MikroTik RouterOS V2.4 IP Packet Packer Protocol (M3P)

Document revision 22-Dec-2001
This document applies to the MikroTik RouterOS V2.4

Overview

The MikroTik Packet Packer Protocol (M3P) optimizes the bandwidth usage of links using protocols that have a high overhead per packet transmitted. The basic purpose of this protocol is to better enable wireless networks to transport VoIP traffic and other traffic that uses small packet sizes of around 100 bytes.

M3P features:

enabled by a per interface setting
other routers with MikroTik Discovery Protocol enabled will broadcast M3P settings
significantly increases bandwidth availability over some wireless links – by approximately four times
offer configuration settings to customize this feature

Contents of the Manual

The following topics are covered in this manual:

Installation
Hardware Resource Usage
MikroTik Packet Packer Protocol Description
MikroTik Packet Packer Protocol Setup

Installation

The MikroTik Packet Packer Protocol feature is included in the “system” package. No installation is needed for this feature.

Hardware Resource Usage

There is no significant resource usage.

MikroTik Packet Packer Protocol Description

The wireless protocol IEEE 802.11 and, to a lesser extent, Ethernet protocol have a high overhead per packet because for each packet it is necessary to access the media, check for errors, resend in case of errors, and send network maintenance messages (network maintenance is only for wireless). The MikroTik Packet Packer Protocol improves network performance by aggregating many small packets into a big packet, thereby minimizing the network per packet overhead cost. The M3P is useful when the average packet size is 50-300 bytes – the common size of VoIP packets.

Specific Properties:

may work on any Ethernet-like media
is enabled by default for all new wireless interfaces
when older version on the RouterOS are upgraded from a version without M3P to a version with discovery, current wireless interfaces will not be automatically enabled for M3P
small packets going to the same MAC level destination (regardless of IP destination) are collected according to the set configuration and aggregated into a large packet according to the set size
the packet is sent as soon as the maximum aggregated-packet packet size is reached or a maximum time of 15ms (+/-5ms)

MikroTik Packet Packer Protocol Setup

IP MikroTik Packet Packer Protocol management can be accessed under the /ip packing submenu:

[MikroTik] ip packing>                                                         
     export  print configuration as set of router commands
        get  get value of property
  interface  Interface packing settings
      print  Show packing settings
        set  Change packing settings
[MikroTik] ip packing> print                                                   
       expected-size: 28
     aggregated-size: 1000
    enable-unpacking: yes
[MikroTik] ip packing>

Argument description:

expected-size – the average size packet you expect for aggregation, i.e., if your VoIP generates 100 byte packets – this would be the expected size. This is used by the protocol to determine if it should wait for another packet to complete the aggregated packet – determined by the 'aggregated-size' setting – or send an aggregated packet immediately even though it has not reached the size of the “aggregated-size” setting.
aggregated-size – the maximum size of the aggregated packet – the suggested setting is 1000 bytes and the maximum setting is the MTU size of the interface (generally 1500 bytes)
enable-unpacking – enables unpacking feature of M3P for all Ethernet like interfaces on the router – should be enabled if you have any interface set to send M3P packets

To see the interface settings use:

[MikroTik] ip packing interface> print
Flags: X - disabled
  #   INTERFACE
  0 X bridge1
  1 X ether1
  2 X Local219
  3   wireless
[MikroTik] ip packing interface>