초록 ▼

A network adapter for a synchronous logical ring network operates on existing physical twisted-pair telephone topologies. Information propagates around the logical ring, reaching every device on each revolution around the network. Network devices are full-duplex, transmitting and receiving informati

A network adapter for a synchronous logical ring network operates on existing physical twisted-pair telephone topologies. Information propagates around the logical ring, reaching every device on each revolution around the network. Network devices are full-duplex, transmitting and receiving information on every clock cycle. Network devices arbitrate to be elected the network clock device. By synchronizing all network devices to a single reference clock, and providing fixed frames of information propagating around the network at consistent time intervals, the logical ring network ensures that information propagates from one device to another at consistent time intervals. The fixed-length frames are divided into two independent streams: a data stream for the distribution of real-time continuous digital media streams; and a system command stream for the distribution of system commands.

대표청구항 ▼

A network adapter for a synchronous logical ring network operates on existing physical twisted-pair telephone topologies. Information propagates around the logical ring, reaching every device on each revolution around the network. Network devices are full-duplex, transmitting and receiving informati

A network adapter for a synchronous logical ring network operates on existing physical twisted-pair telephone topologies. Information propagates around the logical ring, reaching every device on each revolution around the network. Network devices are full-duplex, transmitting and receiving information on every clock cycle. Network devices arbitrate to be elected the network clock device. By synchronizing all network devices to a single reference clock, and providing fixed frames of information propagating around the network at consistent time intervals, the logical ring network ensures that information propagates from one device to another at consistent time intervals. The fixed-length frames are divided into two independent streams: a data stream for the distribution of real-time continuous digital media streams; and a system command stream for the distribution of system commands. ving at the router the packet, the packet having been forwarded to the router from a second router, the first and second routers being in a subset of the network, the second router having forwarded the packet to the first router based upon a first set of unicast routing information maintained by the second router for use in routing multicast packets from devices external to the subset; and forwarding from the first router of the packet received from the second router based upon a second set of unicast routing information for use in routing multicast packets from devices within the subset. 30. Memory according to claim 29, wherein the subset comprises a component of a routing hierarchy, a network domain, a routing domain, or an autonomous routing group. 31. Memory according to claim 29, wherein the second set of unicast information includes identification of an upstream border router for each multicast source device outside said subset. 32. Memory according to claim 29, wherein, as received by the second router, the packet received by the first router is unencapsulated. 33. A system of routers for routing a multicast packet in a network, comprising: a network subset; one or more routers internal to the network subset configured as a border router, the border router maintaining a first set of multicast routing information for devices external to the network subset; and, one or more routers internal to the network subset configured as a non-border router, the non-border router maintaining a second set of unicast routing information only for devices internal to the network subset. 34. A system of routers according to claim 33, wherein the border router is configured as an upstream border router that receives multi-cast packets from a multicast source device external to the network subset and distributes these packets downstream using unicast routing information to routers within the network subset. 35. A system of routers according to claim 34, wherein the second set of routing information includes identification of an upstream border router for each multicast source device external to the subset. 36. A system of routers according to claim 33, wherein the border router is configured as a downstream border router that receives unicast packets from a device within the network subset and distributes