Fixed classification places all packets in the same forwarding class, or the usual multifield (MF) or
behavior aggregate (BA) classifications can be used to treat packets differently. BA classification with
firewall filters can be used for classification based on IP precedence, DSCP, IEEE, or other bits in the
frame or packet header.
However, the ACX Series routers can also employ multiple BA classifiers on the same physical interface.
The physical interfaces do not have to employ the same type of BA classifier. For example, a single
physical interface can use classifiers based on IP precedence as well as IEEE 802.1p. If the CoS bits of
interest are on the inner VLAN tag of a dual-tagged VLAN interface, the classifier can examine either the
inner or outer bits. (By default, the classification is done based on the outer VLAN tag.)
Eight queues per egress port support scheduling using the weighted deficit round- robin (WDRR)
mechanism, a form of round-robin queue servicing. The supported priority levels are strict-high and
default (low). The ACX Series router architecture supports both weighted random early detect (WRED)
and weighted tail drop (WTD).
All CoS features are supported at line rate.
The packet pipeline through an ACX Series router is shown in
. Note that the rate
limiting is done with an integrated architecture along with all other CoS functions. Scheduling and
shaping are supported on the output side.
Figure 5: ACX Series Router Packet Handling
SEE ALSO
ACX Series Universal Metro Router Configuration Guide
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