Juniper ACX2000, Руководство по оборудованию

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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 Figure 8 on page 25 . 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 8: ACX Series Router Packet Handling
g006428
Rate limiting
BA and fixed classification
Forwarding class and packet loss priority
MF classification
Policing can overwrite forwarding class
and packet loss priority
Forwarding class and packet loss priority
determine rewrite value
Scheduling and
shaping
Scheduling and shaping
Forwarding class
Qn + packet loss priority
Qn
WRED
SEE ALSO
ACX2000 and ACX2100 Routers Hardware and CLI Terminology Mapping | 20
Configuring CoS on ACX Series Routers
25