Chapter 17 Quality of Service (QoS)
P-660HN-51 User’s Guide
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IEEE 802.1p specifies the user priority field and defines up to eight separate traffic types. The following
table describes the traffic types defined in the IEEE 802.1d standard (which incorporates the 802.1p).
DiffServ
QoS is used to prioritize source-to-destination traffic flows. All packets in the flow are given the same
priority. You can use CoS (class of service) to give different priorities to different packet types.
Table 78 IEEE 802.1p Priority Level and Traffic Type
PRIORITY
LEVEL
TRAFFIC TYPE
Level 7 Typically used for network control traffic such as router configuration messages.
Level 6 Typically used for voice traffic that is especially sensitive to jitter (jitter is the variations in
delay).
Level 5 Typically used for video that consumes high bandwidth and is sensitive to jitter.
Level 4 Typically used for controlled load, latency-sensitive traffic such as SNA (Systems Network
Architecture) transactions.
Level 3 Typically used for “excellent effort” or better than best effort and would include important
business traffic that can tolerate some delay.
Level 2 This is for “spare bandwidth”.
Level 1 This is typically used for non-critical “background” traffic such as bulk transfers that are
allowed but that should not affect other applications and users.
Level 0 Typically used for best-effort traffic.
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