We have at present, three office sites with on average, 10 people at
each location. Two of these locations are within a few miles of each
other, the third is separated from the first two by a distance of 800
miles or so. We also have a few teleworkers scattered about. We have
a half-dozen or so POTS lines coming in to each location as well as
broadband Internet service at each location, either cable or DSL.
We curently use a mix of small key systems, a 3Com NBX (pseudo VOIP)
and individual POTS lines. We use an outsourced service provider
(VirtualPBX) to host our public telephone numbers which are then
routed to the various locations by the VirtualPBX auto-attendant.
This arrangement is marginally acceptable at present, but we are
seeking a better solution.
Our users have several issues with the current solution:
1. There is no Caller-ID display on the telephone sets, only the
verbal Caller-ID announced by VPBX. Numerous other features one would
expect to have on say a Norstar MICS type system with a PRI between
sites are missing such as conferencing, call parking, etc VPBX does
provide some of these services such as conferencing, but not all our
users have their own VPBX virtual extension.
2. The VPBX fees are rather expensive.
3. There are significant delays when calls are answered and/or
transferred by the VPBX.
4. We have done some VOIP over the broadband Internet connections with
the 3Com NBX, but the call quality was/is poor, likely because we have
no way to control QOS.
5. We pay a per-minute fee to VPBX for all calls, even calls coming in
to our local numbers.
I'm not looking for implementation-specific handholding, but I'm
curious what technologies other folks are using in similar situations?
I'm currently leaning toward an all-Cisco VOIP system with a MPLS VPN
between the sites for both data and voice traffic, but that's quite an
investment to make without knowing for sure that it will give the
results we expect.
We're also willing to consider an open-source product such as Asterisk,
but the same QOS issues would apply. We'd still need the MPLS VPN, but
would save some money on equipment.
In addition to the above, would anyone care to comment on the success
(or lack thereof) of using simple Internet VPN for handling VOIP calls?
We could manage QOS to our network edge, thus preventing a big
download from monopolizing our bandwidth, but once the traffic leaves
our network, what kind of call quality could we expect then?
Thanks in advance to those who read and respond.