Title: Steps in L2 and L3 Handoffs
1Steps in L2 and L3 Handoffs
- Vivek G Gupta
- Intel Corp.
- vivek.g.gupta_at_intel.com
- Jan 2004
2Background..
802.X
802.X
802.Y
zG (WWAN)
- 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
(FR FH SG, TGi, etc. for 802.11) - Inter 802 Handoffs (802.x ?802.y) and extension
to more general case of inter network handoff
(802 ?zG) - Within scope of 802.21
- All further discussion in this presentation
applies only to this category
3Application Perspective
- Voice
- Acceptable Latency 50 ms
- Key issue in handoffs across administrative
domains and heterogeneous networks - Make before Break almost Required
- May be difficult to get this to work reliably
- Person moves out of office/home (Transition from
802.11 to 802.16/WWAN) - Real time Multimedia Streaming
- Acceptable Latency up to 150 ms
- Make before break strongly preferred
- VPN Sessions (in scope of this WG?)
- Latency is not such a key issue
- Make before break preferred
- But may be difficult to achieve. Corporate
policies may not allow split tunnels - Other (Non real time and latency insensitive)
apps - Make before break NOT required
- Email, browsing, etc.
4Steps in 802 based L2 Handoffs
Network Discovery Selection
Authentication
Association
Key Steps in Handoff
Handoff Initiation
With/without IAPP Context Transfer across Access
nodes. Fast Handoff, 2/4 - way Handshake
802.1x (Full)
Network Activation Triggers L2 triggers,
Connection Policies, Power
Mgmt
Active scan (Probe/Response) Passive scan
(Cached/Wait for beacon)
Key Activities
IETF-seamoby IETF-dna
Standards related work
IETF-pana
5Steps in L3 Handoffs
Layer 2 Connectivity
Key Steps in Handoff
Packet Reception
IP Connectivity
Address acquisiti- on DHCP
Network Selection
Service Discovery Provisi oning CUPE
Handoff Initiation Network Activation Triggers
Duplicate Address Detection
Authen -tication Associa- -tion 802.1x
based
Key Activities
Binding Update
Context Transfer QoS Header Compr----ession
Most of 802.21 focus
-Seamoby CARD - dna
mipv4 mipv6 mipshop
Standards related work
Several IETF drafts
Seamoby Context Transfer
-pana
6Conclusion
- Identify Usage Models for handoffs across
different networks and comprehend L2 requirements - Study requirements for vertical handoffs in
liaison with IETF, 3GPP and 3GPP2 - Define a set of abstract handoff properties /
variables and mapping to each 802 protocol