steps in handoffs and use cases
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Steps in Handoffs and Use Cases. Vivek Gupta Intel Corporation [email protected] May 2004. Background…. IEEE 802.21…from PAR and 5 Criteria - PowerPoint PPT PresentationTRANSCRIPT
May 2004
Vivek Gupta, Intel CorpSlide 1
IEEE 802.21
Submission
Steps in Handoffs and Use Cases
Vivek GuptaIntel Corporation
[email protected] 2004
May 2004
Vivek Gupta, Intel CorpSlide 2
IEEE 802.21
Submission
Background….
• IEEE 802.21…from PAR and 5 Criteria– Media Access Independent mechanisms to facilitate
optimization of L3 handoffs (e.g. Mobile IP sessions) between homogeneous or heterogeneous media types
– Optimize Detection and Selection of Network attachment points
– Ensure compatibility with the 802 architectural model and security mechanisms
• No new security algorithms or protocols
May 2004
Vivek Gupta, Intel CorpSlide 3
IEEE 802.21
Submission
Background…Scope of 802.21
• Intra 802 Handoffs (802.x 802.x)– Covered by respective 802 working groups– These 802 WGs will also deliver fast intra 802 handoff solutions that
address ~30 msec or less handoff latency• Through proactive pre-authentication, soft handoffs, and/or fast
reconnections between nodes (TGr, TGi, etc. for 802.11)
• Inter 802 Handoffs (802.x 802.y) and extension to more general case of inter network handoff across cellular systems (802 zG)– Within scope of 802.21– Intra 802 Handoffs across Administrative domains also within scope– Handoffs across 802.11a, 802.11b, 802.11g, 802.11n in scope?
802.X802.X802.Y zG (WWAN)
May 2004
Vivek Gupta, Intel CorpSlide 4
IEEE 802.21
Submission
Customers of 802.21
• Layer 3 and above applications…– Mobile IP for data transfers– Voice based applications
• Network Selection Service– Select best radio
• Others?
May 2004
Vivek Gupta, Intel CorpSlide 5
IEEE 802.21
Submission
Steps in Handoff Process
• Scenario– Multi radio mobile handset roaming in heterogeneous
wireless network environment….
• Steps in Handover Detect Changes in Link Availability L2 Connection and Network Provider Selection Link Selection and Configuration Connection Handover
May 2004
Vivek Gupta, Intel CorpSlide 6
IEEE 802.21
Submission
Steps in Handoff Process Detect Changes in Link Availability
– Availability of New Links• Through Native radios
– Media Sense and Link Quality Estimation
• Through non-Native radios– E.g.Using 802.11 radio, find out about all other radios in vicinity
– Site Report for all radios (Global Network Neighborhood)
• GPS assisted
– Degradation and Loss of Existing links• Link Quality estimation and comparison
– Signal Strength, Signal to Noise Ratio, Bit Error Rate
=> Link layer Triggers to notify higher layers
May 2004
Vivek Gupta, Intel CorpSlide 7
IEEE 802.21
Submission
Steps in Handoff Process L2 Connection and Network Provider Selection
– Establish L2 connection with Available Links• Need Radio specific MAC level parameters
– SSID, BSSID, Channel, etc.
– Network Provider Selection• Based on preferred operator and available services• Provisioning utilities like Microsoft WPS may do most of the work
here– There may be other cases where WPS may not be applicable, (Low
power mode of operation)
=>Extended Site Report (Global Network Neighborhood) can help with Link discovery and selection
– Link layer parameters for existing radios (no probes, beacons, scans, etc.)
– Service provider information
May 2004
Vivek Gupta, Intel CorpSlide 8
IEEE 802.21
Submission
Steps in Handoff Process
Link Selection and Configuration– Link selection
• Input from user policies, available links and services, etc.
• Mostly an OS function
– Link Configuration• IP connectivity
May 2004
Vivek Gupta, Intel CorpSlide 9
IEEE 802.21
Submission
Steps in Handoff Process
Connection Handover– Decision to switch Connections or Maintain
simultaneous connections etc. • Make before Break
• Break before Make
– Context Transfer– Application specific
May 2004
Vivek Gupta, Intel CorpSlide 10
IEEE 802.21
Submission
Use Case #1Steps in Handover Wired Wireless
(Email)Comments
Changes in Link Availability
Abrupt!
Link_down
L2 Connection and Network Provider Selection
WLAN, BT, WWAN
(Global Site Report)
802.21 can help with Network Discovery and Selection
Link Selection and Configuration
Select WLAN and get IP connectivity
Based on policy, cost, bandwidth, etc.
Connection Handover Break before Make. Email app reconnects
No need for MobileIP!
For other Wired Wireless transitions, for time/latency critical applications user may want to use wireless even when device is NOT mobile. E.g. VoIP Phone
May 2004
Vivek Gupta, Intel CorpSlide 11
IEEE 802.21
Submission
Use Case #2
Steps in Handover 802.11 802.16 Cellular (Voice/Video)
Comments
Changes in Link Availability
Gradual decay……. Link_Going_Down Link_Up
802.21 can specify Predictive Triggers.
L2 Connection and Network Provider Selection
Get network and provider preferences. Get provider specific access info.
802.21 can help with Provider Selection and Access info
Link Selection and Configuration
Select network and get connectivity
Notify TCP appropriately when going across networks with big difference in bandwidth
Connection Handover
Make before Break. Seamless handover
Mobile user using VoIP over WLAN in office walks out, gets into car, and drives out of town!
May 2004
Vivek Gupta, Intel CorpSlide 12
IEEE 802.21
Submission
Use Case #3
Steps in Handover Connected to 802.11 (User roaming in an
airport)
Comments
Changes in Link Availability
Link_Available! Better service provider available, based on Global Site Report…
L2 Connection and Network Provider Selection
Select the new/preferred service provider
Link Selection and Configuration
Connection Handover
Break before Make…
User roaming in an airport across domains and Service Providers. 802.21 facilitates handover to preferred Network Service Provider
May 2004
Vivek Gupta, Intel CorpSlide 13
IEEE 802.21
Submission
802.21 Work Items• Things to do in 802.21
– Use cases• Find compelling user scenarios to solve
– Global Network Neighborhood• Discover about other radios through current radio• Neighbor graphs of all radios
– Media Independent Triggers• Notifications about changes in link availability
• Things NOT to do in 802.21– Link Quality Comparison– Link Selection
• Policy decision (Mostly an OS function….)
– Connection handovers• Make before break etc. (Application specific…)
May 2004
Vivek Gupta, Intel CorpSlide 14
IEEE 802.21
Submission
IEEE 802.21 Specification…
• General organization of 802.21 specification– Type of Spec
• More general and abstract in nature than other 802 specs
– Customers of spec• Other 802 WGs and other Standard bodies
– Normative vs Informative• How will compatibility with 802.21 enforced/measured
– Mapping to other technology
May 2004
Vivek Gupta, Intel CorpSlide 15
IEEE 802.21
Submission
Conclusion
• Key areas of contribution for 802.21– Media Independent Triggers– Global Network Neighborhood