H3C Technologies H3C SecPath F1000-E - Manual (Page 311)

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Match packets with classification rules in a class in the configuration order.
Congestion management technology comparison
Table 44 Congestion management technology comparison
Type Number of
queues
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
Configurable
(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 ."
With line rate configured on an interface, all packets to be sent through the interface are firstly handled
by the token bucket at line rate. If the token bucket has enough tokens, packets can be forwarded;