The Lab

Expand all   Collapse all

Versions Compared

Old Version 4

changes.mady.by.user Matthew Whitaker

Saved on

compared with

New Version Current

changes.mady.by.user Unknown User (gbennett)

Saved on

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

  • messageStart
  • messageLength
  • msgSeqNum
  • sendingTime

Message Start

  • MF - usage
  • Corvil - usage
  • Client - optional usage

Background

This is a constant value two four byte magic number at the start of every message.

...

  • The synchronisation of decoding in the middle of a flow.
  • Recovering from missing data.
  • Aiding in the automated detection of protocols from an uncategorised mixture of network traffic.

The two four byte field also ensures that the message header components are optimally aligned for efficient direct access.

Usage

A constant value of 17997 of 1179469389 must always be assigned to this field, this corresponds to an on-the-wire byte representation of "MFMFMF":

  • The MF Reference API populates this value on the Client's behalf in all messages sent to the FH.
  • If a Client implementation should not use the Reference API, then it must implement it's own mechanism to ensure that this value is always populated.
  • The FH will ensure that this is populated in every message sent to the Client.
  • The FH will validate every message received from the Client.

...

Client application software, Corvil and other network analysers can use these fields to in combination with measurements of arrival time in the client network to build up a multi-hop view of the system latency.