Configure Multilink and Link Services MRRU

The maximum received reconstructed unit (MRRU) is similar to a maximum transmission unit (MTU), but applies only to multilink bundles; it is the maximum packet size that the multilink interface can process. By default, the MRRU is set to 1500 bytes; you can configure a different MRRU value if the peer equipment allows. The MRRU includes the original payload plus the 2-byte PPP header, but not the additional MLPPP or MLFR header applied while the individual multilink packets are traversing separate links in the bundle.

To configure a different MRRU value, include the mrru statement at the [edit interfaces ml-fpc/pic/port unit logical-unit-number] or [edit interfaces ls-fpc/pic/port unit logical-unit-number] hierarchy level:

mrru bytes; 

For link services interfaces, you also can configure a different MRRU at the physical interface level by including the mrru statement at the [edit interfaces ls-fpc/pic/port mlfr-uni-nni-bundle-options] hierarchy level:

[edit interfaces ls-fpc/pic/port mlfr-uni-nni-bundle-options]

mrru bytes; 

The MRRU size can be from 1500 through 4500 bytes.

If you set the MRRU on a bundle to a value larger than the MTU of the individual links within it, you must enable a fragmentation threshold for that bundle. Set the threshold to a value no larger than the smallest MTU of any link included in the bundle. Determine the appropriate MTU size for the bundle by ensuring the MTU size does not exceed the sum of the encapsulation overhead and the MTU sizes for the links in the bundle.