ITIL and eTOM
There are some basic fundamental differences between ITIL and eTOM that make it relatively simple to understand the complementary nature of the two frameworks.
Both ITIL and eTOM are frameworks that are supported by professional bodies. For ITIL, the IT Service Management Forum (itSMF) is the professional body that is helping to drive its development. For eTOM the TeleManagement Forum (TMF).
ITIL an acronym for Information Technology Infrastructure Library is a non-presecriptive framework that offers guidance on enhanced service delivery, through improved processes, roles and activity definitions.
eTOM stands for enhanced Telecom Operations Map and is a presecriptive framework that is more widely used in the Telecoms industry. eTOM seeks to ensure common process is used irregardless of the type of service being provided - data, internet, mobiles, etc.
Perhaps two of the easiest ways to understand the differences is their respective focus and certification schemes.
ITIL is focussed on service provision to internal customers. eTOM is focussed on service delivery to external customers.
eTOM has a compliance program that is focussed on tools. ITIL has no compliance program for tools.
Note: ITIL v3 has gone a long way to link internal service provision to the importance of external customers and while some Service Management tools carry an "ITIL compliant" stamp, this is a vendor driven program and not supported by the itSMF.