Comtech EF Data CDM-760, Инструкция по установке и эксплуатации

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Appendix K Revision 4
CDM-760 Advanced High-Speed Trunking Modem MN-CDM760
K–2
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
•
ICMP
• All-IP
• Non-IP
•
All
2 MPLS
3 VLAN
4 TOS
5 Source IP/Mask