Transcript PPT Version

Problem Statement: Media
Independent Handover Signalling
draft-hepworth-mipshop-mih-problem-statement-02
Eleanor Hepworth, Srinivas Sreemanthula,
Stefano Faccin, Yoshihiro Ohba
July 2006
IETF#66, Montreal
Contents
• The IEEE 802.21/IETF mipshop picture
– The overall problem and possible approaches
to decomposition
• Focus of this draft
– ‘Transport’ and other common aspects
• Basic MIH support functions
• What next
An 802.21 Primer
•
802.21 covers a varied bunch of stuff
– Framework for service continuity (i.e. how to incorporate mobility protocols)
– Handover enabling functions (“MIH services”)
– SAP definitions for different link layers
•
•
•
The MIH services are control-plane things which provide information which
improve the operation of handover algorithms
From the (draft) charter:
"MIH services can be delivered through link-layer
specific solutions and/or through a "layer 3 or above"
protocol. MIPSHOP will define the delivery of
information for MIH services for this latter case.
Notice that this allows the network information to
reside anywhere (not necessarily across the link-layer
hop), and enables MIH services even in the absence of
the corresponding link-layer support. An L2 or L3 based
mechanism to identify a valid information server is also
required; in particular for L3, we expect that any of
the several current L3 discovery mechanisms will be
used."
This discussion is about protocol support for the MIH services
802.21 and mipshop
Transport Layer
(used by all MIH services)
IEEE 802.21 Protocol
Architecture
how to use the common transport
protocol for MIH services in IP networks
Assumed scope of IETF
protocol development
Common MIH Protocol
Header
draft-ietf-mipshop-mihinfo-elements
Scope of IEEE 802.21 Standard
Information elements for
each 802.21 MIH service
draft-ietf-mipshop-mihsupport
what is the common transport protocol
IETF mipshop charter items
Focus of this draft …
(*)
• … is a strawman problem statement for the
mih-support item
– Main aspect is common transport part
– Status of common header is unclear
• Could just be an issue of registry issues for some identifiers
carried within ‘transport’
• A solution meeting the goals in the problem
statement should be generally useful
– Initially for transport of 802.21 MIH services
– Possibly other services in the future
(*)
As compared to the next two drafts, which are about applicability to
the specific MIH services (ES/CS/IS) that 802.21 has defined
Basic Protocol Functions
– As derived from consideration of the MIH services so
far …:
• Transport-like functions for moving IEs between
the MIH service endpoints
– Congestion/flow control, large message support, lowlevel reliability, multiplexing
• Core security functions for moving IEs between
the MIH service endpoints
– Integrity (including replay) protection, privacy (of
identity and other data)
• Denial of service mitigation
Components of A Solution
Mobility Support
Services 2 (e.g. Event
Services)
Mobility Support
Services 2 (e.g.
Information Services)
Mobility Support
Services 3 (e.g. other)
Mobility Service Transport Protocol
IP
Mobility
Services
Signaling
Layer
Mobility
Services
Transport
Layer
IEEE 802.21 Transport
Requirements
The transport protocol must
• … work regardless of the network location of the MIH
Protocol Entity
• … be capable to support both IPv4 and IPv6 versions
• … be capable of delivering time- sensitive MIH
information
• … enable Network address Translation (NAT) traversal
for IPv4 networks and enable Firewall pass-through for
IPv4 and IPv6 networks
• ... allow for more than one MIH Protocol Entity to be
discovered at a time
IEEE 802.21 Security
Requirements
The security mechanism
• must provide (through the security mechanisms) a common security
association (SA) negotiation method regardless of the network location
of the MIH Protocol Entity
• must provide (through the security mechanisms) mutual authentication
of MIH end nodes
• may provide one way authentication of either of MIH end nodes
• must provide integrity protection for MIH Protocol exchanges.
• may provide confidentiality for the MIH Protocol exchanges
• must protect against replay attacks
• may protect MIH service entities and discovery resources against denial
of service attacks
• must not be dependent on the MIH protocol
• may provide means to reuse or fast reestablishment the SA due to host
mobility.
Other Considerations on the
Mobility Service Transport Layer
• Congestion Control: transferring of large amounts of data
vs. low latency requirements
• Multiplexing: support of different mobility services 
multiplexing + ability to manage multiple discovery
operations and peering relationships in parallel
• Multihoming: carrying request/response messages over
two different links (e.g. a handover command request on
the current link while the response delivered on the new
link). Depending on the IP mobility mechanism, there is
some impact on the transport option for the mobility
information services (including latency and security
issues)
Summary / What Next
• Draft contains a definition of the problem
that mih-support shall solve
– This draft is a suggestion from people with
802.21 knowledge
– Incorporates requirements officially approved
un IEEE 802.21
• Proposal: adopt of PS statement draft for
WG draft