2.5 An Example: The Ethernet Address Space

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Thus far we have looked at the political economy of identifiers in the abstract, with a few examples thrown in for illustration. It might be helpful at this point to discuss a specific example in more detail. Most local area networks use what are commonly called Ethernet addresses. Compared to the political drama surrounding Internet names and numbers, Ethernet addressing has thrived in obscurity. Officially, Ethernet addresses are called Ethernet Unique Identifiers (EUIs). [7 ]These addresses are burned into the network interface hardware during manufacture.

Ethernet was a standard formalized by the IEEE's 802 Committee, so it is the IEEE that 'owns' the Ethernet address space and takes responsibility for managing it. EUI addresses are divided into two parts. The first, 24-bit part is an Organizational Unique Identifier (OUI), a distinct code given to a manufacturer of the hardware in which the Ethernet address will be embedded. The second part is the 40-bit extension (24 bits in the older number space) that is assigned to a particular piece of hardware by the manufacturer. Address blocks are assigned to network component manufacturers by a one-person Registration Authority within the IEEE. The IEEE Registration Authority controls only the assignment of the company identification numbers. It imposes a one-time charge of US$1,250 for the OUI assignment. Once a company receives its own 24-bit identifier, it assigns the remaining 40 bits (or 24 bits in the older space) to hardware components. The full Ethernet address is thus formed from the concatenation of the unique company ID and the company-assigned value. It is a simple, two-part hierarchy.

The older, 48-bit Ethernet addresses gave manufacturers 16 million unique addresses for every organizational identifying number they received. The new EUI-64 space will give them 1 trillion (1012) unique addresses. As a simple conservation rule, the IEEE Registration Authority requires that organizations must have used up at least 90 percent of the available numbers under an existing OUI before they will be assigned another one: 'It is incumbent upon the manufacturer to ensure that large portions of the unique word block are not left unused in manufacturing.' [8 ]IEEE does not explain how this rule is monitored and enforced.

The Registration Authority imposes few restrictions on the redistribution of EUI-64 values by third parties. The two most significant restrictions are that only one address value can be assigned to a physical component, and organizations that received OUIs must indemnify IEEE against any damages arising from duplicate number assignments. Other than that, anything goes.

The Ethernet addressing scheme is an organizationally lightweight, technically focused form of address management. The costs associated with using the address space are very low and nonrecurring. Policy for the Registration Authority is set by a Registration Authority Committee composed of about a dozen people, mostly delegates of manufacturers, within the IEEE's 802 Committee. The policy component attached to the assignment of numbers is minimal. Assignment policies are not designed to regulate the market for networking products or to control the behavior of users; they are driven entirely by the need to conserve identifiers, to properly identify the source and type of addresses, and to indemnify the assignment organization against ancillary damages.

Why is Ethernet addressing so uncomplicated? Because there is no human interface. Ethernet addresses are an undifferentiated lot of meaningless numbers. No manufacturer and no individual consumer of a Network Interface Card cares which particular numerical value is on it as long as it is unique. OUIs are addresses of and for machines. Along with this total absence of any human interface goes a near-total absence of politics.

[7 ]EUI designations are trademarked by IEEE. The classical 48-bit address space (known as EUI-48) is being phased out in favor of a new, 64-bit address space known as EUI-64.

[8 ]IEEE, Registration Authority Committee, Guidelines for 64-bit Global Identifier (EUI-64), and Guidelines for Use of a 48-bit Global Identifier (EUI-48), March 2000.



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Ruling the Root(c) Internet Governance and the Taming of Cyberspace
Ruling the Root: Internet Governance and the Taming of Cyberspace
ISBN: 0262134128
EAN: 2147483647
Year: 2006
Pages: 110

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