I was noticing that larger backbone providers, who have merged with other large backbone providers, seem to keep both AS numbers. Let's take Verio as a example, though Verio is only one of many who have multiple AS numbers. Verio has 8 AS numbers, AS 93, 97, 114, 275, 280, 253, 1225 and 2914. I noticed that there are no IP routes associated with 6 of the 8 AS numbers and that only AS 97 & AS 2914 has any IP routes. My questions are: 1) Is there a easy mechnisim to give back AS numbers to the ARIN? 2) Would ARIN even reallocate those AS numbers to new requesters? 3) Could those AS numbers be transfered over to new organizations? 4) Is there a advantage for a organzation to have multiple AS numbers? 5) Is there a advantage to having a lower AS number? Thanks!