25 Mar
2011
25 Mar
'11
9:49 a.m.
Single AS worldwide is fine with or without a backbone.
Which is "preferable" is up to you, your situation, and your personal tastes. (I guess one could argue that wasting AS numbers, or polluting the table with lots of AS numbers is bad or un-ashetically pleasing, but I think you should do whatever fits your situation anyway.)
Depends on your routing requirements, for example, you need to rely on a default or disable as_path checks (or re-write the path) to be able to see your other clusters (if they do need to communicate)... -- David Freedman Group Network Engineering Claranet Group