ip bgp
BGP table version is 10, local router ID is 2.2.2.2
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
*> 10.2.0.0/24 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 00:22:28
OSPFでAS内に 172.16.0.252/30 の経路を追加します。
r2(config)#router ospf 1
r2(config-router)#network 172.16.0.252 0.0.0.3 area 0
r2(config-router)#passive-interface s1/2
r3 で状態を確認します。
r3#show ip bgp
BGP table version is 13, 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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:00:40
r4 で状態を確認します。
r4#show ip bgp
BGP table version is 10, local router ID is 4.4.4.4
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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:01:03
疎通確認を実施します。
r4#ping
Protocol [ip]:
Target IP address: 10.2.0.254
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: 10.2.3.254
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.2.0.254, timeout is 2 seconds:
Packet sent with a source address of 10.2.3.254
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/38/44 ms
ピアグループ
事前設定として、r2 でピア設定を追加します。
r2(config)#router bgp 65002
r2(config-router)#neighbor 4.4.4.4 remote-as 65002
r2(config-router)#neighbor 4.4.4.4 update-source loopback 0
状態を確認します。
r2#show ip bgp summ
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 10, main routing table version 10
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP rrinfo entries using 24 bytes of memory
1 BGP AS-PATH entries using 24 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 3 (at peak 4) using 96 bytes of memory
BGP using 1328 total bytes of memory
BGP activity 4/0 prefixes, 5/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 0 0 0 0 0 never Active
172.16.0.253 4 65001 48 52 10 0 0 00:44:05 1
172.16.3.253 4 65002 52 50 10 0 0 00:24:37 2
r4 でピアグループを利用してピア設定を追加します。
r4(config)#router bgp 65002
r4(config-router)#neighbor ccna peer-group
r4(config-router)#neighbor ccna remote-as 65002
r4(config-router)#neighbor ccna update-source loopback 0
r4(config-router)#neighbor 2.2.2.2 peer-group ccna
状態を確認します。
r4#show ip bgp summ
BGP router identifier 4.4.4.4, local AS number 65002
BGP table version is 12, main routing table version 12
4 network entries using 480 bytes of memory
6 path entries using 312 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP rrinfo entries using 24 bytes of memory
1 BGP AS-PATH entries using 24 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 2) using 32 bytes of memory
BGP using 1368 total bytes of memory
BGP activity 5/1 prefixes, 7/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
2.2.2.2 4 65002 6 5 12 0 0 00:00:16 2
3.3.3.3 4 65002 44 41 12 0 0 00:26:18 3
r4#show ip bgp
BGP table version is 12, local router ID is 4.4.4.4
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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
* i 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 2.2.2.2 0 100 0 i
r i 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:00:27
r2 で状態を確認します。
r2#show ip bgp summ
BGP router identifier 2.2.2.2, local AS number 65002
BGP table version is 11, main routing table version 11
4 network entries using 480 bytes of memory
5 path entries using 260 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP rrinfo entries using 24 bytes of memory
1 BGP AS-PATH entries using 24 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 3 (at peak 4) using 96 bytes of memory
BGP using 1380 total bytes of memory
BGP activity 4/0 prefixes, 6/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 5 6 11 0 0 00:00:55 1
172.16.0.253 4 65001 50 54 11 0 0 00:46:28 1
172.16.3.253 4 65002 55 53 11 0 0 00:27:00 2
r2#show ip bgp
BGP table version is 11, local router ID is 2.2.2.2
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
*> 10.2.0.0/24 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r i 4.4.4.4 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 00:46:11
r3 で状態を確認します。
r3#show ip bgp summ
BGP router identifier 3.3.3.3, local AS number 65002
BGP table version is 13, main routing table version 13
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 2) using 32 bytes of memory
BGP using 1240 total bytes of memory
BGP activity 4/0 prefixes, 7/3 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 43 46 13 0 0 00:28:10 1
172.16.3.254 4 65002 54 56 13 0 0 00:28:13 2
r3#show ip bgp
BGP table version is 13, 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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:13:04
パスアトリビュート
練習を進める前に、eBGP 接続を追加します。
r1(config)#router bgp 65001
r1(config-router)#neighbor 172.16.0.250 remote-as 65002
r1(config-router)#network 10.2.0.0 mask 255.255.255.0
状態を確認します。
r1#show ip bgp summ
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 7, main routing table version 7
4 network entries using 480 bytes of memory
4 path entries using 208 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1240 total bytes of memory
BGP activity 5/1 prefixes, 5/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.250 4 65002 0 0 0 0 0 never Active
172.16.0.254 4 65002 73 69 7 0 0 01:05:18 3
r3(config)#router bgp 65002
r3(config-router)#neighbor 172.16.0.249 remote-as 65001
r3#show ip bgp summ
BGP router identifier 3.3.3.3, local AS number 65002
BGP table version is 14, main routing table version 14
4 network entries using 480 bytes of memory
5 path entries using 260 bytes of memory
5/3 BGP path/bestpath attribute entries using 620 bytes of memory
1 BGP AS-PATH entries using 24 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 2 (at peak 2) using 64 bytes of memory
BGP using 1448 total bytes of memory
BGP activity 4/0 prefixes, 8/3 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
4.4.4.4 4 65002 64 68 14 0 0 00:49:33 1
172.16.0.249 4 65001 7 6 14 0 0 00:00:06 1
172.16.3.254 4 65002 75 78 14 0 0 00:49:37 2
r3#show ip bgp
BGP table version is 14, 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
*> 10.2.0.0/24 172.16.0.249 0 0 65001 i
* i 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.249, 00:00:57
r1 で状態を確認します。
r1#show ip bgp summ
BGP router identifier 1.1.1.1, local AS number 65001
BGP table version is 7, main routing table version 7
4 network entries using 480 bytes of memory
7 path entries using 364 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP AS-PATH entries using 24 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 1396 total bytes of memory
BGP activity 5/1 prefixes, 8/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
172.16.0.250 4 65002 7 8 7 0 0 00:01:14 3
172.16.0.254 4 65002 78 74 7 0 0 01:10:12 3
r1#show ip bgp
BGP table version is 7, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
* 10.2.1.0/24 172.16.0.250 0 65002 i
*> 172.16.0.254 0 0 65002 i
* 10.2.2.0/24 172.16.0.250 0 0 65002 i
*> 172.16.0.254 0 65002 i
* 10.2.3.0/24 172.16.0.250 0 65002 i
*> 172.16.0.254 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.1.0 [20/0] via 172.16.0.254, 01:09:54
B 10.2.2.0 [20/0] via 172.16.0.254, 00:50:56
B 10.2.3.0 [20/0] via 172.16.0.254, 00:50:26
r4#show ip bgp summ
BGP router identifier 4.4.4.4, local AS number 65002
BGP table version is 12, main routing table version 12
4 network entries using 480 bytes of memory
6 path entries using 312 bytes of memory
4/3 BGP path/bestpath attribute entries using 496 bytes of memory
1 BGP rrinfo entries using 24 bytes of memory
1 BGP AS-PATH entries using 24 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 2) using 32 bytes of memory
BGP using 1368 total bytes of memory
BGP activity 5/1 prefixes, 7/1 paths, scan interval 60 secs
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
2.2.2.2 4 65002 31 30 12 0 0 00:25:13 2
3.3.3.3 4 65002 70 66 12 0 0 00:51:15 3
r4#show ip bgp
BGP table version is 12, local router ID is 4.4.4.4
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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
* i 172.16.0.249 0 100 0 65001 i
r>i10.2.1.0/24 2.2.2.2 0 100 0 i
r i 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:25:20
Weight
Weightの設定を変更してみます。
r1(config)#access-list 1 permit 10.2.3.0 0.0.0.255
r1(config)#route-map WEIGHT permit 10
r1(config-route-map)#match ip address 1
r1(config-route-map)#set weight 100
r1(config-route-map)#route-map WEIGHT permit 20
r1(config-route-map)#router bgp 65001
r1(config-router)#neighbor 172.16.0.250 route-map WEIGHT in
r1#clear ip bgp 172.16.0.250 soft in
状態を確認します。
r1#show ip bgp
BGP table version is 8, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
* 10.2.1.0/24 172.16.0.250 0 65002 i
*> 172.16.0.254 0 0 65002 i
* 10.2.2.0/24 172.16.0.250 0 0 65002 i
*> 172.16.0.254 0 65002 i
*> 10.2.3.0/24 172.16.0.250 100 65002 i
* 172.16.0.254 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.1.0 [20/0] via 172.16.0.254, 06:18:59
B 10.2.2.0 [20/0] via 172.16.0.254, 06:00:01
B 10.2.3.0 [20/0] via 172.16.0.250, 00:00:32
Local Preference
r2#show ip bgp
BGP table version is 11, local router ID is 2.2.2.2
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
* i10.2.0.0/24 172.16.0.249 0 100 0 65001 i
*> 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r i 4.4.4.4 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 06:29:37
r3#show ip bgp
BGP table version is 14, 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
*> 10.2.0.0/24 172.16.0.249 0 0 65001 i
* i 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.249, 05:21:32
r4#show ip bgp
BGP table version is 12, local router ID is 4.4.4.4
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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
* i 172.16.0.249 0 100 0 65001 i
r>i10.2.1.0/24 2.2.2.2 0 100 0 i
r i 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 05:44:01
Local Reference の値を変更してみます。
r3(config)#access-list 1 permit 10.2.0.0 0.0.0.255
r3(config)#route-map LOCALPREF permit 10
r3(config-route-map)#match ip address 1
r3(config-route-map)#set local-preference 300
r3(config-route-map)#route-map LP permit 20
r3(config-route-map)#router bgp 65002
r3(config-router)#neighbor 172.16.0.249 route-map LOCALPREF in
r3#clear ip bgp 172.16.0.249 soft in
状態を確認します。
r3#show ip bgp
BGP table version is 16, 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
*> 10.2.0.0/24 172.16.0.249 0 300 0 65001 i
* i 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.249, 00:05:14
r2#show ip bgp
BGP table version is 13, local router ID is 2.2.2.2
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
* i10.2.0.0/24 172.16.0.249 0 300 0 65001 i
*> 172.16.0.253 0 0 65001 i
*> 10.2.1.0/24 0.0.0.0 0 32768 i
r>i10.2.2.0/24 172.16.3.253 0 100 0 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r i 4.4.4.4 0 100 0 i
r2#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [20/0] via 172.16.0.253, 06:41:16
r4#show ip bgp
BGP table version is 14, local router ID is 4.4.4.4
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
*>i10.2.0.0/24 172.16.0.253 0 100 0 65001 i
* i 172.16.0.249 0 300 0 65001 i
r>i10.2.1.0/24 2.2.2.2 0 100 0 i
r i 172.16.3.254 0 100 0 i
r>i10.2.2.0/24 3.3.3.3 0 100 0 i
*> 10.2.3.0/24 0.0.0.0 0 32768 i
r4#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 05:56:50
MED
MED の値を変更してみます。
r2(config)#access-list 11 permit 10.2.1.0 0.0.0.255
r2(config)#access-list 12 permit 10.2.2.0 0.0.0.255
r2(config)#route-map MED permit 10
r2(config-route-map)#match ip address 11
r2(config-route-map)#set metric 10
r2(config-route-map)#route-map MED permit 20
r2(config-route-map)#match ip address 21
r2(config-route-map)#set metric 20
r2(config-route-map)#route-map MED permit 30
r2(config)#router bgp 65002
r2(config-router)#neighbor 172.16.0.253 route-map MED out
r2#clear ip bgp 172.16.0.253 soft out
不要な設定を削除した後、状態を確認します。
r1(config)#router bgp 65001
r1(config-router)#no neighbor 172.16.0.250 route-map WEIGHT in
r1#clear ip bgp 172.16.0.250 soft in
r1#show ip bgp
BGP table version is 11, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
*> 10.2.1.0/24 172.16.0.250 0 65002 i
* 172.16.0.254 10 0 65002 i
*> 10.2.2.0/24 172.16.0.250 0 0 65002 i
* 172.16.0.254 20 0 65002 i
*> 10.2.3.0/24 172.16.0.250 0 65002 i
* 172.16.0.254 20 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.1.0 [20/0] via 172.16.0.250, 00:03:18
B 10.2.2.0 [20/0] via 172.16.0.250, 00:03:18
B 10.2.3.0 [20/0] via 172.16.0.250, 00:42:11
r3 で設定変更してみます。
r3(config)#access-list 11 permit 10.2.1.0 0.0.0.255
r3(config)#access-list 12 permit 10.2.2.0 0.0.0.255
r3(config)#route-map MED permit 10
r3(config-route-map)#match ip address 11
r3(config-route-map)#set metric 20
r3(config-route-map)#route-map MED permit 20
r3(config-route-map)#match ip address 21
r3(config-route-map)#set metric 10
r3(config-route-map)#route-map MED permit 30
r3(config-route-map)#router bgp 65002
r3(config-router)#neighbor 172.16.0.249 route-map MED out
r3#clear ip bgp 172.16.0.249 soft out
r1 で状態を確認します。
r1#show ip bgp
BGP table version is 14, local router ID is 1.1.1.1
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
*> 10.2.0.0/24 0.0.0.0 0 32768 i
* 10.2.1.0/24 172.16.0.250 20 0 65002 i
*> 172.16.0.254 10 0 65002 i
*> 10.2.2.0/24 172.16.0.250 10 0 65002 i
* 172.16.0.254 20 0 65002 i
*> 10.2.3.0/24 172.16.0.250 10 0 65002 i
* 172.16.0.254 20 0 65002 i
r1#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.1.0 [20/10] via 172.16.0.254, 00:00:22
B 10.2.2.0 [20/10] via 172.16.0.250, 00:00:22
B 10.2.3.0 [20/10] via 172.16.0.250, 00:00:22
AS PATH
r1 で設定を変更してみます。
r1(config)#ip prefix-list PRFLIST permit 10.2.0.0/24
r1(config)#route-map ASPATH permit 10
r1(config-route-map)#match ip address prefix-list PRFLIST
r1(config-route-map)#set as-path prepend 65001 65001
r1(config-route-map)#route-map ASPATH permit 20
r1(config-route-map)#router bgp 65001
r1(config-router)#neighbor 172.16.0.250 route-map ASPATH out
r1#clear ip bgp 172.16.0.250 soft out
r3 で不要な設定を削除して、状態を確認してみます。
r3(config)#router bgp 65002
r3(config-router)#no neighbor 172.16.0.249 route-map LOCALPREF in
r3#clear ip bgp 172.16.0.249 soft in
r3#show ip bgp
BGP table version is 18, 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
* 10.2.0.0/24 172.16.0.249 0 0 65001 65001 65001 i
*>i 172.16.0.253 0 100 0 65001 i
r>i10.2.1.0/24 172.16.3.254 0 100 0 i
*> 10.2.2.0/24 0.0.0.0 0 32768 i
r>i10.2.3.0/24 4.4.4.4 0 100 0 i
r3#show ip route bgp
10.0.0.0/24 is subnetted, 4 subnets
B 10.2.0.0 [200/0] via 172.16.0.253, 00:02:11
まとめ
Dynagen、Dynamips を使って、BGP を練習しました。
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