Abstract: Exemplary embodiments of a system and method enable application of policy using Layer 2 fields for a data frame, simplified data structures, or both. In accordance with one aspect of the present invention, a policy may be based upon a destination address (DA), a source address (SA), or a virtual local area network identification (VID) associated with a data frame.

Abstract: Techniques are described for providing managed computer networks. In some situations, the techniques include managing communications for computing nodes of a managed computer network by automatically determining to separate a particular outgoing packet or other outgoing communication from a source computing node into multiple parts (e.g., multiple packets) to be independently sent using two or more alternative network paths between the sending computing node and the destination for the communication. For example, a manager module associated with the source computing node may automatically determine to encode the outgoing communication into a dynamically determined quantity of multiple parts (e.g.

Abstract: An apparatus comprising a path computation element (PCE) configured to communicate with a path computation client (PCC) and compute a point-to-multipoint (P2MP) path across an autonomous system (AS) domain. Also included is a network component comprising at least one processor configured to implement a method comprising obtaining a computation request for a P2MP path across a plurality of AS domains, attempting to calculate the P2MP path across the AS domains, thereby generating a computed path or a failure reason, and transmitting a reply comprising the computed path or an indication of the failure reason. Included is a method comprising exchanging a request message and a reply message about a P2MP path across an AS domain between a PCC and a PCE.

Abstract: Systems and methods for hierarchical link aggregation are disclosed. A system for hierarchical link aggregation may include a network interface having a plurality of physical ports. A first plurality of the physical ports may be configured as member ports of a first link aggregation group (LAG). A second plurality of the physical ports may be configured as member ports of a second LAG. The first LAG and second LAG may be configured as member logical ports of a third LAG.

Abstract: A new type of Provider Edge (PE) device is used to support BGP-based IP-VPNs. Each VRF instance in a PE device is associated with a dedicated IP address (Service IP address). Each service IP address is dedicated to a VRF in a PE device. The service IP address is distributed by BGP for VPN route association. Customer/VRF IP packets can be sent to a VRF instance in the egress PE device using service IP header encapsulation (with IP Destination Address=Service IP address of egress PE's VRF & IP Source Address=Service IP address of ingress PE's VRF). This obviates the need for explicit tunnels in the core.

Abstract: A method of enabling extension of a network service of a first domain to a remote customer site hosted by an Access Gateway (AG) in a Provider Ethernet domain. In the first domain, the remote customer site is represented as being hosted by a border gateway (BG) connected to the Provider Ethernet domain, such that subscriber packets associated with the network service are forwarded to or from the remote customer site via the BG. In the Provider Ethernet domain, a trunk connection is instantiated through the Provider Ethernet domain between the host AG and the BG. A trunk cross-connection function is installed in the host AG, for transferring subscriber packets associated with the network service between a respective attachment virtual circuit (AVC) through which the remote customer site is connected to the host AG and an extended AVC tunnelled through the trunk connection.

Abstract: An improved system and method are disclosed for peer-to-peer communications. In one example, the method enables the joining and/or recording of an ongoing peer-to-peer communication session in real time.

Abstract: Aspects of a method and system for peer-to-peer cellular communications are provided in which one or more cellular communication channels may be established between a femtocell and a plurality of communication devices. The femtocell may control routing of data between the plurality of communication devices via the one or more cellular communication channels. The femtocell may enable multicasting and/or broadcasting data from one of the communication devices to two or more remaining ones of the communication devices. The multicast and/or broadcast data may be communicated via the cellular communication channels and may be additionally communicated via an IP connection to the femtocell. Data may be communicated over the cellular communication channels in compliance with 3rd generation partnership project (3GPP) standards and/or 3rd generation partnership project 2 (3GPP2) standards. The femtocell may reformat data prior to communicating it to one or more of the plurality of communication devices.

Abstract: Method and apparatus for providing a control plane across multiple optical network domains is described. In one example, topology and resource discovery is employed in a transport network having a plurality of control domains. Topology information for each of the control domains is summarized to produce summarized topology information. The summarized topology information for each of the control domains is exchanged among the control domains. At each of the control domains, the summarized topology information of each of the control domains is combined to produce combined topology information. The combined topology information is passed among network elements within each of the control domains using an intra-domain routing protocol.

Abstract: A method of filtering packets coming from a communication network (1) comprising, after successful registration of a terminal (20) with a service platform (32): a step of associating a registration context with the terminal, the context comprising registration information transmitted between the terminal and the service platform during registration; a step of creating at least one filtering rule on the basis of the registration context, said rule aiming to block packets that do not conform to at least a portion of the registration information; and a step of filtering the packets as a function of the rule created.

Abstract: In one embodiment a method and apparatus that support virtual services including virtual network interface control functionality for virtual machines running on a server. A method includes receiving a packet at a network interface card from a data communication network, classifying, within the network interface card, the packet to select one of multiple flow tables to which the packet should be assigned to obtain a selected flow table, the classifying being based, at least, on a logical interface with which the packet is associated, processing the packet based on information stored in the selected flow table, and passing the packet to a virtual machine operating on a computer to which the network interface card is communicatively connected, the virtual machine being associated with the logical interface.

Abstract: In some embodiments, an apparatus includes a first switch having an egress port configured to be coupled to a second switch to collectively to define a single logical entity having a set of virtual identifiers. A first set of virtual identifiers from the set of virtual identifiers is associated with the first switch, a second set of virtual identifiers from the set of virtual identifiers is associated with the second switch. The first switch is configured to receive a forwarding table associating a first set of destination addresses with a set of identifiers local to the first switch and associating a second set of destination addresses with a set of identifiers local to the second switch. Each identifier from the first set of identifiers is uniquely associated the first set of virtual identifiers. Each identifier from the set of identifiers is uniquely associated the second set of virtual identifiers.

Abstract: In an access network, a tunnel gateway (TGW) managed network caching architecture is proposed. The proposed TGW receives a terminal request directed to a data server for a flow of data. The terminal request is forwarded to the TGW through a tunnel from a tunnel endpoint located below the TGW. The TGW selects a network cache to handle the data traffic of the flow requested by the requesting terminal. The TGW then redirects the terminal request to the selected network cache to provide the requested service. The TGW redirects the terminal request through a tunnel whose endpoint is the selected network cache.

Abstract: A data center network system and a packet forwarding method thereof are provided. The data center network system includes a virtual bridge and an address resolution protocol (ARP) server. The virtual bridge intercepts an ARP request having an identification field and a destination IP address field and adds a corresponding virtual data center identification to the identification field of the ARP request and redirecting the ARP request to the ARP server. Additionally, the ARP server queries a corresponding MAC address according to an IP address recorded in the destination IP address field of the ARP request and the corresponding VDCID recorded in the identification field of the ARP request, and transmits the corresponding MAC address in response to the ARP request. Accordingly, the same private IP address can be reused in the data center network system.

Abstract: A communication device includes a first acquisition unit that acquires communication setting information of communication device from a server, the communication setting information being information necessary for communication between communication devices through a communication network; a second acquisition unit that acquires network identification information, which is information for identifying the communication network to which the communication device is connected, on the basis of the communication setting information acquired by the first acquisition unit; and a selection unit that, in accordance with the network identification information acquired by the second acquisition unit, selects an operation scheme of the communication device when the communication device communicates with another device through the communication network.

Abstract: The present invention provides, according to one example, a method of route aggregation in a network. The network may include at least two switches connected by a link. The method includes the steps of arranging virtual connection identifiers (VCIs) into groups based on a common prefix. Each of the groups corresponds to an outgoing port of a next switch. The method further includes the steps of allocating a VCI at the incoming port of the next switch, and informing the outgoing port of the previous switch of the allocated VCI number. The step of arranging may include splitting all available VCIs into N subgroups, where N is the number of outgoing ports on the switch on the other end of the link.

Abstract: Methods and apparatuses are provided that facilitate establishing multiple sub-connections between a correspondent node (CN) and a mobile node (MN), through a home agent (HA) to provide multipath functionality over multiple MN interfaces. The MN can connect to multiple networks using multiple MN interfaces, receiving care-of addresses (CoA) at each network. The MN can establish multiple connections to the CN specifying, to the HA, a different 5-tuple (or n-tuple) for each connection. The different 5-tuple can include a different port number related to a home address assigned by the HA. Also, bindings at the HA can be updated to associate the different 5-tuple with a CoA of one of the multiple MN interfaces. In this regard, the HA can route packets to the MN from the CN based at least in part on determining the HoA port number in the packet associated with the CoA of an MN interface.

Abstract: An apparatus comprising an edge virtual bridging (EVB) bridge, and an EVB station coupled to the EVB bridge, wherein the EVB station is configured to send to the EVB bridge a virtual station interface (VSI) discovery and configuration protocol (VDP) request comprising a filter information (info) field without specifying a virtual local area network (VLAN) identifier (ID), and wherein the EVB bridge is configured to send a VLAN ID (VID) to the EVB station in a second filter info field in a VDP response to the VDP request.

Abstract: A method and apparatus for signaling virtual channel support in communication networks. A node receives a data packet from another node to examine whether the other node commonly supports one or more virtual channels of a given type on a point-to-point communication link between the nodes, and the node signaling common support for one or more virtual channels of a given type, based on the content in the received data packet that indicates whether the other node transmitting the data packet has adequate queue resources to support one or more virtual channels of a given type, and based on whether the node has adequate queue resources to support the one or more virtual channels of a given type.

Abstract: An apparatus comprising an edge virtual bridging (EVB) bridge, and an EVB station coupled to the EVB bridge, wherein the EVB station is configured to send to the EVB bridge a virtual station interface (VSI) discovery and configuration protocol (VDP) request comprising a filter information (info) field without specifying a virtual local area network (VLAN) identifier (ID), and wherein the EVB bridge is configured to send a VLAN ID (VID) to the EVB station in a second filter info field in a VDP response to the VDP request.

Abstract: A communication control method of a transmission system that exchanges a transmission frame between a first transmitting apparatus and a second transmitting apparatus, the communication control method including causing the first transmitting apparatus to receive a transmission frame, which is encapsulated using a first method or a second method different from the first method, from the second transmitting apparatus; causing the first transmitting apparatus to determine an encapsulation method of the transmission frame, based on information set according to the encapsulation method in the received transmission frame; causing the first transmitting apparatus to decapsulate the received transmission frame, based on the determination result; and causing the first transmitting apparatus to encapsulate another transmission frame using the determined encapsulation method and transmit another transmission frame.

Abstract: A method and apparatus for performing tunneling signaling over an IP tunneling path connected to an end-to-end path on an IP network are provided, in which an end-to-end signaling flow is received from a sender or a receiver on the end-to-end path, a tunnel signaling flow is generated corresponding to the received end-to-end signaling flow, and the generated tunnel signaling flow is transmitted through the IP tunneling path, the end-to-end signaling flow is forwarded between an entry node and an exit node of the IP tunneling path, and the forwarded end-to-end signaling flow is transmitted to at least any one node on the end-to-end path, wherein the forwarding is simultaneously performed with the transmitting of the tunnel signaling flow, and the transmitting of the end-to-end signaling flow is suspended until the transmitting of the tunnel signaling flow is completed.

Abstract: A technique is provided for mitigating loops in Ethernet networks. A first port in an Ethernet device receives an Ethernet frame. The frame includes a source identifier, a destination identifier, and a Virtual Local Area Network Identifier (VLAN ID). According to various embodiments, the VLAN ID (VID) has the encoding of both a community group as well as a source bridge ID. A VID database is accessed using the destination identifier and the VID to determine whether the first port has ingress enabled. A filtering database is accessed to determine an egress port for forwarding the Ethernet frame.

Abstract: A system for identifying a subscriber includes an access server coupled to a number of subscribers using a first communication network and further coupled to a second communication network, a memory coupled to the access server, and a processor coupled to the memory. The access server receives a communication from a particular subscriber using a particular one of a number of virtual circuits associated with the first communication network. The memory stores path information that identifies a virtual circuit assigned to the particular subscriber. The processor identifies the particular subscriber for connection to the second communication network based upon the path information and the particular virtual circuit used to receive the communication from the particular subscriber.

Abstract: A system and method for providing network connectivity to a host, involving creating a virtual switch on the host, specifying at least one data link attribute of the virtual switch, creating a plurality of virtual network interface cards (VNICs) on the host, associating each of the plurality of VNICs with the virtual switch, and assigning the at least one data link attribute of the virtual switch to each of the plurality of VNICs, where the virtual switch is connected to a physical network interface card (NIC) associated with the host, where each of the plurality of VNICs is associated with a different one of a plurality of execution environments, where the plurality of execution environments is located on the host, and where the plurality of VNICs is located on the host.

Abstract: A switch fabric system and network element based thereon include a N×M switch fabric with M Trail Termination Points (TTPs) each with N timeslots there through in a bidirectional manner, a first connection in the switch fabric, wherein the first connection includes a unidirectional asymmetric connection of X timeslots, wherein X<N, and a second connection in the switch fabric in an opposite direction as the first connection, wherein the second connection includes a unidirectional asymmetric connection of Y timeslots, wherein Y<N, and wherein at least one of the Y timeslots overlaps with one of the X timeslots on a same TTP of the M TTPs, wherein N, M, X, and Y each include an integer. A method includes establishing unidirectional asymmetric connections with overlapping portions therein as well as merging, splitting, and converting connections in-service and minimizing blocking probabilities.

Abstract: There is provided with a remote control method using a terminal device connected to a first network and an information processing server connected to a second network, including: setting a tunnel between the terminal device and the information processing server; transmitting a broadcast or multicast packet output from service providing servers on the first network to the information processing server via the tunnel to cause the server to find the service providing servers and services provided by the service providing servers; notifying the terminal device of the services found, from the information processing server via the tunnel or the second network; and if execution request of the service is received by the information processing server from the terminal device via the tunnel or the second network, conducting data communication concerning the service between a service providing server providing the service and the information processing server, via the second network.

Abstract: Described are a network, computer program product, and method of distributing routing information for a virtual private network (VPN) application through a packet-switched network (PSN) having fully meshed provider edge (PE) routers through Provider Backbone Bridge (PBB) tunnels. A PE router is configured to participate in a VPN and to run a BGP (Border Gateway Protocol) as an auto-discovery process for finding one or more other PE routers participating in the VPN. The VPN is associated with a PBB tunnel. A service instance identifier (I-SID) is assigned to the VPN. The PE router advertises membership in the VPN by including the I-SID assigned to the VPN in a BGP message issued during the auto-discovery process.

Abstract: A method is provided for proxy services between a public network and a private network. Such a method includes receiving a first packet having a destination address and a first source address; generating a second packet having the destination address and a second source address; and transmitting the second packet.

Abstract: System for controlling data transfer between a host system and storage devices. A virtualization controller implements the data transfer and includes first ports for connection with the storage devices, a second port for connection with the host system, a processor, and a memory configured to store volume mapping information which correlates first identification information used by the host system to access a first storage area in one of the storage devices, with second identification information for identifying the first storage area, the correlation being used by the processor to access the first storage area. When data stored in the first storage area is transferred to a second storage area, the processor correlates the first identification information with a third identification information for identifying the second storage area and registers the first identification information and the third identification information in the volume mapping information.

Abstract: A method of enabling extension of a network service of a first domain to a remote customer site hosted by an Access Gateway (AG) in a Provider Ethernet domain. In the first domain, the remote customer site is represented as being hosted by a border gateway (BG) connected to the Provider Ethernet domain, such that subscriber packets associated with the network service are forwarded to or from the remote customer site via the BG. In the Provider Ethernet domain, a trunk connection is instantiated through the Provider Ethernet domain between the host AG and the BG. A trunk cross-connection function is installed in the host AG, for transferring subscriber packets associated with the network service between a respective attachment virtual circuit (AVC) through which the remote customer site is connected to the host AG and an extended AVC tunnelled through the trunk connection.

Abstract: Disclosed are system and methods for distributing data.

Abstract: A method for providing a wireless Internet connection to WiFi-enabled devices (STAs) comprising: wirelessly connecting a first STA to the Internet through a first AP with a first SSID; remaining connected to the first Access Point (AP), the first STA creates a software-based wireless AP with a second SSID for wirelessly connecting other STAs to the Internet through the first STA. A software module running on the first STA allows a second STA a wide access to the Internet only if the second STA has a copy of the software module running installed and active therein. A method for configuring STAs to connect to a wireless network, comprising: a customer first connects a STA by wire to its network; a software on the STA copies to the STA the security information gained through the wired connection, thus setting the security parameters for the STA.

Abstract: A method, apparatus, and computer program product for discovering network paths between network devices in a distance-vector network are provided. The method may include providing a node model of network devices in a distance-vector network. The node model may include a network address corresponding to a network device. The network address may be used to query the network device for routing information. This routing information may be used to identify another network address corresponding to a second network device, and to identify a path from the first network device to the second network device. These devices and the path therebetween may be mapped in the node model. Finally, the second network device may be queried for subsequent routing information to identify and map subsequent devices and paths.

Abstract: Apparatus, systems and methods for receiving one or more input signals and providing output signals in various video, audio, data and mixed formats are described. One or more input processors receive the input signals. Each of the input processors provides one or more packetized signals corresponding to one or more of the input signals received at the input processor. Each output processor can receive one or more packetized signals and generate or more output signals. The output signals correspond to one or more of the input signals, additional locally generated signals or data relating to the signals or any combination of such signals. Use of a packet router according to the invention allows input signals encoded as one set of packetized signals to be recombined to provide additional packetized signals incorporating the same or different combinations of the packetized signals.

Abstract: A terminal connected to a network stores association information between a physical address and a logical address of the terminal as first association information in an address association information storing unit. The terminal obtains association information between a physical address and a logical address, which is transmitted to the terminal via the network, as second association information. The terminal determines, based on the first association information stored in the storing unit and the second association information, whether or not the logical address included in the first association information is duplicate. If the logical address is determined to be duplicate, the first association information is notified to a device belonging to the network to which the terminal belongs, and the device is instructed to resolve duplication of the logical address.

Abstract: A packet node and corresponding methods are provided for providing services to packets received at the packet node. At an ingress card, a packet is classified and a virtual media access control (VMAC) address is attached to the packet. The VMAC address identifies a service component for providing a service to the packet. Layer two switching of the packet is made within the packet node, based on the VMAC address. After processing of the packet by the service component, a new VMAC address is attached to the packet. Further layer two switching of the packet, based on the new VMAC address, may lead to further processing by another service component or to forwarding of the packet beyond the packet node.

Abstract: A method of broadcasting a data packet (D) in an ad hoc network comprising a plurality of groups of mobile nodes traveling along traffic lanes in a road network. The data packet (D) is broadcast within a group (G) during an intragroup broadcasting phase during which the data packet (D) propagates simultaneously in two opposing directions of movement (A1, A2), such that the packet (D) is received by peripheral nodes (B1, B2) of the group (G). During an intergroup broadcasting phase, a peripheral node (B) transmits the data packet (D) to another group.

Abstract: A managed network provides unique network addresses that are assigned to nodes such that no two nodes will have the same address in the managed network and such that each node will always have the same network address regardless of changing its location or changing the network to which it is joined. The nodes, communicating together, comprise a mesh network. Remote management and control of the nodes is possible from the host server, which is located outside of the mesh network, even if a node is located behind a firewall or network address translator (NAT), because server management messages are encapsulated within headers so that a persistent connection between the node and the external host server is maintained once the node sends a message to the host.

Abstract: A network management system (NMS) maintains topology information of a network allowing coexistence of PDH network and SDH network. The network management system (NMS) generates a topology data for path calculation in a path calculation device in accordance with the topology information of the network after converting topology information of the PDH network into topology information of an SDH network. The path calculation device calculates the optimum path in answer to a path calculation request from the network management system (NMS) on the basis of the topology data for path calculation generated therein, and returns the calculation result. The network management system (NMS) reverts the SDH network topology information generated through conversion from the PDH network topology information among the SDH network topology information included in the calculation result received from the path calculation device to the PDH network topology information before the conversion.

Abstract: Efficient and highly-scalable network solutions are provided that each utilize deployment units based on Clos networks, but in an environment such as a data center of Internet Protocol-based network. Each of the deployment units can include multiple stages of devices, where connections between devices are only made between stages and the deployment units are highly connected. In some embodiments, the level of connectivity between two stages can be reduced, providing available connections to add edge switches and additional host connections while keeping the same number of between-tier connections. In some embodiments, where deployment units (or other network groups) can be used at different levels to connect other deployment units, the edges of the deployment units can be fused to reduce the number of devices per host connection.

Abstract: Method and apparatus for providing a control plane across multiple optical network domains is described. In one example, topology and resource discovery is employed in a transport network having a plurality of control domains. Topology information for each of the control domains is summarized to produce summarized topology information. The summarized topology information for each of the control domains is exchanged among the control domains. At each of the control domains, the summarized topology information of each of the control domains is combined to produce combined topology information. The combined topology information is passed among network elements within each of the control domains using an intra-domain routing protocol.

Abstract: Embodiments of the present invention provide a method and a node device for transferring a message based on MPLS TE tunnels. The main principle of the embodiments is to determine a switching node at which MPLS TE tunnel switching is needed, and to set routing and forwarding information for tunnel switching between different MPLS TE tunnels at the switching node. The switching node switches and transfers message into different MPLS TE tunnels according to the routing and forwarding information. The present invention makes the sum of the whole network edge bandwidth resources much higher than that of the bandwidth resource at the network core, allows the network resources to converge layer by layer, and avoids the N-square problem of the tunnel number effectively and lightens the load on the network core nodes by the large number of tunnels and the load of RSVP-TE state refreshing.

Abstract: A Fibre Channel router used to join fabrics. EX_ports are used to connect to the fabrics. The EX_port joins the fabric but the router will not merge into the fabric. Ports in the Fibre Channel router can be in a fabric, but other ports can be connected to other fabrics. Fibre Channel routers can be interconnected using a backbone fabric. Global, interfabric and encapsulation headers are developed to allow routing by conventional Fibre Channel switch devices in the backbone fabric and simplify Fibre Channel router routing. Phantom domains and devices must be developed for each of the fabrics being interconnected. Front phantom domains are present at each port directly connected to a fabric. Each of these is then connected to at least one translate phantom domain. Zoning is accomplished by use of a special LSAN zoning naming convention. This allows each administrator to independently define devices are accessible.

Abstract: An environment information providing method, a video apparatus and a video system using the same are provided. The environment information is generated and inserted in between packets of a video stream. Accordingly, a user can watch the video in an environment similar to the reproduced video.

Abstract: An enclosure is associated with a network address. A management processor of a server device within the enclosure and an enclosure processor of a management mechanism within the enclosure share the network address. A networking switch processor of a networking switch within the enclosure is to route the packet to the enclosure processor, or directly to the management processor without the packet passing through the management mechanism.

Abstract: An information processing terminal device (1) is provided which is reliably connectable to a desired server on the Internet and includes: a cable interface (3) that requests connection to a predetermined server; a connection information obtainment unit (4) that obtains, from the server, connection information which includes an IP address and is necessary for the connection to the server; an obtained IP address obtainment unit (8) that obtains the IP address assigned to a communication interface (2) connected to a different network; an IP address scheme determination unit (7) that determines whether or not the obtained IP address and the IP address included in the connection information have the same address scheme; an IP address setting management unit (6) that determines a method of setting the IP address and the connection information for the cable interface (3) and the communication interface (2); and a connection information setting unit (5) that sets and releases the IP address and the connection informa

Abstract: A method, computer program product and server for use managing connection requests to a pool of servers identified by a given URL. The method begins in response to a connection request from a given client machine that initiates a user session for associating a session identifier with a given server in the pool. The session identifier is then used to generate a “virtual” URL that redirects the connection request to the given server. Thereafter, any additional connection requests issued from the given client machine during the user session are redirected to the given server so that all content is served to the client from the same location. When the user session terminates, the virtual URL is inactivated and the given server is returned to the pool so that it can then be assigned a new user session to manage.

Abstract: A multi-router system is described in which hardware and software components of one or more standalone routers can be partitioned into multiple logical routers. The multiple logical routers are isolated from each other in terms of routing and forwarding functions yet allow network interfaces to be shared between the logical routers. Moreover, different logical routers can share network interfaces without impacting the ability of any of the logical routers to be independently scaled to meet the bandwidth demands of the customers serviced by the logical router.

Abstract: The present invention discloses a method and device for detecting connectivity termination in an IPv6 access network based on a DHCP service model. The method for detecting connectivity termination according to the invention comprises the steps of: creating an entry of the subscriber connectivity cache list corresponding to the subscriber terminal in the access node when the IPv6 connectivity between the subscriber terminal and the access node is established successfully; querying the entry of the neighbor cache list corresponding to the subscriber terminal based on the polling time set in the entry of the subscriber connectivity cache list; deciding whether the connectivity of the subscriber terminal is normal based on the entry information corresponding to the subscriber terminal of the subscriber connectivity cache list and neighbor cache list; and performing termination processing on the connectivity of the subscriber terminal logging off abnormally.