H O M E > ネットワークのおべんきょしませんか? Cisco CCNA/CCNP/CCIE、ネットワークスペシャリスト試験の勉強にピッタリ > 2010年8月
(所属カテゴリー:IPルーティング | シスコ---投稿日時:2010年8月27日)
下記のネットワーク構成で、AS123はAS4とAS5内の特定のネットワークのパケットをルーティングできるようにします。
R1では集約ルート5.5.0.0/16を生成します。また集約前の詳細なルートのうち5.5.0.0/24、5.5.2.0/24もR4にアドバタイズします。このために、Unsuppress-mapを利用するものとします。
R3では集約ルート4.4.0.0/16を生成します。集約前の詳細なルートのうち4.4.1.0/24と4.4.3.0/24もR5にアドバタイズします。これはSuppress-mapを利用します。
各ルータのBGPに関する設定は次の通りです。
R1
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
interface Loopback0
ip address 192.168.0.1 255.255.255.255
!
interface Ethernet0/0
ip address 172.16.14.1 255.255.255.0
!
interface Ethernet0/1
ip address 192.168.12.1 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 192.168.0.0 0.0.255.255 area 0
!
router bgp 123
no synchronization
bgp log-neighbor-changes
aggregate-address 5.5.0.0 255.255.0.0 summary-only
neighbor 172.16.14.4 remote-as 4
neighbor 172.16.14.4 unsuppress-map UNSUPP_R1
neighbor 192.168.0.2 remote-as 123
neighbor 192.168.0.2 update-source Loopback0
neighbor 192.168.0.2 next-hop-self
neighbor 192.168.0.3 remote-as 123
neighbor 192.168.0.3 update-source Loopback0
neighbor 192.168.0.3 next-hop-self
no auto-summary
!
access-list 1 permit 5.5.0.0
access-list 1 permit 5.5.2.0
!
route-map UNSUPP_R1 deny 10
match ip address 1
!
route-map UNSUPP_R1 permit 100
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R2
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
interface Loopback0
ip address 192.168.0.2 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.12.2 255.255.255.0
!
interface Ethernet0/1
ip address 192.168.23.2 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 192.168.0.0 0.0.255.255 area 0
!
router bgp 123
no synchronization
bgp log-neighbor-changes
neighbor 192.168.0.1 remote-as 123
neighbor 192.168.0.1 update-source Loopback0
neighbor 192.168.0.3 remote-as 123
neighbor 192.168.0.3 update-source Loopback0
no auto-summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R3
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
interface Loopback0
ip address 192.168.0.3 255.255.255.255
!
interface Ethernet0/0
ip address 192.168.23.3 255.255.255.0
!
interface Ethernet0/1
ip address 172.16.35.3 255.255.255.0
!
router ospf 1
log-adjacency-changes
network 192.168.0.0 0.0.255.255 area 0
!
router bgp 123
no synchronization
bgp log-neighbor-changes
aggregate-address 4.4.0.0 255.255.0.0 suppress-map SUPP_R3
neighbor 172.16.35.5 remote-as 5
neighbor 192.168.0.1 remote-as 123
neighbor 192.168.0.1 update-source Loopback0
neighbor 192.168.0.1 next-hop-self
neighbor 192.168.0.2 remote-as 123
neighbor 192.168.0.2 update-source Loopback0
neighbor 192.168.0.2 next-hop-self
no auto-summary
!
access-list 1 permit 4.4.1.0
access-list 1 permit 4.4.3.0
!
route-map SUPP_R3 permit 10
match ip address 1
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R4
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
interface Loopback0
ip address 4.4.1.4 255.255.255.0 secondary
ip address 4.4.2.4 255.255.255.0 secondary
ip address 4.4.3.4 255.255.255.0 secondary
ip address 4.4.0.4 255.255.255.0
!
interface Ethernet0/0
ip address 172.16.14.4 255.255.255.0
!
router bgp 4
no synchronization
bgp log-neighbor-changes
network 4.4.0.0 mask 255.255.255.0
network 4.4.1.0 mask 255.255.255.0
network 4.4.2.0 mask 255.255.255.0
network 4.4.3.0 mask 255.255.255.0
neighbor 172.16.14.1 remote-as 123
no auto-summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R5
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
interface Loopback0
ip address 5.5.1.5 255.255.255.0 secondary
ip address 5.5.2.5 255.255.255.0 secondary
ip address 5.5.3.5 255.255.255.0 secondary
ip address 5.5.0.5 255.255.255.0
!
interface Ethernet0/0
ip address 172.16.35.5 255.255.255.0
!
router bgp 5
no synchronization
bgp log-neighbor-changes
network 5.5.0.0 mask 255.255.255.0
network 5.5.1.0 mask 255.255.255.0
network 5.5.2.0 mask 255.255.255.0
network 5.5.3.0 mask 255.255.255.0
neighbor 172.16.35.3 remote-as 123
no auto-summary
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
集約ルートの生成には問題がないようですが、集約前の詳細ルートのアドバタイズが意図したように行われていません。R4では集約前の詳細ルートとして5.5.0.0/24と5.5.2.0/24ではなく、5.5.1.0/24と5.5.3.0/24がBGPテーブルに登録されています。そして、R5では集約前の詳細ルートとして4.4.1.0/24と4.4.3.0/24ではなく、4.4.0.0/24と4.4.2.0/24がBGPテーブルに登録されています。
R4 show ip bgp
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R4#show ip bgp
BGP table version is 13, local router ID is 4.4.0.4
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
*> 4.4.0.0/24 0.0.0.0 0 32768 i
*> 4.4.0.0/16 172.16.14.1 0 123 i
*> 4.4.1.0/24 0.0.0.0 0 32768 i
*> 4.4.2.0/24 0.0.0.0 0 32768 i
*> 4.4.3.0/24 0.0.0.0 0 32768 i
*> 5.5.0.0/16 172.16.14.1 0 0 123 i
*> 5.5.1.0/24 172.16.14.1 0 123 5 i
*> 5.5.3.0/24 172.16.14.1 0 123 5 i
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R5 show ip bgp
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R5#show ip bgp
BGP table version is 9, local router ID is 5.5.0.5
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
*> 4.4.0.0/24 172.16.35.3 0 123 4 i
*> 4.4.0.0/16 172.16.35.3 0 0 123 i
*> 4.4.2.0/24 172.16.35.3 0 123 4 i
*> 5.5.0.0/24 0.0.0.0 0 32768 i
*> 5.5.0.0/16 172.16.35.3 0 123 i
*> 5.5.1.0/24 0.0.0.0 0 32768 i
*> 5.5.2.0/24 0.0.0.0 0 32768 i
*> 5.5.3.0/24 0.0.0.0 0 32768 i
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
集約前の詳細ルートのアドバタイズが意図したように行われていない原因は、R1とR3の設定ミスだと考えられます。そこで、R1とR3で下記のshowコマンドでトラブルの切り分けを行います。
R1/R3
show ip protocols
show ip bgp
show route-map
show access-list
R1 showコマンドの結果
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R1#show ip protocols
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 192.168.0.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.0.0 0.0.255.255 area 0
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
192.168.0.2 110 00:56:49
192.168.0.3 110 00:56:49
Distance: (default is 110)
Routing Protocol is "bgp 123"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
IGP synchronization is disabled
Automatic route summarization is disabled
Unicast Aggregate Generation:
5.5.0.0/16 summary-only
Neighbor(s):
Address FiltIn FiltOut DistIn DistOut Weight RouteMap
172.16.14.4
192.168.0.2
192.168.0.3
Maximum path: 1
Routing Information Sources:
Gateway Distance Last Update
(this router) 200 00:55:46
192.168.0.3 200 00:56:14
172.16.14.4 20 00:56:17
Distance: external 20 internal 200 local 200
R1#show ip bgp
BGP table version is 15, local router ID is 192.168.0.1
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
*> 4.4.0.0/24 172.16.14.4 0 0 4 i
*>i4.4.0.0/16 192.168.0.3 0 100 0 i
*> 4.4.1.0/24 172.16.14.4 0 0 4 i
*> 4.4.2.0/24 172.16.14.4 0 0 4 i
*> 4.4.3.0/24 172.16.14.4 0 0 4 i
s>i5.5.0.0/24 192.168.0.3 0 100 0 5 i
*> 5.5.0.0/16 0.0.0.0 32768 i
s>i5.5.1.0/24 192.168.0.3 0 100 0 5 i
s>i5.5.2.0/24 192.168.0.3 0 100 0 5 i
s>i5.5.3.0/24 192.168.0.3 0 100 0 5 i
R1#show route-map
route-map UNSUPP_R1, deny, sequence 10
Match clauses:
ip address (access-lists): 1
Set clauses:
Policy routing matches: 0 packets, 0 bytes
route-map UNSUPP_R1, permit, sequence 100
Match clauses:
Set clauses:
Policy routing matches: 0 packets, 0 bytes
R1#show access-list
Standard IP access list 1
10 permit 5.5.0.0 (1 match)
20 permit 5.5.2.0 (1 match)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R3 showコマンドの結果
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R3#show ip protocols
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 192.168.0.3
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
192.168.0.0 0.0.255.255 area 0
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
192.168.0.1 110 00:58:03
192.168.0.2 110 00:58:03
Distance: (default is 110)
Routing Protocol is "bgp 123"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
IGP synchronization is disabled
Automatic route summarization is disabled
Unicast Aggregate Generation:
4.4.0.0/16 suppress-map SUPP_R3
Neighbor(s):
Address FiltIn FiltOut DistIn DistOut Weight RouteMap
172.16.35.5
192.168.0.1
192.168.0.2
Maximum path: 1
Routing Information Sources:
Gateway Distance Last Update
(this router) 200 00:57:20
192.168.0.1 200 00:56:52
172.16.35.5 20 00:57:20
Distance: external 20 internal 200 local 200
R3#show ip bgp
BGP table version is 13, local router ID is 192.168.0.3
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
*>i4.4.0.0/24 192.168.0.1 0 100 0 4 i
*> 4.4.0.0/16 0.0.0.0 32768 i
s>i4.4.1.0/24 192.168.0.1 0 100 0 4 i
*>i4.4.2.0/24 192.168.0.1 0 100 0 4 i
s>i4.4.3.0/24 192.168.0.1 0 100 0 4 i
*> 5.5.0.0/24 172.16.35.5 0 0 5 i
*>i5.5.0.0/16 192.168.0.1 0 100 0 i
*> 5.5.1.0/24 172.16.35.5 0 0 5 i
*> 5.5.2.0/24 172.16.35.5 0 0 5 i
*> 5.5.3.0/24 172.16.35.5 0 0 5 i
R3#show route-map
route-map SUPP_R3, permit, sequence 10
Match clauses:
ip address (access-lists): 1
Set clauses:
Policy routing matches: 0 packets, 0 bytes
R3#show access-list
Standard IP access list 1
10 permit 4.4.1.0 (2 matches)
20 permit 4.4.3.0 (2 matches)━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━