Jumbo Frame Support - Cisco Catalyst 4500 Series Software Configuration Manual

Supervisor uplink ports
•
WS-C4500X ports
•
WS-X4306-GB: all ports
•
WS-X4232-GB-RJ: ports 1-2
•
WS-X4418-GB: ports 1-2
•
WS-X4412-2GB-TX: ports 13-14
•
WS-X4506-GB-T
•
the 4648-GB-RJ45V
•
WS-X4648-GB+RJ45V
•
WS-X4648-RJ45V-E
•
WS-X4648-RJ45V+E
•
• WS-X4706-10GE

Jumbo Frame Support

These sections describe jumbo frame support:
• Maximum Transmission Units, page 9-35
Jumbo Frame Support Overview, page 9-35
•
Ethernet Ports, page 9-36
•
VLAN Interfaces, page 9-36
•
Maximum Transmission Units
The Catalyst 4500 series switch allows you to configure a maximum of 32 different maximum transmission unit (MTU) sizes
system wide. This means that the maximum number of different MTU sizes that you can configure with the system mtu, mtu,
ip mtu, and ipv6 mtu command on all Layer 2 and Layer 3 interfaces combined is 32.
Also, the system stores the IPv4 and IPv6 MTU sizes configured on an interface separately. For every system mtu command
or per interface mtu command, two separate MTU values are stored, one for IPv4 and one for IPv6. This further reduces the
number of slots available (out of 32). However, only a single MTU value is stored for each ip mtu and ipv6 mtu commands.
If the new MTU value you are configuring is already present in the system (that is, configured on some other interface), then
no new slot(s) are allocated to store it again.
If the maximum limit of 32 is reached and an attempt is made to configure a new MTU size on a new interface, the system only
allows configuration to proceed if the new MTU size has previously been configured on some interface. Otherwise, an error
message is displayed and the default MTU size is assigned to the interface being configured.
Jumbo Frame Support Overview
A jumbo frame is a frame larger than the default Ethernet size. Enable jumbo frame support by configuring a larger-than-default
MTU size on a port or interface.
Catalyst 4500 series switch Ethernet LAN ports configured with a nondefault MTU size accept frames containing packets with
a size between 1500 and 9216 bytes (including Ethernet payload, header and trailer). (The maximum MTU size for a Catalyst
4948 series switch is 9198 bytes (not including header and trailer.)) With a nondefault MTU size configured, the packet size
of ingress frames is checked. If the packet is larger than the configured MTU, it is dropped.
Chapter 9 Configuring Interfaces
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS
Configuring Optional Interface Features