Oracle Enterprise Linux 5.5 Trails RHEL 5.5
That's pretty quick and in my view, one of the quickest turnarounds yet from Oracle with their version of RHEL. Oracle has been releasing its own version of Linux with OEL, based on RHEL since 2006 and they've been updating OEL as Red Hat updates RHEL.
Over the years, Oracle has told me, that OEL isn't a fork of RHEL, but it is Oracle's effort to provide support for Oracle customers.
"A lot of people think Oracle is doing Enterprise Linux as just
basically a rip off of Red Hat, but that's not what this is about," Wim
Coekaerts, director of Linux engineering at Oracle," told me last year.
OEL isn't the only RHEL variant out there, the community-led CentOS distribution is a popular choice as well, though it lags Oracle in terms of keeping up with Red Hat. CentOS (as of this posting) has not yet release their version 5.5 yet.