ネットワーク構成

下記のネットワーク構成でホスト間のIPv6通信を行います。

ipv6_trouble03.jpg
図 IPv6のトラブル その3 ネットワーク構成

ルーティングプロトコルにはOSPFv3を利用します。また、ホストはルータのLoopback0インタフェースです。R1、R2 F0/0にIPv4アドレスのみ設定しています。R1-R2間ではスタティックトンネルでIPv6パケットをIPv4でトンネリングします。

設定概要

現在のR1、R2のIPv6に関する設定は以下のとおりです。

R1

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ipv6 unicast-routing
!
interface Loopback0
ipv6 address 2001:1:1:1::1/64
ipv6 enable
ipv6 ospf 1 area 0
!
interface Tunnel12
ipv6 address 2001:12:12:12::1/64
ipv6 enable
ipv6 ospf 1 area 0
tunnel source FastEthernet0/0
tunnel destination 192.168.1.20
tunnel mode ipv6ip
!
interface FastEthernet0/0
ip address 192.168.12.1 255.255.255.0
!
ipv6 router ospf 1
router-id 1.1.1.1
log-adjacency-changes
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

R2

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ipv6 unicast-routing
!
interface Loopback0
ipv6 address 2001:2:2:2::2/64
ipv6 enable
ipv6 ospf 1 area 0
!
interface Tunnel12
ipv6 address 2001:12:12:12::2/64
ipv6 enable
ipv6 ospf 1 area 0
tunnel source FastEthernet0/0
tunnel destination 192.168.12.1
tunnel mode ipv6ip
!
interface FastEthernet0/0
ip address 192.168.12.2 255.255.255.0
!
ipv6 router ospf 1
router-id 2.2.2.2
log-adjacency-changes
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

トラブルの症状

R1-R2間のトンネルインタフェースはup/upの状態ですが、トンネルインタフェース上でOSPFv3ネイバーを確立することができていません。そのため、R1-R2間でIPv6パケットのルーティングができません。
原因を調べるために以下のshowコマンドを実行しました。

show interface tunnel12
show ipv6 interface brief
show ipv6 ospf interface
show ipv6 ospf neighbor

R1

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R1#show interface tunnel12
Tunnel12 is up, line protocol is down
Hardware is Tunnel
MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
Tunnel source 192.168.12.1 (FastEthernet0/0), destination 192.168.1.20
Tunnel protocol/transport IPv6/IP
Tunnel TTL 255
Fast tunneling enabled
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input 00:24:39, output 00:24:26, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 4
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
45 packets input, 5860 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
50 packets output, 5456 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
R1#show ipv6 interface brief
FastEthernet0/0            [up/up]
unassigned
Loopback0                  [up/up]
FE80::CE00:24FF:FE90:0
2001:1:1:1::1
Tunnel12                   [up/down]
FE80::C0A8:C01
2001:12:12:12::1
R1#show ipv6 ospf interface
Loopback0 is up, line protocol is up
Link Local Address FE80::CE00:24FF:FE90:0, Interface ID 6
Area 0, Process ID 1, Instance ID 0, Router ID 1.1.1.1
Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host
Tunnel12 is up, line protocol is down
Link Local Address FE80::C0A8:C01, Interface ID 7
Area 0, Process ID 1, Instance ID 0, Router ID 1.1.1.1
Network Type POINT_TO_POINT, Cost: 11111
Transmit Delay is 1 sec, State DOWN,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
R1#show ipv6 ospf neighbor
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

R2

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
R2#show interface tunnel12
Tunnel12 is up, line protocol is up
Hardware is Tunnel
MTU 1514 bytes, BW 9 Kbit/sec, DLY 500000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation TUNNEL, loopback not set
Keepalive not set
Tunnel source 192.168.12.2 (FastEthernet0/0), destination 192.168.12.1
Tunnel protocol/transport IPv6/IP
Tunnel TTL 255
Fast tunneling enabled
Tunnel transmit bandwidth 8000 (kbps)
Tunnel receive bandwidth 8000 (kbps)
Last input 00:25:44, output 00:00:07, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/0 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
21 packets input, 2856 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
196 packets output, 19304 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 output buffer failures, 0 output buffers swapped out
R2#show ipv6 interface brief
FastEthernet0/0            [up/up]
unassigned
Loopback0                  [up/up]
FE80::CE01:24FF:FE90:0
2001:2:2:2::2
Tunnel12                   [up/up]
FE80::C0A8:C02
2001:12:12:12::2
R2#show ipv6 ospf interface
Loopback0 is up, line protocol is up
Link Local Address FE80::CE01:24FF:FE90:0, Interface ID 6
Area 0, Process ID 1, Instance ID 0, Router ID 2.2.2.2
Network Type LOOPBACK, Cost: 1
Loopback interface is treated as a stub Host
Tunnel12 is up, line protocol is up
Link Local Address FE80::C0A8:C02, Interface ID 7
Area 0, Process ID 1, Instance ID 0, Router ID 2.2.2.2
Network Type POINT_TO_POINT, Cost: 11111
Transmit Delay is 1 sec, State POINT_TO_POINT,
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 00:00:02
Index 1/2/2, flood queue length 0
Next 0x0(0)/0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 0 msec
Neighbor Count is 0, Adjacent neighbor count is 0
Suppress hello for 0 neighbor(s)
R2#show ipv6 ospf neighbor
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

問題

  • なぜホスト間でIPv6の通信ができないのですか。
  • ホスト間でIPv6の通信ができるようにするためには、どのように設定を修正すればよいですか。