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

トラブルの症状

SOURCEから送信したマルチキャストグループ239.1.1.1のパケットが正しくルーティングされません。どうやら、R1～R4の間でいくつかの設定ミスが重なっているようです。R5/R6/SOURCEには設定ミスはないことが確実に分かっています。そこで、R1～R4でトラブルを切り分けるために各ルータでshowコマンドを実行しました。

R1/R3
show ip pim interface
show ip pim neighbor
show ip pim bsr-router
show ip pim rp mapping
show ip mroute

R2
show ip pim interface
show ip pim neighbor
show ip pim bsr-router
show ip pim rp mapping
show access-list
show ip mroute

R4
show ip pim interface detail
show ip pim neighbor
show ip pim bsr-router
show ip pim rp mapping
show ip mroute

R1

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R1#show ip pim interface

Address          Interface                Ver/   Nbr    Query  DR     DR
                                          Mode   Count  Intvl  Prior
192.168.0.1      Loopback0                v2/S   0      30     1      192.168.0.1
192.168.12.1     Ethernet0/1              v2/S   1      30     1      192.168.12.2
R1#show ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      S - State Refresh Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.12.2      Ethernet0/1              00:42:33/00:01:33 v2    1 / DR S
R1#show ip pim bsr-router
PIMv2 Bootstrap information
R1#show ip pim rp mapping
PIM Group-to-RP Mappings
 
R1#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
 
(*, 224.0.1.40), 00:35:43/00:02:15, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Loopback0, Forward/Sparse, 00:35:43/00:02:15
 
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R2

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R2#show ip pim interface

Address          Interface                Ver/   Nbr    Query  DR     DR
                                          Mode   Count  Intvl  Prior
192.168.0.2      Loopback0                v2/S   0      30     1      192.168.0.2
192.168.12.2     Ethernet0/0              v2/S   1      30     1      192.168.12.2
192.168.23.2     Ethernet0/1              v2/S   1      30     1      192.168.23.3
R2#show ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      S - State Refresh Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.12.1      Ethernet0/0              00:42:37/00:01:27 v2    1 / S
192.168.23.3      Ethernet0/1              00:43:01/00:01:37 v2    1 / DR S
R2#show ip pim bsr-router
PIMv2 Bootstrap information
  Candidate RP: 192.168.0.2(Loopback0)
    Holdtime 12 seconds
    Advertisement interval 5 seconds
    Next advertisement in 00:00:04
    Group acl: 1
R2#show ip pim rp mapping
PIM Group-to-RP Mappings
This system is a candidate RP (v2)
 
R2#show access-list
Standard IP access list 1
    10 permit 239.1.0.1
R2#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
 
(*, 224.0.1.40), 00:35:43/00:02:54, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Loopback0, Forward/Sparse, 00:35:43/00:02:51
 
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R3

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R3#show ip pim interface

Address          Interface                Ver/   Nbr    Query  DR     DR
                                          Mode   Count  Intvl  Prior
192.168.23.3     Ethernet0/0              v2/S   1      30     1      192.168.23.3
192.168.34.3     Ethernet0/1              v2/S   1      30     1      192.168.34.4
R3#show ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      S - State Refresh Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.23.2      Ethernet0/0              00:45:14/00:01:23 v2    1 / S
192.168.34.4      Ethernet0/1              00:33:25/00:01:25 v2    1 / DR S
R3#show ip pim bsr-router
PIMv2 Bootstrap information
This system is a candidate BSR
  Candidate BSR interface Loopback0
    PIMv2 is not configured - BSR messages not originated
R3#show ip pim rp mapping
PIM Group-to-RP Mappings
 
R3#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
 
(*, 224.0.1.40), 00:37:28/00:02:15, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Ethernet0/0, Forward/Sparse, 00:22:01/00:02:15
 
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R4

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R4#show ip pim interface detail
Loopback0 is up, line protocol is up
  Internet address is 192.168.0.4/32
  Multicast switching: fast
  Multicast packets in/out: 0/0
  Multicast TTL threshold: 0
  PIM: enabled
    PIM version: 2, mode: sparse
    PIM DR: 192.168.0.4 (this system)
    PIM neighbor count: 0
    PIM Hello/Query interval: 30 seconds
    PIM Hello packets in/out: 95/96
    PIM State-Refresh processing: enabled
    PIM State-Refresh origination: disabled
    PIM NBMA mode: disabled
    PIM ATM multipoint signalling: disabled
    PIM domain border: disabled
  Multicast Tagswitching: disabled
Ethernet0/0 is up, line protocol is up
  Internet address is 192.168.34.4/24
  Multicast switching: fast
  Multicast packets in/out: 75/0
  Multicast TTL threshold: 0
  PIM: enabled
    PIM version: 2, mode: sparse
    PIM DR: 192.168.34.4 (this system)
    PIM neighbor count: 1
    PIM Hello/Query interval: 30 seconds
    PIM Hello packets in/out: 96/99
    PIM State-Refresh processing: enabled
    PIM State-Refresh origination: disabled
    PIM NBMA mode: disabled
    PIM ATM multipoint signalling: disabled
    PIM domain border: enabled
  Multicast Tagswitching: disabled
Ethernet0/1 is up, line protocol is up
  Internet address is 192.168.45.4/24
  Multicast switching: fast
  Multicast packets in/out: 0/2
  Multicast TTL threshold: 0
  PIM: enabled
    PIM version: 2, mode: sparse
    PIM DR: 192.168.45.5
    PIM neighbor count: 1
    PIM Hello/Query interval: 30 seconds
    PIM Hello packets in/out: 96/97
    PIM State-Refresh processing: enabled
    PIM State-Refresh origination: disabled
    PIM NBMA mode: disabled
    PIM ATM multipoint signalling: disabled
    PIM domain border: disabled
  Multicast Tagswitching: disabled
Ethernet0/2 is up, line protocol is up
  Internet address is 192.168.46.4/24
  Multicast switching: fast
  Multicast packets in/out: 0/2
  Multicast TTL threshold: 0
  PIM: enabled
    PIM version: 2, mode: sparse
    PIM DR: 192.168.46.6
    PIM neighbor count: 1
    PIM Hello/Query interval: 30 seconds
    PIM Hello packets in/out: 96/97
    PIM State-Refresh processing: enabled
    PIM State-Refresh origination: disabled
    PIM NBMA mode: disabled
    PIM ATM multipoint signalling: disabled
    PIM domain border: disabled
  Multicast Tagswitching: disabled
R4#show ip pim neighbor
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
      S - State Refresh Capable
Neighbor          Interface                Uptime/Expires    Ver   DR
Address                                                            Prio/Mode
192.168.34.3      Ethernet0/0              00:34:21/00:01:24 v2    1 / S
192.168.45.5      Ethernet0/1              00:47:09/00:01:23 v2    1 / DR S
192.168.46.6      Ethernet0/2              00:47:00/00:01:30 v2    1 / DR S
R4#show ip pim bsr-router
PIMv2 Bootstrap information
R4#show ip pim rp mapping
PIM Group-to-RP Mappings
 
R4#show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report,
       Z - Multicast Tunnel, z - MDT-data group sender,
       Y - Joined MDT-data group, y - Sending to MDT-data group
Outgoing interface flags: H - Hardware switched, A - Assert winner
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode
 
(*, 224.0.1.40), 00:47:14/00:02:50, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Loopback0, Forward/Sparse, 00:47:14/00:02:50
 
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問題

• なぜSOURCEから239.1.1.1への通信ができないのですか？
• すべてのルータで239.1.1.1のRPアドレスを正しく認識して、ルーティング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？

マルチキャストルーティングとCiscoルータでの設定・検証方法を詳しく勉強したい方には「詳解IPマルチキャスト」がオススメです。

詳解IPマルチキャスト 概念からCisco製品での設定例まで (NETWORK PROFESSIONAL) Gene by G-Tools