Subject: RE: VOIP question ??

From: Ami Amir <[email-masked]>
Date: Thu, 28 Jan 1999 12:41:42 +0200

Hi All

Once you walk through and analyze the situation, you will find out that a
Gatekeeper is really needed. 

An example of one issue -dialing schemes: If you are willing to support
multiple stage dialing or assign a rigid dialing scheme (e.g. prefix 6 for
PBX A, prefix 7 for PBX B etc) then you can make do w/o gatekeepers - and
sacrifice functionality, mobility and flexibility. 

Another issue is economical: If you have more than 3 PBX's - you have two
options; either create a mesh, and let each PBX support as many trunks as
there are PBX's (= lots of hardware) - or support a flexible scheme, where a
single PBX to GW trunk can support connections to multiple GWs. This, less
expensive, functionality requires a GK.
 
Ami

	-----Original Message-----
	From:	[email-masked] [SMTP:[email-masked]]
	Sent:	Thursday, January 28, 1999 4:35 AM
	To:	[email-masked]
	Cc:	Sebastien Ducarne; IP Telephony
	Subject:	Re: VOIP question ??

	Sebastian:

	gatway serves a function as "translator" between traditional
PSTN/PBX network and IP
	network, you have no problem to connect a gateway to PBX.

	Also According H.3232, gatekeeper is optional. You don't have to
have gatekeeper to
	operate a gateway.

	Best

	_ming

	Bjarne Munch wrote:

	> Hi Sebastian,
	>
	> I'm new to this list, and thought that I migth introduce my
existence by picking
	> up this one. In short;  Yes that is possible !
	>
	> But a few questions migth be in order; why do you state that you
dont want a
	> Gatekeeper ?
	>
	> It may be of interest to have the Gatekeeper for any future
enhancement of the
	> service offering, eg. more PBX's in the network or IP
'supplementary service'
	> offerings.
	> In the initial phase the Gatekeeper could be used to just set up
the routing and
	> nothing
	> more, ie. it would be transparent to the user. Even in a 'simple',
case such as
	> yours, you
	> would for most vendor products need to set up some routing
information even
	> without
	> a Gatekeeper in the network.
	>
	> Another question to ask is what services you would utilise on your
PBX to
	> PBX link ?
	>
	> Is it just pure transmission PBX to PBX, or would you require
support of
	> existing PBX services such as call back or call transfer from one
PBX to
	> the other ? In the latter case you would probably need some level
of QSIG
	> capability in the VoIP network, ie. Gatekeeper signalling seems to
be
	> needed.
	>
	> Bandwidth management can be done, to a certain extend, via the
Gatekeeper
	> but real QoS handling would need to be handled on a network level.
The
	> issue is very much related to the size of the pipe between the two
gateways
	> and the amount of traffic. If the pipe has a reasonable spare
capacity you
	> should be able to provide an acceptable level of quality on your
VoIP.
	>
	> Regards
	> Bjarne Munch
	> Product Management, IP Services
	> Ericsson Australia
	>
	> Sebastien Ducarne wrote:
	>
	> > Hello,
	> >
	> > I am from Global One Operator and work in the engineering team
as responsible
	> > of new access modes to Voice Services. I am familiar with the
Voice over ATM
	> > solutions but less for Voice over IP.
	> >
	> > I have a specific question and I hope that someone could find
time to help me
	> > on it
	> > To be clear, I would like to know if it is possible to connect
Customers PBX
	> > to
	> > a VOIP-Gateway and to transport all the traffic to another
VOIP-Gateway
	> > connected
	> > to our large voice switch, and this without Gatekeeper.
	> >
	> > Is it possible? What is the impact on service ? On bandwidth
management ?
	> >
	> > Thanks in advance for any help on this issue.
	> >
	> > Sebastien DUCARNE
	> > Global One - Voice Engineering PARIS
	> > +33 1 40 79 80 66
	> > [email-masked]
	> >
	> > ---------
	> > This message came from the IETF IPTEL Working Group Mailing
List.
	>
	> ---------
	> This message came from the IETF IPTEL Working Group Mailing List.

	---------
	This message came from the IETF IPTEL Working Group Mailing List.

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This message came from the IETF IPTEL Working Group Mailing List.

---

From: "ronald h. davis" <[email-masked]>
Date: Thu, 28 Jan 1999 11:22:53 -0600

> Gatekeeper is really needed.

h.323 was defined for non-qos lans, so as far as i am able to tell, the
gatekeeper function arose from the need to manage bandwidth on a lan.
this was accomplished through the use of a ras channel and registration
and admission procedures as defined in h.323.

when connecting gateways/endpoints on a wide area network, this role of
the gatekeeper becomes a bit harder to define...

from what i can tell, you're suggesting the role of the gatekeeper is
a sort of application-level router.  this is certainly a valid role
but it can be achieved by h.225 call signalling, and h.245 control
channels only - there is no need for a ras channel.

at the network level there is a need for these application-level
routers to be able to exchange information, both within an
administrative domain, and between administrative domains.  this
creates a role for ospf and bgp equivalent protocols that allow
for the exchange of information.  the inter-domain problem is currently
being addressed by both itu study group 16, h.225 annex g, and by
the ietf iptel wg, gateway location protocol).  there is also a proposal
before iptel (which has been tabled for now while they work on glp) to
address the intra-domain problem, peer gatekeeper routing protocol
(which is horribly misnamed because it really isn't limited to h.323
gatekeepers anyway).  there's also an i.now! proposal which is based
upon a clearinghouse model.  but the objectives of these protocols is 
different from the objectives of the h.323 gatekeeper ras channel.  

so while i see there is a role for an application-level router, which
you may call a gatekeeper is you wish, to me, the term gatekeeper
comes with loading of ras channel functionality that must be supported
(at least according to h.323).  this functionality seems largely
unnecessary in the scenarios that you described.

-- 
  __  ______  __  / __/ |       lucent technologies, naperville il, usa
_/ (_(_) / (_(_/_/_(_/  .       [email-masked]
"if you ain't the lead dog, the scenery never changes"  -- edmund wilson

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