As shown in Figure 1-1, in the traditional multicast
programs-on-demand mode, when hosts, Host A, Host B and Host C, belonging to
different VLANs require multicast programs on demand service at the same time,
the Layer 3 device, Router A, needs to forward a separate copy of the multicast
traffic in each user VLAN to the Layer 2 device, Switch A. This results in not only waste of network bandwidth but also extra
burden on the Layer 3 device.
Figure 1-1 Before and after multicast VLAN is enabled on the Layer 2 device
To solve this problem, you can enable the
multicast VLAN feature on Switch A, namely configure the VLANs to which these hosts
belong as sub-VLANs of a multicast VLAN on the Layer 2 device and enable Layer
2 multicast in the multicast VLAN. After this configuration, Router A
replicates the multicast data only within the multicast VLAN instead of forwarding
a separate copy of the multicast data to each VLAN. This
saves the network bandwidth and lessens the burden of the Layer 3 device.
Multicast VLAN can be applied to both IPv4 networks (IPv4 multicast
VLAN) and IPv6 networks (IPv6 multicast VLAN).
Follow these steps to configure a multicast
VLAN:
|
To do…
|
Use the command…
|
Remarks
|
|
Enter system view
|
system-view
|
—
|
|
Configure a specific VLAN as a multicast
VLAN
|
multicast-vlan
vlan-id enable
|
Required
Disabled by default
|
|
Configure sub-VLANs for a specific multicast
VLAN
|
multicast-vlan
vlan-id subvlan vlan-list
|
Required
No sub-VLAN by default.
|
l
The VLAN to be configured as the multicast VLAN
and the VLANs to be configured as sub-VLANs of the multicast VLAN must exist.
l
The VLANs to be configured as sub-VLANs of the
multicast VLAN must not be multicast VLANs
l
The VLANs to be configured as the sub-VLANs of
the multicast VLAN must not be sub-VLANs of another multicast VLAN
l
The number of sub-VLANs of the multicast VLAN
must not exceed the system-defined limit.
l
The configurations mentioned above are good for
both IPv4 multicast VLAN and IPv6 multicast VLAN.
l
The total number of multicast groups on all the
outgoing interfaces of the multicast VLAN cannot exceed 1024.
l
IPv6 multicast VLAN needs the support of a Type D
board, (a board suffixed with DA, DB, or DC), that is, the incoming port for a
given IPv6 multicast data should be a port on a Type D board. In practice, a device may use different types of boards. If IPv6
multicast data can be delivered to the device only through a port on a
non-Type-D board due to some restrictions, you can configure board intermixing
for IPv6 multicast to enable normal forwarding of IPv6 multicast data. For board intermixing for IPv6 multicast, see IPv6 PIM Configuration
in the IP Multicast Volume.
Caution:
l With the multicast routing-enable or the multicast
ipv6 routing-enable command enabled, you cannot enable multicast VLAN on
the device. For details about these two commands, see Multicast Routing and
Forwarding Commands and IPv6 Multicast Routing and Forwarding Commands
in the IP Multicast Volume.
l After a VLAN is configured into an IPv4 multicast VLAN, IGMP
Snooping must be enabled in the VLAN before the IPv4 multicast VLAN feature can
be implemented, while it is not necessary to enable IGMP Snooping in the
sub-VLANs of the IPv4 multicast VLAN. For details about IGMP Snooping, see IGMP
Snooping Configuration in the IP Multicast Volume.
l After a VLAN is configured into an IPv6 multicast VLAN, MLD Snooping
must be enabled in the VLAN before the IPv6 multicast VLAN feature can be
implemented, while it is not necessary to enable MLD Snooping in the sub-VLANs
of the IPv6 multicast VLAN. For details about MLD Snooping, see IGMP
Snooping Configuration in the IP Multicast Volume.
|
To do…
|
Use the command…
|
Remarks
|
|
Display information about a multicast
VLAN
|
display multicast-vlan [ vlan-id ]
|
Available in any view
|
I. Network requirements
l
As shown in Figure 1-2, Router A (multicast router) connects
to a multicast source through Ethernet 1/1/2 and to Switch A (an S9500 series
Ethernet switch) through Ethernet 1/1/1.
l
PIM-DM is enabled on Ethernet 1/1/1 and Ethernet
1/1/2 of Router A. IGMPv2 is enabled on Router A, and IGMP Snooping is enabled
on Switch A. Router A is the IGMP querier.
l
Switch A’s Ethernet 1/1/1 belongs to VLAN
1024, and Ethernet 1/2/1 and Ethernet 1/3/1 are trunk ports, which belong to
VLANs 1 through 3 and VLANs 4 through 6 respectively.
l
Switch B and Switch C are common switches that
support IGMP Snooping. The ports connecting to Switch A are trunk ports. They
belong to VLANs 1 through 3 and VLANs 4 through 6 respectively. IGMP Snooping
is enabled on Switch B and Switch C.
l
Hosts A through F belong to VLANs 1 through 6
respectively. Configure these six VLANs as the sub-VLANs of the multicast VLAN
1024 so that the six hosts can receive multicast data.
II. Network diagram
Figure 1-2 Network diagram for IPv4 multicast VLAN configuration
III. Configuration procedure
1)
Configure IP addresses
Configure an IP address and subnet mask for
each interface as per Figure
1-2. The detailed configuration steps are omitted here.
2)
Configure Router A
# Enable IP multicast routing, enable
PIM-DM on each interface and enable IGMPv2 on Ethernet 1/1/1.
<RouterA> system-view
[RouterA] multicast routing-enable
[RouterA] interface ethernet 1/1/1
[RouterA-Ethernet1/1/1] pim dm
[RouterA-Ethernet1/1/1] igmp enable
[RouterA-Ethernet1/1/1] igmp version 2
[RouterA-Ethernet1/1/1] quit
[RouterA] interface ethernet 1/1/2
[RouterA-Ethernet1/1/2] pim dm
[RouterA-Ethernet1/1/2] quit
The configurations mentioned above are for reference only.
3)
Configure Switch A
# Configure VLAN 1024 as a multicast VLAN
and configure VLANs 1 through 6 as sub-VLANs of VLAN 1024.
<SwitchA> system-view
[SwitchA] vlan 1 to 6
[SwitchA] vlan 1024
[SwitchA-vlan1024] port ethernet
1/1/1
[SwitchA-vlan1024] quit
[SwitchA] interface ethernet 1/2/1
[SwitchA-Ethernet1/2/1] port
link-type trunk
[SwitchA-Ethernet1/2/1] port trunk permit
vlan 1 to 3
[SwitchA-Ethernet1/2/1] quit
[SwitchA] interface ethernet 1/3/1
[SwitchA-Ethernet1/3/1] port
link-type trunk
[SwitchA-Ethernet1/3/1] port trunk permit
vlan 4 to 6
[SwitchA-Ethernet1/3/1] quit
[SwitchA] multicast-vlan 1024 enable
[SwitchA] multicast-vlan 1024 subvlan
1 to 6
# Enable IGMP Snooping.
[SwitchA] igmp-snooping
[SwitchA-igmp-snooping] quit
[SwitchA] vlan 1024
[SwitchA-vlan1024] igmp-snooping
enable
I. Network requirements
l
As shown in Figure 1-3, Router A connects to an IPv6
multicast source (Source) through Ethernet 1/1/1, and to Switch A (an S9500
series Ethernet switch) through Ethernet 1/1/10.
l
MLDv1 is enabled on Router A. MLD Snooping is
enabled on Switch A. Router A is the MLD querier on the subnet.
l
Switch A’s Ethernet 1/1/10 belongs to VLAN
1024, and Ethernet 1/1/1 through Ethernet 1/1/3 belong to VLANs 10 through 12
respectively. Hosts A through C are attached to Ethernet 1/1/1 through Ethernet
1/1/3 of Switch A.
l
Configure the IPv6 multicast VLAN feature so
that Router A just sends IPv6 multicast data to VLAN 1024 rather than to each
VLAN when the three hosts attached to Switch A need the IPv6 multicast data.
II. Network diagram
Figure 1-3 Network diagram for IPv6 multicast VLAN configuration
III. Configuration procedure
1)
Enable IPv6 forwarding and configure IPv6
addresses
Enable IPv6 forwarding on each device and
configure the IPv6 address and prefix length for each interface as per Figure 1-3. The
detailed configuration steps are omitted here.
2)
Configure Router A
# Enable IPv6 multicast routing, enable
IPv6 PIM-DM on each interface, and enable MLD on the receiver-side interface,
Ethernet 1/1/10.
<RouterA> system-view
[RouterA] multicast ipv6
routing-enable
[RouterA] interface ethernet 1/1/10
[RouterA-Ethernet1/1/10] pim ipv6 dm
[RouterA-Ethernet1/1/10] mld enable
[RouterA-Ethernet1/1/10] mld version 1
[RouterA-Ethernet1/1/10] quit
[RouterA] interface ethernet 1/1/1
[RouterA-Ethernet1/1/1] pim ipv6 dm
[RouterA-Ethernet1/1/1] quit
The configurations
mentioned above are for reference only.
3)
Configure switch A.
# Enable MLD Snooping globally.
<SwitchA> system-view
[SwitchA] mld-snooping
[SwitchA-mld-snooping] quit
# Create VLANs 10 through 12 and add the
corresponding ports to the VLANs.
[SwitchA] vlan 10
[SwitchA-vlan10] port ethernet 1/1/1
[SwitchA-vlan10] quit
[SwitchA] vlan 11
[SwitchA-vlan11] port ethernet 1/1/2
[SwitchA-vlan11] quit
[SwitchA] vlan 12
[SwitchA-vlan12] port ethernet 1/1/3
[SwitchA-vlan12] quit
# Create VLAN 1024, add Ethernet 1/1/10 to
VLAN 1024, and enable MLD Snooping in this VLAN.
[SwitchA] vlan 1024
[SwitchA-vlan1024] port ethernet
1/1/10
[SwitchA-vlan1024] mld-snooping
enable
[SwitchA-vlan1024] quit
# Configure VLAN 1024 as an IPv6 multicast
VLAN, and configure VLANs 10 through 12 as its sub-VLANs.
[SwitchA] multicast-vlan 1024 enable
[SwitchA] multicast-vlan 1024 subvlan
10 to 12
