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Terms and Definitions
Matrix(su)->set policy rule admin-profile port ge.1.10 mask 16
port-string ge.1.10 admin-pid 2
Matrix(su)->set policy rule 1 tcpdestportIP 1720:10.0.0.1 cos 10
port-string ge.1.10
Matrix(su)->set cos port-resource irl 3.1 2 unit pps rate 5
Matrix(su)->set cos reference irl 3.1 10 rate-limit 1
Matrix(su)->set cos 10 priority 5 tos-value 184.0 txq-reference 8
irl-reference 2
Matrix(su)->set cos state enable
Terms and Definitions
Table
2 lists terms and definitions used in this Quality of Service configuration discussion.
Table 2 Quality of Service Configuration Terms and Definitions
Term
Class of Service
(CoS)
DSCP
Flows
Forwarding
Treatment
Jitter
Port Group
Port Type
Priority
Quality of Service
(QoS)
Rate Limiting
Rate Shaping
Type of Service
(ToS)
February 22, 2008
Definition
The grouping of priority and forwarding behaviors that collectively determine packet
bandwidth behavior as it transits the link, including: 802.1p, IP ToS rewrite, priority
Transmit Queue (TxQ), Inbound and/or outbound Rate Limiter (IRL) and outbound
rate shaper.
Differentiated Services Code Point. The lower 6 bits of the ToS field defined by RFC
2474.
In a QoS context, a sequence of IP packets that share a common class of service
and forwarding treatment as they transit the interface.
Queue behavior during the packet egress stage (strict, Weighted Fair, Hybrid).
The change in a flow's packet spacing on the link due to the bursty and congestive
nature of the IP network. This irregular spacing - jitter - can severely degrade the
quality of voice calls or multimedia presentations.
The grouping of ports based upon the same CoS features and port type.
The differentiation of ports based upon TxQ and IRL resource capabilities.
The preference of one packet (classification) or queue (packet forwarding) over
another.
A bandwidth management mechanism able to preferentially treat packets based
upon packet classification and forwarding treatment.
The bounding of bandwidth used by a QoS packet flow such that excess packets are
dropped/clipped.
The rescheduling of bursty traffic while in the queue based upon packet buffering
such that traffic beyond the configured bandwidth threshold is delayed until
bandwidth usage falls below the configured threshold.
An 8-bit field defined by RFC 1349 used for the prioritization of packets within a QoS
context.
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