Network Localized Mobility Management using DHCP

1
Network Localized Mobility Management using DHCP

• draft-templin-autoconf-netlmm-dhcp-04
  fred.l.templin_at_boeing.com
• IETF67 DHCP wg

2
NETLMM Problem Space
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 configs
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
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

10
Deleting State in Old AR

• MAP performs handover exchange with new AR via
  MNs Confirm/Rebind (or network-initiated
  handover)
• MAP sends Reconfigure to old AR
• Old ARs client function sends Information-Request
  to MAP wrapped in Relay-forward message
• MAP sends Reply with CSR options to old ARs
  client function via old ARs relay function

11
Network-initiated handovers

• New AR detects MN coming onto its link via L2
  signal
• New ARs 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 ARs client function with
  CSR options for MN via new ARs relay function
• MAP sends simultaneous Reconfigure to old ARs
  client function to delete old state

12
Support for SLAAC-only MNs(aka Proxy-DHCP)

• SLAAC-only MN sends NS(DAD) for tentative address
• ARs 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 ARs client function with CSR
  options for MN via new ARs 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 ARs 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?