User guide

Chapter 11: Configuring Local Tuning Parameters
134
Increasing Maximum Network Frame Size
Introduction By default, the Proventia Network IPS GX5000 series appliances support a maximum
network frame size of 9216 bytes, including the Ethernet FCS (Frame Check Sequence).
Ordinary Ethernet (and, in particular, IEEE 802.3 standard) frames are limited to 1518
bytes.
Certain types of network equipment support "jumbo" frames; generally, any frame larger
than 1518 bytes is considered a jumbo frame. Most modern network equipment, especially
gigabit-capable equipment, now supports jumbo frames, but many equipment types limit
the frame size to about 9000 bytes. If the network uses jumbo frames larger than 9216
bytes, you can increase the frame buffer size by setting an advanced tuning parameter.
Important: Increase frame size only if it is absolutely necessary for the network. The
amount of memory available to hold network frames is not increased when you increase
the maximum frame size. Instead, using larger buffers means that the appliance will be
able to hold correspondingly fewer frames at any instant. As a result, the "backlog" of
received packets awaiting analysis is shorter, and on very busy networks, the appliance
may drop packets if it cannot analyze them quickly enough.
Procedure To increase the network frame size:
1. Select Local Tuning Parameters.
2. Select the Advanced Parameters tab.
3. Click Add.
4. Complete or change the settings as indicated in the following table.
5. Click OK.
6. Save your changes.
Setting Description
Enabled Select this check box to enable the parameter.
Name
Type
adapter.MaxFrameSize .
Comment Type a unique description for the parameter.
Example: Frame Size Allowance
Value Select Number, and then enter the appropriate number for the
frame size.
Important: You must enter a number greater than or equal to
1536, and less than or equal to 16384. The number must be a
multiple of 512. Otherwise, the value is ignored.