Comtech EF Data CDM-760 - Manual (Page 402)

Appendix K Revision 2
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
K–2
• A non-static WAN capacity such as dynamic Single Carrier Per Channel (dSCPC) is used,
where circuits are being set-up, torn down and re-sized.
It is important to note that traffic shaping takes effect on the traffic moving from the LAN to the
WAN. Traffic shaping does not impact WAN-to-LAN traffic.
K.3 Traffic Shaping Functionality (QoS)
The high-speed Packet Processor functions in a Layer 2 or Layer 3 mode of operation. Traffic
Shaping or QoS can be thought of as three separate processes:
• Classification • Prioritization • Drain
Classification, Prioritization and Drain for DiffServ is specific to DiffServ QoS selection.
See Sect. K.3.3.3.
K.3.1 Classification
Classification of traffic is the basic mechanism by which a packet or frame can be sorted and
associated with a particular priority. Each classification can be considered a classification rule or
“QoS rule”. The more flexible a classification engine is, the more likely the high value services
can be protected.
The CDM-760 offers a very flexible classification engine. If a packet satisfies more than one
classification, Table K-1 lists the classification types that determine which rule is chosen. The
table shows a precedence from 1 to 8, where any packet satisfying more than one rule is
classified by the order of precedence from first to last.
For example: A packet or frame satisfies both an MPLS tag rule and a Source IP/Mask rule. The
MPLS rule takes precedence and is acted on accordingly.
Classification for DiffServ does not follow this precedence. See Sect. K.3.3.3.
Table K-1. Rule Preference and Classification
Order Precedence Classifier
1 (First) Protocol (in this order)
• RTP_VOICE
• RTP_VIDEO
• RTP_SIG
• RTP
• FTP
• HTTP
• TELNET
• SMTP
• SNMP
• UDP
• TCP