Steps in L2 and L3 Handoffs

1
Steps in L2 and L3 Handoffs

• Vivek G Gupta
• Intel Corp.
• vivek.g.gupta_at_intel.com
• Jan 2004

2
Background..
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

3
Application 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.

4
Steps 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
5
Steps 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
6
Conclusion

• 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