"[slides]" means there was stuff I didn't write down and one should
refer to
the presentation slides for info.
-------------------------------------------------------------
IRTF/IETF AAAarch meeting 49th IETF 10-Dec-2000 San
Diego
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interim meeting in Jan/Feb
hope to have a roud of drafts submitted for rfcs by spring IETF 2001
Interlink <www.interlinknetworks.com>
sponsored this room and the t-shirts.
Overview
goal to figure out how to do AAA between apps, user orgs, with
postulated "brokers" in the mix
the lines between entities in the diagram rep SLAs and perhaps security associations
the fact that these are SLAs are impt
overview examples
combining resources
qos + network access
sip conns + netwk bandwidth
muktiple authz
distrib academic course admin
b2b e-commerce stuff
tasks in AAAarch
generic aaa server
working on..
[see slides]
user authn
(various aspects)
lots of related ietf stuff
[see slides]
updated doc from -00 to -01
[see slides]
Policy Language: what do we need?
gave examples of distinctions between "accounting policies" and
"metering policies"
SLA seen as the "information base"
drives the provisioning and config of the accounting environment.
Policy Parameters
[see slides]
Future work & open issues
derivation of policies from sla
binding of user ids to sessions and accounting data is a key aspect,
that's
where the session id doc comes in.
AAA servers need to exchange and parse policies
there's network environment issues wherein it isn't possible to
have a policy
eval'd at a "remote" server.
e.g. proxy environ.
home agent not reachable
[slides]
goal of the policy draft
[slides]
Policies are..
logical exprs
actions attached to results of subexpr
can do computations on varbs
actions can send ? to ASMs (?) [slides]
what possible ways to express policies?
DNF disjunctive normal form
?
XML
Java
XML
adv
off the shelf parsers around
lightweight
supports strict def of policy language
disadv
xml is just a "preparser"
extending the language means extending and spreading new DTDs
(but this is
just schema)
Java
adv
very versitile
byte-compiled: optimizes execution time
easily extendable
disadv
hard to check for validity
security issues
analogy with smartcards
(claim that smartcards provide many of the things we need for
AAA)
[slides]
Termination of distributed policies
TTL, timeout?, loop detection, all the usual stuff in here
Problems left
policy conflicts
must AAA servers resolve them or must policy implementors?
IBM Courteous Logic Programming?
how to represent actions? AVPs?
Policy Language - is v. open question
termination of eval of distrib policies.
Strasner question: are you postulating all AAA servers are omipotent
and
equally-capable. original policy doc acknowledged conflicts but didn't
really
explore it.
main point is to try to align policy terminology
where is draft going?
should be merged into policy working groups
parts into other docs, specfic to authn
distrib policy
intra-domain policy
entirely within one domain
inter-domain policy
origs in a diff domain
extra-domain policy
[slides]
Ed ques: in ipsec there's a policy exch when setting up a tunnel --
there's
multiple levels of policy exchange going on or need to go on, some
might need
to get negotiated, so this concept ought to be included into the terminology.
strasner: in ipsec one goes thru neg to construct a policy, and in other
authz
settings, pol is already constructed and simply needs to be eval'd.
Application vs. generic policy
generic
eval'd by generic aaa server
app-specific
eval'd w/ help from ASM
app proprietary
opaque to generic aaa?
specific policy types
e.g. registration, authn, authz, etc.
RLBob: what about term to describe hierarchically-related domains?
would be nice to have a common terminology basis between aaaarch & policy-wg
historical
had policy terminology bofs at a couple of past ietf meetings.
pol terminology is being worked on in the policy-wg by AD fiat.
PolTerm goals
goal is no creativity -- not attempting a taxonomy. want to doc
the way
words are presently being used today, in order to keep them from
being
redefined.
want to bridge gaps & diffs
usage of draft
reference
as a resource to constrain term migration & creep.
approch
51 terms defined presently, 31 acronyms
scaned & incorp'd many diff docs
using rfc 2828 techniques
current issues
filter issues
filter in terms of packet filtering
SLA
see RFC2475
there's an SLA bof (this meeting?)
recommendations
want input from IRTF aaaarch folks
want to go to last call as soon has have this input
[again, not wanting to do a taxonomy]
JV: so since aaaarch is doing a taxonomy + defining terms, how do we
resolve
this?
JS: one can do a taxonomy w/o doing an explicity definition doc.
Ed?: we can get in input that we can this week, but there'll be more
stuff to
do after the meeting.
[slides]
related work
radus
diameter
www based services
rtsp
sip
sdp/sap
[slides]
JV: it doesn't say anything about the rel between authn ids and session ids.
SZ: need some input on that sort of stuff.
Interdomain SIP usage with AAA and QoS (with SIP mobility)
there's related drafts in other WGs with "sip" in their filenames
VoD -- voice over data?
MA "Media agent"
CH "Clearinghouse"
APS "Application and policy server"
[slides]
slide for "Call setup for interdomain SIP call with AAA and QoS"
very complex
in telephony community there's two concepts: if you don't have qos,
the call
doesn't go thru. another is if you don't get qos, give the end user
a choice
whether to put the call thru (at reduced cost) or not.
ques: what's relation in this work to work in the session id doc. are
there
specific reqs about what entities need to keep knowledge of some of
the state
from the "call" afterwards?
ans: there's a notion in sip of "call id", and that needs to be
kept around.
JV: (some question about
ques: any policy exchange provided for?
ans: nope.
Multi-kingdom AAA with Krb v5
Association is a rel btwn two endpoints
contexts consists of specific context attrs that are used to establish,
maintain, and release associations.
krb sec contexts
sec contexts cover only the krb application exchange and not
the comm with
the kdc
end to end mode
data is opaque to interstitial kingdoms
hop by hop mode
data decrypt & re-encrypt at each hop
need a combo of these modes
use hop-by-hop to send info along path that each interstitial
kingdom needs
to see, use end2end for stuff that needs to be seen just by each end.
dependency on data modeling
need to know the distinctions btwn diff data so it is used in
the proper
sec association type
JV: what's key here is sep of authn and authz in "some very interesting ways"
(taxonomy of the various message types that entities in the AAA model
will
need to exchange)
(taxonomy of various "top level" objects that gett passed around)
[slides]
ques: list of top level objects is nicely abstracted, except "authn
challenge"
-- lots of authn mechs don't know how to challenge.
ans: it's just a place holder for if some info needs to flow in the
opposite
direction.
rlbob: there could be an unlimited # of exchanges in doing the authn
exchange(s), so maybe calling it "challenge" is too specific.
rlbob: is there a higher-level agregation of these objects? have you
persued
it or decided not to do it that way? (object modeling?)
daves: (his answer went down into more detail instead of going "up"
into more
agregated objects -- missunderstood question?)
looking at making a video about AAA reqs.
[slides]
leon.gommans@enterasys.com
betty.de.bruijn@planet.nl
www.ispworld.com -- article on AAA and thsi group (boardwatch zine)
AAAarch is 1 yr old now.
slide on the different perspectives on AAA from a requester (user) asks
for
some service.
perspectives:
service
user
intermediaries
organizational
[slides]
Roles
[slides]
Authorization Models
agent, pull, push
do we need these three models? too much, not enough? discuss
on list.
Starting point
the prior work on having a PDP and PEP
generic AAA engine that uses applciation specific engine as necessary
(in
PDP), and then..
communicates with PEP.
Multi-domain case
Basic principles
RBE - rule based engine
asm - application spec. module
service equip
2. there is a global addres space btwn the rbe and the asm
3. there is only generic stuff in the rbe and all the application specific
stuff is in the ASMs
4. the rel btwn AAA servers is symmetric
5.
[slides]
issues
rels in pcitural model
type 1-7 comm.
internal struc in model
global address space
revine layered model
scalable aaa server model
ques: we're straying outside of aaaarch's orig domain? e.g. resource
discovery, complexity due to genericism?
we need to think about the interim meeting in (probably) Jan. discuss on list
proposal to NANOG for a AAA operations group? source of reqs & practices?
lots of ietf interactions for this group --
authn security context area
accounting/auditing/session id stuff
SLS -- service level specification -- how's that play in the
aaaarch space?
?: CdNP folks are looking at accounting stuff
rlbob: there's work in the "web services" space that's related to the
work in
this group.
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end
CdL - dec 11th 2000 | Visitors of this page: |