1-10
Figure 1-6 Diagram for traffic shaping
Token bucket
Drop
Packet
classification
Packets t o be s ent
through this port
Continue to send
Put tokens in the bucket at the set rate
Queue
For example, if the device A sends packets to the device B. The device B will perform traffic policing on
packets from the device A to drop the packets beyond the specification.
In order to avoid meaningless packet loss, you can perform traffic shaping on the packets on the egress
of the device A and cache the packets beyond the traffic policing specification in the device A. When the
next packets can be sent, the packets cached in the buffer queues will be taken out and sent. In this way ,
all the packets sent to the device B conforms to the traffic specification of the device B.
Traffic Redirecting Traffic redirecting identifies traffic using ACLs and redirects the matched packets to specific ports. By
traffic redirecting, you can change the way in which a packet is forwarded to achieve specific purposes.
VLAN Mapping VLAN mapping identifies traffics using ACLs and maps the VLAN tags carrier in matched packets to
specific VLAN tags. By employing VLAN mapping on a device connecting user networks to the carrier
network, you can map the VLAN tags of specific user network packets to those of specific VLANs in the
carrier network, thus meeting the requirements of the carrier network.
Queue Scheduling When the network is congested, the problem that many packets compete for resources must be solved,
usually through queue scheduling.
In the following section, strict priority (SP) queues, weighted round robin (WRR),and SDWRR (Shaped
Deficit WRR) queues are introduced.