How a Company would move their network to VoIP
There are many different strategies to go about
this. Some companies, if they are a new, come in and just say that we are brand
new company and we don’t want to waste money on PBX system (figure below)
Why don’t we just get a VoIP system (figure below).
But for most companies, they will be running PBX
system for years and for them to move their entire system on VoIP is a shock.
As they had invested 100s of 1000s of dollars on PBX systems (depending on the
size of the business) why would they throw that all away to get free long distance?
And when they will put on cost on a spreadsheet, they will know that the cost
savings would not be realized for decades. So these types of companies might
use a “two phased approach”.
Phase 1:
Phase 1 to move over
VoIP system is ‘to keep all your PBX system’, so you keep your PBX, your phones.
Just re-equipped your routers or buy new routers that allows you to connect the
PBX system through WAN and PSTN.
It is very low cost to get some new routers or new Modules like VWIC
(voice and WAN interface card) that allows the router to connect with PBX
system through a T-1 line and also connect the router to the PSTN via a T-1
line. Now we not only can connect our router with IP WAN, but we can also
connect our router with the voice world (PBX, PSTN).
It gives us the capability to choose one of two paths any time you
communicate to the offices. If your WAN link is up and has bandwidth, your
calls between the offices will go through WAN and if WAN is down then we can
use PSTN as a backup.
It gives us many of
the benefits of VoIP like free long distance between the offices, compressing
the voice across WAN, we get rid of Tie Lines between the offices with
has high reoccurring monthly cost. So we get a lot of cost saving by just
buying some new routers or modules to connect our PBX through WAN rather than
just PSTN. This is phase 1 migration/upgrade. There are companies that have
this phase 1 type set up and they want to upgrade to phase 2 which is difficult
to maintain as compared to phase 1 in which we have a back up of PSTN.
Phase 2:
In phase 2 we get rid of PBX system, it is the new voice system which has Call Manager Express which is now known as Cisco Unified Communication Manager Express as a standalone device OR we have a Communication Manager Express running on Router (this is what we are going to deal with in CCNA voice) and we will use new phones here that connect with switches and your everything is end-to-end VoIP.
In phase 2 we get rid of PBX system, it is the new voice system which has Call Manager Express which is now known as Cisco Unified Communication Manager Express as a standalone device OR we have a Communication Manager Express running on Router (this is what we are going to deal with in CCNA voice) and we will use new phones here that connect with switches and your everything is end-to-end VoIP.
It
is also possible to have a hybrid, we can have half of the network like phase 1
and half like phase 2. For example Intel, which is a big company and has a lot
of offices and all of their new Fabrication Plants will have phase 2 styled
end-to-ends VoIP and all of their existing fabrication plants still has PBX
systems and they want to keep them in that way until the maintenance expires on
the PBX systems then they will move them out. So it is totally possible to have
phase 2 connected through routers to phase 1 and convert back and forth between
those calls.
When
we move over VoIP we should make sure that we take away the fear, it is not
something that next year everything would be VoIP, The Internet Blah Blah Blah
……. Don’t worry about it as PBX system will be around for years, very scary
statistics that 2 million people in America still use rotary phones. People
still use them as they just works fine. So VoIP is not going to be one of those
things that will take the world by storm and everybody running it, it going to
take the back end. As we know rotary phones still exits and users send their audio
to SP via these rotary phones and the SP can be converted to VoIP.
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