IDRM: Inter-Domain Routing Protocol for Mobile Ad Hoc Networks C.-K. Chau, J. Crowcroft, K.-W. Lee, S. H.Y. Wong

Mobile Ad Hoc Networks (MANET)  Do not depend on infrastructural support  A MANET is a mobile, multi-hop wireless network which is capable of autonomous operation.  Easy to set up (possibly) a short-lived network for a collection of nodes.  Characteristics  – Energy constrained nodes  – Bandwidth constrained  – Variable capacity wireless links  – Dynamic topology

Motivation  BGP – Broader Gateway Protocol  For inter-domain routing in Internet.  Allows Autonomous Systems to communicate with each other.  Opaque Interoperation.  GOAL- A BGP like solution for inter-domain routing for MANETs  Challenges in MANET  Dynamic Topology Changes  Newer MANET protocols

 BGP- Broader Gateway Protocol  Why BGP fails in MANETs ?  Path vector protocol Assumptions-  Internal Gateway Detection  Internal Network Knowledge  The above assumptions do not hold true for MANETs using reactive/hybrid routing protocols.  IP prefix aggregation  BGP Aggregates IP addresses in the domain by IP prefixes (e.g., /16).  Creation of arbitrary network partitions and merges in MANETs  IP prefixes may not suitably aggregate the IP addresses in partitioned MANETs. Existing Solutions

 Loop detection in Path vector protocol  Filters path that contain repeated AS numbers.  May fail in MANETs. Existing Solutions

 Plutarch and Turfnet  focus on high level architecture rather than provide a practical solution to the problem  SHARP  uses hybrid routing protocols  Cluster-based networking  Self organizing clusters  Routing backbone among cluster heads Focuses on single-domain Existing Solutions

 Modelled on BGP  Main Feature – Opaque Interoperation  Allows heterogeneous intra-domain routing protocols  Allows heterogeneous inter-domain routing policies  Key Design Points  Handling Domain level Topology changes  How to discover partitions and merges?  IDRM proposes periodic internal gateway detection  Proactive routing domain- partitions discovered using route updates  Reactive routing domain- Maintain soft state by sending beacons periodically.  Generate new MANET ID on partition discovery IDRM

 Computation of MANET ID  Goal is for each gateway to generate the ID and that the collision of IDs is low.  Generate random ID using pseudo random generator with the IDs of all the gateways as input  Prefix it by the domain ID to generate a new MANET ID  Why prefix domain ID ?  Merging of network partitions The dynamic allocation of MANET ID prevents the path vector protocol from detecting a false loop. IDRM

 Membership Management and Announcement  Gateway nodes collect the IDs of all the nodes in the MANET for advertisement to other domains  Membership Digest  Contains node ID information(IP address)  Non-gateway membership  Proactive routing domain- membership information is available through the update messages  Reactive routing domain- initiate membership query  Policy Support  Encoding of the domain ID in MANET ID IDRM

 Data Plane Operations  A node sends packet to one of the reachable intra-domain gateway  A route discovery is initiated in the case of reactive domain to find the gateway node which has the route to the destination  Once the packet reaches the intra-domain gateway, it checks to see if it is directly connected to the destination, if it is connected it forwards the packet to the destination.  If not, the packet is forwarded to the gateway which has the route to the destination IDRM

IDRM- Illustration  Domain Policies  A is willing to provide transit service for B, but not for C,  B,C are willing to provide transit service for others.

IDRM- Illustration

 A1 wants to send packets to a0  Proactive(OLSR)- Based on Link state information a1 know that both the destination a0 and default gateway a3 are disconnected from the MANET.  Reactive(DSR) – initiate route discovery, a2 responds  Forward packet to reachable gateway a2  A2 forwards the packet to b2

Performance Evaluation

 Proactive Intra-Domain Routing Protocol  = # of hello packets/sec  Reactive Intra-Domain Routing Protocol  = beaconing rate between pair of gateways  = avg 3 of hops between a pair of nodes  Inter Domain Routing Protocol Overhead Analysis

 = Connectivity breakage rate of connected pairs of intra-domain gateways Overhead Analysis

Limitations  Scalability  BGP – Scalable  IDRM – not scalable  Isolation of nodes  Special Hardware requirements  Multiple radio channels  Different technology  Gateway nodes require special hardware  Computation Overhead  MANET ID computation

Limitations  Not Stateless  Security Issues  The route updates are not secured  distribution of IDs of all the nodes and gateways within its own domain  requires special mechanism to discover the node IDs and then pass on this information to other nodes

Conclusion  IDRM offers a means for heterogeneous MANETs to interoperate  Identified challenges of inter-domain routing in MANETs  Established feasibility of opaque interoperation in IDRM  IDRM retains the merits of BGP  Future research direction

References  C.-K. Chau, J. Crowcroft, K.-W. Lee, S. H.Y. Wong, IDRM:Inter-domain Routing Protocol for Mobile Ad Hoc Networks.Computer Lab, University of Cambridge. Technical Report UCAM-CL-TR-708  Y. Rekhter and T. Li. RFC 1771: a Border Gateway Protocol 4 (BGP-4), March  J. Crowcroft et. al.. Plutarch: an argument for network pluralism. ACM Computer Communication Review, 33(4):258–266,  S. Schmid et al. TurfNet: An architecture for dynamically composable networks. In Proc. of WAC 2004, October  Y. Chen, A. Liestman, J. Liu. Clustering algorithms for ad hoc wireless networks. In Proc. Ad Hoc and Sensor Networks ’04  V. Ramasubramanian, Z. J. Haas, and E. G. Sirer. SHARP: A hybrid adaptive routing protocol for mobile ad hoc networks.In Proc. ACM MOBIHOC, June 2003.