BACKGROUND

Currently, the majority of methods used for efficiently supporting many-to-many communication (multicasting) in computer networks involve routing trees. Multicast routing trees (multicast trees for short) achieve efficient and simple transfer by forcing a single path between any pair of routers. Accordingly, if multiple sources must transmit information to the same set of destinations, using routing trees requires that either a shared multicast tree be used for all sources or that a separate multicast tree be established for each source. Using a shared multicast tree has the disadvantage that packets are distributed to the multicast group along paths that can be much longer than the shortest paths from sources to receivers. Using a separate multicast tree for each source of each multicast group leads to scaling difficulties. In addition, because trees provide minimal connectivity among the members of a multicast group, the failure of any link in the tree partitions the group and requires the routers involved to reconfigure the tree. During periods of routing-table instability, routers may be forced to stop forwarding packets while they wait for the multicast routing tree to be reconstructed.

DESCRIPTION

Scientists at the University of California have designed the Core-Assisted Mesh Protocol (CAMP) for multicast routing in ad-hoc networks. CAMP generalizes the notion of core-based trees introduced for internet multicasting into multicast meshes that have much richer connectivity. The main goal of using these meshes is to maintain the connectivity of multicast groups even while network routers move frequently. CAMP guarantees that, within a finite time, every receiver of a multicast group has a reverse shortest path to each source of the multicast group. Multicast packets for a group are forwarded along the shortest paths from sources to receivers defined within the group's mesh. CAMP uses cores only to limit the traffic needed for a router to join a multicast group; the failure of cores does not stop packet forwarding or the process of maintaining the multicast meshes.

APPLICATIONS

This multicast routing protocol is designed for use in ad-hoc networks such as wireless and mobile computer networks.

REFER ALSO TO UC CASES 2000-303, 2000-311, 2000-314, 2000-349 THROUGH 356, 2000-360, 2000-380, 2000-383 THROUGH 385

ADVANTAGES

This novel protocol:

• Establishes and maintains routing structures that are far more resilient than trees;
• Makes efficient use of communication resources;
• Does not require flooding an entire network to set up its routing structure (unlike all previous non-tree based protocols);
• Easily outperforms tree-based multicast protocols in simulated dynamic networks.

Patent Status

Country	Type	Number	Dated	Case
United States Of America	Issued Patent	6,917,985	07/12/2005	2000-311

Inventors

• Garcia-Luna-Aceves, Jose Joaquin(JJ
• Madruga, Ewerton L.

Other Information

Contact

University of California, Santa Cruz Office for Management of Intellectual Property / technology@ucsc.edu / tel: View Phone Number. Please reference Tech ID #10182.

Request Additional Information

ADDITIONAL TECHNOLOGIES BY THESE INVENTORS

• Scalable Integrated Services Architecture For Computer Networks
• Receiver Initiated Channel Hopping (Rich)
• Bandwidth Efficient Source Tracing (Best) For Wireless Networks
• On-Demand Loop-Free Multipath Routing
• Differentiating Congestion Vs. Random Loss: A Method For Improving Tcp Performance Over Wireless Links
• Improving Tcp Congestion Control Over Internets With Heterogeneous Transmission Media
• Mpath: A Loop-Free Multipath Routing Algorithm Using Predecessor Information
• Receiver Initiated Multiple Access For Ad-Hoc Networks
• Group Coordination Protocol For Networked Multimedia Systems
• System And Method For Ad Hoc Network Access Employing The Distributed Election Of A Shared Transmission Schedule
• Tree-Based Ordered Multicasting