FabFi Addressing

From Fab Lab wiki

Contents 1 Introduction 2 Architectural Overview 3 Addressing Rules 4 Wireless Configuration 5 Firewall 6 Naming Conventions and Simplifications

Introduction

As of 4/2010 the current version if fabfi is 3.0. If you're looking for 1.0 addressing information go here. v2.x is the same as 3.0 architecturally, but does not include as robust DNS naming.

As with any coherent network architecture there must be a clear organizational structure to FabFi. This page outlines the structure, naming conventions, features and limitations of the addressing scheme we have used in our network.

Architectural Overview

We'll let the pictures do the talking (it's a little too foofy for the wiki, but after all the time we spent making it for the main site, there was no time left to do a techie version :)):

Addressing Rules

• Gateway for any LAN is the the .1 address (exception: OCW is 10.0.0.254)
• Wired MESH network nodes = 10.101.0.<ff#>
• WIFIMESH nodes = 10.102.0.<ff#>
• Fabfi LAN networks are 10.103.<ff#>.xxx (by convention, the gateway is .1)

• Domain suffix of the fabfi network is .mesh, nodes are fabfi#.mesh (broken in versions before 2.1)

Wireless Configuration

Fabfi nodes use the wireless BSSID to identify their network. A Fabfi will only connect to a wireless network with the same BSSID. If a fabfi hears another fabfi with the same BSSID on startup, it will switch to that node's wireless channel. Further, if there are more than a few nodes with the same ESSID and different BSSIDs, the fabfi may fail to connect to a network. Lastly, if two fabfi networks exist on different channels that overlap, they will significantly hamper each other's bandwidth.

Following from the above, the radios on each fabfi node are configured in the following way:

• only non-overlapping channels 1, 6, and 11 are used.
• The BSSID and ESSID reflect the slected channel for any node:
  • BSSID is ##:fa:bf:f1:fa:bf:f1 where ## is the channel with a leading 0 for single digit channels
  • ESSID is fabfi# where # is the channel

Firewall

Naming Conventions and Simplifications

• The broadcast address, by convention is .255
• Unconfigured nodes come to life as fabfi253
• Master node, corresponding to time.mesh, master.mes and status.mesh (deprecated) is the <MESH class C IP of the network>.254
• Every fabfi has a mesh DNS name = fabfi#.mesh
• The local DNS suffix for LAN network is .lan
• every fabfi response to to requests from it's lan on fabfi.lan

Wtgphoben 17 September 2009 (UTC)