1. Network Localized Mobility Management using DHCP
draft-templin-autoconf-netlmm-dhcp-04
IETF67 –DHCP wg

2. NETLMM Problem Space Global Internet NETLMM Domain A Domain B Mobile
Nodes
localized
mobility
global mobility
(out-of-scope)

3. Problem Statement and Goals
support NETLMM domains as small as a home network or as large a major operator network, e.g., metropolitan region WiFi, cellular, etc.
MNs keep same addresses/prefixes as they move within a NETLMM domain (global mobility out-of-scope)
support session continuity across mobility events
reduce routing churn (avoid tracking MNs via IGP)
Problem Statement: draft-ietf-netlmm-nohost-ps-05.txt
Goals: draft-ietf-netlmm-nohost-req-05.txt
TODO: match up NETLMM/DHCP proposal with goals

4. NETLMM Domain Backhaul Network Access Rtrs (ARs) Mobility Anchor
Point(s) (MAPs)
Access Networks
Mobile Nodes (MNs)

5. NETLMM Using DHCP Let each MN be a DHCP client
Let each AR be a DHCP Relay
Let each MAP be associated with a DHCP server (no need for them to be co-located)

6. Route/Tunnel Configuration after MN config’s address/prefix via AR1
MN1AR1
AR1tunnel
MN1on-link
AR1
AR2
MN1

7. Route/Tunnel Configuration After MN moves to AR2
MN1AR2
AR2tunnel
AR1
AR2
MN1on-link
MN1

8. New since -02 version (current version is -04)
AR now has DHCP client co-resident with DHCP relay
Fast/reliable mechanism for deleting stale state in old AR (missing in -02)
Network-initiated handovers
Support for SLAAC-only Mobile Nodes (aka “Proxy-DHCP”)
(Only discussing IPv6 here, but IPv4 also supported)

9. AR Client/Relay Configuration
DHCP client/relay co-resident; use lo0 interface
Relay responsible for managing IP forwarding table (examines messages for RAAN options, aka CSRs)
Client responsible for reliable exchanges, network-initiated handovers and address registration proxy for non-DHCP MNs
Access
network
Backhaul
eth1
eth0
Access Router
DHCP Client
DHCP Relay
lo0

10. Deleting State in Old AR
MAP performs handover exchange with new AR via MN’s Confirm/Rebind (or network-initiated handover)
MAP sends Reconfigure to old AR
Old AR’s client function sends Information-Request to MAP wrapped in Relay-forward message
MAP sends Reply with CSR options to old AR’s client function via old AR’s relay function

11. Network-initiated handovers
New AR detects MN coming onto its link via L2 signal
New AR’s client function sends immediate Information-request to MAP (wrapped in Relay-forward message) with CSR option that includes Client ID option with DUID for client
MAP sends Reply to new AR’s client function with CSR options for MN via new AR’s relay function
MAP sends simultaneous Reconfigure to old AR’s client function to delete old state

12. Support for SLAAC-only MNs (aka “Proxy-DHCP”)
SLAAC-only MN sends NS(DAD) for tentative address
AR’s client function sends immediate Information-request to MAP (wrapped in Relay-forward message) with CSR option with IA_NA that encapsulates the tentative address and Client ID for client
MAP sends Reply to AR’s client function with CSR options for MN via new AR’s relay function
Proxy-DAD needed in case MAP detects duplicate (TBD)

13. Notes
Use Server Reply Sequence Number (SRSN) wherever RAAN options are used
Allow AR’s client function to act as both “Responder” for NETLMM signaling and ordinary client for AR auto-configuration
Need to specify proxy/relay-DAD so that MNs using SEND/CGA that configure duplicate addresses will be detected

14. Technical Questions
Can we rename RAAN as “Classless Static Route (CSR) option for DHCPv6”? Reasons:
symmetry with DHCPv4
“promotes” existing DHCPv4 option to DHCPv6
simplifies documentation (“CSR” used for both DHCPv6; DHCPv4)
Can Reconfigure message carry CSR options (instead of waiting for Info-request/Reply)?
Can Solicit/Reply be used instead of Info-request/Reply for “Proxy-DHCP”?

15. Big-Picture Questions
Should there be a DHCP wg liaison to the NETLMM wg?
Can this work be combined with the NETLMM design team specification as input for a possible DHCPv6(bis) effort?
Can this work be taken as a DHCP wg item?