Televes
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Normally when a router or switch has no response from a Set-Top Box after several attempts asking
about membership in a multicast channel, delete the device joining to the multicast stream, setting a
conservative procedure regarding use of bandwidth and causes the master stops transmitting these
streams to the coaxial network after expiration of timers.
If you have not installed an IGMP Querier in video distribution, or do not want the streams are eliminated
after the expiration, disable timers through the checkboxes in the application.
No purpose of this manual is to define the IGMP protocol or the
elements that comprise it. For details refer to the standards defined
in this regard:
IGMPv2 and
It is recommended not disable timers unless the system do not
support IGMPv3 (only support the old IGMPv2). In practice, if disable
timers then when device does not indicate that leaves a channel
(IGMP leave) by switching channels or disconnected abruptly, he still
remains member of channel with the consequent consumption of
bandwidth.
Additionally, you can configure a number of parameters associated with IGMP:
Forward Unknown/Unmanaged Streams
: All multicast streams are transmitted from the master
to the slave even if no one registered in them. Since there is no list of registered devices in each
multicast, master uses a very conservative modulation which results in excessive bandwidth
consumption. This modulation is named ROBO (ROBust mOdulation) and transmits a maximum
of 5Mbps to all devices on netwok.
It is not recommended to use this option unless you
really know what you are doing.
IGMP Reports to Non-Querier Hosts
: By default, IGMP reports only are sent to Ethernet ports if
IGMP Querier exists on network, ie, IGMP reports are sent to querier. When this option is
enabled allows resend all IGMP join/leaves to Ethernet ports even if IGMP Queriers are not
present (ie , Multicast routers or switches connected to the Master). This allows IGMP reports are
propagate to network even when no multicast IGMP Queriers exists, but STB periodically send
IGMP messages indicated their intention to belong to a specific multicast group.
Although it is possible to implement videostreaming systems that do not require the existence of IGMP
Queriers, Installer is recommended to implement an IGMP querier, with a multicast router or a switch, so
as to provide an automated management and that guarantees that the bandwidth is used only when
users actually want to use video services and releasing those resources when leaving a channel.
Number of Users per Slave
When coaxial data network is implemented in community facilities, is very useful to limit the number of
users for each slave, since customers in their homes can use more than one device. This also increases
engine performance of the system, since it limits the number of links in the system:
MAC Address Limit
: This option sets a limit on the number of hosts connected to MAC Ethernet
ports that a device supports. This option can be used by installers of hotels, buildings, who want
to limit the number of users who use the data service from the slaves and allows control on the
number of total users that will use the data network.
