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mattw

join:2011-02-07

Common ISP-supplied CPEs

Hi,

I'm trying to understand how NAT works for the majority of US consumer and SME CPEs/routers/modems.

I understand that unlike in the UK that most US ISPs/telcos don't want you to replace their equipment with your own, and instead you need to put your own device behind whatever they supply.

Can anyone help me - what are the most popular/common brand (e.g. D-Link, Netgear, Linksys, ...) of CPEs that ISPs provide for you? Even better if you know the particular model an ISP likes to use!

I'm basically trying to find out what type of NAT these devices operate on (I'm doing research into UDP port punching)- Full Cone, Restricted Cone, Port Restricted Cone, Symmetric, etc... and while I've seen some research papers on the issue, I would like to test them out for myself as well.

Thanks!



cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7

1 recommendation

said by mattw:

I understand that unlike in the UK that most US ISPs/telcos don't want you to replace their equipment with your own, and instead you need to put your own device behind whatever they supply.

That's not true. In many cases the ISP either provides it as part of the service, or rents it to the customer. Sometime ISPs allow you to use your own equipment, but still charges a fee for "support". Others don't care if you use your own equipment or theirs, as long as it's a supported model from a list.

Can anyone help me - what are the most popular/common brand (e.g. D-Link, Netgear, Linksys, ...) of CPEs that ISPs provide for you? Even better if you know the particular model an ISP likes to use!

It's all over the board. Usually the cable or dsl modem, or EMTA isn't a consumer brand such as DLink, Netgear, or Linksys. Sometimes the router that sits behind the model is. But often it's a non-consumer-direct brand such as Motorola, Arris, ActionTec, Westel, etc. Models also vary significantly from company to company although there are common ones that many use or support.

I'm basically trying to find out what type of NAT these devices operate on (I'm doing research into UDP port punching)- Full Cone, Restricted Cone, Port Restricted Cone, Symmetric, etc... and while I've seen some research papers on the issue, I would like to test them out for myself as well.

I've never seen a router not support at least Full Cone, but I have seen routers that don't offer anything beyond full cone. It likely will be all over the map with consumer devices and so supporting only a subset of them may ultimately leave someone out.


Anav
Sarcastic Llama? Naw, Just Acerbic
Premium
join:2001-07-16
Dartmouth, NS
kudos:4

1 recommendation

There is no common ISP approach or model that I am aware of.
If people can replace the router functionality of provided modem router combos they usually try to do so. Until I had fibre Op I was only provided with modems. Since wifi has become popular even cable cos have tended to provide modem router with wifi built in.
The change from internet provider to combination internet and TV provider also adds in some complexity and more ISP equipment getting into the equation. I dont see the value in your research on type of NAT etc...
--
Ain't nuthin but the blues! "Albert Collins".
Leave your troubles at the door! "Pepe Peregil" De Sevilla. Just Don't Wifi without WPA, "Yul Brenner"

LlamaWorks Equipment



Hank
Searching for a new Frontier
Premium
join:2002-05-21
Burlington, WV
kudos:2

1 recommendation

Our ISP prefers that customers use the modem/router they supply but you can put your own modem/router online. If you supply your own modem/router the ISP will not support it. As previously mentioned some ISP's provide a list of equipment that they are familiar with and will help you troubleshoot those modem/routers. Our ISP does not have a listed of supported modems. The policy vary from ISP to ISP.


mattw

join:2011-02-07

1 recommendation

reply to cdru

said by cdru:

That's not true. In many cases the ISP either provides it as part of the service, or rents it to the customer. Sometime ISPs allow you to use your own equipment, but still charges a fee for "support". Others don't care if you use your own equipment or theirs, as long as it's a supported model from a list.

Thanks, that's good to know.

said by cdru:

It's all over the board. Usually the cable or dsl modem, or EMTA isn't a consumer brand such as DLink, Netgear, or Linksys. Sometimes the router that sits behind the model is. But often it's a non-consumer-direct brand such as Motorola, Arris, ActionTec, Westel, etc. Models also vary significantly from company to company although there are common ones that many use or support.

Ah ok thanks this is helpful. ActionTec publishes there GPL source code online, so good to confirm it is using linux & iptables for NAT. Will work my way through the others and see what I can find.

said by cdru:

I've never seen a router not support at least Full Cone, but I have seen routers that don't offer anything beyond full cone. It likely will be all over the map with consumer devices and so supporting only a subset of them may ultimately leave someone out.

Very true. To be honest I am expecting the majority of them to use some form of linux and iptables behind the scenes (bar perhaps Cisco or Juniper which I don't think you'd find Telcos supplying by default), which typically means a form of symmetric NAT but with easy to guess ports as iptables preserves source ports where possible.

mattw

join:2011-02-07

1 edit

1 recommendation

reply to Anav

said by Anav:

The change from internet provider to combination internet and TV provider also adds in some complexity and more ISP equipment getting into the equation. I dont see the value in your research on type of NAT etc...

I guess my question on the type of NAT was a bit general. There aren't just 4 standard types of NAT. »nattest.net.in.tum.de/ (warning, link will load a java applet and start a NAT test) has a paper that talks about 3 different aspects that result in about 36 different combinations. Of course the vast majority will(should) flock around one or two approaches (see »nattest.net.in.tum.de/results.php ).

I need to test a NAT port punching solution, and don't want to risk testing it against theoretical NAT setups in a lab environment, which may or may not replicate what a customer will end up experiencing. There's nothing better than testing with the same equipment that customers also have.

For anyone else that is interested, the site I mentioned above also has a good (java applet) tool that analyses what sort of NAT(s) you are behind.


Hank
Searching for a new Frontier
Premium
join:2002-05-21
Burlington, WV
kudos:2

Visited the links you mentioned, the second link attempts to run an application that it says is to collect NAT information and report it anonymously to the University in Munich.


mattw

join:2011-02-07

Yes it does. Sorry I forgot it tries to load the java applet straight away (but doesn't run until you press start/begin). Apologies.


aryoba
Premium,MVM
join:2002-08-22
kudos:4

1 recommendation

reply to mattw

said by mattw:

To be honest I am expecting the majority of them to use some form of linux and iptables behind the scenes (bar perhaps Cisco or Juniper which I don't think you'd find Telcos supplying by default)

If you were referring to a typical Broadband services such as cable or DSL, then the CPE is unlikely to be industrial-grade gear such as Cisco and Juniper. With a "real services" that comes with circuit ID, the ISP-provided CPE can be either Cisco or Juniper.

HELLFIRE
Premium
join:2009-11-25
kudos:13

1 recommendation

reply to mattw

said by mattw:

Can anyone help me - what are the most popular/common brand (e.g. D-Link, Netgear, Linksys, ...) of CPEs that ISPs provide for you? Even better if you know the particular model an ISP likes to use!

From perusing this forum, Cisco DPC2300 is mentioned alot for cable setups, while Actiontech
MI-424 is mentioned alot for xDSL rigs. 2WIRE HG2701 still is mentioned, even though that is
pretty old kit AFAIK.

Dumb question, when you refer to UDP punching, are you referring to STUN? From your choice
of NAT terminology -- full cone, restricted cone, etc. -- is officially mentioned in RFC 3489
which has been depreciated.

Regards