Maximum PDU size on a network

clarkincnet

One quick question and one quick share.

Question: I'm working through the Telecommunications domain and I ran across a statement in Eric Conrad 2nd Edition page 73 that says, "An MTU is the maximum PDU size on a network" but I can't seem to find any explanation of what a PDU stands for. All the quick searches have people quoting this statement with no further explication of the concept. Any ideas?


Share: I did find this neat video that does a decent job at explaining IP fragmentation during my search. I thought I'd share it. https://www.youtube.com/watch?v=n4H26PlmfaQ

Thanks!

gncsmith

A PDU is a Protocol Data Unit which is the OSI generic term. A PDU represents the bits that include the headers, and trailers for thay layer, as well as the encapsulated data. For example, an IP packet using OSI terminology, is a PDU. If fact, an IP packet is a Layer 3 PDU (abbreviated L3PDU) because IP is a Layer 3 protocol. So, rather than use terms segment, packet, or frame, OSI simply refers to the "Layer x PDU" (LxPDU), with "x" referring to the number of the layer being discussed.

Resource: PG 38, Chapter 1, OFG Cisco CCENT/CCNA ICND1 100-101 by Wendell Odom