Subject: "IP/IP" Media gateways?

From: Ruppelt Christian <[email-masked]>
Date: Fri, 17 Mar 2000 13:02:39 +0100

maybe I missed the discussion...

Does H.248/Megaco provide a solution for "IP/IP" Media gateways?

Motivation:

       IP Domain A                                IP Domain B
   MGC--(e.g. BICC)----MGC---------(e.g.BICC---MGC----------MGC
   /                    /                      /

(H.248)               (H.248 ???)            (H.248 ???)
   \                   \                       \
   MG--IP Network A---"IP/IP MG"---Public---"IP/IP MG"----IP NetB
                                            Internet

IP real time streams cross borders between different administrative
domains, (e.g.VoIP VPNs embedded in Telco IP backbones,enterprise
intranets)
The address of MG in Domain A is not known in the Domain B and
vice versa.
A solution for IPv4 and it's restricted address space is required.

For a Call from Domain A into Domain B on a per call basis the MGC
has to select the ports on the "IP/IP MG"

Christian

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From: John Segers <[email-masked]>
Date: Fri, 17 Mar 2000 14:09:18 +0100

Christian,

The box you labeled "IP/IP MG" is, according to your description a NAT
device.  I believe that ETSI TIPHON has started requirements work on
controlling NATs in the media path of calls.  Maybe megaco can meet the
requirements for this IP/IP GW application.

Cheers,

John

--
John Segers                                  email: [email-masked]
Lucent Technologies                                        Room HE 306
Dept. Forward Looking Work                      phone: +31 35 687 4724
P.O. Box 18, 1270 AA  Huizen                      fax: +31 35 687 5954

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From: Chip Sharp <[email-masked]>
Date: Fri, 17 Mar 2000 09:55:23 -0800

H.248 is pretty flexible, so I suppose you could define a package to do
about anything you want.  Whether it makes sense or not is another matter.

IMO, the network architecture you show below (and which I have seen before
in BICC discussions) probably has a lot bigger problems than just the H.248
part.  But that isn't BICC's problem I guess.

Yes, there has been discussions of H.248 controlling what you refer to as
IP-IP gateway devices (e.g., IVRs, transcoders, etc.) and I can envision a
simple first cut at a package to do this.  I'm actually not sure any new
work would need to be done.

As John has mentioned, this looks like a NAT function.  You don't give much
info on what the gateway would have to do so I'm guessing here.

Using H.248, the first MGC in Net A would have to give the first MG in Net
A the IP address of the IP-IP MG as the destination of the RTP stream.  The
MGC controlling the IP-IP MG would have to set up a context with 2 packet
terminations.  One termination has an IP address of an interface on Net A
and the other termination has an IP address of an interface on the Public
Internet.  The same action would have to occur between the other MGC and
IP-IP MG.  The MG would then "just" have to translate the the IP addresses
between terminations.  If the port number needs to be translated, then that
could probably be handled as well.  The MGC controlling the IP-IP MGs would
act like a mediation device between the two domains in terms of translating
the signaling.

Now how you set up your IGP and BGP to handle routing within your network
and between networks is a different matter, especially if you are planning
to support any other applications on your nets other than VoIP.

Chip

>Does H.248/Megaco provide a solution for "IP/IP" Media gateways?

        IP Domain A                  IP Domain B
    MGC--(BICC)----MGC--(BICC)---MGC------
    /              /              /
(H.248)         (H.248 ???)   (H.248 ???)
    \               \              \
    MG--Net A---"IP/IP MG"----"IP/IP MG"--NetB
                            ^
                          Public
                         Internet

>intranets).  The address of MG in Domain A is not known in the Domain B and
>vice versa.  A solution for IPv4 and it's restricted address space is
>required.
>

Support NetAid!  http://www.netaid.org
--------------------------------------------------
Chip Sharp                 Consulting Engineering
Cisco Systems              Telco Bio-region
Reality - Love it or Leave it.
--------------------------------------------------

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From: Stephen Terrill <[email-masked]>
Date: Sun, 19 Mar 2000 18:13:47 +0100

Hi,

Wouldn´t whether the MG is acting as a NAT or not would depend open whether the commucatation between the MGCs tries to iniatate a connection from the left most MG or the right most MG, or if it is such that the MGC communication requests the bearer to be established on a link-by-link bases (ie BICC).  In the latter case, then I would assume that it would H.248 which just happens to do packet-to-packet.

Regards,

..//Steve