Ipv4 Mtu (Bng) - Cisco ASR 9000 Series Command Reference Manual

ipv4 mtu (BNG)

ipv4 mtu (BNG)
To set the maximum transmission unit (MTU) size of IPv4 packets sent on an interface, use the ipv4 mtu
command in an appropriate configuration mode. To restore the default MTU size, use the no form of this
command.
ipv4 mtu bytes
no ipv4 mtu
Syntax Description
bytes
Command Default
If no MTU size is configured for IPv4 packets sent on an interface, the interface derives the MTU from the
Layer 2 MTU.
Command Modes
Interface configuration (for releases prior to R4.2.0)
Dynamic template configuration (for releases R4.2.0 onward)
Command History
Release
Release 3.7.2
Release 4.2.0
Usage Guidelines
The router punts the packets that needs fragmentation; whereas the software path drops the subscriber traffic
that needs fragmentation.
The maximum MTU size that can be set on an interface depends on the interface medium. If the Layer 2 MTU
is smaller than the Layer 3 MTU, the Cisco IOS XR software uses the Layer 2 MTU value for the Layer 3
MTU. Conversely, if the Layer 3 MTU is smaller than the Layer 2 MTU, the software uses Layer 3 MTU
value. In other words the Cisco IOS XR software uses the lower of the two values for the MTU.
All devices on a physical medium must have the same protocol MTU to operate.
For releases R4.2.0 onward, to enter the dynamic template configuration mode, run the dynamic-template
command in the Global Configuration mode.
Cisco ASR 9000 Series Aggregation Services Router Broadband Network Gateway Command Reference,
Release 5.2.x
298
MTU in bytes. Range is 68 to 65535 bytes for IPv4 packets. The maximum MTU size
that can be set on an interface depends on the interface medium.
Modification
This command was introduced.
This command was supported in the dynamic template configuration
mode for BNG.
IPv4 and IPv6 Commands