Specifications
EASTAR UHP-1000 SERIES SATELLITE ROUTER
INSTALLATION AND OPERATION MANUAL, V. 2.3
(SW VERSION 2.2.9)
© ROMANTIS 2010 37 www.romantis.com
Selection of the packet getting into the LOW or HIGH can occur also depending on the DSCP
packet field value. The router understands DSCP values from 0 to 31.
2.8.6 Prioritization and DSCP
IP router
ip map ... ML ...
HIGH
ip map ... MH ...
IP router
ip map ... MD ...
Check
DSCP
DSCP map
DSCP=4,9,16-31
DSCP=0-3,5-8,10-15
0 31
MED
LOW
ip map ... MM ...
HIGH
MED
LOW
Modulator
Modulator
Figure 19 Prioritization of traffic on the modulator
2.8.7 Multicast routing
Group traffic support is implemented in UHP-1000 routers as follows:
To collect Multicast traffic from LAN to specified address you have to assign a map for this
traffic on the modulator. The router will itself understand that the address (network)
belongs to the Multicast range and will tune LAN to receive it.
At the other side, to transmit this traffic to LAN it is necessary (apart from the command to
receive SVLAN used to receive this traffic) to assign a static route to the Multicast address
(network) of the transmitted traffic, having selected, as the destination address, any
address within the range of any of the IP networks assigned to the router. The device with
such address may be missing, it is more important that the packets be routed to LAN.
2.8.8 Compressing RTP packet headers
When transmitting VoIP traffic by IP-protocol the size of headers of IP, UDP and RTP
protocols (in total not less than 42 bytes) can exceed the size of the voice portion of the
packet.
Transmission of such packets via a satellite is extremely inefficient with respect to
bandwidth usage, hence use is made of compression of protocols headers based on the fact
that only few fields change from placket to packet, and furthermore this change can often
be predicted.
In most cases the router compresses packet headers to up to two bytes. To make
compression work, it is essential that at the transmitting side (or at both sides) the ranges
of UDP (destination) port packets that the router will try to compress be adjusted
accordingly. Compression will work also in simplex mode (in one direction only). Packets
passing successful compression will always be sent with high priority.
Statistics of the compression functioning can be made available using ‖show rtp‖ command.