ND SatCom SKYWAN IDU 7000, Manual

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118 Network Design and Engineering Guide 2010-10-26
Data Networking
SkyWAN
®
Internet Protocol Features
allowed on these channels.
For each entry in the multicast forwarding table which defines a multicast flow which should be
received on the secondary demodulator in FMCA mode, the reception channel and a priority
must be defined.
If a host connected to the IDU’s LAN wants to receive a specific multicast stream, it sends an
IGMP ’join’ request to the IDU. The IDU will inspect its multicast forwarding table to map the IP
multicast address to a reception channel and will tune its secondary demodulator to this chan-
nel in order to receive and forward the requested multicast flow. The forwarding will be deacti-
vated if the host signals an IGMP ’leave’ message to the IDU or if there is no response to a
regular IGMP query from the IDU. The priority parameter is used to resolve potential conflicts:
If there are two active join requests for different IP multicast flows which are mapped to different
reception channels, the IDU will tune its demodulator to the channel with the higher priority.
4.2.8 IP Service Differentiation (Quality of Service)
Service differentiation for IP unicast and multicast traffic may be enabled by configuration for
each
Sky WAN
®
IDU.
If enabled each IP microflow which should be forwarded to the satellite interface
-
may be classified using protocol header information and rules defined in the station’s for-
ward aggregate table into a forwarding behavior.
- may be preallocated (for real time forwarding behaviors) according to the forwarding be-
havior stream slot capacity. The traffic flow will be enqueued to a transmit queue defined
by the flow’s forwarding behavior.
Packet flows for which no matching definition is present in the station’s forward aggregate table
will use the default forwarding behavior. Classification of flows can be performed using the fol-
lowing parameters:
-
host or network source and destination IP address.
- source and destination TCP/UDP port range.
- Differentiated Services Code Point (DSCP) field, representing the 6 most significant bits of
the Type Of Service (TOS) field in the IP header.
- transported protocol.
Any combination of these parameters can be used to define an entry in the station’s forwarding
aggregate table. Each entry has a ’weight’ index, the service differentiation module will process
the table entries in the order of these indices. The first matching aggregate determines the for-
warding behavior of the microflow. Therefore, if there are definitions which are not mutually ex-
clusive, the more specific definition must be defined with a lower weight. Up to 64 definitions
for forwarding aggregates can be configured on one
Sky WAN
®
IDU.