Edge Products ES3528-WDM - Manual (Page 60)

Basic Management Tasks
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Configuring the Maximum Frame Size
The maximum transfer unit (or frame size) for traffic crossing the switch should be
set to minimize unnecessary fragmentation and maximize the transfer of large
sequential data streams.
Command Usage
• Fast Ethernet ports are only affected by the System MTU setting.
• Gigabit Ethernet ports are only affected by the Jumbo frame size setting.
• The switch provides more efficient throughput for large sequential data transfers
by supporting jumbo frames on Gigabit Ethernet ports of up to 9216 bytes.
Compared to standard Ethernet frames that run only up to 1.5 KB, using jumbo
frames for Gigabit Ethernet significantly reduces the per-packet overhead required
to process protocol encapsulation fields.
• Frame sizes for Fast Ethernet ports can be extended up to 1546 bytes, and are
used primarily to allow for additional header fields – not to significantly increase the
per-packet data size. These Fast Ethernet extended fames and are more often
called “baby jumbo frames.”
• To use jumbo frames, both the source and destination end nodes (such as a
computer or server) must support this feature. Also, when the connection is
operating at full duplex, all switches in the network between the two end nodes
must be able to accept the extended frame size. And for half-duplex connections,
all devices in the collision domain would need to support jumbo frames.
• After setting the jumbo frame size, remember to implement the new setting by
enabling jumbo frames as described in the next section.
Command Attributes
• System MTU (1500-1548) – Specifies the MTU size for Fast Ethernet ports.
(Range: 1500-1548 bytes)
• Jumbo (1500-9216) – Specifies the jumbo frame size (MTU) for Gigabit Ethernet
ports. (Range: 1500-9216 bytes)
Web – Click System, System MTU. Set the maximum frame size for Fast Ethernet
and Gigabit Ethernet ports, then click Apply.
Figure 4-3 System MTU