3Com CoreBuilder 3500, Руководство по внедрению

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Key Concepts 479
The Resource Reservation Protocol (RSVP)
This connection-oriented IP protocol handles bandwidth reservation. The
request for comments document RFC 2205 describes the details of RSVP.
RSVP aims to meet the demands of real-time voice and video applications
by using a QoS flow specification that mandates parameters such as the
maximum frame transmission rate, long-term average frame transmission
rate, maximum frame jitter, and maximum end-to-end delay. It supports
the QoS flow specifications by managing
resource reservations across the
network.
With RSVP, all devices in the path from the source to the destination must
agree to observe the RSVP call request parameters before traffic can flow.
Terminology The following terms apply to the QoS implementation on your system:
■
Classifiers — Two types of classifiers define how your system groups
packets in order to schedule them with the appropriate service level:
■
Flow classifiers — Apply to routed IP unicast and IP multicast
traffic only (not bridged traffic). (When the system is bridging, you
cannot classify to the IP address or socket level.) These classifiers
are numbered in a range of from
1 to 399. You can define filtering
parameters for a flow classifier by setting the source IP address,
source IP address mask, the destination IP address, destination IP
address mask, and the TCP or UDP port range. Because these
classifiers have lower class numbers, they take precedence over
nonflow classifiers. When a packet falls into more than one
controlled classifier, the system uses the lower-numbered classifier
to classify the packet. The system predefines two flow classifiers for
you: TELNET and FTP.
■
Nonflow classifiers — Apply to both switched and routed traffic.
You define this type of classifier to handle specific link-level
protocols
(IP, TCP/IP
,
IPX,
or
AppleTalk)
, a “cast” type
(broadcast,
unicast, or multicast) , and/or one or more IEEE 802.1p priority tag
values . Nonflow classifiers are numbered in a range of from 400 to
499. The system automatically defines a number of nonflow
classifiers for you. The predefined nonflow classifiers
(401 through
407) employ IEEE 802.1p tagging by default for received frames.
(Before you define an IP, AppleTalk, or IPX classifier, you must have
an IP, AppleTalk, or IPX VLAN for the ports that will come under
jurisdiction of the classifier and applied control.)