>I have a question, Howard - in line: > > >""Howard C. Berkowitz"" wrote in message >[EMAIL PROTECTED]">news:[EMAIL PROTECTED]... >> This is one of those posts where the attributions have gotten very >> confused. Comments inline. >> >snip for brevity >> >> It can be done, if both ISPs agree to it and coordinate their routing >> policies. A public AS, however, is justified in this circumstance. >> >> While doesn't quite describe this situation, look at RFC 2270 for the >> general strategy. Both ISPs have to remove private AS. This will >> also cause more than one ISP to appear to originate the route, which >> is a technical violation of BGP (i.e., it's an "inconsistent route"), >> but that isn't that uncommon and doesn't seem to break anything. >> > >Question: in an ideal world, what would happen when an "inconsistant route" >shows up? idealy, would that route be black holed?
There's no final decision, but I think the sense is that there's nothing really wrong with having a route orginated by two sources, especially when the reasons are documented in a routing registry. There's no question that multihoming scenarios exist where this works. There was discussion of taking the rule that it was illegal out of the new BGP specification, but I don't remember the final decision. Especially if there are documented routing policies that say it's being done deliberately, it just doesn't seem to be much of an operational problem. It can, however, make troubleshooting more difficult. >Since it is "common" and since it "doesn't seem to break anything" in ral >terms, what happens? BGP advertises reachability to other BGP routers, be >they internal or external. But in terms of a packet traveling from my house >to a destination that is "inconsistant" what happens? What matters? My >packet continues to be passed from here to there until some directly >connected router receives it. I'm assuming that "inconsistant" does not >imply "loop" > >thanks. > > > >>snip for brevity< Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=45168&t=45168 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
