Additional options to the Ethernet frame have been incorporated to accommodate
new capabilities and technologies such as VLANs (see next section), MPLS, and so on.
To also accommodate a more efficient transmission of latency sensitive application data
(such as video), larger MTU sizes called Jumbo frames??”typically greater than 9000
Bytes??”are being supported in commercial solutions.
VLAN Tagging Option A Virtual LAN (VLAN) tag was introduced between the SA and
the Length/Type fields of an Ethernet frame. This VLAN is defined in IEEE 802.1Q and
provides these key capabilities:
?– Allows data traffic to be prioritized.
?– Allows data traffic to be categorized for more efficient handling; for instance, traffic
can be separated or categorized and each of these categories treated differently.
Traffic in an enterprise, for example, may be split by which department it belongs
to, so that traffic belonging to the accounting department, the marketing department,
and so on, may be separated using a corresponding VLAN identifier and
treated accordingly. As will be evident shortly, this creates a lot of efficiency in the
operation of LANs and also introduces additional flexibility as far as handling data
within an enterprise is concerned.
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