TANDBERG High Definition Professional Recevier/Decoder TT1280 - Manual (Page 73)

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Reference Guide: TT128x High Definition Professional Receiver/Decoder Page 6-7
ST.RE.E10141.5
6.6 IP Input Card (TT1280/HWO/IP)
The IP Input card provides a 10/100BaseT Ethernet port, on which a
transport stream can be received in UDP packets at up to 50 Mbit/s.
The mapping of MPEG-2 TS packets into IP data frames is done according
to the protocol stack shown in Figure 6.1. The figure shows the Protocol
Stack in use when mapping MPEG-2 into IP frames and Ethernet.
Figure 6.1: The Protocol Stack
The MPEG-2/DVB layer is specified in ISO/IEC IS 13818 – Generic Coding
of Moving Pictures and Associated Audio. The UDP layer is compliant with
RFC768 – User Datagram Protocol. A configurable number of 188-byte
MPEG-2 TS packets are mapped straight into an UDP frame with no
additional overhead. The MTU for Ethernet is usually 1500 bytes. This
limits the number of MPEG-2 TS packets per UDP frame to lie within
one to seven.
The IP layer is according to RFC791 – Internet Protocol Specification.
Figure 6.2 shows a more detailed picture of the MPEG-2 data transfer.
TS-packets are mapped in a datagram, using User Data Protocol (UDP),
Internet Protocol (IP) and Ethernet.
Figure 6.2: Building the Ethernet Frame
UDP datagram
IP datagram
Ethernet frame
188 TS packets (1 to 7) 188 …
Information 8 H
Information 20 H
Information 14H
Link layer – 10/100BaseT Ethernet
Transport layer - IP
TCP/UDP UDP – User Datagram Protocol
MPEG-2/DVB layer
MPEG-2 Transport Stream
(Multi-Program Transport
Stream or Single-Program
Transport Stream) Control traffic for in-band
management
(telnet, http, snmp)