Distributed cache updating algorithm for the dynamic source routing protocol
We see great potential for DSR running between clouds of mobile nodes around fixed base stations. - Historically, DSR grew from our contemplation of a multi-hop ARP protocol [6, 7] and source routing bridges . - Technically, we designed DSR to be simple enough that that it could be implemented directly in network interface cards, well below the layer 3 software within a mobile node. Internet-Draft, draft-ietf-ipngwg-ipv6-spec-v2-01.txt, November 1997. When using source routing, each packet to be routed carries in its header the complete, ordered list of nodes through which the packet must pass. 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. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time.
The protocol allows nodes to dynamically discover a source route across multiple network hops to any destination in the ad hoc network.
In IPv4, we require two new protocol numbers be issued to identify the next header as either an IPv6-style destination option, or an IPv6-style routing header.
Furthermore, this document defines four new types of destination options, each of which must be assigned an Option Type value: - The DSR Route Request option, described in Section 6.1.1 - The DSR Route Reply option, described in Section 6.2.1 - The DSR Route Error option, described in Section 6.2.2 - The DSR Acknowledgment option, described in Section 6.2.3 DSR also requires a routing header Routing Type be allocated for the DSR Source Route defined in Section 6.3.
An experimental optimization to improve the handling of errors is to support the caching of "negative" information in a node's Route Cache. An Ethernet Address Resolution Protocol: Or Converting Network Protocol Address to 48Ethernet Addresses for Transmission on Ethernet Hardware.
All nodes on the route before this hop are still reachable on this route, but subsequent nodes are not.