|
North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: That pesky AS path corruption bug...
On Tue, May 23, 2000 at 10:41:24AM -0700, Vadim Antonov wrote: > Peter T. Whiting <[email protected]> wrote: > > > As I understand the current spec, a router, upon receiving a malformed > > as_path is supposed to respond with a notification message (3.11) and > > drop the BGP connection. Your suggestion to maintain the connection > > and drop the announcement is a practical one, but doesn't put as much > > pressure on vendors to fix the bug. > > This is not only practical, but, in fact, the only sane way to do things. > Dropping BGP session causes withdrawal of hundreds or thousands of > acceptable routes. When the BGP session is reestablished, these routes > will be acquired again, causing a wave of announcements. When the > invalid route shows up, the cycle is repeated. > > What a perfect way to kill the Internet :) good point. In defense of the spec here is a cut from rfc 1771: If a BGP speaker detects an error, it shuts down the connection and changes its state to Idle. Getting out of the Idle state requires generation of the Start event. If such an event is generated automatically, then persistent BGP errors may result in persistent flapping of the speaker. To avoid such a condition it is recommended that Start events should not be generated immediately for a peer that was previously transitioned to Idle due to an error. For a peer that was previously transitioned to Idle due to an error, the time between consecutive generation of Start events, if such events are generated automatically, shall exponentially increase. The value of the initial timer shall be 60 seconds. The time shall be doubled for each consecutive retry. pete
|