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· 3

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.

·     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.

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

Each IPv6 PIM-capable router in the VLAN, 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 in secondary VLANs. For more information about secondary VLANs, see Layer 2—LAN Switching Configuration Guide. ·     Make sure the IPv6 packet length of join/prune messages is less than the MTU of receiver-side IPv6 PIM interfaces that connect to IPv6 PIM snooping devices. Otherwise, IPv6 multicast data might not be correctly forwarded. The IPv6 packet length of join/prune messages is the packet length of join/prune messages plus the IPv6 header length. To set the maximum size of join/prune messages, use the jp-pkt-size command. To set the MTU for an Ethernet interface, use the mtu command. For more information about the command, see Interface Command Reference.

 

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

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

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.	vlan vlan-id	N/A
5.     Enable MLD snooping for the VLAN.	mld-snooping enable	By default, MLD snooping is disabled in a VLAN.
6.     Enable IPv6 PIM snooping for the VLAN.	ipv6 pim-snooping enable	By default, IPv6 PIM snooping is disabled in a VLAN.
7.     (Optional.) Set the aging time for global neighbor ports on the new master device after an IRF master election.	ipv6 pim-snooping graceful-restart neighbor-aging-time interval	The default setting is 105 seconds. A global neighbor port is a Layer 2 aggregate interface that acts as a neighbor port.
8.     (Optional.) Set the aging time for global downstream ports and global router ports on the new master device after an IRF master election.	ipv6 pim-snooping graceful-restart join-aging-time interval	The default setting is 210 seconds. A global downstream port or a global router port is a Layer 2 aggregate 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
Display IPv6 PIM snooping neighbor information.	display ipv6 pim-snooping neighbor [ vlan vlan-id ] [ slot slot-number ] [ verbose ]
Display IPv6 PIM snooping router port information.	display ipv6 pim-snooping router-port [ vlan vlan-id ] [ slot slot-number ]
Display IPv6 PIM snooping routing entries.	display ipv6 pim-snooping routing-table [ vlan vlan-id  ] [ 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

Network requirements

As shown in Figure 2:

·     OSPFv3 runs on the network.

·     Source 1 sends multicast data to IPv6 multicast group FF1E::101, and Source 2 sends multicast data to IPv6 multicast group FF2E::101.

·     Receiver 1 belongs to IPv6 multicast group FF1E::101, and Receiver 2 belongs to IPv6 multicast group FF2E::101.

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

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

Configure MLD snooping and IPv6 PIM snooping on Switch A. Then, Switch A forwards IPv6 PIM protocol packets and IPv6 multicast data packets to only the routers that connect to receivers.

Figure 2 Network diagram

 

Configuration procedure

1.     Assign an IPv6 address and prefix length to each interface according to 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 ten-gigabitethernet 1/1/1

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

[RouterA-Ten-GigabitEthernet1/1/1] quit

[RouterA] interface ten-gigabitethernet 1/1/2

[RouterA-Ten-GigabitEthernet1/1/2] ipv6 pim sm

[RouterA-Ten-GigabitEthernet1/1/2] quit

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

[RouterA] ipv6 pim

[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 ten-gigabitethernet 1/1/1

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

[RouterB-Ten-GigabitEthernet1/1/1] quit

[RouterB] interface ten-gigabitethernet 1/1/2

[RouterB-Ten-GigabitEthernet1/1/2] ipv6 pim sm

[RouterB-Ten-GigabitEthernet1/1/2] quit

5.     Configure Router C:

# Enable IPv6 multicast routing.

<RouterC> system-view

[RouterC] ipv6 multicast routing

[RouterC-mrib6] quit

# Enable MLD on Ten-GigabitEthernet 1/1/1.

[RouterC] interface ten-gigabitethernet 1/1/1

[RouterC-Ten-GigabitEthernet1/1/1] mld enable

[RouterC-Ten-GigabitEthernet1/1/1] quit

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

[RouterC] interface ten-gigabitethernet 1/1/2

[RouterC-Ten-GigabitEthernet1/1/2] ipv6 pim sm

[RouterC-Ten-GigabitEthernet1/1/2] quit

6.     Configure Router D:

# Enable IPv6 multicast routing.

<RouterD> system-view

[RouterD] ipv6 multicast routing

[RouterD-mrib6] quit

# Enable MLD on Ten-GigabitEthernet 1/1/1.

[RouterD] interface ten-gigabitethernet 1/1/1

[RouterD-Ten-GigabitEthernet1/1/1] mld enable

[RouterD-Ten-GigabitEthernet1/1/1] quit

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

[RouterD] interface ten-gigabitethernet 1/1/2

[RouterD-Ten-GigabitEthernet1/1/2] ipv6 pim sm

[RouterD-Ten-GigabitEthernet1/1/2] quit

7.     Configure Switch A:

# Enable MLD snooping globally.

<SwitchA> system-view

[SwitchA] mld-snooping

[SwitchA-mld-snooping] quit

# Create VLAN 100, assign Ten-GigabitEthernet 1/1/1 through Ten-GigabitEthernet 1/1/4 to the VLAN, and enable MLD snooping and IPv6 PIM snooping for the VLAN.

[SwitchA] vlan 100

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

[SwitchA-vlan100] mld-snooping enable

[SwitchA-vlan100] ipv6 pim-snooping enable

[SwitchA-vlan100] quit

Verifying the configuration

# On Switch A, display information about IPv6 PIM snooping neighbors 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):

      XGE1/1/1                  (00:32:43)

  FE80::2

    Slots (0 in total):

    Ports (1 in total):

      XGE1/1/2                  (00:32:43)

  FE80::3

    Slots (0 in total):

    Ports (1 in total):

      XGE1/1/3                  (00:32:43)

  FE80::4

    Slots (0 in total):

    Ports (1 in total):

      XGE1/1/4                  (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):

        XGE1/1/1

      Downstream Slots (0 in total):

      Downstream ports (1 in total):

        XGE1/1/3

          Expires: 00:03:01, FSM: J

  (*, FF2E::101)

    Upstream neighbor: FE80::2

      Upstream Slots (0 in total):

      Upstream ports (1 in total):

        XGE1/1/2

      Downstream Slots (0 in total):

      Downstream ports (1 in total):

        XGE1/1/4

          Expires: 00:03:01, FSM: J

The output shows that:

·     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.

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

4.     If the problem persists, contact H3C Support.