Multiplex communications – Diagnostic testing – Fault detection
Reexamination Certificate
1998-11-09
2004-11-16
Ho, Duc (Department: 2665)
Multiplex communications
Diagnostic testing
Fault detection
C370S352000, C370S357000, C370S469000, C714S027000
Reexamination Certificate
active
06819655
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to accessing and testing communication networks. More particularly, this invention relates to remotely accessing, monitoring, and analyzing network protocols, such as used in public switched networks.
2. Description of the Related Technology
Current communication technology accommodates the transmission of voice, data, and video over multiple communication networks. The transmission standard employed by one communication network is often different than the standard employed by another. These standards include frame relay, asynchronous transfer mode (ATM), integrated services digital network (ISDN), fiber distributed data interface (FDDI), and Internet, for example. These transmission standards specify a variety of signal protocols, thereby requiring conversion of signals from one protocol to another, and vice versa.
Generally, a protocol refers to an agreed-upon format for transmitting data between two devices. The protocol determines, among other things, the type of error checking to be used, method of data compression, if any, and how a device indicates that it has finished sending or receiving a message. Several of the most significant protocols in use today are frame relay, ATM, ISDN, FDDI, and TCP/IP.
Frame relay is a packet-switching protocol for connecting devices on a wide area network (WAN). Frame relay networks support data transfer rates at 1.544 Megabits per second (Mbps) (also known as DS
1
or T
1
rate) and 44.736 Mbps (also known as DS
3
or T
3
rate). ATM is a packet-based network supporting data transfers between 25 and 622 Mbps. ATM offers a fixed point-to-point connection known as a “virtual circuit” (VC) between a source and destination. ATM is often transmitted over a physical medium known as a synchronous optical network (SONET) which employs fiber optic links. SONET defines a fiber optic transmission system offering optical channels from OC-1 at 51 Mbps to OC-96 at 4.8 Gigabits per second (Gbps).
ISDN is an international communications standard for sending voice, data, and video over digital telephone lines. ISDN requires special metal wires and supports data transfer rates of 64 kilobits per second (kbps). FDDI is a set of American National Standards Institute (ANSI) protocols for sending digital data over fiber optic cable. FDDI networks support data rates up to 100 Mbps. FDDI networks are typically used as backbones for WANs. Finally, data traffic on the largest public network in the world, the Internet, conforms to Transmission Control Protocol/Internet Protocol (TCP/IP) standard which is a suite of communication protocols for connecting host computers on the Internet.
An open systems interconnection (OSI) model is often implemented to facilitate the interoperability of systems conforming to different standards. The OSI model provides a widely accepted structuring technique called “layering” whereby the communications functions are partitioned into a hierarchical set of layers. Each layer performs a related subset of the functions required to communicate with another system. Ideally, the layers are defined so that changes in one layer do not require changes in other layers. The OSI model defines the following: physical, data link, network, transport, session, presentation, and application layers. The following is a brief description of the function and purpose of each layer.
The physical layer defines the transmission of unstructured bit streams over physical links, involving parameters such as voltage swings and bit durations. The data link provides reliability to the bit stream by defining error detection and control bits. The network layer is responsible for establishing, maintaining, and terminating connections across one or more networks between two communicating systems. The transport layer is responsible for maintaining proper sequence and error-free delivery of data between two communicating systems. The session layer controls the dialogue between two communicating systems by specifying discipline (e.g., half- or full-duplex), grouping of data, and checkpoint mechanism for recovering lost data. The presentation layer defines data formats exchanged between applications by offering a set of transformation services, such as compression or encryption. Finally, the application layer defines the mechanism of accessing the OSI environment to support the exchange of information between two or more applications, such as file transfer and electronic mail.
As the number of communication networks increases, so does the complexity of managing, maintaining, and troubleshooting a malfunction in these networks.
FIG. 1
is a pictorial diagram depicting an exemplary scenario of a current network management procedure when a failure occurs. Typically, upon experiencing a failure in service, at block
110
, a network user contacts a network operation center and complains about the loss in service. A network user may be any organization or entity, such as a bank, which uses or leases one or more communication links from one or more network providers, such as a telephone company. At block
120
, the network operations center dispatches a technician(s) to the site of the suspect transmission lines to determine if a problem exists in the physical layer of transmission. The physical transmission layer generally refers to the OSI physical layer, including the specification of wiring, cables, connectors, switches, and other similar physical components which make up the physical transmission path.
At block
130
, if the technician detects a problem in the physical layer, the physical component is repaired. However, if the technician does not detect a problem in the physical layer, specialized technicians with protocol analyzers are dispatched to determine if a defect exists in the logical layer of transmission (block
140
). Generally, the logical transmission layer refers to the OSI data link, network, transport, session, presentation, and/or application layers. More particularly, the logical transmission layer refers to the OSI data link, network, and/or transport layers. At times, the specialized technicians may have to communicate several times, back and forth, with the technicians at the physical layer before they can determine and isolate the problem. Possibly many hours later, the network operations center notifies the network user of the nature of the problem and time needed to restore normal network operation (block
150
). Once the problem is determined, an appropriate fix to hardware or software is made to correct the problem which caused the failure in transmission.
As shown in the above exemplary scenario, isolating and correcting a malfunction in a multiprotocol network may be a very time consuming process involving multiple levels of expertise. During this process, actual examination of a link at multiple locations may be necessary to isolate the source of the malfunction in the network. Moreover, the network user's operation is shut down or, in some cases, transferred to more costly back-up solutions. In troubleshooting a network, the network provider is often compelled to dispatch technicians with expensive, bulky testing units to determine where a problem may exist in the network, thereby making network maintenance costly and inefficient.
Therefore, there is a need in communications network technology to provide network providers with the ability to maintain and troubleshoot their network in an efficient and cost-effective manner.
SUMMARY OF THE INVENTION
To overcome the limitations of the prior art, the invention provides a system for analyzing a first communications network. The system comprises a device collecting data from the first network, and a server computer in data communication with the device via a second communications network. The server computer executes an application to analyze data protocol. The system further comprises a client computer configured for communicating with the server computer over the second communications network.
In another e
Applied Digital Access, Inc.
Ho Duc
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