Spring 2004

Network MobilityNetwork Mobility

School of Electronics and InformationKyung Hee University

Choong Seon HONGcshong@khu.ac.kr

http://networking.khu.ac.kr

2Spring 2004

Contents Contents Overview

Terminology Usage Scenario Problem Scope & Requirements

Basic Solution Operation overview Message Formats

• Binding Update/ Binding Acknowledgement• Mobile Network Prefix Option• Mobile Router Operation

Home Agent Operation Et Cetra

3Spring 2004

Many IP devices will be mobile Moreover, many networks (LAN & PAN) will be mobile.

in moving vehicles (cars, trains, planes, ships, etc) in moving bodies (humans, animals, equipment, etc)

Permanently connected to the Internet

Internet

BackgroundBackground

4Spring 2004

What is a Mobile Network What is a Mobile Network

A Mobile Network is an entire network, moving as a unit, which changes its point of attachment to the Internet. A NEMO may be composed by one or more IP-subnets

5Spring 2004

TerminologyTerminology MR MR one or more IP-subnets mobile as a unit connected to the Internet via 1 or more mobile routers (MR) MR changes its point of attachment

AR

MRMRMR

AR

MR

Internet

home link

NEMO link

visited link egress interface

ingress interface

6Spring 2004

Terminology: Mobile Network NodesTerminology: Mobile Network Nodes

MNNs: any node attached a NEMO MR: Mobile Router LFN: Local Fixed Node

• LFR: ~ Router

• LFH: ~ Host LMN: Local Mobile Node

• LMR: ~ Router

• LMH: ~ Host VMN: Visiting Mobile Node

• VMR: ~ Router

• VMH: ~ Host

CN: Correspondent Node any node corresponding with 1 or more MNNs

CN

AR

LFH

LFR

MR

VMH

AR

MH

LMH

LMH

AR

7Spring 2004

Terminology: Nested MobilityTerminology: Nested Mobility

AR

Top-Level MR

AR

Internet

MR

root-NEMO

child-NEMO

NEMO

AR

VMR

LMR

MRTLMR

child-NEMOLMR

parent-NEMO

leaf-NEMO

leaf-NEMO

8Spring 2004

Terminology: Multi-HomingTerminology: Multi-Homing

AR

Internet

MRMR

ARDomain 1 Domain 2

9Spring 2004

NEMO & MANETNEMO & MANET

Different Problem

MRMR

AR

Internet

ARNEMO

MANET

MR

MANET NEMO

10Spring 2004

Usage ScenarioUsage Scenario

PAN (Personal Area Network)

Public Safety System

Vehicular Network Train, Car, Airplane

11Spring 2004

PANPAN

Office

Airport

Hotel

12Spring 2004

Public Safety SystemPublic Safety System

MNNs

MR

MNNs

MR

MR MRMNNs MNNs

MNNs

MR

MR

MNNs

13Spring 2004

Vehicular Network: InternetCarVehicular Network: InternetCar ~ 70 computers in a vehicle. 3 subnetworks, in general.

Multimedia network (for Car Audio, Navigation System) Body network (for Head light, Power Window) Control network (for Engine, Break)

At first, Multimedia network will be using Internet Protocol. Multi-homing

A vehicle has more than one communication devices( cellular phone, DSRC (which is designed for automobile), PHS,

Wireless LAN, etc)

Car Navigation Car AudioSpeakerPDA GW

GW

Body network

Control network

Cellular Phone Wireless Lan

Key

DSRC : Dedicated Short Range Communications

14Spring 2004

Requirement Requirement Migration Transparency (Permanent Connectivity) Performance Transparency (Seamless Mobility) Mobility Management Transparency for MNNs Scalability

Large NEMO Large number of NEMO Large number of CN

Minimum Signaling Overload Routing Optimization Nested Mobility No impact on CNs or Internet routing Security

Confidentiality Authentication Authorization Location Privacy Access Control

15Spring 2004

Basic SolutionBasic Solution Nemo Basic Support Protocol

draft-ietf-nemo-basic-support-02.txt

NEMO solution requires setting up a bi-directional tunnel between the MR and its HA All traffic between the nodes in the Mobile Network and CNs passes through th

e HA

Mobile Router Default gateway for the Mobile Network moving away from the home link and attaches to a new AR

acquires a CoA from the visited link sends a BU(‘R’ bit) to its HA as a mobile router

Home Agent successfully processes the BU and sets up forwarding for the Mobile N

etwork Prefix sends a BA to the MR establishes a bi-directional tunnel

16Spring 2004

Operation overviewOperation overview

CN

AR

Internet

AR

MR

LFNs

HA

Mobile Network

17Spring 2004

Mobile N/W in Home N/W Mobile N/W in Home N/W

CN

AR

Internet

AR

MR

LFNs

HA

Foreign N/W with Prefix

C::

Home N/W PrefixA::

Mobile N/W PrefixB::

18Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

MR with HOA A::1

Home PrefixA::

Mobile N/W in Home N/W Mobile N/W in Home N/W

19Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

Mobile N/W moves to Foreign N/W

MR gets COA C::1

PrefixC::

Mobile N/W in Foreign N/W Mobile N/W in Foreign N/W

20Spring 2004

BU with Mobile N/W PrefixBU with Mobile N/W Prefix

CN

AR

Internet

AR

MR

LFNs

HA

MR sends HABU

which bindsA::1 and C::1and notifiesMobile N/W Prefix B::

HA repliesBA

HA changes its Binding Cache

21Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

Bi-directional tunnelis made

between MR & HA

Bi-directional tunnel Set-UpBi-directional tunnel Set-Up

22Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

HA updates its Routing Table according to

Mobile N/W Prefixes from MR

The Next Hop of MNNs is MR.

HA propagates this Routing Information.

Advertising Mobile N/W Reachability Advertising Mobile N/W Reachability

23Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

CN sends a packet to a LFN

HA receives the packet.

Route lookup on HA returns MR as the next hop

Forwarding Packets Forwarding Packets

24Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA

With Binding Cache, HA sends

encapsulated packet to MR.

MR decapsulates the packet and forw

ards to theLFN.

Forwarding Packets Forwarding Packets

25Spring 2004

Message FormatsMessage Formats

BU Mobile Router flag (R)

• 1: BU from the MR• 0: BU from the MN

– SHOULD not forward packets destined for the mobile network to the MR

Mobility Options (MNP option, MNP Length option)

BA Status

• 140: Mobile Router Operation not permitted• 141: Invalid Prefix• 142: Not Authorized for Prefix• 143: Mobile Network Prefix information unavailable

Sequence #

Mobility options

LifetimeReservedA H L K R

26Spring 2004

Message FormatsMessage Formats

Mobile Network Prefix Option in the BU To indicate to the HA the prefix information for the mobile network

Type Length=18 Reserved Prefix Len(8bits)

Mobile Network Prefix

27Spring 2004

MR operationMR operation

Exchanges specific binding message with HAUses various data structuresJoins certain multicast groups

Joins multicast group at Home N/W NOT joins multicast group at Foreign N/W

28Spring 2004

Sending Binding UpdateSending Binding Update MR MUST sets the ‘R’ bit to 1 & also set the ‘H’ bit Three modes

Implicit• not include any options in BU

• HA can determine the Mobile Network Prefix owned the mobile router (e.g. pre-configured prefix table)

Explicit• MR includes one or more Mobile Network Prefix Optionsone or more Mobile Network Prefix Options in

the BU

29Spring 2004

Data structure/ Prefix information fieldData structure/ Prefix information field

Like a MN, a MR maintains a Binding update list Prefix information fieldPrefix information field

• is used to store any prefix information

• MR sets the ‘R’ bit in the BU and not include any prefix info– (in implicit mode) set to null

Dest. IP addr. Max. of seq#

Home addr.Time at which BU was last sent to this dest.- used in rate limiting restriction

CoA - to determine if BU was sent after handoff Rtx. state for BU

Initial value of lifetime in BU

A flag - whether or not future BU should be sent to this dest.

Remaining lifetime of binding Prefix informationPrefix information

<Binding Update list structure>

30Spring 2004

HA operationHA operation

Uses various data structuresMobile Network Prefix RegistrationAdvertising Mobile Network Reachability

Injects routes for Mobile Network into InternetEstablishment of Bi-directional TunnelForwarding Packets

31Spring 2004

Prefix TablePrefix Table

HA MUST maintain this table if the Mobile Routers operate under the implicit mode Entry in the prefix table

• The Home Address of MR Home Address of MR – is used as the key for searching the pre-configured prefix

table

• The Mobile Network PrefixMobile Network Prefix of the Mobile Router associated with the Home Address

Home address of MR Mobile Network Prefix of MR

32Spring 2004

Mobile Network Prefix RegistrationMobile Network Prefix Registration

HA’s check list BU MUST be authenticated by IPsec Home Registration (H) bit MUST be set MNP Length opt. is present, only one instance of this

opt. Check list OK! retrieves the Mobile Ne

twork Prefix information Mobile Network Prefix Length Option

• Home Address & Mobile Network Prefix Length Mobile Network Prefix Option

• Mobile Network Prefix field and the Prefix Length field

No Option• Find the MNP in pre-configured prefix table

33Spring 2004

Sending BASending BA

‘0’(BU accepted) ‘140’(Mobile Router Operation not permitted) ‘141’(Invalid Prefix) ‘142’(Not Authorized for Prefix) ‘143’(Mobile Network Prefix information unavailable)

By sending a BU with the lifetime set to zero

Mobile Network Prefix De-registrationMobile Network Prefix De-registration

34Spring 2004

Forwarding PacketsForwarding Packets

to forward a received data packet to MR HA uses only the routing table, only the BC or combination

S: HA_MR’s addr

D: MR’s CoA

S: CN’s addr

D: MR or MNN

S: HA_MR’s addr

D: MR’s CoA

S: CN’s addr

D: MR or MNN

Inner

Oute

rIn

ner

Oute

r

HA_MR

MR

Bi-directional tunnel

<Example 1>

<Example 2>

Example 1(combination) HA:

Example 2 HA:

Next hop = MR’s Home Address

MR’s HoA MR’s CoA

<in Routing Table>

<in BCE>

Outgoing interface=tunnel interface bt HA and MR

35Spring 2004

Support for Dynamic routing protocolSupport for Dynamic routing protocol

HA and MR run a intra-domain routing protocol like RIPng and OSPF through the bi-directional tunnel

Advantages: useful when mobile network is large with multiple subnets routing changes are propagated very quickly

S: MR’s CoA

D: HA_MR’s addr

S: MR’s link-local addr

D: HA’s link-local addr

S: HA_MR’s addr

D: MR’s CoA

S: HA’s link-local addr

D: MR’s link-local addr

Inner

Oute

rIn

ner

Oute

r

HA_MR

MR

Bi-directional tunnel

MR (in home link) runs a routing

protocol by sending routing updates through its egress interface

HA

in routing entry

Next hop : MR’s link-local addr

36Spring 2004

CN

AR

Internet

AR

MR

LFNs

HA for MR

HA for MH

MH

Pinball RoutingPinball Routing

37Spring 2004

Pinball RoutingPinball Routing

CN

AR

Internet

AR HA for MR

HA for MH

MHMR

LFNs

38Spring 2004

Pinball RoutingPinball Routing

CN

AR

Internet

AR HA for MR

HA for MH

MR

LFNs MH

39Spring 2004

Next Step/ Route OptimizationNext Step/ Route Optimization

Candidate Solutions IPv6 Reverse Routing Header and its applicat

ion to Mobile Networks • draft-thubert-nemo-reverse-routing-header-04

ND-Proxy based Route Optimization for Mobile Nodes in Mobile Network

• draft-jeong-nemo-ro-ndproxy-02.txt

40Spring 2004

Current NEMO Internet DraftsCurrent NEMO Internet Drafts

"Network Mobility Support Goals and Requirements", Thierry Ernst, 18-Feb-04

"Network Mobility Support Terminology", Thierry Ernst, Hong Lach, 18-Feb-04

"Nemo Basic Support Protocol", Vijay Devarapalli, 23-Dec-03.