Contents

Configuring IPv6 PIM snooping· 1

Overview·· 1

Configuring IPv6 PIM snooping· 2

Displaying and maintaining IPv6 PIM snooping· 3

IPv6 PIM snooping configuration example (for VLANs) 4

Network requirements· 4

Configuration procedure· 4

Verifying the configuration· 6

Troubleshooting IPv6 PIM snooping· 7

IPv6 PIM snooping does not work on a Layer 2 device· 7

 

Configuring IPv6 PIM snooping

Overview

IPv6 PIM snooping runs on Layer 2 devices. It works with MLD snooping to analyze received IPv6 PIM messages, and adds the ports that are interested in specific multicast data to an IPv6 PIM snooping routing entry. In this way, the multicast data can be forwarded to only the ports that are interested in the data.

Figure 1 Multicast packet transmission without or with IPv6 PIM snooping

 

As shown in Figure 1, Source 1 sends multicast data to multicast group G1, and Source 2 sends multicast data to multicast group G2. Receiver 1 belongs to G1, and Receiver 2 belongs to G2. The Layer 2 switch's interfaces that connect to the IPv6 PIM-capable routers are in the same VLAN or VSI.

·     When the Layer 2 switch only runs MLD snooping, it performs the following actions:

a.     Maintains the router ports according to the received IPv6 PIM hello messages that IPv6 PIM-capable routers send.

b.     Floods all other types of received IPv6 PIM messages except PIM hello messages in the VLAN or VSI.

c.     Forwards all multicast data to all router ports in the VLAN or VSI.

Each IPv6 PIM-capable router in the VLAN or VSI, whether interested in the multicast data or not, can receive all multicast data and all IPv6 PIM messages except IPv6 PIM hello messages.

·     When the Layer 2 switch runs both MLD snooping and IPv6 PIM snooping, it performs the following actions:

a.     Examines whether an IPv6 PIM router is interested in the multicast data destined for a multicast group according to the received IPv6 PIM messages that the router sends.

b.     Adds only the ports that connect to the router and are interested in the data to an IPv6 PIM snooping routing entry.

c.     Forwards IPv6 PIM messages and the multicast data only to the router according to the multicast forwarding entry, which saves network bandwidth.

For more information about MLD snooping and the router port, see "Configuring MLD snooping."

IPv6 PIM snooping can run in IPv6 PIM-SM and IPv6 PIM-SSM networks. Do not configure IPv6 PIM snooping in IPv6 PIM-DM or IPv6 BIDIR-PIM networks. For more information about IPv6 PIM, see "Configuring IPv6 PIM."

Configuring IPv6 PIM snooping

IMPORTANT: ·     Do not configure IPv6 PIM snooping in secondary VLANs because IPv6 PIM snooping does not take effect on secondary VLANs. For more information about secondary VLANs, see Layer 2—LAN Switching Configuration Guide. ·     For IPv6 PIM snooping to correctly forward IPv6 multicast data, make sure the maximum size of an IPv6 PIM join or prune message is smaller than the path MTU of devices connected to IPv6 PIM snooping devices. For more information about setting the maximum size of a join or prune message, see "Configuring IPv6 PIM."

 

To configure IPv6 PIM snooping for a VLAN or VSI, enable MLD snooping globally on the Layer 2 device, and enable MLD snooping and IPv6 PIM snooping for the VLAN or VSI.

After you enable IPv6 PIM snooping for a VLAN or VSI, IPv6 PIM snooping works only on the member interfaces of the VLAN or VSI.

To configure IPv6 PIM snooping:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enable MLD snooping globally and enter MLD-snooping view.	mld-snooping	By default, MLD snooping is disabled.
3.     Return to system view.	quit	N/A
4.     Enter VLAN view or VSI view.	·     Enter VLAN view: vlan vlan-id ·     Enter VSI view: vsi vsi-name	N/A
5.     Enable MLD snooping for the VLAN or VSI.	mld-snooping enable	By default, MLD snooping is disabled in a VLAN or VSI.
6.     Enable IPv6 PIM snooping for the VLAN or VSI.	ipv6 pim-snooping enable	By default, IPv6 PIM snooping is disabled in a VLAN or VSI.
7.     (Optional.) Set the aging time for global neighbor ports on the new active MPU after an active/standby switchover.	ipv6 pim-snooping graceful-restart neighbor-aging-time seconds	The default setting is 105 seconds. A global neighbor port is a Layer 2 aggregate interface or AC interface that acts as a neighbor port.
8.     (Optional.) Set the aging time for global downstream ports and global router ports on the new active MPU after an active/standby switchover.	ipv6 pim-snooping graceful-restart join-aging-time seconds	The default setting is 210 seconds. A global downstream port or a global router port is a Layer 2 aggregate interface or, AC interface that acts as a downstream port or router port.

 

Displaying and maintaining IPv6 PIM snooping

Execute display commands in any view and reset commands in user view.

 

Task	Command
(In standalone mode.) Display IPv6 PIM snooping neighbor information.	display ipv6 pim-snooping neighbor [ vlan vlan-id | vsi vsi-name ] [ slot slot-number ] [ verbose ]
(In IRF mode.) Display IPv6 PIM snooping neighbor information.	display ipv6 pim-snooping neighbor [ vlan vlan-id | vsi vsi-name ] [ chassis chassis-number slot slot-number ] [ verbose ]
(In standalone mode.) Display IPv6 PIM snooping router port information.	display ipv6 pim-snooping router-port [ vlan vlan-id | vsi vsi-name ] [ slot slot-number ] [ verbose ]
(In IRF mode.) Display IPv6 PIM snooping router port information.	display ipv6 pim-snooping router-port [ vlan vlan-id | vsi vsi-name ] [ chassis chassis-number slot slot-number ] [ verbose ]
(In standalone mode.) Display IPv6 PIM snooping routing entries.	display ipv6 pim-snooping routing-table [ vlan vlan-id | vsi vsi-name ] [ slot slot-number ] [ verbose ]
(In IRF mode.) Display IPv6 PIM snooping routing entries.	display ipv6 pim-snooping routing-table [ vlan vlan-id | vsi vsi-name ] [ chassis chassis-number slot slot-number ] [ verbose ]
Display statistics for the IPv6 PIM messages learned through IPv6 PIM snooping.	display ipv6 pim-snooping statistics
Clear statistics for the IPv6 PIM messages learned through IPv6 PIM snooping.	reset ipv6 pim-snooping statistics

 

IPv6 PIM snooping configuration example (for VLANs)

Network requirements

As shown in Figure 2:

·     OSPFv3 runs on the network.

·     Source 1 and Source 2 send IPv6 multicast data to IPv6 multicast groups FF1E::101 and FF2E::101, respectively.

·     Receiver 1 and Receiver 2 belong to IPv6 multicast groups FF1E::101 and FF2E::101, respectively.

·     Router C and Router D run MLD on GigabitEthernet 1/0/1.

·     Router A, Router B, Router C, and Router D run IPv6 PIM-SM. GigabitEthernet 1/0/2 on Router A acts as a C-BSR and a C-RP.

To ensure that Switch A forwards IPv6 PIM protocol packets and IPv6 multicast data packets only to routers that are connected to receivers, perform the following tasks:

·     On Switch A, configure MLD snooping and IPv6 PIM snooping.

·     On all IPv6 PIM routers connected to Switch A, set the maximum size of a join or prune message to 1400 bytes, which is less than the path MTU.

Figure 2 Network diagram

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Configuration procedure

1.     Assign an IPv6 address and prefix length to each interface, as shown in Figure 2. (Details not shown.)

2.     Configure OSPFv3 on the routers. (Details not shown.)

3.     Configure Router A:

# Enable IPv6 multicast routing.

<RouterA> system-view

[RouterA] ipv6 multicast routing

[RouterA-mrib6] quit

# Enable IPv6 PIM-SM on each interface.

[RouterA] interface gigabitethernet 1/0/1

[RouterA-GigabitEthernet1/0/1] ipv6 pim sm

[RouterA-GigabitEthernet1/0/1] quit

[RouterA] interface gigabitethernet 1/0/2

[RouterA-GigabitEthernet1/0/2] ipv6 pim sm

[RouterA-GigabitEthernet1/0/2] quit

# Set the maximum size of a join or prune message to 1400 bytes.

[RouterA] ipv6 pim

[RouterA-pim6] jp-pkt-size 1400

# Configure GigabitEthernet 1/0/2 as a C-BSR and a C-RP.

[RouterA-pim6] c-bsr 1001::1

[RouterA-pim6] c-rp 1001::1

[RouterA-pim6] quit

4.     Configure Router B:

# Enable IPv6 multicast routing.

<RouterB> system-view

[RouterB] ipv6 multicast routing

[RouterB-mrib6] quit

# Enable IPv6 PIM-SM on each interface.

[RouterB] interface gigabitethernet 1/0/1

[RouterB-GigabitEthernet1/0/1] ipv6 pim sm

[RouterB-GigabitEthernet1/0/1] quit

[RouterB] interface gigabitethernet 1/0/2

[RouterB-GigabitEthernet1/0/2] ipv6 pim sm

[RouterB-GigabitEthernet1/0/2] quit

# Set the maximum size of a join or prune message to 1400 bytes.

[RouterB] ipv6 pim

[RouterB-pim6] jp-pkt-size 1400

5.     Configure Router C:

# Enable IPv6 multicast routing.

<RouterC> system-view

[RouterC] ipv6 multicast routing

[RouterC-mrib6] quit

# Enable MLD on GigabitEthernet 1/0/1.

[RouterC] interface gigabitethernet 1/0/1

[RouterC-GigabitEthernet1/0/1] mld enable

[RouterC-GigabitEthernet1/0/1] quit

# Enable IPv6 PIM-SM on GigabitEthernet 1/0/2.

[RouterC] interface gigabitethernet 1/0/2

[RouterC-GigabitEthernet1/0/2] ipv6 pim sm

[RouterC-GigabitEthernet1/0/2] quit

# Set the maximum size of a join or prune message to 1400 bytes.

[RouterC] ipv6 pim

[RouterC-pim6] jp-pkt-size 1400

6.     Configure Router D:

# Enable IPv6 multicast routing.

<RouterD> system-view

[RouterD] ipv6 multicast routing

[RouterD-mrib6] quit

# Enable MLD on GigabitEthernet 1/0/1.

[RouterD] interface gigabitethernet 1/0/1

[RouterD-GigabitEthernet1/0/1] mld enable

[RouterD-GigabitEthernet1/0/1] quit

# Enable IPv6 PIM-SM on GigabitEthernet 1/0/2.

[RouterD] interface gigabitethernet 1/0/2

[RouterD-GigabitEthernet1/0/2] ipv6 pim sm

[RouterD-GigabitEthernet1/0/2] quit

# Set the maximum size of a join or prune message to 1400 bytes.

[RouterD] ipv6 pim

[RouterD-pim6] jp-pkt-size 1400

7.     Configure Switch A:

# Enable MLD snooping globally.

<SwitchA> system-view

[SwitchA] mld-snooping

[SwitchA-mld-snooping] quit

# Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/4 to the VLAN.

[SwitchA] vlan 100

[SwitchA-vlan100] port gigabitethernet 1/0/1 to gigabitethernet 1/0/4

# Enable MLD snooping and IPv6 PIM snooping for VLAN 100.

[SwitchA-vlan100] mld-snooping enable

[SwitchA-vlan100] ipv6 pim-snooping enable

[SwitchA-vlan100] quit

Verifying the configuration

# On Switch A, display IPv6 PIM snooping neighbor information for VLAN 100.

[SwitchA] display ipv6 pim-snooping neighbor vlan 100

Total 4 neighbors.

 

VLAN 100: Total 4 neighbors.

  FE80::1

    Slots (0 in total):

    Ports (1 in total):

      GE1/0/1                  (00:32:43)

  FE80::2

    Slots (0 in total):

   Ports (1 in total):

      GE1/0/2                  (00:32:43)

  FE80::3

    Slots (0 in total):

    Ports (1 in total):

      GE1/0/3                  (00:32:43)

  FE80::4

    Slots (0 in total):

    Ports (1 in total):

      GE1/0/4                  (00:32:43)

The output shows that Router A, Router B, Router C, and Router D are IPv6 PIM snooping neighbors.

# On Switch A, display IPv6 PIM snooping routing entries for VLAN 100.

[SwitchA] display pim-snooping ipv6 routing-table vlan 100

Total 2 entries.

FSM flag: NI-no info, J-join, PP-prune pending

 

VLAN 100: Total 2 entries.

  (*, FF1E::101)

    Upstream neighbor: FE80::1

      Upstream Slots (0 in total):

      Upstream ports (1 in total):

        GE1/0/1

      Downstream Slots (0 in total):

      Downstream ports (1 in total):

        GE1/0/3

          Expires: 00:03:01, FSM: J

  (*, FF2E::101)

    Upstream neighbor: FE80::2

      Upstream Slots (0 in total):

      Upstream ports (1 in total):

        GE1/0/2

      Downstream Slots (0 in total):

      Downstream ports (1 in total):

        GE1/0/4

          Expires: 00:03:01, FSM: J

The output shows the following information:

·     Switch A will forward the multicast data intended for IPv6 multicast group FF1E::101 to only Router C.

·     Switch A will forward the multicast data intended for IPv6 multicast group FF2E::101 to only Router D.

Troubleshooting IPv6 PIM snooping

This section describes common IPv6 PIM snooping problems and how to troubleshoot them.

IPv6 PIM snooping does not work on a Layer 2 device

Symptom

IPv6 PIM snooping does not work on a Layer 2 device.

Solution

To resolve the problem:

1.     Use the display current-configuration command to display information about MLD snooping and IPv6 PIM snooping.

2.     If MLD snooping is not enabled, enable MLD snooping globally, and then enable MLD snooping and IPv6 PIM snooping for the VLAN or VSI.

3.     If IPv6 PIM snooping is not enabled, enable IPv6 PIM snooping for the VLAN or VSI.

4.     If the problem persists, contact H3C Support.