Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1998-12-01
2001-04-03
Olms, Douglas W. (Department: 2661)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S428000, C370S401000
Reexamination Certificate
active
06212195
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to an apparatus and method for integrating voice and data on a single telecommunication network. More specifically, the invention relates to a telecommunication apparatus and method for forwarding voice and data packets to the network on communication paths having separate collision domains.
BACKGROUND OF THE INVENTION
Many modem businesses use two separate telecommunication networks for voice and for data. The costs associated with installing and maintaining two networks have induced some businesses to seek ways to integrate voice and data on a single telecommunication network infrastructure. As a result, the telecommunications industry has produced systems that integrate telephones and computers onto the same network. In such systems, telephones and computers share the same cabling infrastructure for transmitting voice data and computer data.
Advances in technology, though, continually increase the data rate capability of networks. The Ethernet network, which is a prevalent type of local area network (LAN), is an example. Devices (or nodes) connected to an Ethernet network communicate with each other using packets having a structured format. The packets include a destination address, a source address, and the data. Initially, the 10 Mbps Ethernet network was the basis for the IEEE 802.3 standard, but Ethernet has since evolved to support network data rates of 100 and 1,000 Mbps. While current implementations of integrated telecommunication systems can adequately support network data rates of an order of 10 Mbps, such systems cannot adequately provide equivalent functionality at network speeds of 100 Mbps and beyond. This is due, in part, to the use of hubs by current implementations of integrated telecommunication systems to forward Ethernet packets on the LAN. A hub is a network device that deposits Ethernet packets received on one communication path onto another communication path. Many communication paths can meet at a hub. Because a hub does not provide separate collision domains, the devices using these communication paths compete against each other for use of the hub. A collision domain is a segment of the LAN where a collision occurs when any two devices attempt to transmit packets simultaneously on that segment.
When a packet collision occurs on a segment, the devices sending the packets become alerted to the collision and “back off,” that is, the sending devices wait a predetermined period of time before attempting to complete the transmission of the packets on that segment. The IEEE 802.3 standard specifies a back-off algorithm that each sending device must perform to be compliant with the standard when involved in a packet collision.
A problem, however, is that at high data rates (e.g., 100 Mbps data rates and beyond), a sending device can incorrectly deem a packet transmission to have been successful although that packet later encounters a collision after propagating through the network. Normally, at lower data rates (e.g., 10 Mbps), this collision causes the sending device to back-off on future attempts to transmit the packet. However, the high data rates enable the sending device to complete the packet transmission before the collision occurs or is detected. Further, the sending device may even have continued to transmit other packets on that network segment. At high data rates, the propagation delay incurred in the network can prevent the timely detection of collisions and render the operation of the integrated telecommunication system impracticable.
SUMMARY
In one aspect, the invention features a telecommunication apparatus for providing packets to at least one of a first network and a second network. The apparatus includes a first I/O device in electrical communication with the first network via a first communication path. A second I/O device is in electrical communication with the second network via a second communication path. An input port receives signals (e.g., audio signals) from an input device. A packet controller in communication with the first and second I/O devices and the input port: (a) forwards packets received by the first I/O device to the second I/O device for transmission to the second network; and (b) generates packets from the signals received by the input port for transmission to at least one of the first and second networks.
In one embodiment, the invention includes memory for storing packets, and a direct memory access (DMA) controller in electrical communication with the memory and the I/O devices. The DMA controller forwards packets from the first I/O device to the second I/O device via the memory. The invention also can include a table that stores addresses. The DMA controller compares a destination address of each received packet to the addresses stored in the table to determine whether that packet is to be used by the packet controller to perform an action as prescribed by that packet.
The memory can be organized into sections. Each memory section can be associated with one of the I/O devices and can include a receive region for storing packets received by the associated I/O device and a transmit region for storing packets to be forwarded to the associated I/O device. The receive region can include a specific block for storing packets addressed to the apparatus and a general block for storing packets addressed to other devices. The transmit region can include a priority block for storing prioritized packets and a general block for storing non-prioritized packets.
The invention can include a first media access control (MAC) device and a second MAC device. The first MAC device includes the first I/O device and the second MAC device includes the second I/O device. The first I/O device can receive a packet that includes an address. In response to that address, the packet controller can perform an action as prescribed by that packet. The packet controller can discard the packet with or without forwarding the packet to the second I/O device. The packet controller can prioritize the packet prior to forwarding the packet to the second I/O device. The packet controller uses the priority data to determine an order in which to forward packets.
The first and second I/O devices, the input port, and the packet controller can be disposed on an integrated circuit device. In one embodiment, the first network can be an Ethernet network and can operate at a data rate of 10 Mbps or higher.
In another aspect, the invention features an telecommunication apparatus that includes an input port, a first I/O device in electrical communication with a first network via a first communication path, a second I/O device in electrical communication with a second network via a second communication path, and a packet controller in electrical communication with the I/O devices. The packet controller forwards a first portion of the packets received by the first I/O device to the second I/O device and discards a second portion of the received packets without forwarding such packets to the second I/O device.
The packet controller can include an address table that stores addresses. The packet controller can discard each packet of the second portion of received packets when that packet includes a destination address that matches an address stored in the address table. The first portion of packets received by the first I/O device are non-prioritized and the packet controller can prioritize the first portion of packets prior to forwarding such packets.
In another aspect, the invention features a telecommunication apparatus that includes a first and a second I/O device, an input port, and a packet controller. The first I/O device is in electrical communication with the first network via a first communication path. A second I/O device is in electrical communication with the second network via a second communication path. An input port receives signals (e.g., audio signals) from an input device. A packet controller (a) forwards packets received by the first I/O device to the second I/O device for transmission to the secon
Dryer Paul Francis
Fayngersh Lee Diana
McCormack Michael Sean
Weeks Steven Victor
3Com Corporation
McGlew and Tuttle , P.C.
Olms Douglas W.
Pizarro Ricardo M.
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