R3721-F3210-F3171-HP High-End Firewalls Network Management Configuration Guide-6PW101

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{ Match packets with classification rules in a class in the configuration order.
Congestion management technology comparison
Table 45 Congestion management technology comparison
Type
Number
of
q
ueues
Advantages Disadvantages
FIFO 1
• No need to configure, easy to use
• Easy to operate, low delay
• All packets are treated equally. The
available bandwidth, delay and
drop probability are determined by
the arrival order of packets.
• No restriction on the uncooperative
data sources (flows without any flow
control mechanism, UDP for
example), resulting in bandwidth loss
of cooperative data sources such as
TCP.
• No delay guarantee for
time-sensitive real-time applications,
such as VoIP
CBQ
Configura
ble (0 to
64)
• Flexible traffic classification based on
various rules and differentiated queue
scheduling mechanisms for expedited
forwarding (EF), assured forwarding
(AF) and best-effort (BE) services.
• Highly precise bandwidth guarantee
and queue scheduling on the basis of
AF service weights for various AF
services
• Absolutely preferential queue
scheduling for the EF service to meet the
delay requirement of real-time data;
overcoming the disadvantage of PQ
that some low-priority queues are not
serviced by restricting the high-priority
traffic.
• WFQ scheduling for best-effort traffic
(the default class).
The system overheads are large.
Line rate
Line rate also uses token buckets to evaluate traffic specifications for traffic control. The line rate of a
physical interface specifies the maximum rate for forwarding packets (including critical packets).
Compared with traffic policing, line rate can only limit traffic rate on a physical interface. To limit the rate
of all the packets on an interface as a whole, using line rate is easier.
NOTE:
For more information about token buckets, see "Traffic evaluation and token buckets."