ND SatCom SKYWAN IDU 7000, Manual

Page: 124 / 154

120 Network Design and Engineering Guide 2010-10-26
Data Networking
SkyWAN
®
Internet Protocol Features
Gold-TCP-A, Gold, Silver, Bronze, Default
All of these forwarding behaviors are mapped to the same transmit queue, i.e. they have the
same transmit priority. However, packets belonging to a specific forwarding behaviors will only
be accepted in the queue if its filling level is below a forwarding behavior dependent threshold,
otherwise packets will be discarded (refer to table 4-3).
Table 4-3 Threshold of Forwarding Behaviors
Therefore a packet mapped to a gold forwarding behavior will have a very low discard proba-
bility even if the network is congested. Gold-TCPA flows are additionally subject to TCP accel-
eration procedures, which will be discussed later.
Titanium
The Titanium forwarding behavior defines a high priority non real time traffic flow. To prevent
that such a flow is consuming too much bandwidth and potentially disrupts lower priority serv-
ices, it is necessary to define a maximum data rate for each Titanium aggregate. Traffic ex-
ceeding this limit will be discarded.
Platinum
Platinum forwarding aggregates define a permanent real time traffic flow. When the aggregate
is activated, the IDU will request sufficient streaming bandwidth to serve the aggregate’s con-
figured data rate.
When this capacity is allocated by the master, the aggregate becomes operational and packets
will be forwarded if the data flow does not exceed the aggregate’s configured data rate. If the
allocation is not possible due to a lack of available streaming slots on the channel, the aggre-
gate will be blocked and packets will be discarded.
Platinum aggregate definitions must include a destination host or network IP address, so that
the routing module can determine on which frequency channel the capacity has to be allocated.
Multicast IP addresses are also possible as destination if multicast forwarding is enabled on
the station.
Note that the Platinum aggregate capacity will be allocated permanently if the destination is
reachable, even if the traffic flow is not permanently active.
Forwarding Behavior Name Threshold [kB]
Gold-TCP-A 300
Gold 200
Silver 160
Bronze 120
Default 80