
Chapter 4: Feature Description
Ethernet Features
•
Undersized frames (good only)
•
Fragments frames (undersized bad)
•
Counts jabber frames – frames with length > 1518 bytes (1522 for VLAN-tagged frames) with
errors
•
Frames with length 64 bytes, good or bad
•
Frames with length 65-127 bytes, good or bad
•
Frames with length 128-255 bytes, good or bad
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Frames with length 256-511 bytes, good or bad
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Frames with length 512-1023 bytes, good or bad
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Frames with length 1024-1518 bytes, good or bad
•
VLAN-tagged frames with length 1519-1522 bytes, good or bad
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Frames with length > MAX_LEN without errors
•
Frames with length > MAX_LEN with errors
Logical Interfaces
A logical interface consists of one or more physical interfaces that share the same traffic ingress
and egress characteristics. From the user’s point of view, it is more convenient to define interface
behavior for the group as a whole than for each individual physical interface that makes up the
group. Therefore, classification, QoS, and resiliency attributes are configured and implemented on
the logical interface level, in contrast to attributes such as interface speed and duplex mode, which
are configured on the physical interface level.
It is important to understand that the user relates to logical interfaces in the same way in both a
one-to-one scenario in which a single physical interface corresponds to a single logical interface,
and a grouping scenario such as a link aggregation group or a radio protection group, in which
several physical interfaces correspond to a single logical interface.
The following figure illustrates the relationship of a LAG group to the switching fabric. From the
point of view of the user configuring the logical interface attributes, the fact that there are two
Ethernet interfaces is not relevant. The user configures and manages the logical interface just as if
it represented a single Ethernet interface.
Figure 52 Relationship of Logical Interfaces to the Switching Fabric
SP
SP
SP
SP
Service
LAG 1
Ethernet
Interface 1
Ethernet
Interface 2
LAG
Physical Interface 1
Physical Interface 2
Logical Interface
Physical Interface 3
Logical Interface
Physical Interface 4
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