HP 2610, Руководство по продвинутому управлению трафиком

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Quality of Service (QoS): Managing Bandwidth More Effectively
Introduction
Table 6-5.Precedence Criteria for QoS Classifiers
Precedence Criteria Overview
UDP/TCP Takes precedence based on a layer 4 UDP or TCP application, with a user-specified application
port number (for example, Telnet). Default state: Disabled
If a packet does not meet the criteria for UDP/TCP priority, then precedence defaults to the Device Priority
classifier, below.
Device Takes precedence based on an inbound packet having a particular destination or source IP
Priority address. If a given packet has a destination IP address matching a QoS configuration, this
(IP packet takes precedence over another packet that has the matching IP address as a source
Address) address. (This can occur, for example, on an outbound port in a switch mesh environment.)
Also, if the source and destination IP addresses (SA and DA) in the same packet match for
different QoS policies, the DA takes precedence.
Default state: No IP address prioritization.
If a packet does not meet the criteria for device priority, then precedence defaults to the IP Type of Service
(ToS) classifier, below.
3 IP Type- Takes precedence based on the TOS field in IP packets. (Applies only to IP packets.) The ToS
of- field is configured by an upstream device or application before the packet enters the switch.
Service
• IP Precedence Mode: QoS reads an inbound packet’s IP precedence (upper three) bits in
(IP ToS)
the Type-of-Service (ToS) byte and automatically assigns an 802.1p priority to the packet (if
specified in the QoS configuration) for outbound transmission.
• Differentiated Services (Diffserve) Mode: QoS reads an inbound IP packet’s differentiated
services, or codepoint (upper six), bits of the Type-of-Service (TOS) byte. Packet
prioritization depends on the configured priority for the codepoint. (Some codepoints default
to the DSCP standard, but can be overridden.)
For more on IP ToS, see “QoS IP Type-of-Service (ToS) Policy and Priority” on page 6-34.
Default state: Disabled.
If a packet does not meet the criteria for ToS priority, then precedence defaults to the VLAN classifier.
4 VLAN Takes precedence based on the ID number of the VLAN in which the inbound packet exists.
Priority For example, if the default VLAN (VID = 1) and the “Blue” VLAN (with a VID of 20) are both
assigned to a port, and Blue VLAN traffic is more important, you can configure QoS to give Blue
VLAN traffic a higher priority than default VLAN traffic. (Priority is applied on the outbound
port.)
Default state: No-override.
If a packet does not meet the criteria for VLAN priority, then precedence defaults to the Source-Port
classifier, below.
Source- Takes precedence based on the source-port (that is, the port on which the packet entered the
Port switch).
If a packet does not meet the criteria for source-port priority, then precedence defaults to Incoming 802.1p
criteria, below.
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