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Address Configuration in Adhoc Networks in IPv4.

Address Configuration in Adhoc Networks in IPv4. By Meenakshi Sundaram V. Problem Definition. In a MANET, group of nodes dynamically form a network. No dedicated machine providing DHCP services. Providing an efficient addressing scheme for an infrastructure less network (adhoc).

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Address Configuration in Adhoc Networks in IPv4.

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  1. Address Configuration inAdhoc Networks in IPv4. By Meenakshi Sundaram V

  2. Problem Definition • In a MANET, group of nodes dynamically form a network. • No dedicated machine providing DHCP services. • Providing an efficient addressing scheme for an infrastructure less network (adhoc). • Existing adhoc literature bypass node configuration, assume nodes are configured prior.

  3. DHCP

  4. DHCP • Network admin. assigns a range of IP addresses to DHCP • client computer on the LAN has its TCP/IP software configured to request an IP address from the DHCP server when that client computer's network interface card starts up • Request and grant process uses a lease concept. • Dynamic reuse of IP address.

  5. DHCP in ADHOC domain • Centralized administration is an impossible task. • Automated Dynamic assignment of IP address a desirable goal. • Resolution of addresses when two or more partitions merge.

  6. Characteristics for IP address protocol • IP address valid only for the duration for for which node stays in network. • Node departs, IP address should become reusable. • Resolve if two nodes happen to have same address. could arise because of reusability.

  7. [S] S E B C A H I Figure 2.Using routing protocol’s flooding Related Work • Perkins et.al - Node i picks random address. Issues RREQ. if no reply beyond a timeout, address distinct.

  8. Related Work • IP address treated as shared resource. assignment of new IP address requires approval from all other nodes. Each node maintains list of used addresses. not scalable.[ Nesargi et.al] • Zero Configuration Choose a random address and use ARP to check for duplication.

  9. Basic Idea • A distributed approach, extending the functionality of DHCP across all nodes in an adhoc network. • Dynamically configure each new node also as a DHCP server. • Add a small address space to each node, for it to allocate addresses.

  10. Local link address • Use the IPV4 local link address – 169.254/16 • Use sub netting. • Net[0].net[1].net[2].net[3]. • Of the 16 host bits, set 13 bits for subnet. • Theoretically number of hosts=2^13*8 adhoc nodes.

  11. Sub netting. • Address of the first node 169.254.000.001 Subnet add: 255.255.255.248 11111111.11111111.11111111.11111000 IP Address 169.254.255.001 11111111.11111111.00000000.00000001 Subnet add: 169.254.255.000 11111111.11111111.00000000.00000000 • Address of the second node 169.254.000.002 • Subnet Allocated to second node 169.254.000.008

  12. 1st Node: IP: 169.254.000.001 Subnet: 169.254.000.000 2nd Node: IP: 169.254.000.002 Subnet 169.254.000.008 Figure 3.Configuring Nodes. Node Configuration

  13. Address request • A new node broadcast’s a request with hop count=1 • If more than one neighbor offer’s an address, use the one with least host part. • The server-node, generates subnet_request packet, broadcasts.

  14. New Subnet Request • Includes its subnet value in the request. • Every receiving node : • check if subnet value greater than in packet. • If so, replace with greater subnet in packet &forward. • Else if contains reusable subnets, append to packet and forward. • Else discard. • subnet allocated to the new node, using the reply generated.

  15. State at Each node • Each node i maintains: Client • Server’s address. • A lease timer. Server • For every allocated address, by node i: maintain subnet address, shutdown timer. • List of un-allocated addresses. • List of released subnet’s.

  16. IP Renewal • If timer expires at both client and server end & lease not renewed. • Add the address to the free pool at server end. • Subnet reusable after a recovery timeout. • Client sends a 1 hop address request again. • Acquire new address, subnet. Allot existing clients, new addresses & reset timer (s).

  17. Split • Network Split • Lease timer expires. • adjacent neighbor’s detected could be of original network or new network. • Irrespective, new address allocated. Network split gracefully handled. • If no neighbor, first node of new network.

  18. Merger • Network Merger • Assume Network Merger detected. • Node x and y in transmitting range of each other detect they belong to different networks • One node loses competition, gets new address and subnet from the other node. • Trigger’s further changes. • Merger is expensive.

  19. Comments • Quick node configuration. • Eliminates random assignment of IP address. Until a merge occurs ,address duplication not possible. • Nodes belonging to multiple network segments. • Proactive?

  20. Questions?

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