[Ieprep] draft-polk-ieprep-scenarios-00.txt

["King, Kimberly S." <[e-mail]>]

Hi James,

Comments on draft-polk-ieprep-scenarios-00.txt...

"2.0 Overview of IEPREP

IEPREP is an international mechanism for signaling preferential treatments
of communications used by only a select few of our population."

IEPREP isn't limited to signaling nor IP telephony.  So, the title of the
document "IEPREP Topology Scenarios" doesn't convey your limited scope of IP
telephony.  I have concluded that IP telephony is the scope you are
considering by statements even in the pure IP scenario that indicate "call"
and example protocols of SIP and MEGACO.  In addition, you aren't just
providing scenarios but also mixing comments about when
authentication/authorization could/should occur.  




"3.1 Topology A û IP in the Middle

Otherwise known as IP Bridging two CSNs. In this topology, a CSN phone of
any type makes a call to another CSN phone with an IP core between the two
CSNs. This topology should behave as the GETS (in the US) or GTPS (in the
UK) service behaves today, any IP section in the call path should be for
transport only, though should convey the appropriate signaling for IEPREP or
ETS behaviors within the packets (defined elsewhere)."

What do you mean by "should convey the appropriate signaling for IEPREP or
ETS behaviors within the packets (defined elsewhere)"?  Are you asserting a
requirement on the topology?  Are you saying that CSN signaling should be
preserved, say by encapsulation, or are you indicating some sort of
preferential treatment in the IP network should occur?



"3.2 Topology B û IP at the Start
...If the caller is authorized to perform some form of preferential
treatment with that call, the CSN needs a mechanism to convey that
authorization back to the caller's device in such a way that the IP network
will understand."

Your statement is referring to authorization within a CSN and it implies
that the IP network needs to understand that the CSN has
authorized the call.  Presumably you need this so as to provide some
preferential treatment in the IP network?  Unless I miss my guess, access to
a port on a gateway is a place where real contention for resources could
occur.  But the above idea of "authorization occurs in the CSN" presumes
you've already been granted this resource.  To provide any preferential
treatment on a gateway without first authorizing in an IP network is a setup
for security problems.   Are you making requirements of the topology and the
CSN?

Is "Topology B : IP at the Start" assumed to be a carrier that has deployed
VoIP or could this be an enterprise?  For example, if a business has an
IP-PBX and a local gateway with say a PRI into the CSN's end office, is this
"IP at the start"?  

What is "the start"?  If a customer has a POTS phone connected to a LEC's
gateway into a LEC IP network, is this IP at the start?  



"This topology has the calling party placing the call from an CSN phone 
(somewhere), and the called party being in an IP network. 

Authentication/Authorization in topology C should occur within the CSN on 
the originating side of the call path. In time, there might be situations 
where the CSN is only a transport into the IP network of an IEPREP call, 
therefore similar attributes to topology B should occur within C; where 
the IP authentication/authorization mechanism must be conveyed to the CSN 
Gateway (and on to the calling user) in such a way as to identify that 
call on an e2e basis to behave according to the goals set forth by the 
IEPREP WG for that call."

I'm afraid I don't understand what you mean.    

Is "In time, there might be situations 
where the CSN is only a transport into the IP network of an IEPREP call," by
definition topology C or are you defining something new?  

Is the 
"'where' in 'In time, there might be situations 
where the CSN is only a transport into the IP network of an IEPREP call, 
therefore similar attributes to topology B should occur within C; where 
the IP authentication/authorization mechanism must be conveyed to the CSN 
Gateway (and on to the calling user) in such a way as to identify that 
call on an e2e basis to behave according to the goals set forth by the 
IEPREP WG for that call" 
referring to topology B or topology C?  



"4.0 Security Considerations

This document does not suggest anything other than a common naming 
convention within IEPREP WG discussions, therefore there should be no 
special security considerations"

The document suggests more than a naming convention since it talks about the
possible placement of authentication and authorization.  
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