http://ftp.scientificlinux.org/linux/scientific/7x/contexts/example/$basearch
http://ftp1.scientificlinux.org/linux/scientific/7x/contexts/example/$basearch
http://ftp2.scientificlinux.org/linux/scientific/7x/contexts/example/$basearch
ftp://ftp.scientificlinux.org/linux/scientific/7x/contexts/example/$basearch