3Com 9100 manual Vlan

102CHAPTER 7: QUALITY OF SERVICE (QOS)

The Blackhole QoS In the description of various options for configuring Policy-Based QoS,

Profilethere is an option to specify blackhole in place of a named QoS profile. As its name implies, a traffic grouping assigned to the “blackhole” goes nowhere, and is not forwarded by the switch. There are noted exceptions. For example, any QoS profile including blackhole cannot apply to traffic that is normally handled by the switch management processor, such as ICMP traffic. The blackhole profile can be used as a flexible security or performance measure to effectively terminate a particular traffic grouping.

Traffic Groupings Once a QoS profile is modified to the desired settings for bandwidth and and Creating a QoS priority, you can assign the profile to a particular traffic grouping. A traffic

Policygrouping is a classification of traffic that has one or more attributes in common.

Traffic groupings are separated into the following categories for discussion:

■Destination MAC (MAC QoS groupings)

■Packet priority information, such as 802.1p

■Physical/logical configuration (physical source port or VLAN association)

A QoS profile is assigned to a desired traffic grouping to form a QoS Policy. In the event that a given packet matches two or more grouping criteria, there is a predetermined precedence for which traffic grouping will apply. In general, the more specific traffic grouping takes precedence. By default, all traffic groupings are placed in the QoS profile named qp2.

The supported traffic groupings and their options by QoS mode are listed in Table 26. The groupings are listed in order of precedence (highest to lowest).

Table 26 Traffic Groupings by Precedence

Destination Address	Packet Priority	Physical/Logical
MAC-based Groupings	Groupings	Groupings
Permanent	802.1p prioritization bits	Source port
Dynamic		VLAN

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