Some DSL modems do have an auto-detect where they cycle through the most
common VPI/VCI values.
Frank
-----Original Message-----
From: wireshark-users-bounces@xxxxxxxxxxxxx
[mailto:wireshark-users-bounces@xxxxxxxxxxxxx] On Behalf Of Kok-Yong Tan
Sent: Wednesday, July 02, 2014 7:09 PM
To: Guy Harris; Community support list for Wireshark
Subject: Re: [Wireshark-users] Using Wireshark for a DSL "link no surf"
problem [UPDATE]
On 7/2/14 19:31, Guy Harris wrote:
>
> On Jul 2, 2014, at 3:46 PM, Kok-Yong Tan <ktan@xxxxxxxxxxxxxxxxxxx>
> wrote:
>
>> This segues to my next question: Is there any way to use Wireshark
>> to ascertain the VPI/VCI of the ATM circuit from the Layer 2
>> packets that were said to have been flowing? Or must I have
>> specialized software or hardware to do this?
>
> If you're capturing on the Ethernet into the modem, I wouldn't expect
> to see any ATM information from the capture - if, for example, the
> modem has an HTTP-based configuration interface for use on the local
> user side, Ethernet traffic to and from its Web server won't even
> necessarily go out over the DSL circuit.
>
> To capture traffic on the ATM side of the modem, you'd need
> specialized hardware, and probably some level of specialized software
> to talk to that hardware.
>
>> I noticed that the rep had nothing more than his laptop connected
>> via ethernet cable to the DSL modem when he noticed the different
>> VPI/VCI settings on a possibly in-house-only software running on
>> it.
>
> According to the manual for your modem at the URL you sent in an
> earlier message, there's an HTTP-based configuration interface.
> That's probably what the rep was using.
>
Okay, noted on the ATM info. Thanks.
Unfortunately, he wasn't using that HTTP-based interface (I looked at
what he was looking at and it's not the Broadxent Briteport's
interface). The Broadxent Briteport's web-based interface is just a
status interface. There's nothing that can be set on it except for the
PPPoE settings and there's also a reset-to-defaults button. All through
the case when I was offline, it just displayed a VPI/VCI of 0/35. I
suspect that there is another port which allows an admin user to login
and manipulate the settings, just like on the replacement ZyXEL P660R-F1
the onsite tech provided me with.
