Hi
The following is the work description of LCI (Link Characteristic Information
for Mobility). Jouni Korhonen, Hannes Tschofenig and I are thinkig of having a
new BOF in the IETF-66 on this subject (Target Area is TBD, but presumably, TSV
or RTA&Infra).
The problem statement is available via the link below before IETF repository.
http://daniel.vsix.net/lci/draft-korhonen-lci-link-characteristics-ps-00.txt
Tip: To illustrate what we are trying to achieve in conjunction with LCI, a
simple flash demo is attached below. Look at the undesirable disruption of
Non-LCI mobile terminal comparing with LCI mobile terminal (service quality is
scalable) carefully. Note: It is JUST for your information, so please don't
consider it seriously...:-)
http://daniel.vsix.net/lci/lci_concept.html
Our mailing list is http://eeca16.sogang.ac.kr/mailman/listinfo/lci
==================================
Link Characteristic Information for Mobility (LCI)
Updated: 2006-05-10
Version: 0.9
Description:
Recently more and more mobile terminals are equipped with multiple
interfaces for different L2 technologies. These mobile terminals make
it possible to communicate through different wireless networks at
the same time, or allow the most appropriate interface to be selected
according to current conditions. In the latter case, transitions
between heterogeneous links (vertical handovers) occur. Vertical
handovers often cause an ongoing connection to experience sudden
path characteristic changes (e.g. available bandwidth and delay).
Although some transport protocols and application mechanisms provide
congestion/flow control mechanisms, they are unable to detect and adapt
quickly, and require to send a number of probes to determine the new
network characteristics some time after the handover. The network
capacity may have already been misused during the probing process,
and the user experience can be disrupted. In some cases, handovers
between the same type of links (horizontal handovers) may also lead
to abrupt link characteristic changes, due to the different traffic
loads on the old and the new networks. Moreover, even if handovers
do not occur, the access link characteristics may change significantly
due to the variations of the traffic load on current link. Both of
these situations can lead to similar adverse effects as those on
vertical handovers.
As a matter of fact, the wireless access links are most likely the
bottlenecks for wireless internet connections. Therefore, it would
be ideal for mobile terminals to have the capability of sharing their
access link characteristic information (LCI) with their relevant
remote network nodes (including remote peers, mobility agents, and
any other network nodes that may consider this information useful
for optimizing network capacity usage and user experience). In case
the bottleneck of a peer-to-peer connection locates in the middle
of its path rather than its wireless access link (e.g. in the WLAN+ADSL
access scenario, the ADSL link can be the bottleneck, instead of the
WLAN), the access LCI would still be informational and the access LCI
delivery mechansim can be extended to support path characteristics
discovery. Sometimes, mobile terminals may have difficulties to obtain
precise access LCI at any time, however, it is also important and
heuristic to know the magnitude of change even without exact values,
since this can act as a timely trigger to other mechansims at the
relevant network nodes to re-investigate and renew their network
capacity usage status.
Existing IP mobility enabling technologies, however, do not provide a
method to deliver the access LCI to the relevant remote network nodes.
The principal objective of this work is to explore the possible
signaling solutions for delivering the access LCI at the IP layer or
above. Apparently, existing IP mobility protocols and transport protocols
could be extended to support this useful feature, while the potential
benefits and limitations need serious investigation. A new generic
lightweight signaling protocol may need to be designed for carrying the
LCI to tackle the limitations caused by using other protocol extensions.
Importantly, the adoptable LCI delivery mechanism(s) must be secured,
middlebox traversable, and must avoid significantly increasing the amount
of signaling traffic load, especially over wireless links. At the same
time, the tradeoff between the added LCI delivery and computation load
and gained advantages is also an issue that needs careful examination.
In multihoming scenarios, when multiple interfaces on the mobile terminal
are used for one application for load sharing, it is desired that the
LCI of each interface can be delivered simultaneously to the relevant
remote network nodes. However, the methods of collecting the access LCI
as accurate and timely as possible are out of the scope of this work.
The proposed work will also cooperate with the working groups that may
consider the access LCI useful, in order to facilitate the LCI utilization
by them. Especially, it is expected that the transport area may benefit
from the LCI delivery. It is also expected that real-time streaming
services can be enhanced based on the availability of the LCI signaling.
For example, SVC (Scalable Video Coding or H.264 Extended Profile) and
BSAC-Bit Sliced Arithmetic Coding are designed to support a flexible
control in terms of video and audio coder respectively following the
receiver's network qualities, while their functions are limited at the
moment due to the lack of dynamic signaling from the receiver when the
link characteristic changes.
Goals:
- Produce "Link Characteristic Information for Mobility Problem
Statement" to describe the problem and limitation of the current
mobility solutions without link characteristic information delivery,
and clarify the motivation of designing the LCI signaling.
- Produce "Link Characteristic Information Description" to describe the
required link characteristic information for delivery.
- Evaluate a set of candidate proposals for Link Characteristic Information
Delivery (probably multiple documents required).
- Produce "A lightweight signaling protocol for carrying Link Characteristic
Information" to design a new signaling mechanism for carrying Link
Characteristic Information including middlebox traversal and security
soluctions.
Related Documents:
- Link Characteristic Information for Mobility Problem Statement
ID: draft-korhonen-lci-link-characteristics-ps-00
- Link Characteristics Information for Mobile IP
ID: draft-daniel-mip-link-characteristic-02
- Link Characteristic Information Delivery Analysis
ID: In progress
- Quick-Start for TCP and IP
ID: draft-ietf-tsvwg-quickstart-01
- Datagram Congestion Control Protocol Mobility and Multihoming
ID: draft-kohler-dccp-mobility-01
- Mobile SCTP (mSCTP) for IP Handover Support
ID: draft-sjkoh-msctp-01
- IEEE P802.21/D01.00 Draft IEEE Standard for Local and Metropolitan Area
Networks: Media Independent Handover Services (accessable via MIPSHOP chairs)
- Architectural Implications of Link Indications
ID: draft-iab-link-indications-04
==================================
Questions about this work can also be directed to the:
Soohong Daniel Park <soohong(_dot_)park(_at_)samsung(_dot_)com>
Jouni Korhonen <jouni(_dot_)korhonen(_at_)teliasonera>
Hannes Tschofenig <hannes(_dot_)tschofenig(_at_)siemens(_dot_)com>
All comments are highly welcome....!
Daniel (Soohong Daniel Park)
Mobile Convergence Laboratory, SAMSUNG Electronics.
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