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IP-LOGIC AV over IP Technical Manual
TM-003-0001-100-00 | July 15, 2019
© 2019 Zigen Corporation
www.zigencorp.com
Layer 2 10 Gbps switches could also be used provided they support the multicast configuration
listed below:
•
IGMP Version 2 Support
•
IGMP Snooping
•
Filter/Drop Unregistered Multicast Traffic
•
Disable Unregistered Multicast Flooding
•
Enable Fast Leave Support
•
Disable Green, Energy Efficient Ethernet (EEE), or any Energy Saving feature.
IP-Logic uses Multicast broadcasting to enable transmission of video streams to multiple
endpoints. An unmanaged Ethernet switch may default broadcast traffic to all ports on the
switch all video packets will be sent to every decoding device.
The Internet Group Management Protocol (IGMP) is an integral part of IP multicast and is a
communications protocol implemented by hosts and adjacent routers on IPv4 networks to
initiate and manage multicast group membership. IGMP Snooping is an important feature for
Ethernet switches used in an IP-Logic AVoIP environment. IP-Logic devices implement the IGMP
protocol by requesting data from transmitted multicast groups. The Ethernet switch then
employs IGMP snooping to identify IGMP messages and targets the multicast packets only to
specific receivers who want to receive them, thereby, optimizing Multicast traffic. Ensure that
all Ethernet switches have IGMP Snooping enabled.
By default, multicast traffic should be blocked until the packets are requested by a multicast
group member. An IGMP Querier is the master router or switch that manages the IGMP filter
lists. The Querier’s responsibilities are as follows:
•
To send out IGMP group membership queries on a timed interval.
•
To retrieve IGMP membership reports from active members.
•
To allow updating of the group membership tables.
A Layer 2 Network Switch supporting IGMP snooping passively checks IGMP packets passing
through the network, determines group registration, and configures multicasting accordingly.
Without IGMP Querying and Snooping, Multicast traffic will be similar to a Broadcast
transmission, which sends packets to all ports on the network. With IGMP Querying and
Snooping, Multicast packets are only forwarded to network ports that connected to members of
that Multicast group optimizing network traffic passing through the switch.
When an IP-Logic endpoint wants to leave a Multicast group, the IGMP Leave Group command is
sent to the Ethernet switch. Leaving this group could take some time unless the Enable Fast
Leave function is enabled. With this feature enabled on an Ethernet switch, video switching times
could be dramatically shortened.
System Deployment Guidelines
