What is difference between SLA & OLA

[luman]

what is the main difference between sla & ola if i select the type as ola, in sla form visible "Underpinning contract" ,what is the need of underpinning............please let me know about of this question please..

[david_legrand]

http://advisera.com/20000academy/knowledgebase/slas-olas-ucs-itil-iso-20000/

The easiest way to understand it is:

• SLA for end users
• OLA inside (IT) department
• UC with external people (vendors)

[jscherer]

I found some sample test questions for System Admin, and one of them is 'What is the difference between SLA, OLA, and Underpinning Contracts?'  I would have thought the answer would be similar to what David Posted.  But the answer for this question was 'Type Field'. Does that make sense? If so could you explain?

ps: I've not been through training as of yet, maybe it is explained there.