Configuring the Maximum Packet Size

To configure a maximum IP packet size for an LSP, complete the following steps.
  1. Enable the device for configuration.
    device# configure
  2. Enable the MPLS router.
    device(config)# router mpls
  3. enable and configure the label switched path (LSP).
    device(config-router-mpls)# lsp tunnel1
    In this example, the LSP specified name is tunnel1.
  4. Configure the IP packet maximum transmission unit size.
    device(config-router-mpls-lsp-tunnel1)# ipmtu 1500
    In this example, the packet-size variable specifies the maximum packet size in bytes for IP packets transiting the LSP without being fragmented.

Example

The following example configures a maximum IP packet size of 1500 bytes for LSP tunnel1.

device# configure terminal
device(config)# router mpls
device(config-router-mpls)# lsp tunnel1
device(config-router-mpls-lsp-tunnel1)# ipmtu 1500