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Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
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Chapter 4 Configuring Ethernet, Fast Ethernet, and Gigabit Ethernet Switching
Setting the Port Configuration
Configuring the Jumbo Frame Feature
These sections describe the jumbo frame feature:
•
Configuring the Jumbo Frame Feature on the Supervisor Engine, page 4-11
•
Configuring the Jumbo Frame Feature on MSFC2, page 4-12
Configuring the Jumbo Frame Feature on the Supervisor Engine
When you enable the jumbo frame feature on a port, the port can switch large (or
jumbo
) frames. This
feature is useful in optimizing server-to-server performance.
The default maximum transmission unit
(MTU) frame size is 1548 bytes for all Ethernet ports.
By enabling the jumbo frame feature on a port,
the MTU size is increased to 9216 bytes.
To enable the jumbo frame feature on a per-port basis, follow these guidelines:
•
The jumbo frames feature is supported on the following:
–
Ethernet ports
Note
The following modules only support a maximum of 8092 bytes: WS-X6148-RJ-45V,
WS-X6148-RJ21V, WS-X6248-RJ-45, WS-X6248A-RJ-45, WS-X6248-TEL,
WS-X6248A-TEL, WS-X6348-RJ-45, WS-X6348-RJ45V, WS-X6348-RJ-21, and
WX-X6348-RJ21V.
The WS-X6548-RJ-21 and WS-X6548-RJ-45 modules use different hardware at the
PHY level and support the full jumbo frame default value of 9216 bytes.
Note
The WS-X6516-GE-TX (10/100/1000) module only supports a maximum of 8092 bytes
at the 100 Mbps speed. At 10 Mbps and 1000 Mbps the module supports the jumbo frame
default of 9216 bytes.
–
Trunk ports
–
EtherChannels
•
Jumbo frames are supported on all Optical Services Modules (OSMs).
•
Jumbo frames are not supported on ATM modules (WS-X6101-OC12-SMF/MMF).
•
The Multilayer Switching Feature Card 2 (MSFC2) supports routing of jumbo frames.
•
The Gigabit Switch Router (GSR) supports routing of jumbo frames.
•
The Multilayer Switching Feature Card (MSFC) and Multilayer Switch Module (MSM) do not
support jumbo frame routing; if jumbo frames are sent to these routers, router performance is
significantly degraded.
Note
Occasionally, you might see a
“Jumbo frames inconsistent state”
message for a port or multiple ports
after entering the
show port jumbo
command. If this occurs, enter the
set port jumbo
command to
reenable the ports.