Netgear GSM5212P GSM5212P/GSM7212P/GSM7212F/GSM7224P Administration Manual - Page 226

14. MVR (Multicast VLAN Registration) 14 This chapter provides the following examples: • Configure MVR in Compatible Mode • Configure MVR in Dynamic Mode The IGMP Layer 3 protocol is widely used for IPv4 network multicasting. In Layer 2 networks, the IGMP protocol uses resources inefficiently. For example, a Layer 2 switch multicasts traffic to all ports even if there are receivers connected to only a few ports. To fix this problem, the IGMP Snooping protocol was developed. But the problem reappears when receivers are in different VLANs. Multicast VLAN Registration (MVR) is intended to solve the problem of receivers in different VLANs. It uses a dedicated manually configured VLAN, called the multicast VLAN, to forward multicast traffic over Layer 2 network in conjunction with IGMP snooping. MVR, like the IGMP Snooping protocol, allows a Layer 2 switch to snoop on the IGMP control protocol. Both protocols operate independently of each other. Both protocols can be enabled on the switch interfaces at the same time. In such a case, MVR listens to the join and report messages only for groups configured statically. All other groups are managed by IGMP snooping. There are two types of MVR ports: source and receiver. • The source port is the port to which the multicast traffic flows using the multicast VLAN. • The receiver port is the port where a listening host is connected to the switch. It can utilize any (or no) VLAN, except the multicast VLAN. This implies that the MVR switch performs VLAN tag substitution from the multicast VLAN source port to the VLAN tag used by the receiver port. The Multicast VLAN is the VLAN that is configured in the specific network for MVR purposes. It has to be manually specified by the operator for all source ports in the network. It is a VLAN that is used to transfer multicast traffic over the network to avoid duplication of Chapter 14. MVR (Multicast VLAN Registration) | 226