Distributed cache updating algorithm for the dynamic source routing protocol
Acknowledgments The protocol described in this draft has been designed within the CMU Monarch Project, a research project at Carnegie Mellon University which is developing adaptive networking protocols and protocol interfaces to allow truly seamless wireless and mobile node networking [8, 14]. Free BSD is based on a variety of free software, including 4.4 BSD Lite from the University of California, Berkeley. Requirements for Internet Hosts -- Communication Layers. The Next Header values indicating these two extension headers thus must be reserved within the IPv4 Protocol number space. BROADCAST_JITTER 10 milliseconds MAX_ROUTE_LEN 15 nodes Interface Indexes IF_INDEX_INVALID 0x7F IF_INDEX_MA 0x7E IF_INDEX_ROUTER 0x7D Route Cache ROUTE_CACHE_TIMEOUT 300 seconds Send Buffer SEND_BUFFER_TIMEOUT 30 seconds Request Table MAX_REQUEST_ENTRIES 32 nodes MAX_REQUEST_IDS 8 identifiers MAX_REQUEST_REXMT 16 retransmissions MAX_REQUEST_PERIOD 10 seconds REQUEST_PERIOD 500 milliseconds RING0_REQUEST_TIMEOUT 30 milliseconds Retransmission Buffer DSR_RXMT_BUFFER_SIZE 50 packets Retransmission Timer DSR_MAXRXTSHIFT 2 This document proposes the use of the Destination Options header and the Hop-by-Hop Options header, originally defined for IPv6, in IPv4.
A key advantage of source routing is that intermediate hops do not need to maintain routing information in order to route the packets they receive, since the packets themselves already contain all of the necessary routing information.
We considered two different options: routing at the link layer (ISO layer 2) and routing at the network layer (ISO layer 3).
Location of DSR Functions in the ISO Reference Model When designing DSR, we had to determine at what level within the protocol hierarchy to implement source routing. In Proceedings of the IEEE Workshop on Mobile Computing Systems and Applications, pages 158--163, December 1994.
Since a Route Error packet names both ends of the hop that is no longer valid, any of the nodes receiving the error packet may update their Route Caches to reflect the fact that the two nodes indicated in the packet can no longer directly communicate.
All nodes SHOULD process all of the Route Error messages they receive, regardless of whether the node is the destination of the Route Error, is forwarding the Route Error, or promiscuously overhears the Route Error.