MPLS VPN Inter-AS IPv4 BGP Label Distribution

まず最初に

この検証内容は、2011年に MPLS VPN についてラボで確認した時の結果をローカルのwikiサーバーに保存していました。その後、誰かの参考になったのかどうかは分からないのですが、もうwikiサーバーも動いていませんので、誰もこの内容を見ることもないと思います。でも、最近になって自分でも見直すことがありましたので、少しでも参考になればと思い、こちらにアップすることにしました。

Topology

summary

configの注意点

• send-labelの設定は両端のルータに設定すること
• ASBRにroute-mapを設定する場合は、out側のroute-map内にsend-labelを明示的に書かないとラベルが送信されないので注意**(route-mapをneighborに設定していなければ問題ない)**
• RRにno bgp default route-target filterを設定する必要はない**(RRはデフォルトでroute-targetsをフィルタしない)**

send-labelの結果

peerルータのR2から、20.1.1.3(PE2のloopback)へのラベルは2001という情報が来る。

log

ASBR1#show ip bgp labels 
   Network          Next Hop      In label/Out label
   10.1.1.1/32      0.0.0.0         imp-null/nolabel
   10.1.1.2/32      172.10.13.3     nolabel/nolabel
   10.1.1.3/32      172.10.13.3     1001/nolabel
   20.1.1.2/32      172.30.12.2     nolabel/nolabel
   20.1.1.3/32      172.30.12.2     nolabel/2001    <<<<<=====!!!!!
   172.10.13.0/24   0.0.0.0         imp-null/nolabel
   172.10.35.0/24   172.10.13.3     nolabel/nolabel
ASBR1#

log

RR1#show ip bgp labels 
   Network          Next Hop      In label/Out label
   10.1.1.1/32      10.1.1.1        nolabel/imp-null
   20.1.1.2/32      172.30.12.2     nolabel/nolabel
   20.1.1.3/32      172.30.12.2     nolabel/2001    <<<<<=====!!!!!
   172.10.13.0/24   10.1.1.1        nolabel/imp-null
RR1#

2001のラベル情報がPE1までRRを経由して届く。

log

PE1#show ip bgp labels         
   Network          Next Hop      In label/Out label
   10.1.1.1/32      10.1.1.1        nolabel/imp-null
   20.1.1.2/32      172.30.12.2     nolabel/nolabel
   20.1.1.3/32      172.30.12.2     nolabel/2001    <<<<<=====!!!!!
   172.10.13.0/24   10.1.1.1        nolabel/imp-null
PE1#

VPNラベルを見る

VPN用のラベルが、6005であることが分かる。 宛先は、20.1.1.3になっているが、これはVPNv4のpeerを張っているRR上でnext-hop-unchangedを設定しているから。

log

PE1#show ip bgp vpnv4 all 2.2.2.2
BGP routing table entry for 1:100:2.2.2.2/32, version 6
Paths: (1 available, best #1, table blue)
  Not advertised to any peer
  200
    20.1.1.3 (metric 1) from 10.1.1.2 (10.1.1.2)
      Origin incomplete, metric 0, localpref 100, valid, internal, best
      Extended Community: RT:1:100
      mpls labels in/out nolabel/6005
PE1#

send-labelの結果から、20.1.1.3へのラベルは、BGP経由で得た2001だけど、2001へのnext-hopは172.30.12.2なので、この宛先へのラベルを見ると3002であることが分かる。

log

PE1#show mpls forwarding-table 172.30.12.2
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
5003       3002       172.30.12.2/32   0             Et0/0      172.10.35.3 
PE1#

最終的に、3000,2001,6005とラベルをpushする。

life of a ping

traceroute

log

CE1#traceroute 2.2.2.2

Type escape sequence to abort.
Tracing the route to 2.2.2.2

  1 192.168.57.5 16 msec 20 msec 20 msec
  2 172.10.35.3 [MPLS: Labels 3002/2001/6005 Exp 0] 60 msec 60 msec 60 msec
  3 172.10.13.1 [MPLS: Labels 1000/2001/6005 Exp 0] 60 msec 72 msec 60 msec
  4 172.30.12.2 [MPLS: Labels 2001/6005 Exp 0] 48 msec 52 msec 80 msec
  5 172.20.24.4 [MPLS: Labels 4000/6005 Exp 0] 60 msec 60 msec 60 msec
  6 192.168.68.6 [MPLS: Label 6005 Exp 0] 20 msec 28 msec 32 msec
  7 192.168.68.8 60 msec *  32 msec
CE1#

log

CE2#traceroute 1.1.1.1

Type escape sequence to abort.
Tracing the route to 1.1.1.1

  1 192.168.68.6 28 msec 20 msec 20 msec
  2 172.20.46.4 [MPLS: Labels 4002/1001/5005 Exp 0] 60 msec 60 msec 60 msec
  3 172.20.24.2 [MPLS: Labels 2000/1001/5005 Exp 0] 60 msec 56 msec 60 msec
  4 172.30.12.1 [MPLS: Labels 1001/5005 Exp 0] 48 msec 60 msec 60 msec
  5 172.10.13.3 [MPLS: Labels 3000/5005 Exp 0] 52 msec 60 msec 60 msec
  6 192.168.57.5 [MPLS: Label 5005 Exp 0] 36 msec 28 msec 40 msec
  7 192.168.57.7 40 msec *  24 msec
CE2#

R5 (PE1)

log

PE1#show ip cef vrf blue 2.2.2.2
2.2.2.2/32
  nexthop 172.10.35.3 Ethernet0/0 label 3002 2001 6005
PE1#

R3 (RR1)

3002を1000にswap

log

RR1#show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
3000       Pop Label  10.1.1.3/32      8620          Et1/0      172.10.35.5 
3001       Pop Label  10.1.1.1/32      0             Et0/0      172.10.13.1 
3002       1000       172.30.12.2/32   5396          Et0/0      172.10.13.1 
3003       Pop Label  172.30.12.0/24   0             Et0/0      172.10.13.1 
RR1#

R1 (ASBR1)

1000をpop

log

ASBR1#show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
1000       Pop Label  172.30.12.2/32   32946         Se1/0      point2point 
1001       3000       10.1.1.3/32      8404          Et0/0      172.10.13.3 
1002       Pop Label  10.1.1.2/32      0             Et0/0      172.10.13.3 
1003       Pop Label  172.10.35.0/24   0             Et0/0      172.10.13.3 
ASBR1#

R2 (ASBR2)

2001を4000にswap

log

ASBR2#show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
2000       Pop Label  172.30.12.1/32   35216         Se1/0      point2point 
2001       4000       20.1.1.3/32      6964          Et0/0      172.20.24.4 
2002       Pop Label  20.1.1.2/32      0             Et0/0      172.20.24.4 
2003       Pop Label  172.20.46.0/24   0             Et0/0      172.20.24.4 
ASBR2#

R4 (RR2)

4000をpop

log

RR2#show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
4000       Pop Label  20.1.1.3/32      7620          Et1/0      172.20.46.6 
4001       Pop Label  20.1.1.1/32      0             Et0/0      172.20.24.2 
4002       2000       172.30.12.1/32   7732          Et0/0      172.20.24.2 
4003       Pop Label  172.30.12.0/24   0             Et0/0      172.20.24.2 
RR2#

R5 (PE1)

6005をpop

log

PE2#show mpls forwarding-table 
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop    
Label      Label      or Tunnel Id     Switched      interface              
6000       Pop Label  20.1.1.2/32      0             Et0/0      172.20.46.4 
6001       Pop Label  172.20.24.0/24   0             Et0/0      172.20.46.4 
6002       4001       20.1.1.1/32      0             Et0/0      172.20.46.4 
6003       4002       172.30.12.1/32   0             Et0/0      172.20.46.4 
6004       4003       172.30.12.0/24   0             Et0/0      172.20.46.4 
6005       No Label   2.2.2.2/32[V]    4984          Se1/0      point2point 
6006       No Label   192.168.68.0/24[V]   \
                                       2772          aggregate/blue 
PE2#

config

R1

config

hostname ASBR1
!
mpls label range 1000 1999
mpls label protocol ldp
!
interface Loopback0
 ip address 10.1.1.1 255.255.255.255
!
interface Ethernet0/0
 ip address 172.10.13.1 255.255.255.0
 mpls ip
!
interface Serial1/0
 ip address 172.30.12.1 255.255.255.0
 mpls bgp forwarding
!
router ospf 1
 log-adjacency-changes
 redistribute connected metric 1 subnets
 network 10.1.1.1 0.0.0.0 area 0
 network 172.10.13.1 0.0.0.0 area 0
!
router bgp 100
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 10.1.1.2 remote-as 100
 neighbor 10.1.1.2 update-source Loopback0
 neighbor 172.30.12.2 remote-as 200
 !
 address-family ipv4
  no synchronization
  redistribute ospf 1
  neighbor 10.1.1.2 activate
  neighbor 10.1.1.2 send-label
  neighbor 172.30.12.2 activate
  neighbor 172.30.12.2 route-map map_in in
  neighbor 172.30.12.2 route-map map_out out
  neighbor 172.30.12.2 send-label
  no auto-summary
 exit-address-family
!
access-list 1 permit 10.1.1.3 log
access-list 2 permit 20.1.1.3 log
access-list 3 permit 10.1.1.2 log
access-list 4 permit 20.1.1.2 log
!
route-map map_in permit 10
 match ip address 2
 match mpls-label
!
route-map map_in permit 20
 match ip address 4
!
route-map map_out permit 10
 match ip address 3
!
route-map map_out permit 20
 match ip address 1
 set mpls-label
!

R2

config

hostname ASBR2
!
mpls label range 2000 2999
mpls label protocol ldp
!
interface Loopback0
 ip address 20.1.1.1 255.255.255.255
!
interface Ethernet0/0
 ip address 172.20.24.2 255.255.255.0
 mpls ip
!
interface Serial1/0
 ip address 172.30.12.2 255.255.255.0
 mpls bgp forwarding
!
router ospf 1
 log-adjacency-changes
 redistribute connected metric 1 subnets
 network 20.1.1.1 0.0.0.0 area 0
 network 172.20.24.2 0.0.0.0 area 0
!
router bgp 200
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 20.1.1.2 remote-as 200
 neighbor 20.1.1.2 update-source Loopback0
 neighbor 172.30.12.1 remote-as 100
 !
 address-family ipv4
  no synchronization
  redistribute ospf 1
  neighbor 20.1.1.2 activate
  neighbor 20.1.1.2 send-label
  neighbor 172.30.12.1 activate
  neighbor 172.30.12.1 route-map map_in in
  neighbor 172.30.12.1 route-map map_out out
  neighbor 172.30.12.1 send-label
  no auto-summary
 exit-address-family
!
access-list 1 permit 20.1.1.3 log
access-list 2 permit 10.1.1.3 log
access-list 3 permit 20.1.1.2 log
access-list 4 permit 10.1.1.2 log
!
route-map map_in permit 10
 match ip address 2
 match mpls-label
!
route-map map_in permit 20
 match ip address 4
!
route-map map_out permit 10
 match ip address 1
 set mpls-label
!
route-map map_out permit 20
 match ip address 3
!

R3

config

hostname RR1
!
mpls label range 3000 3999
mpls label protocol ldp
!
interface Loopback0
 ip address 10.1.1.2 255.255.255.255
!
interface Ethernet0/0
 ip address 172.10.13.3 255.255.255.0
 mpls ip
!
interface Ethernet1/0
 ip address 172.10.35.3 255.255.255.0
 mpls ip
!
router ospf 1
 log-adjacency-changes
 network 10.1.1.2 0.0.0.0 area 0
 network 172.10.13.3 0.0.0.0 area 0
 network 172.10.35.3 0.0.0.0 area 0
!
router bgp 100
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 10.1.1.1 remote-as 100
 neighbor 10.1.1.1 update-source Loopback0
 neighbor 10.1.1.3 remote-as 100
 neighbor 10.1.1.3 update-source Loopback0
 neighbor 20.1.1.2 remote-as 200
 neighbor 20.1.1.2 ebgp-multihop 255
 neighbor 20.1.1.2 update-source Loopback0
 !
 address-family ipv4
  no synchronization
  neighbor 10.1.1.1 activate
  neighbor 10.1.1.1 route-reflector-client
  neighbor 10.1.1.1 send-label
  neighbor 10.1.1.3 activate
  neighbor 10.1.1.3 route-reflector-client
  neighbor 10.1.1.3 send-label
  no auto-summary
 exit-address-family
 !
 address-family vpnv4
  neighbor 10.1.1.3 activate
  neighbor 10.1.1.3 send-community extended
  neighbor 10.1.1.3 route-reflector-client
  neighbor 20.1.1.2 activate
  neighbor 20.1.1.2 send-community extended
  neighbor 20.1.1.2 next-hop-unchanged
 exit-address-family
!

R4

config

hostname RR2
!
mpls label range 4000 4999
mpls label protocol ldp
!
interface Loopback0
 ip address 20.1.1.2 255.255.255.255
!
interface Ethernet0/0
 ip address 172.20.24.4 255.255.255.0
 mpls ip
!
interface Ethernet1/0
 ip address 172.20.46.4 255.255.255.0
 mpls ip
!
router ospf 1
 log-adjacency-changes
 network 20.1.1.2 0.0.0.0 area 0
 network 172.20.24.4 0.0.0.0 area 0
 network 172.20.46.4 0.0.0.0 area 0
!
router bgp 200
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 10.1.1.2 remote-as 100
 neighbor 10.1.1.2 ebgp-multihop 255
 neighbor 10.1.1.2 update-source Loopback0
 neighbor 20.1.1.1 remote-as 200
 neighbor 20.1.1.1 update-source Loopback0
 neighbor 20.1.1.3 remote-as 200
 neighbor 20.1.1.3 update-source Loopback0
 !
 address-family ipv4
  no synchronization
  neighbor 20.1.1.1 activate
  neighbor 20.1.1.1 route-reflector-client
  neighbor 20.1.1.1 send-label
  neighbor 20.1.1.3 activate
  neighbor 20.1.1.3 route-reflector-client
  neighbor 20.1.1.3 send-label
  no auto-summary
 exit-address-family
 !
 address-family vpnv4
  neighbor 10.1.1.2 activate
  neighbor 10.1.1.2 send-community extended
  neighbor 10.1.1.2 next-hop-unchanged
  neighbor 20.1.1.3 activate
  neighbor 20.1.1.3 send-community extended
  neighbor 20.1.1.3 route-reflector-client
 exit-address-family
!

R5

config

hostname PE1
!
ip vrf blue
 rd 1:100
 route-target export 1:100
 route-target import 1:100
!
mpls label range 5000 5999
mpls label protocol ldp
!
interface Loopback0
 ip address 10.1.1.3 255.255.255.255
!
interface Ethernet0/0
 ip address 172.10.35.5 255.255.255.0
 mpls ip
!
interface Serial1/0
 ip vrf forwarding blue
 ip address 192.168.57.5 255.255.255.0
 serial restart-delay 0
!
router ospf 1
 log-adjacency-changes
 network 10.1.1.3 0.0.0.0 area 0
 network 172.10.35.5 0.0.0.0 area 0
!
router rip
 version 2
 no auto-summary
 !
 address-family ipv4 vrf blue
  redistribute bgp 100 metric 1
  network 192.168.57.0
  no auto-summary
  version 2
 exit-address-family
!
router bgp 100
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 10.1.1.2 remote-as 100
 neighbor 10.1.1.2 update-source Loopback0
 !
 address-family ipv4
  no synchronization
  neighbor 10.1.1.2 activate
  neighbor 10.1.1.2 send-label
  no auto-summary
 exit-address-family
 !
 address-family vpnv4
  neighbor 10.1.1.2 activate
  neighbor 10.1.1.2 send-community extended
 exit-address-family
 !
 address-family ipv4 vrf blue
  no synchronization
  redistribute rip
 exit-address-family
!

R6

config

hostname PE2
!
ip vrf blue
 rd 1:100
 route-target export 1:100
 route-target import 1:100
!
mpls label range 6000 6999
mpls label protocol ldp
!
interface Loopback0
 ip address 20.1.1.3 255.255.255.255
!
interface Ethernet0/0
 ip address 172.20.46.6 255.255.255.0
 mpls ip
!
interface Serial1/0
 ip vrf forwarding blue
 ip address 192.168.68.6 255.255.255.0
 serial restart-delay 0
!
router ospf 1
 log-adjacency-changes
 network 20.1.1.3 0.0.0.0 area 0
 network 172.20.46.6 0.0.0.0 area 0
!
router rip
 version 2
 no auto-summary
 !
 address-family ipv4 vrf blue
  redistribute bgp 200 metric 1
  network 192.168.68.0
  no auto-summary
  version 2
 exit-address-family
!
router bgp 200
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 neighbor 20.1.1.2 remote-as 200
 neighbor 20.1.1.2 update-source Loopback0
 !
 address-family ipv4
  no synchronization
  neighbor 20.1.1.2 activate
  neighbor 20.1.1.2 send-label
  no auto-summary
 exit-address-family
 !
 address-family vpnv4
  neighbor 20.1.1.2 activate
  neighbor 20.1.1.2 send-community extended
 exit-address-family
 !
 address-family ipv4 vrf blue
  no synchronization
  redistribute rip
 exit-address-family
!

R7

config

hostname CE1
!
interface Loopback0
 ip address 1.1.1.1 255.255.255.255
!
interface Serial0/0
 ip address 192.168.57.7 255.255.255.0
 serial restart-delay 0
!
router rip
 version 2
 network 1.0.0.0
 network 192.168.57.0
 no auto-summary
!

R8

config

hostname CE2
!
interface Loopback0
 ip address 2.2.2.2 255.255.255.255
!
interface Serial0/0
 ip address 192.168.68.8 255.255.255.0
 serial restart-delay 0
!
router rip
 version 2
 network 2.0.0.0
 network 192.168.68.0
 no auto-summary
!