Introduction

Media access control (MAC) addresses play an important role in local-area networks. They also pack a lot of information into 48-bit hexadecimal strings!

The macaddress library makes it easy to evaluate the properties of MAC addresses and the extended identifiers of which they are subclasses.

Installing macaddress

macaddress is available on GitHub at https://github.com/critical-path/macaddress-js.

To install macaddress, run the following command from your shell.

[user@host ~]$ npm install git+https://github.com/critical-path/macaddress-js.git

Using macaddress

While macaddress contains multiple classes, the only one with which you need to interact directly is MediaAccessControlAddress.

Require MediaAccessControlAddress.

> var MediaAccessControlAddress = require("macaddress").MediaAccessControlAddress
undefined

Instantiate MediaAccessControlAddress by passing in a MAC address in plain, hyphen, colon, or dot notation.

> var mac = new MediaAccessControlAddress("a0b1c2d3e4f5")
undefined

> var mac = new MediaAccessControlAddress("a0-b1-c2-d3-e4-f5")
undefined

> var mac = new MediaAccessControlAddress("a0:b1:c2:d3:e4:f5")
undefined

> var mac = new MediaAccessControlAddress("a0b1.c2d3.e4f5")
undefined

To determine whether the MAC address is a broadcast, a multicast (layer-two), or a unicast address, access its isBroadcast, isMulticast, and isUnicast properties.

> mac.isBroadcast
false

> mac.isMulticast
false

> mac.isUnicast
true

To determine whether the MAC address is a universally-administered address (UAA) or a locally-administered address (LAA), access its isUAA and isLAA properties.

> mac.isUAA
true

> mac.isLAA
false

To work with the MAC address's octets, access its octets property, which contains six Octet objects.

> mac.octets
[ Octet { original: 'a0' },
  Octet { original: 'b1' },
  Octet { original: 'c2' },
  Octet { original: 'd3' },
  Octet { original: 'e4' },
  Octet { original: 'f5' } ]

To determine whether the MAC address is an extended unique identifier (EUI), an extended local identifier (ELI), or unknown, access its type property.

> mac.type
'unique'

To determine whether the MAC address has an organizationally-unique identifier (OUI) or a company ID (CID), access its hasOUI and hasCID properties.

> mac.hasOUI
true

> mac.hasCID
false

To view the decimal equivalent of the MAC address, access its decimal property.

> mac.decimal
176685338322165

To view the binary equivalent of the MAC address, access its binary and reverseBinary properties. With binary, the most-significant digit of each octet appears first. With reverseBinary, the least-significant digit of each octet appears first.

> mac.binary
'101000001011000111000010110100111110010011110101'

> mac.reverseBinary
'000001011000110101000011110010110010011110101111'

To return the MAC address's two "fragments," call the toFragments method. For an EUI, this means the 24-bit OUI as the first fragment and the remaining interface-specific bits as the second fragment. For an ELI, this means the 24-bit CID as the first fragment and the remaining interface-specific bits as the second fragment.

> mac.toFragments()
[ 'a0b1c2', 'd3e4f5' ]

To return the MAC address in different notations, call the toPlainNotation, toHyphenNotation, toColonNotation, and toDotNotation methods.

> mac.toPlainNotation()
'a0b1c2d3e4f5'

> mac.toHyphenNotation()
'a0-b1-c2-d3-e4-f5'

> mac.toColonNotation()
'a0:b1:c2:d3:e4:f5'

> mac.toDotNotation()
'a0b1.c2d3.e4f5'

Testing macaddress

To conduct testing, run the following commands from your shell.

[user@host ~]$ cd node_modules
[user@host node_modules]$ cd macaddress
[user@host macaddress]$ npm install
[user@host macaddress]$ npm test