Subject: [Ecrit] (114) Comments on ECRIT Reqs ID (part II)

From: "James M. Polk" <[email-masked]>
Date: Sat, 14 May 2005 21:09:26 -0500

All

[*** this is part 2 of a 2 part message to the list - since I received an 
error posting a message that exceeded 40k, the break between parts is at 
section 6 of the ID]

Comment #60
6.  Identifying  the Appropriate Emergency Call Center

    From the previous section, we take the requirement of a single (or
    small number of) emergency addresses which are independent of the
    caller's location.  However, since for reasons of robustness,
    jurisdiction and local knowledge, PSAPs only serve a limited
    geographic region, having the call reach the correct PSAP is crucial.
    While a PSAP may be able to transfer an errant call, any such
    transfer is likely to add tens of seconds to call setup latency and
    is prone to errors.  (In the United States, there are about 6,100
    PSAPs.)

I'd like to see the data justifying this last claim of 10s of seconds 
statement going forward with IP.

Comment #61
6.  Identifying  the Appropriate Emergency Call Center

    From the previous section, we take the requirement of a single (or
    small number of) emergency addresses which are independent of the
    caller's location.  However, since for reasons of robustness,
    jurisdiction and local knowledge, PSAPs only serve a limited
    geographic region, having the call reach the correct PSAP is crucial.
    While a PSAP may be able to transfer an errant call, any such
    transfer is likely to add tens of seconds to call setup latency and
    is prone to errors.  (In the United States, there are about 6,100
    PSAPs.)

And only about 600 regions, so this might not be so hard with IP and 
endpoint provided location

Comment #62
  Section 6, second paragraph at the end:
    A UA could conceivably
    store a complete list of all PSAPs across the world, but that would
    require frequent synchronization with a master database as PSAPs
    merge or jurisdictional boundaries change.

"change"? This likely isn't so often, BTW

Comment #63
Section 6, forth paragraph:
    Note that the first proxy, the ESRP, doing the translation may not be
    in the same geographic area as the UA placing the emergency call.

"...the first proxy, the ESRP..." Does this assume that any proxy that can 
route based on the location of the caller is an ESRP?

Comment #64
    I4.  Choice of IPSAPs: The emergency caller SHOULD be provided a
       choice of emergency call centers if more than one exists and is
       relevant.

This gets into defining what an ECC is (which hasn't been done yet), and 
that if another number is dialed, it doesn't constitute an emergency call IMO.

Comment #65
    I5.  Assuring IPSAP identity: The emergency caller SHOULD be able to
       determine conclusively that he has reached an accredited emergency
       call center.

How can this possibly be done? If my display says "Dallas Police Dept." , 
do I trust it, or do I take the time to verbally question the identity of 
the calltaker? Do we suggestion questions to be asked to verify the 
identity of the calltaker?

Comment #66
  I5      Motivation:  This requirement is meant to address the threat that
       a rogue, possibly criminal, entity pretends to accept emergency
       calls.

How can't this be easily faked?

Comment #67
    I6.  Warnings for unidentifiable IPSAP. Implementations SHOULD allow
       callers to proceed, with appropriate warnings or user
       confirmations, if the identity of the destination IPSAP cannot be
       verified.

How is this verified without there being a root key installed in all UAs?

Comment #68
    I7.  Traceable resolution: Particularly for mediated resolution, the
       caller SHOULD be able to definitively and securely determine who
       provided the emergency address resolution information.

Is this suggesting that all Proxies must remain post transaction/dialog 
stateful to the user for them to later investigate something? For how long 
after?

Comment #69
    I10.  Incrementally deployable: An Internet-based emergency call
       system MUST be able to be deployed incrementally.  In the initial
       stages of deployment, an emergency call may not reach the optimal
       PSAP.  If allowed, emergency calls must only be routed to PSAPs
       that have agreed to accept non-optimally routed calls.

       [Ed.  Can this be merged with R6?]

yes

Comment #70
    I11.  ECC Availability:  ECC communication MUST be continuously
       available.

       Motivation:  From any Internet-connected device it MUST be
       possible at any time to contact the ECC responsible for the
       current location with the most appropriate method for
       communication for the user and the device.

is this the famous five 9s?

Comment #71
    I13.  Cross-Jurisdiction Device Support:  Devices SHOULD support
       alternate emergency service systems between countries.

       Motivation:  Even as each country is likely to operate their
       emergency calling infrastructure differently, SIP devices should
       be able to reach emergency help and, if possible, be located in
       any country.

       [Ed. above text needs clarification]

yeah, this doesn't make much sense now

Comment #72
    I15: It MUST be possible to route a call based on either a civic or a
       geo location without requiring conversion from one to the other.
       This requirement does not prohibit an implementation from
       converting and using the resulting conversion for routing.

how is this different from I14?

Comment #73
    I16: It MUST be possible for a designated 9-1-1 authority to a PSAP
       to approve of any geocoding database(s) used to assist in
       determining call routing to that PSAP.  Mechanisms must be
       provided for the PSAP designated 9-1-1 authorities to test and
       certify a geocoding database as suitable for routing calls to the
       PSAP.  The PSAP may choose to NOT avail itself of such a
       mechanism.

This is implementation - and shouldn't be in here

Comment #74
    I17: It MUST be possible for the designated 9-1-1 authority to
       supply, maintain, or approve of databases used for civic routing.
       Mechanisms must be provided for a designated authority for a PSAP
       to test and certify a civic routing database as suitable for
       routing calls to that PSAP.

This is implementation - and doesn't belong here

Comment #75
    I18: It MUST be possible for the PSAP itself (or a contractor it
       nominates on its behalf) to provide geocode and reverse geocode
       data and/or conversion services to be used for routing
       determination.  This implies definition of a standard interchange
       format for geocode data, and protocols to access it.

This has nothing to do with Routing the call, and shouldn't be in here.

Comment #76
    I20: Boundaries for civic routing MUST be able to be specific to a
       street address range, a side of a street (even/odd street
       addresses), a building within a "campus", or any of the location
       fields available.

       [Ed.  Available from where?  Please clarify.

In the PIDF-LO I think

Comment #77
    I21: It MUST be possible to use various combined components of the
       location object for determination of routing.  Some areas may only
       require routing to a country level, others to a state/province,
       others to a county, or to a municipality, and so on.  No
       assumption should be made on the granularity of routing boundaries
       or about the combination of components used.

The last sentence alone should be the requirement:

   "No assumption should be made on the granularity of routing boundaries
    or about the combination of components used."

and the text above this sentence removed or used as explanation only.

Comment #78
    I22: Boundaries mechanisms for geo routing MUST be able to be
       specific to a natural political boundary, a natural physical
       boundary (such as a river), or the boundaries listed in the
       previous requirement.

This is repetitive

Comment #79
    I23: Any given geographic location SHOULD result in identification of
       a unique governmentally-authorized PSAP entity for that location?

This is repetitive

Comment #80
    I24: Routing databases using 9-1-1 Valid Addresses or lat/lon/
       altitude as keys MUST both be available to all entities needing to
       route 9-1-1 calls.

Too US centric

Comment #81
    I25: Carriers, enterprises and other entities that route emergency
       calls MUST be able to route calls from any location to its
       appropriate PSAP.

"... to its appropriate PSAP

should be replaced with

"...towards its appropriate ECC."

as the first proxy might no have enough knowledge to do it all

Comment #82
    I26: It MUST be possible for a given PSAP to decide where its calls
       should be routed.

repetitive

Comment #83
    I27: It is desirable for higher level civic authorities such as a
       county or state/province to be able to make common routing
       decisions for all PSAPs within their jurisdiction.

implementation - should be in NENA, not IETF

       For example, a
       state may wish to have all emergency calls placed within that
       state directed to a specific URI.  This does NOT imply a single
       answering point; further routing may occur beyond the common URI.

Comment #84
    I28: Routing MAY change on short notice due to local conditions,
       traffic, failures, schedule, etc.

this is true with anything IP based, what's the requirement?

Comment #85
    I32: Multiple types of failures MAY have different contingency
       routes.

Is this a requirement?

Comment #86
    I33: It MUST be possible to provide more than one contingency route
       for the same type of failure.

Duplicate of I31

Comment #87
    I34: A procedure MUST be specified to handle "default route"
       capability when no location is available or the location
       information is corrupted.

I34 and I35 state the same thing currently

Comment #87
    I35: Default routes MUST be available when location information is
       not available.

I34 and I35 state the same thing currently

Comment #88
    I36: Entities routing emergency calls SHALL retain information used
       to choose a route for subsequent error resolution.

"... retain information" for how long?

Comment #89
    I37: Access Infrastructure providers MUST provide a location object
       that is as accurate as possible when location measurement or
       lookup mechanisms fail.

"... MUST provide a location object". This is stated incorrectly, the AIP 
doesn't give the UA its PIDF-LO, it gives it an LCI in most cases. The UA 
builds/generates the PIDF-LO.

Comment #90
    I38: Location available at the time that the call is routed MAY not
       be accurate.

Is this a requirement? It's not written as one

Comment #91
    I39: It SHOULD be possible to have updates of location (which may
       occur when measuring devices provider early, but imprecise "first
       fix" location) which can change routing of calls.

"... updates of location"... This is a duplicate (L13)

Comment #92
7.  Emergency Address Directory

General comment on this whole section - isn't this sufficiently in the 
background that this is "architecture" and not "identification" or 
"routing" in that it doesn't belong in the IETF (but more like NENA)?

Comment #93
    D1.  ECC Identification:  Public access to ECC selection information
       MUST be assumed.

Need to mention this is "read only" access

Comment #94
    D2.  Assuring directory identity: The query agent (e.g UA or server)
       MUST be able to assure that it is querying the intended directory.

Without a shared key exchange (ensuring the correct destination is 
contacted), how can this be accomplished?

Comment #95
    D3.  Query response integrity: The query agent MUST be able to be
       confident that the query or response has not been tampered with.

Suggested rewrite to: "The query agent MUST take appropriate steps to 
ensure the query or response maintained integrity."

Comment #96
    D4.  Assurance of Update integrity: Any update mechanism for the
       directory MUST ensure that only authorized users can change
       directory information and must keep an audit log of all change
       transactions.

This smells like an architectural implementation requirement, therefore it 
doesn't belong here

Comment #97
    D6.  Multiple directories: A UA or proxy SHOULD be able to use
       multiple (separate) directories to resolve the emergency
       identifier.

If this can ever be manually entered in a UA or a network server to then be 
distributed to that network's UAs, then this requirement needs to be opened 
up to "UA or Proxy or other server SHOULD..."

Comment #98
    D7.  Referral: All directories SHOULD refer out-of-area queries to an
       appropriate default or region-specific directory.

  Not sure how this applies to ECRIT

Comment #99
    D8.  Multiple query protocols: Directories MAY support multiple query
       protocols.

What does this have to do with routing or identification?

Comment #100
    D9.  Baseline query protocol: A mandatory-to-implement protocol MUST
       be specified.

Suggested rewording: " A single mandatory-to-implement protocol MUST be 
specified. Other optional protocols may be listed to give guidance if 
another protocol is preferred."

Comment #101
    C1.  Identity: The system SHOULD allow (but not force) the
       identification of both the caller's identity and his or her
       terminal network address.

Doesn't this violate a previous requirement stating the caller's identity 
cannot be assumed (L21). Plus the definition of "basic emergency service" 
states this.

Comment #102
    C2.  Privacy override: The end system MUST be able to automatically
       detect that a call is an emergency call and override any privacy
       settings that conflict with emergency calling.

This doesn't go deep enough into how a jurisdiction may limit how private a 
caller can remain when calling an ECC. Or the opposite can be true.

Comment #103
    C3.  Recontacting Endpoint:  The ECC SHOULD have the capability to
       recontact the initiating endpoint after disconnection.

Retitle "Reestablish Communication with Endpoint"

Comment #104
   C3      Motivation:  Capability to re-contact the contacting device from
       the ECC in case of disruption or later query for a tbd period of
       time.  This should also be possible from conventional ECC via
       temporary (virtual) E.164 numbers.

All IP means you cannot assume E.164.

Comment #105
    S1.  Authentication override: All outbound proxies and other call
       filtering elements MUST be able to be configured so that they
       allow unauthenticated emergency calls.

Reword "... MUST be able to be configured..." to "...MUST be configurable..."

Comment #106
    S2.  Mid-call features: The end system MUST be able to recognize an
       emergency call and allow configuration so that certain call
       features are not triggered accidentally.

Reword " The end system MUST be able to recognize an emergency call and 
allow configuration so that certain call features are not triggered 
accidentally." To " The end system MUST recognize it initiated an emergency 
call and prevent certain call features that interfere with that call (e.g. 
call waiting, call hold)."

Comment #107
In Just after S2 - there needs to be a requirement added stating something 
to the affect that "...once a UA initiates an emergency call, system 
resources SHOULD be prevented from certain call features that interfere 
with that call (e.g. Barge, call preemption). The latter example is for 
military or government networks.

Comment #108
    S3.  Testable: A user SHOULD be able to test whether a particular
       address reaches the appropriate PSAP, without actually causing
       emergency help to be dispatched or consuming PSAP call taker
       resources.

How can't this be faked?

Comment #109
    S6 Tracking and Tracing Facilities for all calls MUST be provided.
       This includes all routing entities as well as all signaling
       entities.

"Facilities" reads like circuits and lines. What is meant here?

Comment #110
    S7 Each element in the signaling and routing paths solution SHALL
       maintain call detail records that can be accessed by management
       systems to develop call statistics in real time.

Does it really need to be in real-time? Are we talking RTCP statistics? Is 
this something CALEA would want? How far towards the UAC can a ECC Net Mgmt 
station gain access to SIP element CDR information? How doesn't this look 
like a means of attack into an enterprise?

Comment #111
    S8 Each element of the signaling and routing paths SHALL provide
       congestion controls.

We're talking RSVP and/or MPLS now? Diffserv doesn't do this, and the ECN 
proposal from Nortel is getting some pushback from Sally Floyd and Fred Baker.

Comment #112
    S9 It SHALL be possible to determine the complete call chain of a
       call, including the identity of each signaling element in the
       path, and the reason it received the call (Call History).

We're talking RSVP and/or MPLS now? Diffserv doesn't do this, and the ECN 
proposal from Nortel is getting some pushback from Sally Floyd and Fred Baker.

Comment #113
10.  Supplemental Information

Owner of the structure or tenant? Where is this in our Charter?

SOMETHING TO ADD TO THIS DOCUMENT

It is the case in Sweden that when a person calls for emergency help, they 
MUST provide two different locations in the call set-up.

#1 - they MUST provide the location they are calling from (in civic or 
coordinate format);

#2 - they MUST provide their billing location (where they personally 
receive their bills from.

The next version of draft-ietf-sipping-location-requirements-02 (in the SIP 
WG) will account for this. But I on't know if should only be mentioned there.

cheers,
James

                                 *******************
                 Truth is not to be argued... it is to be presented.

                      Alas, few *truths* exist without the math.

                             ...all else is a matter of perspective

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