[nsp] VWIC-1/2-MFT-E1 issues with lines from Deutsche Telekom ?

[Daniel Roesen]

On Tue, Jul 01, 2003 at 06:21:49PM +0200, Gregor von Stangen wrote:
> I then talked to Deutsche Telekom and they said, they had to switch
> the Sa5 und Sa6 bits transparently to make the line running (which
> it did indeed after the change). They further said, that this is
> a known issue with the VWIC-1/2-MFT-E1 modules, because these modules
> use the Sa5 and Sa6 bits for synchronisation which other modules
> (like NM-1/2-CE1B for example) don't do. And at least, the technician
> said, the switch to transparent of the mentioned bits was good will
> from Deutsche Telekom and that they might not do this in other cases...

Hehe, those SA bits are as far as I know "reserved" with undefined
behaviour. DTAG uses them for remote management of their HDSL modems
which they use to realize E1s via DSL. One of the uses of those bits
(there are more than SA5+6) are to activate loops e.g.

Juniper Channelized STM1 Interfaces send them more or less randomly.
Guess what happens...

This is what you get from Vendors using unstandardised, reserved
header bits for proprietary stuff (in this case Cisco and the vendor
who makes those DSL modems). :-(

Basically, every equipment reacting on reserved bits is "off-limits".
Then again, Devices should send these bits off. :-)

I would say DTAGs DSL modems are in standard violation, so they should
fix them at least on request.


Regards,
Daniel