Comtech EF Data MD2401 - Manual (Page 83)

MD2401 L-Band Multi Demod Installation and Operation Manual Rear Panel Interfaces
MN-MD2401 5–3
Revision 7
5.4 Ethernet Data Interface
When equipped with the optional 10/100/1000 Base-T Ethernet interface, the MD2401 provides
the same simple plug-and-play functionality found in all Radyne Ethernet Data Interfaces.
There’s nothing to configure, no IP Addresses or Subnet masks to worry about, no reconfiguring
of LAN equipment, simply plug it in and you’re up and running. Any and all types of Ethernet and
IP traffic passes transparently through the MD2401 and the embedded Quality of Service (QOS)
provides the same functionality as many commercially available QOS switches costing hundreds
of dollars.
5.4.1 Compatibility
The MD2401 Ethernet interface is compatible with all existing Radyne modulators running legacy
or enhanced Ethernet bridge applications. This includes the DMD20, DMD2050, and the DMD50.
5.4.2 Auto-Crossover, Auto-Polarity, and Auto-Negotiation
With these standard features, the 10/100/1000 Base-T interface will automatically connect to the
terrestrial LAN at the highest possible rate and you never have to worry about having cross-over
or pass-thru cables.
5.4.3 Automatic Demodulator card detection and dedicated HDLC decoders
The MD2401 Ethernet interface automatically detects the presence and operational readiness of
each of the demodulator cards. In addition, the interface provides a dedicated HDLC decoder for
each demodulator so that received satellite traffic from multiple demodulators is processed
simultaneously in real-time. Valid Ethernet packets are output from the individual decoders to the
QOS processor as soon as they’re received.
5.4.4 Ingress Quality of Service
When Ethernet packets arrive simultaneously from two or more demodulators, the Queue
Manager accepts the packet from demodulator 1 first, demodulator 2 second, demodulator 3
third, and demodulator 4 last at gigabit rates insuring that all received packets from even the
lowest priority demodulator can be accepted and processed before new packets arrive.
5.4.5 Egress Quality of Service
The Queue Manager determinations the type of QOS information available in each Ethernet
packet in real-time and places the packet in the appropriate output queue automatically. This
QOS determination is compatible with various industry standards and is performed in the
following manner:
1. If the packet contains an optional IEEE 802.3ac tag containing IEEE 802.1p priority
information, the information in this tag is used to determine the packets priority.
2. When an IEEE 802.3ac tag is not present
a) If the packet contains an IPv4 header, the packets priority is determined by the Type
of Service field (RFC 791) or Differentiated Services field (RFC 2474) contained in
header.
b) If the packet contains an IPv6 header, the Traffic Class field (RFC 2460) is used to
determine the packets priority.