Comtech EF Data CDM-IP 300L - Manual (Page 48)

CDM-IP 300L IP-Centric Satellite Modem Rev. 1
CD/CDMIP300L.IOM
20
Expedited Forwarding and Assured Forwarding DSCP – Another implementation of
DiffServ uses all 6 bits of the DSCP to define Expedited and Assured Forwarding:
DiffServ Type
Class Selector DSCP
CDM-IP
Priority
Expedited Forwarding Precedence 1 101 110 1
Assured Forwarding – Class 1 Precedence 8 001 xx0 8
Assured Forwarding – Class 2 Precedence 8 010 xx0 8
Assured Forwarding – Class 3 Precedence 8 011 xx0 8
Assured Forwarding – Class 4 Precedence 8 100 xx0 8
Expedited Forwarding (EF) DSCP – This defines premium service and is
recommended for real time traffic applications such as VoIP and video conferencing.
Assured Forwarding (AF) DSCP – This defines 4 service levels and also uses the last 3
bits of the DSCP to define the Drop Precedence (Low, Medium, or High). The Drop
Precedence determines which packets will most likely be dropped during periods of over
congestion, similar to Weighted Random Early Detection (WRED). As a result, each of
the 4 AF service levels also have 3 Drop Precedence levels for which the CDM-IP
provides 12 seperate queues.
Minimum Bandwidth (AF only) - Minimum specification that allows a committed
information rate (CIR) to be applied to user defined classes of traffic, or the default of no
minimum bandwidth can be selected.
Maximum Bandwidth (AF only) - This can be assigned to a flow to restrict the
maximum bandwidth that any particular flow will utilize, or the default of no bandwidth
restriction can be selected.
NOTE: Minimum and maximum bandwidth is only configurable for each of the 4
Assured Forwarding classes.
NOTE: Typically, DiffServ is implemented using exclusively Class Selector DSCP or
exclusively Expedited and Assured Forwarding DSCP. The CDM-IP is fully DiffServ
compliant and will work with either DiffServ implementation or with a combination of
both.
1.4.5 P
AYLOAD
C
OMPRESSION
Traffic optimization through Payload Compression is another optional feature of the
CDM-IP modem.
- Framer II required
- FAST feature to upgrade
- Uses AHA chip
- Compression algorithm applied to all data (HDLC header excluded)