Abstract: Aspects describe using a Policy Access Gateway to facilitate scalability within a communication network and to provide a solution to deploy an enhanced policy gateway. The Policy Access Gateway can enhance standard defined Diameter Routing Agent (DRA) functions with session binding mechanisms. Further, the Policy Access Gateway is scalable and can be deployed in a very large network that supports hundreds of millions of users. Further, the Policy Access Gateway can provide additional policy information to enable policy information consolidation and caching capabilities.

Abstract: Some embodiments provide a method for configuring a logical middlebox in a hosting system that includes a set of nodes. The logical middlebox is part of a logical network that includes a set of logical forwarding elements that connect a set of end machines. The method receives a set of configuration data for the logical middlebox. The method uses a stored set of tables describing physical locations of the end machines to identify a set of nodes at which to implement the logical middlebox. The method provides the logical middlebox configuration for distribution to the identified nodes.

Abstract: Techniques for determining which resource access requests are handled locally at a remote computer, and which resource access requests are routed or “redirected” through a virtual private network. One or more routing or “redirection” rules are downloaded from a redirection rule server to a remote computer. When the node of the virtual private network running on the remote computer receives a resource access request, it compares the identified resource with the rules. Based upon how the identified resource matches one or more rules, the node will determine whether the resource access request is redirected through the virtual private network or handled locally (e.g., retrieved locally from another network). A single set of redirection rules can be distributed to and employed by a variety of different virtual private network communication techniques.

Abstract: A request from a user device is received for a service by a network management server via a communication network. The network management server determines multiple routes for delivering content associated with the requested service based on a provisioning profile for the user device. Content associated with the requested service is then delivered via the determined multiple routes. The provisioning profile is updated and includes preferred service types, desired QoS for one or more services, client account information, and/or client credit verification information. The network management server manages the delivery of the content associated with the requested service via the determined multiple routes. The content includes packets that are the same, which are communicated or delivered simultaneously via the determined multiple routes. The network management server allocates one or more of the determined multiple routes for delivering the content based on priorities associated with the routes.

Abstract: Methods and apparatuses for inspecting packets are provided. A primary security system may be configured for processing packets. The primary security system may be operable to maintain flow information for a group of devices to facilitate processing of the packets. A secondary security system may be designated for processing packets upon a failover event. Flow records may be shared from the primary security system with the secondary security system.

Abstract: A market making node in a network routes machine readable documents to connect businesses with customers, suppliers and trading partners. The self defining electronic documents, such as XML based documents, can be easily understood amongst the partners. Definitions of these electronic business documents, called business interface definitions, are posted on the Internet, or otherwise communicated to members of the network. The business interface definitions tell potential trading partners the services the company offers and the documents to use when communicating with such services. Thus, a typical business interface definition allows a customer to place an order by submitting a purchase order or a supplier checks availability by downloading an inventory status report.

Abstract: A communication device that allows a proxy reception device to perform proxy reception of data directed to the communication device. The communication device establishes a SIP protocol-based session through a call controller connected to a network and performs data communication. The communication device holds proxy reception device destination information representing an IP address of the proxy reception device that performs proxy reception of data transmitted to a SIP URI of the communication device, and registers, into the call controller, registration information comprised of communication device destination information and proxy reception device destination information according to which the communication device sends proxy reception instruction information that instructs to perform proxy reception to the proxy reception device.

Abstract: A novel method for logically routing a packet between a source machine that is in a first logical domain and a destination machine that is in a second logical domain is described. The method configures a managed switching element as a second-level managed switching element. The method configures a router in a host that includes the second-level managed switching element. The method communicatively couples the second-level managed switching element with the router. The method causes the router to route a packet when the router receives a packet from the first logical domain that is addressed to the second logical domain.

Abstract: System(s), device(s), and method(s) are provided to route data in a mesh network of devices that can communicate wirelessly through a plurality of technologies. One or more of such devices receive broadcast message(s) from a destination device intended to receive the data, and generate a first radio link quality metric (RLQM) value based on the broadcast message(s). A source device originates and delivers a quantum of data with an embedded first RLQM value. A set of intermediate devices relays the quantum of data if a forwarding criterion is fulfilled; the forwarding criterion is based in part on the first RLQM value and a second RLQM value generated by an intermediate device in the set of intermediate devices based on the broadcast message(s). The intermediate device exploits an optical interface to transmit the quantum of data. The destination device broadcasts an acknowledgement signal in response to receiving intended data.

Abstract: According to one aspect, the subject matter described herein includes a system for providing a Diameter signaling router with integrated monitoring functionality. The system includes a Diameter signaling router comprising a network interface for receiving, from a first Diameter node, a first Diameter message having Diameter information. The system also includes an integrated monitoring module located within the Diameter signaling router for copying at least a portion of the first Diameter message and providing the copied information associated with the first Diameter message to an application.

Abstract: Some embodiments of the invention provide a robust scaling-out of network functionality by providing a software layer, called the network hypervisor, that sits between the network forwarding functions (i.e., the forwarding plane) and the network control interfaces (i.e., the control plane). The network hypervisor of some embodiments provides a logical abstraction of the network's forwarding functionality, so that network operators make their control decisions in terms of this abstraction, independent of the details of the underlying networking hardware. The network hypervisor of some embodiments may then “compile” commands placed against this abstraction into configurations of the underlying hardware. Accordingly, in some embodiments, there are two design challenges: (1) the choice of the network abstraction, and (2) the technology needed to compile the logical “abstract” controls into low-level configurations.

Abstract: Using the ALTO Service, networking applications can request through the ALTO protocol information about the underlying network topology from the ISP or Content Provider. The ALTO Service provides information such as network resource preferences with the goal of modifying network resource consumption patterns while maintaining or improving application performance. This document describes, in one example, an ALTO server that implements enhancements to the ALTO service to assign a PID-type attribute to each of a set of one or more PIDs each associated with a subset of one or more endpoints of a network, wherein a PID-type attribute specifies a type for the subset of endpoints associated with the PID. The ALTO server generates an ALTO network map that includes a PID entry to describe each of the PIDs, wherein each PID entry includes a PID-type field that stores the assigned PID-type attribute for the PID described by the PID entry.

Abstract: Many mobile devices can access websites on the Internet. A mobile device running a web server application can host websites and provide services. For a first mobile device to access services on a second mobile device, the first mobile device needs the IP address of the second mobile device. The first mobile device sends a connection request to the second mobile device. The first mobile device receives, from the second mobile device, the network address of the second mobile device, identification of services that are available on the second mobile device, and a security token. The first mobile device selects a service and sends an HTTP or HTTPS request for the service to the network address of the second mobile device, and also sends the security token. The second mobile device authenticates the request based on the token and allows the first mobile device to access the selected service.

Abstract: Systems and methods of managing keystroke data in embedded keyboard environments may involve transferring a mode request from a management controller to an embedded controller of a keyboard via a dedicated communication channel. Keystroke activity can be detected at the keyboard, and keystroke data may be transferred from the embedded controller to the management controller via the dedicated communication channel in response to the keystroke activity and the mode request. In addition, the management controller may be used to encrypt the keystroke data, wherein the encrypted keystroke data can be transmitted from the management controller to an off-platform service via a network controller.

Abstract: A router maintains routing information including (i) route data representing destinations within a computer network, (ii) next hop data representing interfaces to neighboring network devices, and (iii) indirect next hop data that maps a subset of the routes represented by the route data to a common one of the next hop data elements. In this manner, routing information is structured such that routes having the same next hop use indirect next hop data structures to reference common next hop data. In particular, in response to a change in network topology, the router need not change all of the affected routes, but only the common next hop data referenced by the intermediate data structures. This provides for increased efficiency in updating routing information after a change in network topology, such as link failure.

Abstract: A host computer is coupled to data storage and has access to the data storage. The host computer has multiple network interfaces, which are associated with multiple logical networks. The host computer detects a network address of the data storage, and identifies one of the network interfaces that is associated with a best-performing logical network for accessing the data storage. The host computer then receives a routing configuration that routes traffic to the data storage via the identified network interface.

Abstract: A wireless client terminal includes an application module, a service mapping module, and an address determination module. The application module determines first and second services requested by applications. The service mapping module stores a table that maps services to access point names. Each access point name identifies a respective packet data network. The address determination module transmits an address request message, including access point names corresponding to the services, to a media access gateway and receives an address response message. The address determination module determines first and second addresses based on address information in the address response message. The application module transmits a first packet to the media access gateway. The source address of the first packet is set to the first address when the first packet is related to the first service and to the second address when the first packet is related to the second service.

Abstract: Techniques are described for providing encryption and authentication for different types of routing protocol communications based on a variety of factors. A method comprises configuring, on a network router, a set of logical interfaces for communicating routing protocol messages with one or more peer routing devices, maintaining a set of security associations that define corresponding authentication information and encryption information for the routing protocol messages, and maintaining one or more descriptor sets that each specify a set of criteria, wherein, for at least one of the descriptor sets, the set of criteria specifies one of the logical interfaces of the network router. The method further comprises selecting one of the descriptor sets having criteria that match an individual flow, selecting one of the security associations based on the selected descriptor set, and applying the selected security association to secure the outbound flow of the routing protocol messages.

Abstract: A method of determining compatibility of a virtual machine or virtual machine disk file with a host, including a storage host, is disclosed. A lookup matrix is created to provide a fast compatibility lookup. To create the lookup matrix, computing object properties are retrieved from each of the plurality of computing objects. The computing object properties include resource requirements of each of the plurality of computing objects. Further, host properties are retrieved from each of the plurality of hosts. The method further includes creating host logical groups of a subset of the plurality of hosts having substantially same host properties and creating a plurality of computing object logical groups of a subject of the plurality of computing objects having substantially same computing object properties. The lookup matrix answers whether each member of a selected computing object logical group can be transferred to a selected host logical group.

Abstract: Node Interconnect architectures to implement a high performance supercomputer are provided. For example, a node interconnect architecture for connecting a multitude of nodes (or processors) of a supercomputer is implemented using an all-to-all electrical and optical connection network which provides two independent communication paths between any two processors of the supercomputer, wherein a communication path includes at most two electrical links and one optical link.

Abstract: A method and apparatus for providing a topology for interconnection of telecommunication nodes in a communication network are disclosed. For example, the method obtains input data, and determines values of: at least one set, at least one parameter, and at least one variable associated with the communication network in accordance with the input data. The method then determines the topology for the interconnection via microwave links of the telecommunication nodes from an objective function in accordance with the at least one set, at least one parameter, and at least one variable, wherein the objective function is based on a plurality of penalty factors.

Abstract: In general, techniques are described for dynamically generating attributes from routing topology information and assigning dynamically generated attributes to network map entries to further characterize PIDs described therein. For example, a provider or other entity assigns, within a network device, endpoint types to one or more address prefixes for which the network device originates or forwards route advertisements. For each typed prefix, the network device adds an endpoint type identifier for the assigned endpoint type to route advertisements that traverse or originate with the network device and specify the prefix. An ALTO server peers with router advertisers to receive route advertisements. When the ALTO server receives a route advertisement that includes an endpoint type identifier, the ALTO server maps the endpoint type identifier to a PID attribute and assigns the PID attribute to a PID that includes a prefix identified in the route advertisement.

Abstract: The test analysis system of a network according to an exemplary embodiment of the present invention includes: a server group having at least one server performing at least any one of generation of real-time information and storage of a server local log according to test scenarios; a client group having at least one client. communicating with the server group and performing at least any one of the generation of the real-time information and the storage of the local log according to the test scenarios; and a monitoring system storing the real-time information as a system log while monitoring the real-time information received from the server group and the client group during the execution of the test scenarios and informing a test manager of the monitored real-time information.

Abstract: A network device receives a join request on a downstream interface, wherein the join request specifies a source device and multicast group, wherein the network device is positioned within a core network of a multicast virtual private network (MVPN) that transmits multicast traffic between the source device and a plurality of receivers associated with customer sites. The network device selects an upstream router to which to send the join request from among a plurality of upstream routers on paths leading to the source device, so as to avoid creating a join request loop in the core network. At least one of the upstream routers is positioned on an Exterior Border Gateway Protocol (EBGP) path toward the source device, and at least one of the upstream routers is positioned on an Interior BGP (IBGP) path toward the source device. The network device sends the join request to the selected upstream device.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for facilitating communication between enterprise software applications. Some enterprise software systems communicate using a message protocol designed for use with an exchange system. Those systems require the exchange system to communicate using that message protocol. To communicate with systems using that message protocol, a local system can build a message formatted in accordance with the message protocol, even without an exchange system. The local system stores configuration data and uses the configuration data to build the message.

Abstract: In the gateway device, the global address (GA) of the host table is set to the same value, and the GA and the local port (LP) of the transfer table are respectively set to the same value. In the IP packet analysis unit, the sorting unit analyzes the packet from the WEB client and sorts the destination of the packet, the redirection unit supplies the GA and the global port (GP) to the WEB client that has made a request by the packet according to a result of analysis to perform redirection, and the translation/transfer unit analyzes the packets transmitted through the sorting unit, translates the addresses (GA/LA: local address) and the ports (GP/LP) respectively with each other and transfers the translated packets, and then the procedure after connection establishment is repeated.

Abstract: In general, this disclosure describes techniques for applying, with a network device, subscriber-specific packet processing using an internal processing path that includes service objects that are commonly applied to multiple packet flows associated with multiple subscribers. In one example, a network device control plane creates subscriber records that include, for respective subscribers, one or more variable values that specify service objects as well as an identifier for a packet processing template. A forwarding plane of the network device receives and maps subscriber packets to an associated subscriber record and then processes the packet by executing the packet processing template specified by the subscriber record. When the forwarding plane reaches a variable while executing the specified packet processing template, the forwarding plane reads the associated variable value from the subscriber record to identify and then apply the subscriber-specific service object specified by the variable.

Abstract: Systems and methods for providing the progressive download of media content using techniques that preferentially identify and use periods of surplus network capacity to maintain the content delivery. A buffer of a receiving system is maintained and pre-filled with enough content to bridge playback intervals where a network is unable to deliver content as fast as it is played out. When no surplus network capacity is available, a user requesting content may be given the option to continue the delivery in the background so that the content may be played at a later time. The user may then resume their playback experience once the content has been completely delivered using surplus network capacity as it becomes available. A first portion of a content file may be pre-delivered to the receiving system so that users may consume the first portion content while the buffer is pre-filled.

Abstract: In order to achieve location transparency and routing slip extensibility, a system and a method for orchestrating a web service using Business Process Execution Language are disclosed. The method includes: receiving a message, wherein the message comprises an address identifying an extension element; determining, from the address, a location of the extension element identified by the address; responsive to determining the location of the extension element, directing the message to an appropriate location; and storing the message in a computer readable storage medium.

Abstract: Techniques are described for preventing network attacks. More specifically, the techniques involve classification of routes based on the network protocol from which the routes were learned, and filtering of packets based on the classification. A network device, for example, is described that includes interface cards to receive routing information via one or more routing protocols, wherein the routing information defines network routes. The network device further includes a control unit to classify the routes based the routing protocol by which the routes were received, and selectively forward packets associated with the routes based on the classification of the routes. Edge routers within a service provider network, for example, may classify routes as either “internal” or “external” based on the protocols from which the routes were learned, and automatically filter packets to prevent network attacks using the techniques.

Abstract: A method for managing data stream exchanges in an autonomic telecommunications network including a first phase consisting in extracting from each stream routing data and data for measuring the transfer function between at least one data producer Pi and at least one data consumer Cj, sharing the extracted routing data between processing and decision-making functional modules distributed across the said network, selecting at least one decision-making or processing module for which the access time to the measuring data of the transfer function is minimal, dynamically defining by at least one of the selected modules the said rules for optimizing the transfer settings of the stream according to the said measuring data and distributed over the said network select processing modules located on the path of the said streams in order to apply the said rules.

Abstract: A computerized appointment confirmation system for communication with a mobile device comprising a database comprising data regarding an appointment and a server configured to communicate with an MMS server, the MMS server configured to send an MMS message to the mobile device and receive an MMS response message, receive a communication from the MMS server indicating receipt of the MMS response message by the MMS server, communicate with an SMS server if no MMS response message is received from the mobile device within a predetermined time period, the SMS server configured to send an SMS message to the mobile device and receive an SMS response message, update the database to indicate whether confirmation data was received by the MMS or SMS server from the mobile device, and store in the database data indicating whether an MMS response message or SMS response message was received by the mobile device.

Abstract: A communications system includes a mobile wireless communications device, a trusted server, and a plurality of host servers. A given one of the host servers is in communication with the mobile wireless communications device. The given host server is configured to generate and send a redirection request to the mobile wireless communications device, the redirection request requesting the mobile wireless communications device to communicate with an other one of the host servers. The mobile wireless communications device is configured to send the redirection request to the trusted server, and the trusted server configured to send the redirection request to the mobile wireless communications device based upon verification of the redirection request.

Abstract: A method for load balancing virtual machines includes accessing specification and utilization information for selected networked hardware platforms published on a network, the networked hardware platforms configured to run virtual machines and scoring the selected networked hardware platforms based on parameters from the utilization information to indicate resource availability for each of the selected networked hardware platforms. The method also includes removing a networked hardware platform from the selected networked hardware platforms based on a collocation policy to produce candidate platforms to receive a first virtual machine, wherein the collocation policy prohibits placement of the first virtual machine on the networked hardware platform based on at least one of consumer rules, provider rules, and industry rules.

Abstract: A scheme for redirecting data to a mobile communication device capable of communicating via at least one short-range wireless communication path and at least one long-range wireless communication path. An embodiment comprises one or more of the following: a structure for setting a redirection flag configured for a user associated with a mobile communication device to enable continuous redirection of data items thereto from a host system until the redirection flag is reset to indicate cessation of redirection of the data items. Thereafter, the embodiment is operable to determine whether the mobile communication device is within coverage of a cell of a plurality of cells, each cell being operable with an associated short-range wireless communication path, whereby a data item is redirected accordingly.

Abstract: A system and method are provided to route packets in a data center network. Individual packets are encapsulated at an edge of the data center network, so that each encapsulated packet includes a set of header fields, such as a tenant identifier. For each encapsulated packet, a hash class is determined from the set of header fields. A routing virtual local area network (VLAN) is selected for the packet based on the tenant identifier and the hash class.

Abstract: An apparatus and a method for layer-2 and layer-3 VPN discovery are disclosed. The apparatus is incorporated in a network, and the network includes a first carrier network. The first carrier network includes at least two layer-1 provider edge devices. Layer-1 VPN information is created within the first carrier network. BGP next hop information passes within the first carrier network. The BGP next hop information is for a selected one of the following: a layer-2 VPN-based provider edge device, a layer-3 VPN-based provider edge device, and a layer-2 and layer-3 VPN-based provider edge device. The network also includes a second carrier network within which the BGP next hop information is used for VPN discovery.

Abstract: A method and apparatus for processing path-based database operations is provided. According to one aspect, a path cache is maintained. For each hierarchical node that is traversed during a path-determining operation, it is determined whether a cache entry corresponding to that node is already contained in the path cache. If such a cache entry is already contained in the path cache, then the path indicated in that cache entry is used to complete the pathname for the node for which the operation is being performed. As a result, hierarchically higher nodes do not need to be traversed to complete the operation. Alternatively, if such a cache entry is not already contained in the path cache, then a cache entry for the node currently being traversed is generated and inserted into the path cache for use in subsequent path-determining operations.

Abstract: A method is provided for a router to implement non-stop routing of a routing protocol. The router has primary and backup routing engines or a single routing engine. When the primary routing engine or the only routing engine is operating normally, neighbor state information is backed up to the backup routing engine or a nonvolatile memory in the router. After the backup routing engine takes over for the primary routing engine or the single routing engine reboots, the backup routing engine or the single routing engine maintains neighbor relationships based on the neighbor state information, obtains routing information based on the saved neighbor state information. The backup routing engine or the single routing engine then generates local routes based on the routing information, determines best routes based on the local routes, sends the best routes to the neighboring routers, and saves the best routes to local hardware.

Abstract: Prioritizing network traffic among two or more distinct channels of communication within a single application in a node configured to communicate with one or more other nodes over a network is disclosed. For a particular time quantum, a bandwidth quantum may be distributed amongst two or more communication channels according to priorities associated with those channels. Ready data for each channel may be transmitted over a network path up to the size of the reserved portion for that channel and not greater than a path maximum transmission unit (MTU) size for a network path. This abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: An embodiment of the invention is a method and corresponding system for improved network address translation (NAT) operation, to enable efficient translation for packets destined for communication systems within a domain utilizing network addresses that are incompatible with source and destination addresses indicated in packets delivered from the global Internet. Since the addresses are not compatible with global Internet addresses, delivery cannot be accomplished except by some method of address translation. Traditional systems have not been constructed to enable such inbound translations, providing, instead, only communication outbound from the incompatibly addressed domain towards the global Internet. The example embodiment employs history and pattern matching between observable characteristics of the inbound payload, associated over time with specific destinations.

Abstract: Concepts and technologies are described herein for continuously deploying applications. In accordance with the concepts and technologies disclosed herein, a first host environment executes an application. An upgrade for the application is released by creating a backup of the application and content used by the application and restoring the backup at a second host environment. The application hosted by the second host environment is upgraded, traffic is routed to the second host environment, and performance of the upgraded application is monitored. If errors are detected in the upgraded application, the upgrade can be rolled back, and traffic can be rerouted back to the first host environment. If the errors are not detected, traffic can be increasingly routed to the second host environment and the first host environment can be deactivated.

Abstract: The present description refers to a computer implemented method, computer program product, and computer system to store a node dependency network that includes a plurality of data nodes and one or more links between two or more data nodes, each link representing a data dependency between instances of the two or more data nodes, to forward a requested change to a first data node from a first change control component to a change control manager, identify, by the change control manager based upon the links within the node dependency network, one or more dependent data nodes that are dependent upon the first data node, and determine one or more dependent changes to be performed to one or more instances of the dependent data nodes to maintain consistency among instances of the data nodes.

Abstract: A content delivery network (CDN) aggregation system is disclosed. A user requesting content from a content provider has his or her DNS request forwarded to a CDN selector. The CDN selector intelligently selects an optimal CDN from amongst a number of partner CDNs to provide the requested content.

Abstract: A method of detecting and responding to an email address harvest attack at an Internet Service Provider (ISP) email system includes counting a number of failed email address look-ups during a single Simple Mail Transfer Protocol (SMTP) session associated with an originating Internet Protocol (IP) address and responding to the originating IP address with a positive acknowledgement that an otherwise invalid email address exists when the count of the number of failed email address look-ups exceeds a threshold.

Abstract: Systems and methods are provided for a media device including one or more movement-based interfaces for interfacing with or controlling the media device.

Abstract: An information communication system of an overlay network includes: a first apparatus requesting the content; a second apparatus storing the content; and a third apparatus including: a first reception unit receiving a retrieval message transmitted from the first apparatus, the retrieval message including content identification information and location information; a storage unit storing the apparatus identification information of the second apparatus and the content identification information of the content stored in the second apparatus; and a transmission unit transmitting the apparatus identification information. The second apparatus includes: a second reception unit receiving the apparatus identification information from the third apparatus; and a control unit allowing the first apparatus to acquire the content stored in the second apparatus if the apparatus identification information received by the second reception unit matches the apparatus identification information of the second apparatus.

Abstract: A method and system for transferring an ongoing communication session from one application server (AS) to another is described. Multiple ASs are monitored and serviced by a Transfer Management Module (TMM). Each of the ASs serves a different network and each network includes various end devices. During an ongoing communication session, whether the session is to continue using the current AS is determined based on a set of rules. If the session is to be transferred, an alternative AS that provides the same application as the current AS is selected using a set of conditions. Upon selection of the alternative AS, the current AS transfers the control and/or media state of the ongoing session for one to all users through the TMM to the selected AS, and the session is continued.

Abstract: A method and system supports subscriber based IP data breakout at the edge of a mobile data network without monitoring the use of security keys or breaking into ciphered message exchanges. The system employs a first service mechanism operating at the edge of the mobile data network a second service mechanism operating at the core on the S11 interface. The second service mechanism at the core collects subscriber related data, subscriber identifiers and tunnel identifiers and sends this data to the first service mechanism. The second service mechanism at the core collects subscriber related data, subscriber identifiers and tunnel identifiers and sends this data to the first service mechanism. The first service mechanism uses the tunnel identifiers received from the second service mechanism to identify sessions and tunnels carrying subscriber dependent data packets (S1-U packets) in order to perform subscriber-based IP data breakout, offloading and optimization.

Abstract: The invention relates to a protocol for communications between networked devices. The devices are logically arranged as a hierarchy of device types including a controller device type (52) from which no other device type depends and a basic device type (54) from which a number of other device types depend. The devices implement a simple device description message of fixed length and format which includes the device type, and some devices further implement an extended device description message including additional information.