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christcorp
Premium
join:2001-05-21
Cheyenne, WY
 ·Bresnan Online
 ·VOIPo
| [Packet8] NAT Transversal?
Qwestion about nat transversal. I understand that it's a way for VOIP to work around nat, but isn't that already accomplished with Port Forwarding or using the DMZ?
My bigger question concerns the different types of nat transversal. Packet8 uses their OWN nat transversal protocal in their adapters. (I'm sure other providers do also). Packet8 adapters however offer the choice of theirs, STUN, TURN, or ICE. Now to use STUN or TURN, it requires putting in a server address. Are there public servers that are free? Also, would any of these other protocals be better than using Packet8's nat transversal protocal? Just trying to tweak and get the most out of the VOIP adapter and learn more about the technology. Any inputs would be appreciated. Thx... Mike.... | |
cgigate
join:2003-05-12
Fort Worth, TX
1 edit | No need nat transversal in most situation.
I put my DTA-310 behind triple nat routers. it still works fine! | |
christcorp
Premium
join:2001-05-21
Cheyenne, WY
·Bresnan Online
·VOIPo
| By default, the 310 I think is using Packet8's nat transversal protocal. Was just wondering if the other protocals like STUN, TURN, and ICE have any advantages. Also, if you use port forwarding or DMZ if it is doing the same as what nat transversal is doing also. Later... Mike... | |
christcorp
Premium
join:2001-05-21
Cheyenne, WY | Bump | |
stevech1
join:2005-01-08 | reply to christcorp
If you please: protocol, not protocal | |
christcorp
Premium
join:2001-05-21
Cheyenne, WY
·Bresnan Online
·VOIPo
1 edit | If you please: Find something more important to complain about in life. Fat fingering and Spelling mistakes are definatly one of my many weaknesses. I rarely spell check and check the correct homonym for forums. My bad!!! To actually worry about it to the point where you need to correct someone is; Your Bad! Lighten up, Relax, and have a nice New Year.
Oooooh, almost forgot. Did you have any input on the different nat transversal protoc(o)ls and on the different affects they have on VOIP? Just wondering! | |
nathana
Premium
join:2004-05-27
Moscow, ID
|  reply to christcorp
Yes, you are correct: "nat traversal" can be accomplished with an open-ended DMZ or a true one-to-one nat, but requiring all customers with a nat gateway to "waste" the DMZ option on the DTA is not only a technical support nightmare, but limits the customer's freedom to use the DMZ for other things on other occasions (the DTA is, presumably, going to be plugged in and on-line 24/7). The whole point of nat traversal is to make installation and use of the service easier for the customer.
As I understand it from the limited reading that I have done on the subject, the way that most nat traversal protocols work is by requiring that the device being natted (the DTA/CPE) initiate contact to a server on the outside somewhere that can in turn tell the CPE things about its path to the internet that it itself does not know (such as the routable IP address it will eventually be mapped to by the nat border router, for example). This will in turn help the CPE/SIP endpoint to know how best to open a path of communication to the SIP gateway it is trying to talk to as well as figure out the best way for two SIP endpoints to be able to see each other. Sometimes, such a server can even act as a media relay or proxy for both SIP endpoints (pretend that *both* devices -- the caller's and the callee's -- are natted...how are they supposed to talk to each other?). Not all nat traversal protocols and methods are mutually-exclusive; sometimes it is even best to use multiple methods in combination with each other.
What you need to realize, however, is that you are restricted to the methods that have been set up for you to use by the provider that you're using (this might not necessarily be the case if all calls were pure IP end-to-end, but the reason we pay our $20/month is for the privilege of interconnecting with the POTS, something which is, alas, still a necessity if you want to be able to talk to the rest of the world and have them listen in return). Obviously you need to be able to connect to your provider's servers, and they have set up nat traversal servers of their own that you have no choice but to use as long as you wish to continue to be able to use that particular service. What this all boils down to is that it is quite futile to ask "what is the best nat transversal (sic) method" UNLESS you are setting up your own VoIP service for other people to use since, as a customer of a particular VoIP service, you have no choice but to use the protocol(s) and method(s) that your provider picked when they implemented their VoIP offering. In your case as a Packet8 customer, you have no choice but to use the proprietary Packet8 nat traversal method. Packet8 does not run a STUN server (at least not one that adheres fully to RFC 3489) or any other standards-based nat traversal method (8x8 claims that the Packet8 method was actually conceived and written well before STUN was proposed as a standard, and so they felt they didn't have a choice...they weren't really trying to "reinvent the wheel"), and so you cannot use STUN with the Packet8 service. My guess is that the options you see on the nat Traversal screen to pick from are legacy options left over from the day when 8x8 was a "fabless semiconductor" company (Netergy) who was willing to license and sell their VoIP server and client technology to other manufacturers seeking to create a CPE that adhered to standards that everybody else used. Now that 8x8 and Packet8 are almost strictly in the service business now, these options are not needed any longer, and I suppose it will only be a matter of time before they are ripped out of the Packet8 DTA firmware; I'm sure they haven't made doing so a top-priority at this point and probably won't until they need to make room in the flash ROM for more "relevant" features. 
Presumably, you have access to the LAN and SIP configuration sections of your Packet8 DTA, which is why you are posing theis question to begin with. However, nat traversal is not a customer-configurable choice that can be made. If you try to choose it, you will find yourself without service. More likely than not, unless Packet8's firmware ignores changes made to the settings there (as they do for other options present in their firmware, such as the SIP gateway FQDN/IP, or the dial plan), changing this option to something other than what it was programmed to be set to by Packet8 themselves will probably cause your service *not* to work as intended. In fact, I may be so bold as to propose that questions such as yours is what pushes the Packet8 engineers to "lock" their customers out of fiddling with the advanced configuration options on their DTAs. From a support and customer experience perspective, it makes perfect sense. If everyone had access to the nat Traversal screen or any of the other now-exposed screens in the unlocked firmware versions, then every Packet8 customer would have an "equal opportunity" at screwing up their DTAs and rendering them unusable until the customer manages to get through to technical support (whose lines are jammed thanks to all the other John and Jane Does calling in on account of their DTA which they also screwed up). In fact, assuming that your DTA works just fine for you without having to resort to using the DMZ or port forwarding tricks, you may want to take this moment to ask yourself *why* you would want to change the nat traversal option from "Packet8" to something else. You can't ask for anything better than "it works!" What is there to tweak when it comes to nat traversal if your service already works as you expect it to?
Please understand that I don't say all of this because I wish to squelch your curiosity about the way that this technology works or your desire to get the most out of it (both of which are quite commendable!). My desire is simply to inject some common sense into the frenzy that has become the Packet8 "unlocked firmware." I just want to avoid the possibility that other people might run into this thread out of happenstance and then, in response, go out to load some unsupported firmware on their DTA and consequently become known to Packet8 technical support agents as "yet another idiot who changed his advanced settings and can now no longer use the service." If we don't want to see Packet8 engineers making it more difficult than it currently is to "unlock" their firmware, then we need to see to it that we use any means necessary to prevent flies from getting into their ointment, lest they become more annoyed than they already probably are. About the only real useful utility that the "unlocked" firmware provides is the ability to change audio CODECs; all the other newly-exposed settings really should be left alone, as-is. The Packet8 firmware was intended for Packet8 customers to use on Packet8's servers; if you want to use the DTA with a different provider that uses standard nat traversal methods or other features that the Packet8 firmware may or may not implement, then take the Packet8 firmware off and put a different one one, a completely-standard SIP-compliant firmware such as the Leadtek one that has been posted about here so often. But if you do so, don't expect to be able to use your DTA with Packet8 anymore!
In closing, I'll just say that a couple minutes with Google can really pay off sometimes. Here is a link to a whitepaper that I found which describes some of the common nat traversal methods employed by SIP-based VoIP providers, and what each method's strengths, weaknesses, and purposes are:
»ag-projects.com/docs/PressArticl···ices.pdf
Happy VoIP'ing!
-- nathan | |
christcorp
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join:2001-05-21
Cheyenne, WY
·Bresnan Online
·VOIPo
| FWIW, I did do quite a bit of googling for nat transversal. The link you provided is also a good one, thanks. As far as the Packet8 adapter goes, there are 3 options about nat transversal on the adapter that made me question. 1st: The fact that you could in fact change it and it wasn't locked out or removed as an option. 2nd: The fact the choice of using "NO nat transversal" was an option. 3rd: Beside the other 4 choices of STUN, TURN, ICE, and Packet8; the is one for "PACKET8 WITH ICE".
Now, you can say what you want about not touching anything that already works, but that goes again the natural fiber that people in the tweaking and Overclocking world live in. Matter of fact, less than 10% of any type user even goes to forums like this for any type of advice and communications.
Having said that, I know what nat transversal does and that's why I asked the question about the DMZ. You confirmed my suspicions with the DMZ. I would assume that manual port forwarding would also accomplish the same thing. This is what makes me wonder about the adapter's ability to choose "NO nat transversal" as a choice. If you had ports forwarded, would there be a need for nat transversal? If not, would turning it OFF eliminate 1 extra layer of processing to improve service?
If nat transversal IS REQUIRED no matter what, then the option of using "Packet8 WITH ICE" creates questions. If Packet8's protocol was the only one needed or able to be used, why would one called "Packet8 WITH ICE" be an option?
You might be the type that is quite content with buying a TV from the stroe and turning it on and watching it. Buying a computer, turning it on and using it. etc... Some of us aren't. My big screen TV has been calibrated to ensure that the grayscale and color decoder match real life colors as perfectly as possible. My CPU in my computer is tweaked to get the greatest speed and performance possible without overheating the cpu. The point is, for some folks, there is nothing wrong with wanting to squeaze the most performance out of what we own. Doesn't mean it's right for everyone to do, but it's not wrong for those who want to.
It's the tweakers, overclockers, hackers, etc... that have forced technology to advance. It's man's nature to improve on something that forces the manufacturers to improve their product. Believe me, the average manufacturer would be tickled pink if they could make one style of product that all people would be satisfied with and that they never had to improve upon. They would save and make so much money. Fortunately, it's man's dissatisfaction with the Status Quo and his eventual boredom that forces improvements. It has been this way since the caveman and will continue on.
I am not trying to trash my Packet8 adapter. But then, if I did.... So What? I buy another one. I want to get the most out of what product the manifacturer presents me with. Just like those who have to modify and soop up a new car or the teenager who has to modify his or her bicycle. Some people find their creativity and curiosity in different venues. Technology happens to be one some of us like to experiment with.
Thanks however for some really good information about nat transversal. Much of it I knew, but you are correct that it is wise to inform those less skilled as to the potential hazards of screwing around. Just like computers, there are many people who have burned up their CPU trying to overclock it. Later... Mike... | |
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