Transcript 00-03-0031-00-0000Handoff_WMAN_Presentation

July. 2003
doc.: 802_Handoff_WMAN_Presentation
802 Handoff
A Technical Preview
David Johnston
[email protected]
[email protected]
Submission
Slide 1
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Purpose (of these slides)
• To date, a lot has been said about scope,
purpose, goals, interworking, liason, PARs
and other such things
• This presentation skips rapidly through that
and gets to the meat of some technical
aspects of 802 handoff that could become
part of the standard
Submission
Slide 2
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Problem Statements
• Three problem statements approved as findings of
the group
– #1 Detection of a useable attachment to a network is impacted by the ambiguous
indicators of network attachment in certain 802 MACs. Thus there is a need to
develop a standard that allows a mobile terminal to optimize detection of a useable
attachment to a network above the LLC.
– #2 The information necessary to make effective handoff decisions is lacking in part
because 802 networks provide insufficient information to the upper layers. Thus
there is a need to develop a standard that permits information exchange between
mobile terminals and/or networks to enable mobile terminals and/or networks to
make more effective handoff decisions.
– #3 There is no standardized mechanism in 802 for information exchange between
mobile terminals and network attachment points. This impacts the ability to make
informed decisions to select between disparate network attachment points or to
initiate handoffs between heterogeneous network types or between administrative
domains within a single network type. Thus there is a need to develop a standard
that permits mobile terminals and network attachment points to access information
on which to base effective handoff decisions.
Submission
Slide 3
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Draft Scope
• For the purposes of converging towards a consensus on
purpose and scope, the group approved the following text
as a working copy of the scope for discussion prior to the
September interim
“The scope of this project is to develop a standard that shall
define mechanisms that may be adopted into
implementations so that handoff of handoff-capable upper
layer entities, e.g. MobileIP sessions, can be optimized
between homogeneous or heterogeneous media types both
wired and wireless, where handoff is not otherwise defined.
Consideration will be made to ensure compatibility with the
802 architectural model.
Consideration will be made to ensure that compatibility is
maintained with 802 security mechanisms including 802.1x.
Neither security algorithms nor security protocols shall be
defined in the specification.”
Submission
Slide 4
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Draft Purpose
• For the purposes of converging towards a consensus on
purpose and scope, the group approved the following text
as a working copy of the purpose for discussion prior to
the September interim
“The scope of this project is to develop a standard that shall
define mechanisms that may be adopted into
implementations so that handoff of handoff-capable upper
layer entities, e.g. MobileIP sessions, can be optimized
between homogeneous or heterogeneous media types both
wired and wireless, where handoff is not otherwise defined.
Consideration will be made to ensure compatibility with the
802 architectural model.
Consideration will be made to ensure that compatibility is
maintained with 802 security mechanisms including 802.1x.
Neither security algorithms nor security protocols shall be
defined in the specification.”
Submission
Slide 5
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Relevant Elements in Network
L3 Network
AR
AP
mIP
802.y
AP
mIP
802.x
AP
mIP
802.x
AR
AR
AP
mIP
802.x
AP
mIP
802.y
Potential links
One or more
802 interfaces
Submission
802.x
802.y
interface select
mIP
Mobile Device
y=x | y!=x
Slide 6
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Handoff Cases
Within L2
boundary
Across L2
boundaries (via L3)
802.x – 802.x
Either L1,2 support (eg. .11)
Or No L1,2 support (e.g. .3)
Use L3 mobility aided by L2 to L3
trigger mechanisms
802.x – 802.y
Either Use L2 HO
mechanisms
Or use L3 HO mechanisms
aided by L2 to L3 trigger
mechanisms
Use L3 mobility aided by L2 to L3
trigger mechanisms
802.x - other
Submission
N.A.
Mechanism defined by other
Slide 7
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
What Can We Do?
• Easy:
–
–
–
–
–
Enable make before break handoffs
Reduce length of break before make handoffs
Prevent inappropriate attachment attempts
Improve scanning speed
Prevent unnecessary DHCP attempts
• Hard:
–
–
–
–
–
Submission
Pre authenticate via backbone
Transfer QoS context
Remotely interrogate base stations
Media independent handoff decisions on network side
L2 end to end triggers
Slide 8
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
How do we do it
• Easy
– Provide an information base with defined
structure and semantics
• Provide access via the top (API, MAC SAP
messages, management interface (oids, ndis snmp)
• Provide access via link (extended 802.1x model,
encapsulation)
• Hard
– Define new media independent inter base
protocols
– Other (Left as exercise to the reader)
Submission
Slide 9
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
L1,2 – L3 Triggers
• Meets emerging requirements in IETF for
fast mobile IP and for effective DNA
(Detection of Network Attachment)
• Maps elsewhere (non IP, handoff-able L3
nets)
• Sends events upwards from L2 to L3
– Indicated specific states or state changes
• Link Up, Handoff decision, etc
– May contain per trigger metadata
• Link ID, VLAN etc.
Submission
Slide 10
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
The 802.1x Model
Submission
MobileIP
AppleTalk
Etc..
EAPoL
LSAP
LSAP
LSAP
LSAP
LLC
LLC
MAC
MAC
PHY
PHY
Slide 11
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Extending The 802.1x Model
MobileIP
LSAP
Submission
Secured
Handoff
Information
base
LSAP
EAPoL
LSAP
Non secured
Handoff
Information
base
LSAP
LLC
LLC
MAC
MAC
PHY
PHY
Slide 12
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Extending the 802.1x model
• 2 Handoff ethertypes, one for secure, one
for insecure
• Device on other end of link can interrogate
the information bases using packets marked
with the appropriate ethertypes
• Packets passed are traditional MSDUs
common to all 802 MACs
– Thus information can be made available
independent of media type
Submission
Slide 13
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Define Handoff Decision Data
• Pre defined information to support handoff
decisions
–
–
–
–
Network vendor
Auth types supported
L3 network media (internet/PSTN/ATM etc)
Etc
• Make it extensible
• Supports proprietary vendor codes/extensions
• Supports playpen data types
Submission
Slide 14
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Transporting The Decision Data
• It needs a coding and encapsulation for
transmission
– Ethertypes to map into extended 802.1x model
– ASN.1 or XML or canonical S expressions
• I prefer canonical S expressions due to opportunities
for easy parsing, signing and stateless expression
• XML canonicalisation needed for signing
– VERY compute intensive
Submission
Slide 15
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
Define Media Independent HO Decision
Data Encapsulation
EG:
<base_descriptor>
<media_type>802.11</media_type>
<auth_required>
<auth_vendors>
ipass
boingo
</auth_vendors>
<backbone_pre_auth>
yes
</backbone_pre_auth>
<CS_descriptor>
<type>mIPv6</type>
<address>192.168.0.1</address>
</CS_descriptor>
<adjacent_bases>
base1 base2 etc.
</adjacent_bases>
</base_descriptor>
• Pick XML/ ASN.1/
Canonical S Expressions
• Make it suitably
extensible
Submission
Slide 16
David Johnston, Intel
July. 2003
doc.: 802_Handoff_WMAN_Presentation
More ‘out there’ ideas
• Make link signaling carry more elaborate
semantics than ‘fetch’
– Get/Set, Forward, Remote Request
• Enable end to end triggers through
information conduit
– Allows remote triggering, network side handoff
commands to mobile part
Submission
Slide 17
David Johnston, Intel