HP StorageWorks Scalable File Share System Installation and Upgrade Guide Version 2.2

G–1
G Configuring HP ProCurve Switches for non-standard
MTU sizes
The Maximum Transfer Unit (MTU) of a network interface is the maximum IP packet size that can be sent or
received by the interface. You can set the MTU size on the Gigabit Ethernet interconnect interface at
installation time (see Section 2.4 and Section 6.8.2 for more information). By default, the MTU size on the
Gigabit Ethernet interconnect interface is set to the Ethernet standard of 1500 bytes. However, in some
network configurations, you may wish to use a larger packet size; such larger Ethernet packets are
commonly known as Jumbo packets.
This appendix provides information that you will need if you intend to configure an HP ProCurve switch in
an HP SFS system to support Jumbo packets. The instructions given here are based on the HP ProCurve
Networking Switch 2800 series.
The Management and Configuration Guide and the Advanced Traffic Management Guide for the HP
ProCurve Networking Switch 2800 series are available in PDF format at the following location:
http://www.hp.com/rnd/support/manuals/2800.htm
.
To support Jumbo packets on a Gigabit Ethernet interconnect, the following configuration is required:
• The firmware version on the HP ProCurve Networking Switch 2800 switch must be at Version I.08.55
or higher.
• Jumbo packet operation can only be supported on switch ports that operate at speeds of 1GB or
higher.
• You must disable flow control on any ports or trunks that use Jumbo packets. If flow control is enabled
on a port, a high number of Jumbo packets may be dropped on the port.
Refer to Chapter 10 Port Status and Basic Configuration of the switch Management and
Configuration Guide for more information on enabling and disabling flow control.
• You must enable QoS Passthrough Mode on the switch to optimize Jumbo packet bandwidth. Note
that the default setting is to have QoS Passthrough Mode disabled.
Refer to Chapter 10 Port Status and Basic Configuration of the switch Management and
Configuration Guide for more information on enabling and disabling QoS Passthrough Mode.
• If there is network traffic of multiple MTU sizes flowing through the switch, you must segregate the
different traffic flows by grouping switch ports onto separate virtual local area networks (VLANs).
Refer to Chapter 10 Port Status and Basic Configuration of the switch Management and
Configuration Guide and Chapter 2 Static Virtual LANs (VLANs) of the switch Advanced Traffic
Management Guide for more information on VLANs.