Televes Coaxdata 1Gbps-HDTV COAX+PLC 1ETH+1SFP - Manual (Page 19)

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 Multicast (default CAP1): Prioridad asignada a streams multicast que no son gestionados por
IGMP; es decir, aquellos streams multicast para los cuales no se han generados IGMP reports
ni existen IGMP queries que los gestionen.
 Multicast gestionados por IGMP (default CAP3): Prioridad asignada a streams multicast que
han sido gestionados por los dispositivos mediante IGMP Snooping.
Priority Levels Assignment
Packets can be assigned to the desired priority level based on:
• VLAN 802.1P Priority : VLAN tags are small data field in 802.1 Ethernet packets and
determines or specifies the packet type in question. This tag is normally assigned at source or
swiches established by the network depending on the input port (or any other parameter:
multicast, UDP. Destination port, etc). You can set the "User Priority" Tag VLAN 802.1P priority
levels CAP0-CAP3.
• IP Traffic Class : Priority based on ToS (Type of Service) of IP packets. RFC 1349 describes
this field and values like delay, rate optimization or reliability. You can assign one of four priority
levels CAP0-3 device according to the first 3 bits of the ToS field (ToS Precedence).
TTL - Time to Live
CoaxDATA devices allow you to specify a parameter called TTL (Time to Live) for each priority level,
CAP. This parameter indicates how long a packet can stay in the buffers (SDRAM) before exceeding
the maximum lifetime. Once established time is out packet is dropped.
The time a packet remains in the device buffers before transmission depends on network traffic
conditions, the number of modems that make up the network and its effective occupation, so that the
establishment of these values should be account the implementation and the estimated rate of service.
By example, this mechanism is often used in VoIP or Video packets where packet time on buffer is
excessive and can be discarded because elapsed time is too late at the receiver and is not necessary
for decoding.
TTL values for each priority queue and MME (Management Messages, which are used by the
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