3Com 3500 - Manual (Page 694)

694 C HAPTER 22: Q UALITY OF S ERVICE (Q O S) AND RSVP
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qos classifier define For CoreBuilder 9000: Applies to Layer 3 switching modules only.
Defines a flow or nonflow classifier.
Valid Minimum Abbreviation
q cl def
Important Considerations
■
Classifiers define how the system groups packets so that it can
schedule them with the appropriate service level. QoS supports flow
and nonflow classifiers:
■
Flow classifiers apply to routed IP multicast and IP unicast packets.
You can define up to 100 flow classifiers. Each filter (address and
port pattern) in a flow classifier counts toward the limit.
■
Nonflow classifiers apply to bridged or routed traffic that is
associated with a specific protocol (IP, TCP/IP, IPX, and AppleTalk) or
to a custom protocol (Ethertype or Destination Service Access
Point/Source Service Access Point (DSAP/SSAP). You can also use
them to apply IEEE 802.1p tag values to forwarded frames. You
can define up to 16 nonflow classifiers. All 16 nonflow classifiers
are in use by default.
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The default classifier number is 499 . You cannot remove or modify
this default classifier. However, you can remove any of the predefined
classifiers (for example, if you need another nonflow classifier). See
“qos classifier remove” later in this chapter for more information.
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When you define a filter (address and port pattern) for a flow
classifier, select a source and destination start and end port ranges
that are as small as possible (for example, a single port). If the classifier
applies to a wide range of Transmission Control Protocol (TCP) or User
Datagram Protocol (UDP) ports, you increase the amount of classified
traffic on the system and consume valuable QoS resources.
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A classifier can have only one control applied to it.
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If you select custom when you define a nonflow classifier, you are
prompted to select the protocol by Ethertype or DSAP/SSAP. After you
select a protocol, you are prompted to provide the hexidecimal ranges.
Depending on the number of VLANs defined, you can define a maximum
of 3 custom protocols that can have controls applied to them. This
limitation does not apply to non-controlled custom protocols.