I have been looking at this as well, and yes there are some advantages but you really have to have the need. The good news: - STUN will result in lower CPU on the SD since the keepalives dont need to be responded to. Chances are this will not be a factor. - Can be used when the customers endpoint is behind multiple layers of NAT, Acme HNT falls flat on its face in this environment. - STUN mangled traffic will not trigger the broken ALG's in many newer home routers since it doesnt match the lan-side network any longer. If you have had the displeasure of experiencing these broken ALG's in customer routers (linksys, dlink etc etc), and the fact that they quite often cannot be disabled, it can lead to a very frustrating customer experience. Once again HNT and poorly implemented ALG's do not make for happy customers. The bad news - STUN is a less stateful keepalive, i.e. when the endpoint fails to send a keepalive you cannot use forced un-registration or anything similarly clever to keep the presence on the softswitch in sync. - It requires client configuration whereas HNT is completely dynamic. My plan was to have both on tap, and make use of adaptive HNT for most customers but simply having a built-in STUN solution available as a tool for that 4-5% of customers might need it makes it absolutely worthwhile, however if you are in an environment where the access network is tightly controlled there is likely little need for it, but if you are broadband agnostic and just have to cope with whatever rinky-dink ISP/network setup the customer brings, then my advice is get as many tools in your toolbox as possible, just make sure you understand all of them inside and out or you will simply cause yourself unnecessary headache. On Tue, 2009-09-22 at 11:07 -0400, Parkin, Tyler wrote:
Has anybody used the STUN functionality of the Acme SD? I posed the following questions to our SE and engineer, but if anybody has actual experience with it I?d be curious to know how it works.
-Does it work? J
-Re: performance, is STUN less costly than a very short registration refresh rate (<30 seconds)? Some impact on performance of a fully loaded SD 4000 would be appreciated.
-Is it a better solution than their hosted NAT traversal?
Thanks,
Tyler
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