Subject: RE: [IPTEL] I-D ACTION:draft-ietf-iptel-trip-02.txt

From: James Yu <[email-masked]>
Date: Fri, 2 Jun 2000 09:49:39 -0500

Jonathan,

By glancing through the document quickly, I did not find any text describing
the nature/type of the phone numbers or number ranges mentioned in the TRIP
document.  For calls terminated to those countries that support number
portability (NP), the server (in Internet) may have both the subscriber
phone number and the network routing number (or routing number) after
retrieving the NP information.  How to retrieve the NP information is
outside the scope of the TRIP discussion.   For calls terminated to
countries that do not support NP, the subscriber phone numbers are used as
the network routing number for call routing.   IMHO, the network routing
number instead of the subscriber phone number should be used for call
routing (e.g., TRIP table lookup) because the "network routing number"
applies to both NP and non-NP environments. 

In the North America, the network routing numbers are called Location
Routing Numbers (LRNs).  They "look" like subscriber phone numbers (e.g.,
the same length) and can overlap with the subscriber phone numbers.  In some
European countries, special digit (e.g., A and B) are used to differentiate
the network routing numbers from the subscriber phone numbers.  Those
network routing numbers may have shorter length than their national
subscriber phone numbers and their values do not overlap with the subscriber
phone numbers.   The TRIP document should be specific about the nature/type
of number, the network routing number, that is to be advertised.  This is
particularly important for the North American markets.  So if a GW can reach
a particular GSTN switch or network that is allocated a network routing
number (every switch or network is allocated a network routing number in the
NP environment).   It can use the TRIP to broadcast its reachability to that
switch or network.

The network routing numbers for NP are usually national numbers.  I assume
that the number ranges broadcasted using TRIP are "international" numbers
(e.g., with country code).

If TRIP broadcasts the network routing numbers or the prefixes of the
network routing numbers (e.g., the first six digits of the LRN is unique),
the information in the TRIP tables will remain "static."  There won't  be
many changes due to the changes to the network routing numbers used by the
GSTN switches or networks.  The likely changes would be from the GWs
themselves because they may add or delete the GWs they can reach.

If TRIP is used to broadcast reachability of subscriber phone numbers in the
NP environment, the TRIP broadcast will propagate through various domains
everytime there is a number porting event.  For countries that have
implmented NP and the network routing numbers overlap with the subscriber
phone numbers, it is very important for TRIP to specify the nature/type of
the numbers to be broadcasted.  Otherwise, some may broadcast the network
routing numbers and others may broadcast the subscriber phone numbers.

James

James Yu
Principal Technical Industry Liaison
NeuStar Inc.
1120 Vermont Avenue, NW,
Suite 550
Washington, D.C. 20005
USA
+1-202-533-2814 (B)
+1-202-533-2976 (Fax)
+1-202-256-1200 (Mobile)
[email-masked]
http://www.neustar.com

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---

From: "Hussein F. Salama" <[email-masked]>
Date: Fri, 02 Jun 2000 17:49:19 -0700

> applies to both NP and non-NP environments.

From TRIP's perspective all numbers/prefixes it advertises are routing
numbers, otherwise these numbers/prefixes should not have been injected
into TRIP in first place. This has been stated clearly in Section 11 of
the "Framework for Telephony Routing over IP" draft. It says: "Since
TRIP is a routing protocol, the routes it propagates should be to
routable numbers, not to names which are eventually translated to
routable numbers."

> the network routing numbers from the subscriber phone numbers.  Those

I think TRIP should be extended advertising these European formats. Is
this an extended form of E.164, or should it be a separate address
family?

> (e.g., with country code).

Is there a reason that prevents expanding routing numbers to full E.164
numbers before injecting them into TRIP?

Hussein

-- 
Hussein F. Salama
Cisco Systems
Mail Stop SJC6/3, 170 W. Tasman Drive, San Jose, CA 95134
Voice: +1 (408) 527-7147, Fax: +1 (408) 527-1714