Although very similar, both shaping and limiting are designed to do separate functions, and could in fact operate together. Generally speaking, shaping uses a queuing mechanism to "delay" flows that do not meet predefined bandwidth parameters. Shaping attempts to keep your average throughput the same, giving you a more predictable flow. Rate limiting is a little more rudimentary with respect to policing traffic flows. When packets exceed bandwidth thresdholds defined, the router makes a decision to 1) lower the priority of packets that have exceeded the threshold, or 2) discard the packet. You can actually utilize both technologies in your network. Policing could be done inbound or outbound and shaping could be done on outbound interfaces. Shaping is usually a little more forgiving with respect to bursy traffic flows, however, queueing is introduced that may introduce additional delays. So, I think the answer is, it depends. It depends on where you are in the network, edge vs. core, and giving up processing/delay vs. overall throughput. My 2 cents worth, Brad -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Christopher J. Wolff Sent: Tuesday, October 02, 2001 11:36 AM To: nanog@merit.edu Subject: Traffic Shape or Rate Limit Hello, I'm wondering what the list's opinions are on Traffic-Shaping vs. Rate-Limit for DIA customers (Frac DS3, for example). From what I've read, Traffic Shaping is a better option since it doesn't drop packets. Just curious as to what the opinions are. Regards, Christopher J. Wolff, VP, CIO Broadband Laboratories, Inc. http://www.bblabs.com email:chris@bblabs.com phone:520.622.4338 x234