Subject: RE: [SIP] SIP, PAM, and Presence

From: G A Venkatesh <[email-masked]>
Date: Thu, 16 Nov 2000 12:09:47 -0500

I will answer both questions related to PAM in this message.

> The PamForum displays the logo: "Establishing the Internet
> Standard" :(
> Are they an acredited (Internet) standards organization?

Please don't read too much into the logo! The original designer got a
bit carried away. The site is being redesigned for a new launch shortly.

PAMforum is an industry consortium that has been established as a
non-profit organization to promote PAM specifications in the spirit of
Parlay, VoiceXML, WAPforum, etc.

> >The dynamicsoft white paper on SIP and Presence shows
> >an interesting
> >additional use for the SIP protocol
> >
> >http://www.dynamicsoft.com/resources/pdf/Presence_White_Paper.pdf
> >
> >I wonder what relation SIP-Presence  has to PAM, the
> >Presence and
> >Availability Management API that is being put forward
> >by Lucent, Novell,
> >and others (www.pamforum.org). I realize that PAM is
> >an API while SIP is a
> >protocol, but it does not seem at first glance that
> >you might implement PAM
> >with SIP.

That is a common question. There will be a white paper shortly on the
above when the new PAMforum web site is launched. A "brief" answer is

PAM is orthogonal to the Presence capabilities in SIP (or IMPP or 3GPP
or any other protocol for that matter). PAM is designed to promote
inter-operability over multiple networks and communication mediums and
to enable presence servers to share/export presence information with
security/charging considerations. There are three different but related
aspects of presence (and availability) management where the relationship
between protocols and PAM should be explored.

1. Presence registration or detection: There is not going to be a single
model of presence storage due to administrative jurisdictions and
heterogeneity of networks.
Case 1a: Presence registered explicitly by devices. We expect this will
be done via protocols such as SIP that are natural to those devices. PAM
based presence servers will translate these registration messages to the
PAM APIs in the implementation back end.
Case 1b: Presence registered explicitly by heterogeneous networks into
an aggregating presence server or to peer networks. Not very different
from the above except that the networks may use multiple protocols
native to them (including SIP) or may use PAM APIs directly if the
interaction requires some of the authentication/charging mechanisms not
supported by a native protocol.
Case 2: Presence is exposed via a network implicitly: Networks can
choose to expose presence information via a single protocol or via an
API such as PAM based on the capabilities of the protocol and the
privacy/security requirements of the networks. The advantage of having
an API standard such as PAM here is that it is not tied to a specific
application (unless "SIP everywhere" is realized as hoped by members of
this group) protocol and the networks do not have to support multiple
protocols for different communication types.

2. Presence query: Here PAM differentiates between query for presence
(of devices) and query for availability (of people owning those
devices). If the device is synonymous with the person then there is no
difference but in services that can operate over devices in multiple
networks (messaging via WAP/SMS or IMPP) or when people have more than
one device capable of a particular communication type (messaging) and
have preferences as to how they wish to use one or the other, we need
that explicit differentiation.
Queries for presence by simple devices to a presence server are still
expected to be done via a protocol native to them (such as SIP). PAM
based servers at the back end will translate those messages to PAM APIs
and may even convert "presence queries" to "availability queries" if the
protocol is naive about such things.
Queries for presence between networks or aggregating services over
multiple networks would use a protocol such as SIP (if SIP was
everywhere and supported the type of authentication/charging
arrangements necessary between them) or an application and network
independent API such as PAM.

3. Presence and Availability Management: This part consists of tying
static user information (identity/address information and the ownership
of one or more devices) with dynamic information about those devices and
user control of how they are to be available to others over those
devices based on personal preferences and/or enterprise policies. This
is more of a backend management that cannot be fully (nor is it
necessary to be) addressed by individual protocols, mostly to keep the
protocols simple. As an example, LDAP is a simple and useful protocol
for directory access and update but the directory management (schema
management, access control lists, etc.) is beyond (and should sensibly
remain beyond) the scope of a protocol such as LDAP. The need for
standardization via PAM here is to allow "north-bound" applications to
be written by independent ISVs to enable users to manage their
communications. In some cases, certain management features (for example,
turning a preference off or replacing one preference by the other) may
be supported by these applications via protocols such as SIP if they
wish to do so. PAM is neutral about this and will be able to support
such implemenations.

Hope this gives some flavor of where PAM sits in relation to a protocol
such as SIP. PAMforum is establishing liaison activities with other
forums so as not to re-invent the wheel on either side or to lead to
divergent paths. Hopefully some co-ordination can be done with the SIP
community just as there is between Parlay and SIP communities.

Guda Venkatesh
Bell Laboratories
Lucent Technologies
[email-masked]
+1 908 582 5517

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---

From: hammer michael <[email-masked]>
Date: Mon, 16 Oct 2000 13:32:14 -0700

It sounds like you should emphasize the Management in PAM, as it
appears this is very much provisioning-like, and supports your
explanation of being orthogonal.

Mike

At 12:09 PM 11/16/2000 -0500, G A Venkatesh wrote:

I will answer both questions related to PAM in
this message.

> Are they an acredited (Internet) standards organization?

Please don't read too much into the logo! The original designer got
a

bit carried away. The site is being redesigned for a new launch
shortly.

non-profit organization to promote PAM specifications in the spirit
of

> >and others
(www.pamforum.org).
I realize that PAM is

> >with SIP.

That is a common question. There will be a white paper shortly on
the

above when the new PAMforum web site is launched. A "brief"
answer is

PAM is orthogonal to the Presence capabilities in SIP (or IMPP or
3GPP

inter-operability over multiple networks and communication mediums
and

to enable presence servers to share/export presence information
with

security/charging considerations. There are three different but
related

aspects of presence (and availability) management where the
relationship

1. Presence registration or detection: There is not going to be a
single

Case 1a: Presence registered explicitly by devices. We expect this
will

be done via protocols such as SIP that are natural to those devices.
PAM

based presence servers will translate these registration messages to
the

Case 1b: Presence registered explicitly by heterogeneous networks
into

an aggregating presence server or to peer networks. Not very
different

interaction requires some of the authentication/charging mechanisms
not

choose to expose presence information via a single protocol or via
an

privacy/security requirements of the networks. The advantage of
having

an API standard such as PAM here is that it is not tied to a
specific

application (unless "SIP everywhere" is realized as hoped by
members of

this group) protocol and the networks do not have to support
multiple

2. Presence query: Here PAM differentiates between query for
presence

devices). If the device is synonymous with the person then there is
no

difference but in services that can operate over devices in
multiple

networks (messaging via WAP/SMS or IMPP) or when people have more
than

one device capable of a particular communication type (messaging)
and

have preferences as to how they wish to use one or the other, we
need

Queries for presence by simple devices to a presence server are
still

expected to be done via a protocol native to them (such as SIP).
PAM

based servers at the back end will translate those messages to PAM
APIs

and may even convert "presence queries" to "availability
queries" if the

3. Presence and Availability Management: This part consists of
tying

static user information (identity/address information and the
ownership

of one or more devices) with dynamic information about those devices
and

devices based on personal preferences and/or enterprise policies.
This

necessary to be) addressed by individual protocols, mostly to keep
the

protocols simple. As an example, LDAP is a simple and useful
protocol

for directory access and update but the directory management
(schema

management, access control lists, etc.) is beyond (and should
sensibly

standardization via PAM here is to allow "north-bound"
applications to

communications. In some cases, certain management features (for
example,

turning a preference off or replacing one preference by the other)
may

be supported by these applications via protocols such as SIP if
they

wish to do so. PAM is neutral about this and will be able to
support

such implemenations.

Hope this gives some flavor of where PAM sits in relation to a
protocol

forums so as not to re-invent the wheel on either side or to lead
to

divergent paths. Hopefully some co-ordination can be done with the
SIP

Guda Venkatesh

Bell Laboratories

Lucent Technologies

[email-masked]

+1 908 582 5517

SIP mailing list

[email-masked]