Both the Internet and North American cellphones are choking under a 32 bit limitation and reactions from protagonists involved in both cases offer striking similarities.

1983 saw the debut of IPv4 and North American mobile telephony started in earnest with Bell’s analog AMPS (Advanced Mobile Phone Service). Responding to the need to uniquely identify the growing number of mobile devices in order to bill their owner, the FCC ordered that handsets be equipped with a unique identification number embedded on a chip. This became the 32 bit ESN (Electronic Serial Number); allocation was first managed by the FCC and since 1997 by the TIA (Telecommunications Industry Association). The, by now venerable AMPS, gave way to TDMA and CDMA and the US and Canada continued to be happy with their 32 bit ESN’s. Just like IPv4 addresses, the ESN was considered sufficient to uniquely identify mobile phones long enough to ignore any alarmist views of impending shortages.

A lot has been said and written about IPv4 address exhaustion, address conservation and transition. In the meantime TIA members have struggled with exactly the same issues. The November 2007 TIA white paper on the exhaust of ESN’s and the migration to the Mobile Equipment Identifiers (MEID) is really worth reading. MEID is to ESN what IPv6 is to IPv4. The 56 bit long MEID was adopted in 2002 and procrastinators talked conservation and reclamation programs and transition methods such as hashing MEID identifiers into “pseudo ESN’s” with its inherent risk of duplication (hashing IPv6 addresses into IPv4 addresses, anyone?). The TIA white paper advocates recovery of unused portions of previous allocations, allocation of smaller ESN blocks (sounds familiar?), to diligently work on the transition and to increase awareness and global education campaigns. And in the meantime the ESN number supply apparently ran out in February this year.

Serious implications? If the CDMA people get tangled up in their transition, there is always GSM. Indeed the cell phone industry has two major competing camps and standards; CDMA and GSM. While CDMA has North American roots the competing GSM originated in Europe and both have extensive implementations. The equivalent of ESN in the GSM world are two zones, one called IMEI (International Mobile Equipment Identity) used to identify the device while the subscriber is identified by the IMSI (International Mobile Subscriber Identity) number, stored on the SIM card and transmitted when a call is placed. Interestingly, GSM has been gaining a considerable lead over CDMA in global market share in recent years.

In our IP world we have the luxury of another couple of years before exhaustion but we should learn from our brethren and colleagues in the North American cell phone industry. Our task is even more daunting as the world’s IP network customers do not really have alternate network implementations or standards they can fall back on.

Migrations or transitions, whatever they’re called, chafe at the bit when harnessed by a plan.

Any opinions, findings, conclusions or recommendations expressed in these articles are solely those of the author and are not in any way attributable to nor reflect any existing or planned official policy or position of his employer in respect thereto.