How do you specify multiple yum repos in /etc/sysconfig/rhn/sources

[Yusuf Goolamabbas]

Assuming that I want to setup my own yum mirror (to have some form of
guaranteed access), how do I specify the same in
/etc/sysconfig/rhn/sources. I plan to use the up2date client to manage
my Fedora box

Currently, the format seems to be 

### an yum style repo 
### format:
### type  channel-label     url 

yum fedora-core-1 http://fedora.redhat.com/releases/fedora-core-1
yum updates-released http://fedora.redhat.com/updates/released/fedora-core-1

Can I point the channel to multiple urls and how will the urls be
selected (in order of listing or roundrobin)
Is there a list of existing Fedora Yum repositories or is everybody
going to hammer fedora.redhat.com as soon as the first update is
released

Is it possible to have username:password in the URL's so I can use
basic/digest authentication

Regards, Yusuf

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