Understanding Components & Challenges of Host Mobility in Mobile Networking, Lecture notes of Energy Efficiency

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Mobile Networking ITS 413 – Internet Technologies and

Applications

ITS 413 - Mobile Networking

Next Generation Wireless Networks

Ubiquitous mobile access to Internet

ITS 413 - Mobile Networking

Next Generation Wireless Networks • Example Scenarios^ –^ Spontaneous or ad hoc networking^ •^ A group of users get together for a meeting and share information amongst theirportable devices (phones, PDAs, laptops, MP3 players, …)^ •^ Some of the users have direct access to wireless networks provided by operators (andhence to Internet); some users do not – they access via the users that do have access^ –^ Integration of all scenarios^ •^ A user moves between different networks/environments, all the time with no noticeableinterruption in the communication services

ITS 413 - Mobile Networking

Enabling Technologies

•^ What technologies will enable these scenarios?^ –^ Wired Networks^ •

Even though many scenarios required freedom from wires, wired networksare still vital (providing access where possible; interconnecting networks; …) – Wireless Networks (Physical, Data link layers) • Faster data rates, more efficient use of spectrum, energy efficiency, …^ –^ 3G+ mobile networks: 14Mb/s download to mobile phone available^ –^ IEEE 802.16 (WiMax), IEEE 802.20: 10’s Mb/s over km’s^ –^ IEEE 802.11n (300Mb/s) and beyond – Internet Mobility (Network layer) • Ability to move between networks without changing your IP address (HostMobility) • Ability for entire networks to move within Internet without changing networkaddress or IP address of hosts on network (Network Mobility) – Infrastructure-less or Ad Hoc Networks (Network and other layers) • No longer rely on fixed (expensive) base stations with wired connections • Wireless connections between users for dynamic networks^ –^ Mesh networks, Mobile Ad Hoc Networks, Sensor Networks

ITS 413 - Mobile Networking

Contents

•^ Host Mobility^ – IP Mobility and Mobile IP •^ Network Mobility^ – NEMO •^ Ad Hoc Networking^ – MANETs

Host Mobility^ Mobile IP

ITS 413 - Mobile Networking

Assumptions: Wireless Access Networks • Lets assume an “AccessNetwork” is a single IP networkwhere end-user hosts connect(via layer 2 technologies) to arouter–^ Hosts and router all use sameNetwork portion of IP address• Access Networks are connectedtogether via other IP networks(often called Core, Backbone orTransport networks)

X.a

RouterX.z X.b^ X.c^ X.d Access Network X AccessNetworkX

AccessNetworkY

AccessNetworkZ Internet

Problems with Mobility in Internet • The Internet uses topologically correct routing – Routers in the Internet know about the location of other

Networks^

(not hosts)

-^ E.g. when Z.a sends to X.b, Internet routing finds a path to Network X, then Router X.zuses direct delivery to send to X.b – Therefore, if a mobile host changes Access Networks, then must change IPaddress, otherwise routing will not work •^ E.g. when X.b moves to Network Y, it cannot use the same IP address X.b!

Internet X.a^ Router X.bX.z

RouterZ.z RouterY.z Y.f Y.e

Z.a

Hostmobility

?

ITS 413 - Mobile Networking

IETF IP Mobility Solutions

•^ IETF began working on extensions of IPv4 to support mobility in1990’s^ –^ Major development was protocol generally referred to as

Mobile IP

in

RFC 3344 – Significant amount of research and development continues in IETF andelsewhere to:^ •^ Add new features Mobile IP: security, route optimisation, handoversmoothing^ •^ Support IPv6^ •^ Cover specialised scenarios: Network Mobility, ad hoc networks – Mobile IPv4 is optional (FA’s and HA functionality not required in IPv4routers) – Mobile IPv6 is built-in to IPv6 (IPv6 routers contain functionality forFA/HA operations) – We will focus on Mobile IPv4, but similar concepts apply to Mobile IPv

ITS 413 - Mobile Networking

Mobile IP Basics

-^ A Mobile Node is assigned a visiting, or Care-Of-Address, at the networks it visits^ –^ Application sessions still use to original Home IP address^ –^ Normal IP Routing forwards packets to the Home Network^ –^ Mobile IP then forwards packets from the Home Network to the Mobile Nodes currentForeign Network

Internet X.a^ Router X.bX.z^ HA

Router Router: Y.z FA Y.fY.e Z.z FA

Z.a

HomeIP: X.bCOA: Y.m Home Network (for X.b)

Foreign Network (for X.b)

Foreign Network (for X.b)

HomeIP: X.bCOA: Z.t

ITS 413 - Mobile Networking

Mobile IP Components

-^ Home IP Address^ –^ The IP address assigned to the MN in its Home Network^ –^ The Home IP address is within the Home Network address range^ •

E.g. home network: 25.105.0.0/16; home address: 25.105.23.88/

-^ Care-of-Address (COA)^ –^ An IP address assigned to MN visiting a Foreign Network^ –^ The COA is an IP address within the Foreign Network address range^ •

E.g. foreign network: 172.16.37.0/24; COA: 172.16.37.65/24 – The IP address of FA may be assigned as the COA of visiting MN • E.g. FA 172.16.37.1/24; COA: 172.16.37.1/

ITS 413 - Mobile Networking

Mobile IP Forwarding

-^ Correspondent Node to Mobile Node^ –^ CN is not aware that MN is “mobile”^ –^ Sends packets to Home IP, e.g. X.b^ –^ HA intercepts and realises the MN isnot home, and forwards to ForeignNetwork where MN is visiting -^ Mobile Node to Correspondent Node^ –^ MN sends packets to CN (e.g. Z.a) viathe local FA^ –^ Source Address is MN’s Home IP (e.g.X.b) X.a^ RouterX.z^ HA

Router Router: Y.z FA Y.fY.e Z.z FA

Z.aCN

Home Network (for X.b)^ HomeIP: X.bCOA: Y.m

Foreign Network (for X.b)

Foreign Network (for X.b)

Mobile IP Registration

-^ First Registration (for example, Mobile Node powers on in a new ForeignNetwork)^ 1.^ MN discovers it is in a Foreign Network (see Agent Discovery)^ 2.^ MN sends a Mobile IP Registration Request to the FA^ –

Source IP: Home IP; Dest IP = FA – Registration Request contains the IP address of the MN’s HA – Note FA is configured to receive Mobile IP messages from nodes with an IP address^ not on the local network 3. FA notes the MNs Home IP and allocates a COA 4. FA sends Registration Request to HA (including the allocated COA) 5. HA authenticates the MN, updates its Mobility Binding Table and returns aRegistration Reply to FA 6. Upon receipt of positive Registration Reply, FA updates its Visitors List, andforwards reply to MN. FA will now

service^ the MN

Mobile Node^

Foreign Agent

Home Agent

2. Registration Request
3. Registration Request
   5. Registration Reply
   6. Registration Reply

ITS 413 - Mobile Networking

Mobile IP Agent Discovery

-^ How does a MN know the IP address of the FA?^ –^ When it first powers up?^ –^ When it performs a handover from an old FA to a new FA? •^ Three options for Agent Discovery:^ –^ IP Level Agent Advertisements^ •

Agent broadcasts periodic advertisements, indicating its own IP address • ICMP Router Advertisement messages, extended to carry Mobile IP information • Rate at which advertisements are sent must be limited (default: 1 per sec) • Agent^ may

be configured to only send advertisement after receiving solicitation

-^ IP Level Router Solicitation^ •^ MN broadcasts a solicitation message to the network^ •^ ICMP Router Solicitation messages are used^ •^ Rate MUST be limited (1 per second for the 3 initial solicitation messages, and thenwith exponential back-off)^ •^ The FA has to respond to solicitation with an advertisement message –^ Layer 2 Supported Techniques^ •^ Local broadcasts of L2 beacon frames with all necessary information (including FAaddress, supported functionality, CoA etc…)^ •^ MN can solicit beacon (or other L2 “welcome”) frames upon gaining L2 connectivity^ •^ Example: Wireless LAN beacons are extended to carry Mobile IP information, such asFA address