mtu
To adjust the maximum transmission unit (MTU) value for packets on the interface, use the mtu command
in interface configuration mode. To return the interface to the default MTU for the interface type, use the no
form of this command.
mtu bytes
no mtu
Syntax Description
Maximum number of bytes in a Layer 2 frame. Range is from 64 through 65535.
bytes
Command Default
The default MTU for each interface is as follows:
• Ethernet—1514 bytes
• POS—4474 bytes
• Tunnel—1500 bytes
• Loopback—1514 bytes
• ATM—4470 bytes
Command Modes
Interface configuration
Command History
ModificationRelease
This command was introduced.Release 3.7.2
Usage Guidelines
Use the mtu command to set a specific MTU value for an interface, or use the no mtu command to return
the interface to the default MTU value for that interface type. The MTU value can be increased or decreased
using the mtu command, subject to minimum and maximum MTU limits for the interface type.
If the MTU value is not configured, then each interface will have a default MTU value that is specific to the
interface type. The default MTU value is generally the largest Layer 2 frame size possible for the interface
type.
The default/configured MTU value on an atm interface includes the L2 header.
The MTU size consists of L2 header that includes either SNAP(8bytes)/MUX(0)/NLPID(2) header or the
AAL5 SDU. The AAL5 SDU includes the L3 datagram and the optional Logical Link Control/Subnetwork
Access Protocol (LLC/SNAP) header.
The Ethernet interface is the Layer 3 datagram plus 14 bytes. For ATM main interface, the MTU is L3 datagram
+ 0 bytes.
Cisco ASR 9000 Series Aggregation Services Router Interface and Hardware Component Command Reference,
Release 5.3.x
509
Global Interface Commandsonthe Cisco ASR 9000 Series Router
mtu
To Next Page
Loading...
Need help?
General
