Configuring the Switch to Fragment Outgoing IP Packets

Context

During actual packet forwarding, the length of an IP packet may exceed the MTU value. When the remote device or intermediate forwarding device receives IP packets, if it checks the packet length and discards packets whose length is longer than the Maximum Transmission Unit (MTU) on the interface, network communication is interrupted. In this case, fragmentation for outgoing IP packets can be configured so that the system fragments the packets. In this way, all IP packets can be forwarded properly.

Procedure

Configure fragmentation for outgoing forwarding-plane IP packets.
1. Run system-view
  The system view is displayed.
2. Run ipv4 fragment enable
  Fragmentation is enabled for outgoing forwarding-plane IP packets.
  
  By default, fragmentation for outgoing forwarding-plane IP packets is disabled.
  
  This command takes effect only for the forwarding-plane packets but not for the control-plane packets.
  
  Only the S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-HI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this command.
Configure fragmentation for outgoing control-plane IP packets
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run clear ip df
  The fragmentation is enabled for outgoing control-plane IP packets.
  
  By default, fragmentation for outgoing control-plane IP packets on an interface is disabled.
  
  This command takes effect only for the control-plane packets but not for the forwarding-plane packets.