LLC or VC-Mux - and what's the modulation type?

Hi,

A client has an BT managed business broadband service with a eight static
IP's assigned.

The BT router was blown during electrical work but unfortunately when BT
replaced the router they were never able to get the static IP's working
properly.

I've got a feeling they were never able to switch off NAT and the firewall.
So the router would get its own IP address via DHCP but traffic for the
static IP addresses would never get past the router.

The reason I'm not sure is that the BT router is in a locked down mode and
can not be worked with.

So we gave up on BT and put our own router in which had been borrowed from
another company. After setting NAT to off and turning off the firewall
then traffic would be passed through to other routers which handled
firewalling, VPN and port-forwarding to an email server.

Now this D-Link router has been working perfectly - this is with the
connection type set to PPPoA LLC.

BT 'support' staff say it should be Vc-Mux. Indeed, Vc-Mux works for
traffic when clients on-site want to access the internet - but doesn't seem
to work for the traffic trying to get from the internet to one of the
static IP addresses.

So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the difference?


And if any BT guys/gals are on this NG could you please point out any lists
RE how to set up this router - what should be the modulation type?

It's really frustrating trying to set up BT's own router when they can't do
it themselves!

Cheers,

Kevin

On 2007-03-09, kevin bailey <(E-Mail Removed)> wrote:
> Now this D-Link router has been working perfectly - this is with the
> connection type set to PPPoA LLC.
[...]
> So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the difference?

The difference between PPPoA LLC and PPPoA VCMux encapsulation is that
PPPoA LLC has the 4 bytes 0xfe, 0xfe, 0x03, 0xcf prepended to the front
of each packet while PPPoA VCMux doesn't. Everything else is the same.

I can't imagine what difference this would make. The only problem with
using the LLC encapsulation (other than that it adds 4 bytes to each
packet) is that BT might some day install equipment which didn't
understand packets with the bytes on the front, though this is fairly
unlikely.

Can you figure out what it is which is failing to route your subnet
address when you run VCMux? Being able to traceroute from off site
might help to see if it is the BRAS router or the D-Link which is
having the trouble.

Dennis Ferguson

Dennis Ferguson wrote:

> On 2007-03-09, kevin bailey <(E-Mail Removed)> wrote:
>> Now this D-Link router has been working perfectly - this is with the
>> connection type set to PPPoA LLC.
> [...]
>> So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the
>> difference?
>
> The difference between PPPoA LLC and PPPoA VCMux encapsulation is that
> PPPoA LLC has the 4 bytes 0xfe, 0xfe, 0x03, 0xcf prepended to the front
> of each packet while PPPoA VCMux doesn't. Everything else is the same.
>
> I can't imagine what difference this would make. The only problem with
> using the LLC encapsulation (other than that it adds 4 bytes to each
> packet) is that BT might some day install equipment which didn't
> understand packets with the bytes on the front, though this is fairly
> unlikely.
>
> Can you figure out what it is which is failing to route your subnet
> address when you run VCMux? Being able to traceroute from off site
> might help to see if it is the BRAS router or the D-Link which is
> having the trouble.
>
> Dennis Ferguson

Good idea.

I'll run a traceroute from another server when I get chance.

The strange thing is that either setting works for outgoing.

Kevin

Strange thing is that according to

http://www.samknows.com/broadband/ex...p?ecode=WWPTON

The exchange is not LLU enabled - but setting LLU on the router works fine.

Either;

The router is not really switching to LLU mode

The exchange info is out of date.

Even if the router is set to LLU it can handle Vc-Mux traffic.

I had initial problems with receiving the data for the 5 static IP addresses
when the setting was Vc-Mux even though the other traffic going out from
clients on the LAN was ok.

I'll have to check the Vc-Mux setting again.

Kevin

kevin bailey wrote:

> Strange thing is that according to
>
> http://www.samknows.com/broadband/ex...p?ecode=WWPTON
>
> The exchange is not LLU enabled - but setting LLU on the router works fine.

What do you mean by "setting the router to LLU" ?

Is your ISP incapable of telling you if you're on an LLU circuit or not ?

Graham

On Mar 10, 9:32 am, kevin bailey <kbai...@freewayprojects.com> wrote:
> Strange thing is that according to
>
> http://www.samknows.com/broadband/ex...p?ecode=WWPTON
>
> The exchange is not LLU enabled - but setting LLU on the router works
> fine.

Hmmm. Local Loop Unbundling != Logical Link Control.

One would have thought if it's BT Retail broadband, then they'd be
buying it from BT Wholesale, and by definition it wouldn't be LLU.

alexd

kevin bailey wrote:

> The BT router was blown during electrical work but unfortunately when BT
> replaced the router they were never able to get the static IP's working
> properly.

Was this a BT wholesale owned router by any chance? A siemens?

> I've got a feeling they were never able to switch off NAT and the firewall.
> So the router would get its own IP address via DHCP but traffic for the
> static IP addresses would never get past the router.

If it was an BT wholesale router it sounds like nobody downloaded it's
config file, and seeing as how they disabled that functionality some
months ago now I'm not suprised you had issues like that.

> So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the difference?

Should be vc-mux as you say but will probably work with either.

> And if any BT guys/gals are on this NG could you please point out any lists
> RE how to set up this router - what should be the modulation type?
>
> It's really frustrating trying to set up BT's own router when they can't do
> it themselves!

Did nobody offer to pass you through to BTs "ITSM" desk? They should
talk you through configuring your router though you will have to pay
£25 for the privilege when it is set up.

It sounds like you are having serious problems getting stuff working
there Kevin, if you want my advice get another new BT router, a
HG2700, it's supported by their helpdesks for setting up static IPs
and will work ok on their service - if the line you are working on is
a fixed rate line (ie not up to 8Mbs) then ask for a regrade and ask
for new equipment - monthly costs are the same, you're just into
another new contract, BTs customer options team should be able to sort
you out with a HG2700 router/regrade if you explain to them the issues
you are having - 0800800871.

Regards

William MacLeod

Dennis Ferguson wrote:
> On 2007-03-09, kevin bailey <(E-Mail Removed)> wrote:
>> Now this D-Link router has been working perfectly - this is with the
>> connection type set to PPPoA LLC.
> [...]
>> So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the difference?
>
> The difference between PPPoA LLC and PPPoA VCMux encapsulation is that
> PPPoA LLC has the 4 bytes 0xfe, 0xfe, 0x03, 0xcf prepended to the front
> of each packet while PPPoA VCMux doesn't. Everything else is the same.
>
> I can't imagine what difference this would make. The only problem with
> using the LLC encapsulation (other than that it adds 4 bytes to each
> packet) is that BT might some day install equipment which didn't
> understand packets with the bytes on the front, though this is fairly
> unlikely.

Can't speak for other LLU providers but I know our LLU offering will not
work using LLC encapsulation.

Rgds,

--
|Bob Pullen Broadband Solutions for
|Support Home & Business @
|PlusNet plc. www.plus.net
+------ PlusNet - The smarter way to Internet! -----

On 3ÔÂ10ÈÕ, ÉÏÎç5ʱ47·Ö, kevin bailey <kbai...@freewayprojects.com> wrote:
> Hi,
>
> A client has an BT managed business broadband service with a eight static
> IP's assigned.
>
> The BT router was blown during electrical work but unfortunately when BT
> replaced the router they were never able to get the static IP's working
> properly.
>
> I've got a feeling they were never able to switch off NAT and the firewall.
> So the router would get its own IP address via DHCP but traffic for the
> static IP addresses would never get past the router.
>
> The reason I'm not sure is that the BT router is in a locked down mode and
> can not be worked with.
>
> So we gave up on BT and put our own router in which had been borrowed from
> another company. After setting NAT to off and turning off the firewall
> then traffic would be passed through to other routers which handled
> firewalling, VPN and port-forwarding to an email server.
>
> Now this D-Link router has been working perfectly - this is with the
> connection type set to PPPoA LLC.
>
> BT 'support' staff say it should be Vc-Mux. Indeed, Vc-Mux works for
> traffic when clients on-site want to access the internet - but doesn't seem
> to work for the traffic trying to get from the internet to one of the
> static IP addresses.
>
> So which should it be - PPPoA LLC or PPPoA Vc-Mux? What's the difference?
>
> And if any BT guys/gals are on this NG could you please point out any lists
> RE how to set up this router - what should be the modulation type?
>
> It's really frustrating trying to set up BT's own router when they can't do
> it themselves!
>
> Cheers,
>
> Kevin

Good!
http://fy4.net/03.htm

(E-Mail Removed) wrote:

> kevin bailey wrote:
>
>> The BT router was blown during electrical work but unfortunately when BT
>> replaced the router they were never able to get the static IP's working
>> properly.
>
> Was this a BT wholesale owned router by any chance? A siemens?
>

Yep -The model number is in my notes somewhere - a 2430 springs to mind.

>> I've got a feeling they were never able to switch off NAT and the
>> firewall. So the router would get its own IP address via DHCP but traffic
>> for the static IP addresses would never get past the router.
>
> If it was an BT wholesale router it sounds like nobody downloaded it's
> config file, and seeing as how they disabled that functionality some
> months ago now I'm not suprised you had issues like that.
>

Makes sense

>>
>> It's really frustrating trying to set up BT's own router when they can't
>> do it themselves!
>
> Did nobody offer to pass you through to BTs "ITSM" desk? They should
> talk you through configuring your router though you will have to pay
> £25 for the privilege when it is set up.

I'll give that a try.

>
> It sounds like you are having serious problems getting stuff working
> there Kevin, if you want my advice get another new BT router, a
> HG2700, it's supported by their helpdesks for setting up static IPs
> and will work ok on their service - if the line you are working on is
> a fixed rate line (ie not up to 8Mbs) then ask for a regrade and ask
> for new equipment - monthly costs are the same, you're just into
> another new contract, BTs customer options team should be able to sort
> you out with a HG2700 router/regrade if you explain to them the issues
> you are having - 0800800871.
>

Thanks - sounds like good advice.

I'll try on Monday

> Regards
>
> William MacLeod