advanced topics in manet - multi cast, qos, and security _pres

Session 1829

Advanced Topics in MANET Multicast, QoS, and SecurityTechnology TutorialsCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

1829 Advanced Topics in MANET--Multicast, QoS, and Security

AgendaMANET Overview Unicast Routing Protocols Neighborhood Discovery Protocol MANET Packet/Message Format

Multicast architecture Multicast details and configuration Multicast routing protocols Simple Multicast Forwarding

QoS architecture QoS based routing Choices, selection and configuration options in QoS

Approaches to security How to choose and implement security

Current research topicsCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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MANET OverviewMANETMobile Ad Hoc NETworks A collection of wireless mobile hosts capable of forming a temporary network without the aid of any centralized administration or fixed infrastructure support. Hosts are either an end-device as well as a router. MANET is a multi-hop autonomous system The system may operate in isolation, or may have gateways to and interface and interoperate with a fixed network Routing protocols developed to support changing topologies and mobile networks Physical characteristics (e.g., power, antenna) and surrounding conditions (e.g., terrain, environment) determine the communication range

CONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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MANET NodesMANET Nodes are functionally equivalent nodes Wireless communication medium with a common TCP/IP stack Layer-3 (IP), Layer-2 (MAC), and Layer-1 (PHY) are the most important layers when discussing MANET networks since they are wireless networksApplications

Transport (TCP/UDP)

Network Layer (IP)

MAC Layer (802.11, 802.16)

PHY (OFDM) Rx Tx


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MANET ApplicationsMilitary usage Where no infrastructure is present, sensor networks

Disaster areas Earthquake, tornado hit areas, quick network setup time

Remote and inhospitable terrains Vehicle-to-vehicle communication In intelligent transportation system

Personal Area Computing Cell phones, laptops, wearable computers

Mesh-based mobile networks Robust, inexpensive alternatives to cell-based mobile network infrastructures


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MANET AdvantagesEasy deployment No centralized or fixed infrastructure required Can be deployed at remote geographical locations

Robustness No dependence on a centralized infrastructure

Low cost Requires minimum setup and administration costs

Integration with Internet and wireless infrastructure networks Increases the network capacity, coverage area and application domain


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MANET ChallengesRouting: Traditional unicast and multicast routing protocols are not suited for rapidly changing networks with unstable links. Routing protocols need to address the following: Simple, Reliable, and Efficient Quickly adapt to changes in topology and traffic pattern Protocol reaction to topology changes should result in minimal control overhead High throughput (bandwidth) Low convergence delay Low power consumption

Lower bandwidth on degraded wireless links Difficult to provide Quality of Service to end users

Decentralized and wireless network Security approaches must be specific for MANET weaknesses, in addition to traditional approaches Attacks are designed specifically for MANETs and nodes or networked embedded systems that exist in the network


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Unicast Routing Protocols (i)Proactive Unicast Routing Protocols: Constantly maintains routing information and tables of the current network. Nodes continuously broadcast information that they are still in the network and who their discovered neighbors are (Examples: OLSR, MMRR). Multipoint Relay (MPR) Nodes are selected as leads to perform controlled flooding, so messages are not flooded throughout the network by all nodes. These node forward global information such that it reaches the largest number of nodes.

HELLO

HELLO HELLO HELLO


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OLSRv2Optimized Link State Routing Proactive link-state protocol Periodic local signaling Neighbor and link discovery Periodic global signaling

Utilizes a normalized packet format Utilizes Multi-Point Relays (MPR) Nodes are selected as MPRs that flood the network with forwarded routing messages Rather than every node forwarding messages, only a subset of them forward messages Acts as a routing backbone in the network Reduces overhead, less flooding of information, reduces channel accessCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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OLSRv2Advantages Routes immediately available Minimizes flooding by using MPR Reaction to topological changes can be adjusted by changing the time interval for HELLO messages Utilizes common packet format

Disadvantages Bigger overhead than reactive protocols but may vary depending on the amount of traffic generated Needs more power (CPU/battery) due to periodic link state calculation


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Unicast Routing Protocols (ii)Reactive Unicast Routing Protocols: On-demand, route requests flood the network in attempt to find a path to the destination. (Examples: AODV, DYMO) No periodic routing messages or discovery

B

A D C


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DYMODynamic MANET On-demand routing protocol draft-ietf-manet-dymo-14 Major components Route discovery Route maintenance Route Request (RREQ), Route Reply (RREP) messages, and route error (RERR) messages Link monitoring required, RERR messages are sent when topology changes and routes break, RREQ messages are resent to find a route, RREP messages sent when the destination is discovered Stores routes to all nodes in path when a RREQ is sent and RREP returned Uses sequence numbers in messages to avoid loops in the networkCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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DYMOAdvantages Initially silent, no need for constant traffic, control generated on demand Better for CPU/battery constrained devices Conserves bandwidth in the network and memory for storing links that may not be needed Simpler to implement than AODV Uses path accumulation unlike AODV, routes for neighbors along the path are discovered with RREQ messages Does not specifically require HELLO messages but indicates that NHDP could be used

Disadvantages Traffic needs to wait until a route is discovered, results in higher latency RREQ are broadcasted at every hop in attempt to find the route Unlike AODV, no gratuitous RREP to keep a route active


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Unicast Routing Protocols (iii)Hybrid (Proactive/Reactive): Initially nodes and routes are discovered through a proactive method, unknown nodes and routes are discovered reactively when needed. (Examples: ZRP, TORA)

Where is Node E? Where is Node E? B Here is Node E

E B

E

A

Here is Node E D Where is Node E?

A D

C

C


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Neighborhood Discovery Protocol (NHDP)Generic Neighborhood Discovery Protocol for MANETs, utilized by both unicast and multicast routing protocols. Introduced by OLSRv2 team. draft-ietf-manet-nhdp-07

Nodes exchange HELLO messages to determine 1-hop and symmetric 2-hop neighbors Neighborhood stored in an Information Base for other protocols to use Useful for both Layer-3 and Layer-2 protocolsNodeE HELLO A B HELLO HELLO

1-hop B, C A, D, E A, D B,C B

C

HELLO HELLO

D

A B C D E

2-hop (Next Hop) D(B), E(B) C(A) B(A) A(B), E(B) A(B), D(B)15



NDHP: One-Hop Symmetrical LinksSymmetric neighbors are those that have knowledge that they have been discovered themselves by their own neighborsNode A HELLO Node A Node B HELLO Node B Node C HELLO Node C Node D HELLO Node D 1-hop B, C 1-hop A, D, E 1-hop A, D 1-hop B,C

Node E HELLO Node E

1-hop B16



NHDP: Two-Hop Neighbors

Node A HELLO Node A Node B HELLO Node B

1-hop B, C 1-hop A, D, E

2-hop D, E (From Node B HELLO)


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NHDPNHDP is useful because it creates a common MIB that all MANET protocols can utilize Almost all MANET protocols require NHDP in some form Node Information Base per Network Interface Neighbor Set Interface addresses (one or more) Symmetric link (links can be asymmetrical) Lost Neighbors Expiration time


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MANET Packet Format: packetbbGeneralized MANET Packet/Message Format draft-ietf-manet-packetbb-13

All protocols have common messages that can be combined into a single message format HELLO Messages TC Messages RREQ, RREP, RERR MessagesType (Protocol Information) Length (Number of Bytes) Value (Variable information)

A generalized Type-Length-Value (TLV) message is used to represent various parameters and control information for multiple protocols Allows for compact message headers, less overhead, less wireless channel accessCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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AgendaMANET Overview Unicast Routing Protocols Neighborhood Discovery Protocol MANET Packet/Message Format

Multicast architecture Multicast details and configuration Multicast routing protocols

QoS architecture QoS based routing Choices, selection and configuration options in QoS

Approaches to security How to choose and implement security

Current research topicsCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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What is Multicasting?

Why its Needed: More and more applications where one-tomany dissemination is necessary Multicast service is critical in applications characterized by the close collaboration of teams Shared situational awareness (first responder, military,) Collaborative science Distributed business processes


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Multicasting in MANETs

Multicasting reduces the communication costs for applications that send the same data to multiple recipients Minimizes the link bandwidth consumption, sender and router processing, and delivery delay, power consumption Exploits the inherent broadcast property of wireless transmission Difficult to control and limit flooding


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Important Design Considerations for Multicast Protocols in MANETRobustness Support high packet delivery ratio with dynamic mobile nodes

Efficiency Efficiently utilize limited bandwidth of wireless network, minimize control overhead and flooding Reduce wireless channel access for certain MAC protocols Utilize limited power and memory resources effectively (e.g., Wireless Sensor Networks)

Scalability Generally a problem with all MANET, needs to be flexible to networks of increasing size

QoS Multicast traffic flows given QoS despite lossy network conditions

Independence Independent of UNICAST routing protocol if possible The multicast routing protocol must trade off Efficiency vs. Robustness How do we classify Multicast routing protocols?CONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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Classifying Multicast Routing Protocols: Topology


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Classifying Multicast Routing Protocols: Topology (cont.)


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Classifying Multicast Routing Protocols: Topology MaintenanceSoft State Provides improved reliability Uses periodic control packet flooding Has high packet delivery ratio Has high control overhead Provides improved efficiency Exchanges control packets on link failures Has low packet delivery ratio Has low control overhead Leverages unicast routing protocol for forwarding decisions Low to no control packet flooding Overhead in-line with packet data, rather than control packets Group members must be known by senders, designed for small networks Channel accesses are reduced28

Hard State

Stateless



Related IETF MANET WGThe IETF MANET WG works to standardize IP wireless routing protocol functionality for both static and dynamic topologies The group is pursuing a standards track for both reactive and proactive protocols, as well as an experimental track for multicast protocols Proactive Protocol OLSRv2, derived from existing OLSR, draft-ietfmanet-olsrv2-07 Reactive Protocol Dynamic MANET on-demand (DYMO), derived from existing AODV, draft-ietf-manet-dymo-14 Neighborhood Discovery Protocol (NHDP) Variations used by most routing protocols to discover 1-hop neighbors in a wireless network, draftieft-manet-nhdp-07 Multicast Protocol Simplified Multicast Flooding (SMF), based on optimized flooding, draft-ietf-manet-smf-07


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Common Multicast ProtocolsProtocol AMRoute AMRIS LAM MAODV CAMP ODMRP DDM SMF Multicast Topology Hybrid Tree Tree Tree Mesh Mesh Stateless Tree Flooding Loop Free No Yes Yes Yes Yes Yes Depends on unicast No Dependence on unicast protocol Yes No Yes Yes No No No No Periodic Message Yes Yes No Yes Yes Yes No No No No No QoS Control packet flooding done/required Yes Yes No Yes No Yes No No30



Simplified Multicast Forwarding (i)Internet Draft: draft-ietf-manet-smf-07 Goal is to build efficient relay sets of nodes to minimize the amount of flooding, more advanced than just classical flooding (CF) Carefully does not retransmit packets it has already processed, duplicate packet detection (DPD) Uses hash functions or unused ID or sequence number fields in network protocol headers to encode information to avoid packet duplication Forwarding rules can range from default flooding, where every nonduplicate packet is forwarded out its wireless interface, to controlled flooding, where a node may only forward incoming packets based on source MAC addresses Offers improvements in terms of efficiency over classical flooding, and provides robustness to link or node failureCONFIDENTIAL RESTRICTED ACCESS: This information may not be disclosed, copied, or transmitted in any format without the prior written consent of OPNET Technologies, Inc. 2008 OPNET Technologies, Inc.

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Simplified Multicast Forwarding (ii)Six Rules for Forwarding Multicast Packets* Multicast packets with TTL

advanced topics in manet - multi cast, qos, and security _pres

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