General Configuration Guidelines For Mvr; Igmp Snooping - AMX NXA-ENET8-2POE Instruction Manual

MVR Conf iguration parameters (Cont.)
MVR Conf iguration (Cont.)
• Immediate Leave
Multicast VLAN Registration (MVR) is a protocol that controls access to a single network-wide VLAN most commonly used for
transmitting multicast traffic (such as television channels or video-on-demand) across a service provider's network. Any multicast
traffic entering an MVR VLAN is sent to all attached subscribers. This protocol can significantly reduce to processing overhead
required to dynamically monitor and establish the distribution tree for a normal multicast VLAN. This makes it possible to support
common multicast services over a wide part of the network without having to use any multicast routing protocol. MVR maintains
the user isolation and data security provided by VLAN segregation by passing only multicast traffic into other VLANs to which the
subscribers belong. Even though common multicast streams are passed onto different VLAN groups from the MVR VLAN, users in
different IEEE 802.1Q or private VLANs cannot exchange any information (except through upper-level routing services).
MVR Concept
FIG. 75
General Conf iguration Guidelines for MVR
Enable MVR globally on the switch, and select the MVR VLAN.

Set the interfaces that will join the MVR as source ports or receiver ports.

If you are sure that only one subscriber attached to an interface is receiving multicast services, you can enable the

immediate leave function.
Although MVR operates on the underlying mechanism of IGMP snooping, the two features operate independently of each

other. One can be enabled or disabled without affecting the behavior of the other. However, if IGMP snooping and MVR are
both enabled, MVR reacts only to join and leave messages from multicast groups configured under MVR. Join and leave
messages from all other multicast groups are managed by IGMP snooping. Also, note that only IGMP version 2 or 3 hosts
can issue multicast leave messages. Immediate leave therefore cannot be used for IGMP version 1 clients.
1. Click Conf iguration, MVR.
2. Enable MVR globally on the switch, and select the MVR VLAN.
3. Set each port that will participate in the MVR protocol as a source port or receiver port, and optionally enable Immediate
Leave on any receiver port to which only one subscriber is attached.
4. Click Save.

IGMP Snooping

Multicasting is used to support real-time applications such as video conferencing or streaming audio. A multicast server does not
have to establish a separate connection with each client. It merely broadcasts its service to the network, and any hosts that want to
receive the multicast register with their local multicast switch/router. Although this approach reduces the network overhead
required by a multicast server, the broadcast traffic must be carefully pruned at every multicast switch/router it passes through to
ensure that traffic is only passed on to the hosts which subscribed to this service.
This switch can use Internet Group Management Protocol (IGMP) to filter multicast traffic. IGMP Snooping can be used to passively
monitor or snoop on exchanges between attached hosts and an IGMP-enabled device, most commonly a multicast router. In this
way, the switch can discover the ports that want to join a multicast group, and set its filters accordingly.
If there is no multicast router attached to the local subnet, multicast traffic and query messages may not be received by the switch.
In this case (Layer 2) IGMP Query can be used to actively ask the attached hosts if they want to receive a specific multicast service.
IGMP Query thereby identifies the ports containing hosts requesting to join the service and sends data out to those ports only.
NXA-ENET8-2POE - Instruction Manual
Configures the switch to immediately remove an interface from a multicast stream as soon as it receives a leave
message for that group. (This option only applies to an interface configured as an MVR receiver). Remember that
only IGMP version 2 or 3 hosts can issue multicast leave messages. If a version 1 host is receiving multicast traffic,
the switch can only remove the interface from the multicast stream after the host responds to a periodic request
for a membership report.
Configuring the NXA-ENET8-2POE
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