MIPMANET Mobile IP for Mobile Ad Hoc Networks

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MIPMANET Mobile IP for Mobile Ad Hoc Networks

• Jösson, Alriksson, Larsson, Johansson, and
  Maguire
• IEEE MOBIHOC 2000

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Abstract
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I. INTRODUCTION

• Motivation
• Mobility and IP are two strong trends nowadays.
• Desire for mobility concerning access to
  information on the Internet is increasing.
• The need to utilize Ad-hoc network and Mobile IP
• Ad hoc network
• Formed on temporary basis
• Easy to set up
• Can operate without any preexisting
  infrastructure
• Untethered multihop communication
• IETF MANET (Mobile Ad-hoc Network) working group
• Mobile IP allows roaming between different
  networks.

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I. INTRODUCTION -2

• This paper looks into
• how an ad-hoc network using on-demand routing can
  be connected to the Internet
• and how to provide roaming service that Mobile IP
  enables.
• This paper proposes a solution called MIPMANET
  (Mobile IP for Mobile Ad-hoc Network)
• Simulation
• Using Network Simulator 2 (ns-2)
• Using AODV (Ad-hoc On-demand Distance Vector)
  routing algorithm within ad-hoc networks

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II. PROTOCOL DESCRIPTIONS

• A. Mobile IP
• Proposed for location independent routing
• Makes mobility transparent for the applications
  and higher level protocols like TCP and UDP
• Allows mobile nodes to have seamless and
  untethered access to the Internet while roaming
  between different networks

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II. PROTOCOL DESCRIPTIONS -2

• Every mobile node is registered to its home agent
  (HA) in the home network and is assigned a home
  address.
• When the mobile node (visiting node, VN) is
  attached to a network other than its home network
  (foreign network), it must register to a foreign
  agent (FA) with its home address and its
  authentication. The FA notifies and authenticates
  to the HA of the VN.
• The VN then uses the care-of address, which is
  the address of the FA.
• When a node, the corresponding node (CN), tries
  to send packets to a VN, it first sends packets
  to the HA of the VN. The HA tunnels the packets
  to the FA and informs CN about the care-of
  address of the VN so that the CN can tunnel
  subsequent packets directly to FA.

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II. PROTOCOL DESCRIPTIONS -3

• The need of care-of address for VN
• All nodes in the same network use the same
  network ID of the IP address.
• VN needs an care-of address that is accessible in
  the FN, e.g. DHCP can be used.
• Selecting a FA
• FA broadcasts Agent Advertisement periodically
  for a VN to select the FA.
• VN broadcasts Agent Solicitation. FA receiving
  Agent Solicitation unicasts Agent Advertisement
  to the requesting VN.

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II. PROTOCOL DESCRIPTIONS -4

• B. AODV
• A distance vector routing protocol for ad-hoc
  networks, that operates on-demand.
• Distance Vector
• Using traditional routing table, one entry per
  destination, but without periodic routing table
  exchanges.
• Only the nodes that lie on the path between the
  two end nodes keep information about the route.
• On-demand
• Routes are only set up when a node wants to
  communicates with some other node.

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II. PROTOCOL DESCRIPTIONS -5

• On-demand routing
• When a node wants to communicates with a
  destination, it initiates route discovery, by
  flooding with Route Request (RREQ) packets.
• Every node receiving RREQ looks in its routing
  table to see if it is the destination or it has a
  fresh route to that destination.
• If it does, it unicasts a Route Reply (RREP) back
  to the source through the reverse route created
  by the RREQ, otherwise it rebroadcasts the RREQ.
• It keeps a set of predecessor nodes for each
  entry, indicating the set of neighboring nodes
  that use that entry to route packets.

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II. PROTOCOL DESCRIPTIONS -6

• Local connectivity maintenance
• Each node keeps track of its local connectivity,
  i.e. its neighbors, by either
• Periodic exchange of HELLO messages, or
• Feedback from the data link layer upon
  unsuccessful transmission.
• If a node detects the next hop node of some
  routes is unreachable, it will propagate an Route
  Error (RERR) message to all the upstream
  neighbors of these routes.
• A node receiving a RERR message will do the same
  connectivity check and will propagate RERR
  further toward the source.

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II. PROTOCOL DESCRIPTIONS -7

• Table freshness maintenance and routing loop
  check
• Each entry has a sequence number.
• All routing packets carry this sequence.
• The entry is expired if it is not used recently.
• Every packets are checked to see if it passes
  twice.

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III. INTERNET ACCESS

• A. Route and Address
• Traditional Internet routing
• All nodes in the same network use the same
  network ID of the IP address.
• To use one route for the entire network
• Ad-hoc network routing
• Nodes in an ad hoc network may have different
  network Ids
• Since data link connectivity with all other nodes
  is not possible, thus IP layer routing must be
  used.
• On-demand routing has been shown preferable

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III. INTERNET ACCESS -2

• Problems in routing for ad-hoc networks
• Cant route using network ID of a node.
• No routes are known beforehand for on-demand
  routing.
• The destination may be found unreachable after
  route discovery.
• How to make a node reachable for the
  Internet?Sol. A border node with reachable IP
  address is needed between an ad-hoc network and
  the fixed Internet.

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III. INTERNET ACCESS -3

• B. Mobile IP
• Since ordinary Mobile IP was designed primarily
  for the fixed Internet and the wireless leaf
  networks, problems arise when applying to ad hoc
  networks
• B.1 Implications of Multihop Communication
• Instead of using link-layer connectivity, FA and
  VN must use network-layer routing.
• Broadcasts are more costly (bandwidth and energy)
  for a multihop ad hoc network than on a single
  link.
• To select among several possible FAs by the
  quality of multiple links, not by a single link.
• Nodes not using Mobile IP suffer with the
  flooding of Agent Advertisements and Agent
  Solicitations.
• B.2 Implications of On-Demand Routing
• Mobile IP uses proactive routing, while many
  promising routing protocols for ad hoc networks
  are on-demand.

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IV. MIPMANET

• To use Mobile IP foreign agents as the access
  points to the Internet
• To keep track of in which ad hoc network a node
  is located
• To direct packets to the border of that ad hoc
  network
• Ad hoc routing protocol is used to deliver
  packets between FA and VN.
• A layered approach with tunneling is used for the
  outward data flow to separate the Mobile IP
  functionality and the ad hoc routing protocol.

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IV. MIPMANET -2

• MIPMANET works as follows
• VN registers to a FA with its home address
• To send a packet to the Internet
• Tunnel the packet to the FA
• To receive packets from a host on the Internet
• The packets are routed to the FA by the ordinary
  Mobile IP mechanism
• The FA will then deliver the packets to the node
  in the ad hoc network
• Nodes that do not need Internet access will see
  the ad hoc network as a stand-alone network

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IV. MIPMANET -3

• The layering of Mobile IP and ad hoc routing
  functionality is illustrated in Fig. 1.
• By the use of tunneling, the ad hoc network
  becomes transparent to the Mobile IP.

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IV. MIPMANET -4

• A. Foreign Agents and Tunneling
• Using a single care-of address, a node with
  arbitrary home address can attach to any ad hoc
  network.
• Since an ad hoc network dose not have a network
  ID, it is not possible to decide whether a
  destination is located within the same ad hoc
  network or not by simply looking at the
  destinations network ID.
• MIPMANET lets the route discovery mechanism of
  the ad hoc network search for the destination
  within the ad hoc network. If the destination is
  not within the same ad hoc network, the packet is
  tunneled to the FA by the ad hoc routing
  mechanism.
• If a node is not registered to any FA, the
  destination is considered to be unreachable.

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IV. MIPMANET -5

• Only registered VNs get Internet access.
• The only traffic that will enter the ad hoc
  network from the Internet is the traffic that is
  tunneled from the HA of a registered VN.
• The only traffic that will leave the ad hoc
  network is the traffic that is tunneled to the FA
  from a registered VN.

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IV. MIPMANET -6

• B. Adapting Mobile IP
• Instead of using link-layer addresses,
  network-layer identifier, i.e. IP addresses, must
  be used.
• B.1 Periodic Agent Advertisement
• In ordinary Mobile IP, the minimum time between
  two consecutive Agent Advertisements is 1 second.
• In ad hoc networks, every periodic advertisement
  involves flooding, thus the advertisement period
  should be longer. (5 seconds is used in the
  simulation)

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IV. MIPMANET -7

• B.2 Movement Detection
• ?Multiple hops between FAs and VNs.?None of
  the movement detection methods provided by Mobile
  IP is suitable.
• Lazy Cell Switching (LCS)
• A node should stick to a FA for as long as
  possible
• Eager Cell Switching (ECS)
• It assumes movement along a straight line
• It does not allow a VN to switch back and forth
  between two FAs.
• MIPMANET uses hop count as the metric to decide
  whether to switch FAs.
• A registered VN should register to another FA if
  it is two hops closer to this FA than to the FA
  currently registered.

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IV. MIPMANET -8
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IV. MAC PROTOCOL -2

• B. MAC Signaling
• The radio capacity with OFDM-CDMA is structured
  as
• K orthogonal codes that can be used
  simultaneously.
• Each code is used in a time-division
  multiple-access fashion a time slot carries a
  MAC_PDU (TSLOT TMAC_PDU).
• RT ID, Other Info., Data Load
• Time is structured into frames (TFRAME) lasting N
  time slots by K N MAC_PDUs.
• The structure is referred to as the TC-matrix
  (time slots-code matrix).

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IV. MAC PROTOCOL -4

• The capacity assignment is performed frame by
  frame.
• Each RT can transmit (uplink) on several time
  slot-code pairs (TC-pairs) without restrictions.

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IV. MAC PROTOCOL -5

• The basic MAC signaling consists of
• the request channel (ReqCh)
• an UL ( Uplink Logical) channel to make capacity
  requests
• the allocation channel (AlCh)
• a DL (Downlink Logical) channel to answer the
  requests
• The ReqCh and AlCh is structured in minislots.
• A ReqCh-AlCh minislot pair is dedicated to each
  RT.

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IV. MAC PROTOCOL -6

• The ReqCh in UL is structured in minislots
• Each minislot contains the bandwidth request.
• RT ID, Request GB Class, Request BE Class
• The request issued in the kth frame by each RT is
  just the number of MAC_PDUs of each service class
  found in the RT at the beginning of the kth frame
  for which there is no pending request.

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IV. MAC PROTOCOL -7

• The AlCh in DL has the same minislot structure as
  the ReqCh.
• Each minislot contains the allocation reply.
• Starting Code, Starting Offset, No. of TC-pairs
• The RN uses the AlCh to signal to each RT
• the number of assigned TC-pairs,
• the starting code (the row of the TC-matrix)
• the starting offset in the code row.
• A ReqCh-AlCh minislot pair is dedicated to each
  RT.
• Detailed format and dimensioning of ReqCh and
  AlCh are re-ported in 14.

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IV. MAC PROTOCOL -3
(1) UL Request Channel
RN to RT
(2) DL Allocation Channel
RT to RN
(N 3)
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V. THE FWA SYSTEM AS AN ACCESS RSVP CLOUD
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VI. PERFORMANCE ANALYSIS
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VII. CONCLUSION
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