TELECOM Digest OnLine - Sorted: Re: VoIP

Re: VoIP

Robert Bonomi (
Fri, 29 Apr 2005 12:34:52 -0000

In article <>, Robert Bonomi
<> wrote:

> In article <>, Choreboy
> <> wrote:

>> For several months I've been getting calls with spoofed Caller IDs. I
>> understand spoofing requires either VoIP or a PBX system with DSL.

>> Can anybody with cable internet access and suitable software make VoIP
>> calls?

>> The other day I received a wrong-number call from an exchange belonging
>> to Level 3 Communications. Among other services, they offer residential
>> VoIP services through wholesalers such as ISPs and cable operators. I'm
>> confused. Does a consumer need these services to use VoIP?

>> [TELECOM Digest Editor's Note: I don't think either 'VOIP' or 'PBX
>> system' have anything to do with it. If I understand correctly what
>> I have read here in the Digest, it requires a 'PRI' type thing;
>> that is, a multi-channel set of lines going to DID, or Direct
>> Inward Dialing,

>> Would you believe "DOD" -- direct *OUTWARD*
>> dial?

>> "DID" trunks handle incoming calls only. "DOD" trunks
>> handle outgoing calls only.

>> "DID/DOD" trunks handle both.
>> Caller-id data _origination_ occurs only for outgoing calls.
>> which would, I guess, be similar to a PBX arrangement.

>> Some sort of a 'switch', usually a PBX-equivalent, is required to
>> handle DID / DOD trunks.

>> Then there are the "big boys" -- who have SS7-compatible switches,
>> which are a C.O.-equivalent, rather than PBX-equivalent, device.
>> Companies who have those lines _can_ set the caller ID to be
>> whatever is appropriate in their instance.

>> Sometimes the telco 'filters' what CID data the
>> company can send, sometimes not. When "not", an unscrupulous
>> company can set the ID info to _anything_.

>> Unfortunately, the "lowest-priced" PRI providers are the ones least
>> likely to do filtering, *and* are the ones that said unscrupulous
>> companies are most likely to use.

TELECOM Digest Editor continued:

>> I suspect the fact that the ID shown was
>> that company may have been just coincidental. You do need either
>> cable internet or DSL to use VOIP; regular 'dialup' lines are just
>> not wide enough or fast enough to do VOIP. But other than having
>> DSL or cable, VOIP takes nothing especially fancy; just an adapter
>> box from the place where you get the VOIP service and any regular
>> telephone instrument will do the job. And if you planned on
>> totally getting rid of your landline phone taking VOIP instead,
>> that is generally not possible with DSL, since most telcos will not
>> give stand-alone DSL.

Mr. Bonomi continued:

>> Unless you buy SDSL service, which is
>> _always_ delivered on it's own pair.

>> Unless you get your DSL
>> from MCI, Covad, or New Edge Networks -- or a >'reseller' of any of
>> those carriers -- all of whom offer dedicated-pair ADSL.
>> Unless Qwest is your ILEC.

>> [TELECOM Digest Editor's Note: But I _defy you_ to pick up your
>> phone right now and talk to the first service rep who answers and
>> order SDSL service. They will not know what you are talking about;
>> probably no one in the vicinity will know.

I guess I just deal with a better class of service rep than you do.
I've _never_ had any problem ordering SDSL. And I've only done it more
than a dozen times. Providers in CA, WA, FL, NY, and IL. Never dealt
with New Edge; _have_ dealt with MCI, Covad, and several other
no-longer-existent physical-services providers, e.g. 'northlight'.

TELECOM Digest Editor continued:

> And if you _do_ order it satisfactorily
> from MCI, Covad, New Edge or others, then God bless you; it will be
> extraordinarily expensive and if your intent was to save money by
> going with VOIP instead of landline, you've completely killed that
> plan.

*ANY* dedicated internet connection with VoIP will be more expensive
than a simple POTS land-line, This is a given.

SDSL is generally more expensive -- yes, even "much more expensive" --
because of the 'class of service' provided with that physical
transport. It doesn't _have_ to be, SDSL head-end equipment is no
more expensive than ADSL gear is.

The higher price tag generally buys you:

Pro-active monitoring of circuit and head-end equipment, with vendor-
initiated maintenance _before_ problems reach 'noticeable' levels

LESS oversubscription of the upstream link(s). This means that you
have a _much_better_ chance of getting all the bandwidth you
need/want, *WHEN* you need/want it.

*immediate* contact with _knowledgeable_ tech-support staff. none
of this 'wait 30 minutes on hold, while being told how 'important
your call is to us', crap. No 'first-line' droids who don't know
how to deal with anything that isn't in one of the 'scripts' they
had to memorize. But actual _thinking_ people. The types who
_don't_ suggest that you need to restart Windows when the problem
is that traceroute is dieing two hops _upstream_ of the DSLAM.

If ones own time has any significant value, the 'opportunity
cost' of the time spent "waiting on hold", with the typical
consumer ISP, reaches significant figures in very short order.
Cable companies seem to be especially bad in _this_ respect.
Dealing with *one* recent problem, where their cable internet
service was totally out for almost a week, my folks spent nearly
_twelve_hours_ "on hold", trying to get the problem fixed. As
semi-retired professional business consultants, their time bills
at only $80/hr. That's a 'cost' of nearly $1,000, above and
beyond the amounts invoiced. If paying an _additional_ $75/month
for service would have avoided the problem, they would have come
out 'ahead' for the year. Unfortunately, they _don't_ have ANY
choice for high-speed access. They're too far from the telco
C.O. for DSL. And there is only the one cable company "in town".
Well,"in town", sort-of. The customer support phones are
answered in another state.

"Business class" service costs more than bottom-of-the-bucket.

If you grossly oversubscribe the uplink from the DSLAM -- and I've
seen a full shelf of 24 ports (at 768k down) serviced by a _single_
T-1 -- your costs are relatively low.

OTOH, 'business class' service often feeds four shelves of 768kbit
ports with at 45mbit T-3.

TELECOM Digest Editor continued:

> In essence -- in real life practice and experience -- you cannot
> get stand alone DSL (and pay your VOIP bill each month on top of that)
> in any reasonable cost-effective way. After arguing with the service
> reps for some period of time on the matter, you will decide cable is a
> better and less expensive way to go. PAT]

*THAT* depends on what your needs are.

If you need _reliable_ amounts of bandwidth, especially uplink
bandwidth, cable generally cannot deliver it. The sheer number of
customers sharing the same limited capacity on the cable prevents it.
Cable typically has several hundred -- up to a few _thousand_ --
customers sharing the circa 60mbit of cable capacity. And usually
only a single T-3 feeding the head- end for that run. It doesn't take
many 'bandwidth hogs' to saturate the upstream capacity.

*Very*few* cable companies can provide you with more than a *single*
IP address.

Many cable companies _forbid_ running 'servers' of any sort in their
contract. (Typical allocation of cable bandwidth is 10=15% for 'up'
from the customer, and 85-90% for 'down' to the customer -- with
servers usually generating much more outbound traffic than inbound,
they chew up a disproportionate chunk of the 'up' bandwidth, adversely
impacting all the other cable customers on the same run.)

Virtually no cable company will give you more than a _single_ IP

A fair number of cable companies do not offer the option of a true
'static' address. DHCP pools *only*.

If you can get a static address, forget about getting 'reverse DNS'
that reflects _your_ information.

With, generally, a choice of *one* cable company in any locale, you
have only a 'take it or leave it' choice.

Some DSL providers, particularly the lowest-price ones, do make
similar engineering decisions, and impose similar restrictions on use
of their service. Doing so is one way of being able to hold costs
down, so that you _can_ offer service at a 'cheaper' price-point.

Virtually all DSL providers, however, offer a _much_wider_ range of
services, at a correspondingly wider range of price-points, than cable
companies do. They can do this because, unlike cable companies, there
is _only_one_ customer on any given run of wire exiting the head-end.
And, therefore, they *can* connect different customers -- on a
customer-by-customer basis -- to different head-end equipment,
providing different levels of service. They can put the _sustained_
high-bandwidth users -- with minimal 'over-subscription' -- all
together on gear that is engineered to handle the sustained loads, and
priced accordingly, while still advertising high-speed service, albeit
'grossly oversubscribed' to the casual user at a bargain price.

Cable service _is_ "absolutely great" for the 'early adopters'. As
long as the number of customers sharing the same 'run' from the
head-end is small, it works superbly.

On the other hand, there are routine complaints from cable subscribers
in Chicago proper, that the "high-speed" service is nearly unusable
from around 3:30 in the afternoon till on towards 10:00PM. That they
get throughput of a whopping 60-100k bits/second download speed on
their "advertised as multi-megabit" connection. It seems directly
attributable to all the school-kids coming home and getting online to
play games.

"Too many users, not enough bandwidth"

No way to 'fix' it, either, short of physically *re-wiring* the
territory (the 'outside physical plant'), so that there are fewer
customers per run from the head-end.

The architecture of DSL 'scales' better, because there is *no*
'sharing' of the data connection between the customer and the head
end. Thus, one customer cannot adversely affect the 'last mile'
bandwidth available to another customer.

Cable Internet isn't necessarily "bad", but there are more places, and
more ways, where the quality of service can, _as_delivered_to_the_
customer_, get clobbered.

*ANY* assertation that any particular technology choice is alway "better" is
patent nonsense.

One has to consider:
1) what the customer _requirements_ are
2) what the available alternatives are *in*their*area*
3) what the advantages/disadvantages of _those_ offerings are.

In _my_ situation, 'cable' was simply *not* a viable alternative.

Firstly, because until quite recently, the cable company in my area
*DID*NOT* *OFFER* internet service. This _is_ an 'insurmountable
barrier' to choosing cable internet service. <grin>

Now that they do, their only offering is STILL not compatible with my
needs I need multiple public-network IP addresses (NAT is not a viable
option for technical reasons -- d*mn those protocols that put IP
addresses _inside_ the data part of the packet!) and the cable company
will only provide _one_ such address.

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