Abstract: The present invention provides a system which maintains a function of monitoring and controlling a network regardless of an increase of data to be downloaded by a computer whose access to the network is restricted.

Abstract: In a GPRS system, a method of a mobile station acquiring an IP network address. The method comprises the steps of: the mobile station generating a link identifier and sending it to a gateway over a wireless link in a network address request together with a request to check if the link identifier is unique; the gateway receiving the network address request and checking if the link identifier is unique; the gateway responding with a network address request response including either the sending a unique link identifier confirmed as being unique or a different unique link identifier; the gateway sending a network prefix to the mobile station; the mobile station combining the interface identifier and the network prefix to generate the IP network address.

Abstract: The present invention relates to communications between computing devices. Particularly there is provided a method for enabling communication between a local device of a first network having a predetermined upper layer address space, and a remote device having an upper layer address outside the first network's address space and a lower layer address. In the illustrative embodiments, the present invention enables communication with a remote device as though it were part of a local network by providing a virtual presence for the remote device in the local network address space.

Abstract: A redundancy protection scheme comprises sending a protection packet from the primary network interface to the secondary network interface, the protection packet having a hardware address of the primary network interface as a source address and a hardware address of the secondary network interface as a destination address. The scheme further comprises determining whether the secondary network interface receives the protection packet from the primary network interface, operating the primary and secondary network interface as active and standby network interface in response to the secondary network interface receiving the protection packet, or operating both the primary and secondary network interface as active network interface in response to the secondary network interface not receiving the protection packet, and providing the hardware address of the active secondary network interface to devices coupled thereto.

Abstract: Method and apparatus for network protocol filtering of a packet is described. An index to a table is obtained and stored to travel with the packet. The index is obtainable to access the table to obtain packet information. In particular, a method for inbound network address translation packet filtering and a method for outbound packet filtering are described.

Abstract: A method, device, and computer readable medium for adaptively configuring a router monitors data packets propagating in a network to detect a statically configured network device. A network interface within the router is adapted to network parameters associated with the statically configured network device to operatively couple the statically configured network device to the router.

Abstract: A method, apparatus and computer program in a telecommunication network (111, 112, 121) for routing a media stream from an IMS domain to an MSC (107, 107a) associated with a mobile station in a circuit switched domain of a PLMN (109), wherein a service control node (111, 112, 121) receives a first request for routing path data for routing said media stream to a logical address associated with said mobile station (110), and wherein said logical address is converted into a physical address of the mobile station (110) and subsequently converted into a physical address of the MSC (107, 107a). A service control node (111, 112, 121) in the IMS domain obtains the MSRN for the mobile station (110). The MSRN is used to route the call as an IMS call right up to the MSC (107, 107a). The service control node (111, 112, 121) may comprise a SIP-AS, an ENUM server or a Client Gateway.

Abstract: Packet switch operating methods and packet switches compare a quantity of virtual interfaces associated with a virtual switch to a threshold. If the quantity of virtual interfaces is not greater than the threshold, and the packet switch is configured to learn forwarding fields of packets forwarded by the virtual switch, the methods and switches configure the packet switch to not learn forwarding fields of packets subsequently forwarded by the virtual switch. Other methods and packet switches compare a quantity of virtual interfaces associated with a virtual switch to a threshold. If the quantity of virtual interfaces associated with the virtual switch is not greater than the threshold and the packet switch is configured to learn forwarding fields of packets forwarded by the virtual switch, the methods and packet switches configure the packet switch to not learn forwarding fields of packets subsequently forwarded by the virtual switch.

Abstract: One aspect of the embodiments utilizes an information processing apparatus connected to another information processing apparatus via a transmitting path. An embodiment includes a communication request generation unit generating a communication request to the other information processing apparatus, a network management unit outputting a first data having an address of a first form to the other information processing apparatus based on the communication request, and a sending unit sending the second data to the transmitting path. The address converting unit converts the first data that the network management unit has output to second data including an address of a second form and outputs the second data when the address converting unit has received a sending request of the first data from the network management unit or when designated time has elapsed before receiving the sending request of the first data from the network management unit.

Abstract: Methods and apparatus for processing a DNS query by a NAT device are disclosed. A NAT device (e.g., NAT-PT device) receives the DNS query from a node. The NAT device then sends two DNS queries to a DNS server. Specifically, each of the DNS queries requests an IP address in a different version of IP (e.g., IPv4 or IPv6). For example, each of the DNS queries may request an A record or an AAAA record. When the NAT device receives two DNS replies from the DNS server, it forwards only one of the DNS replies to the node. Specifically, the DNS reply that is forwarded includes at least one answer record. DNS replies that do not include at least one answer record, or are received subsequent to forwarding the DNS reply to the node, are dropped by the NAT device.

Abstract: In a packet processing apparatus and method in an ethernet switching system, an introduced packet is discarded by switching to a dummy port instead of trapping the packet until a layer 3 table of an ethernet switch chip is updated, thereby operating an Address Resolution Protocol (ARP) after having minimized a central processing unit (CPU) load. The packet processing apparatus, upon receipt of a first packet headed for a destination Internet protocol (IP) address not existing in the packet processing unit from a source host, transmits an ARP request packet to the destination IP address so as to acquire routing information of a destination host.

Abstract: A modular distributed I/O system that allows one or more modules of an island to be omitted without requiring reconfiguration of the system and a method for auto-addressing the system. The island includes a network interface module that is operably connected to a user interface. The user interface allows a user to indicate for each of the nodes of the island whether the node has an I/O module physically present or not physically present. This allows a constant process image in a system where the process image is dependent upon node ID's of modules, and modules are assigned addresses (i.e., ID's) automatically without using unique markers or signatures.

Abstract: A temporary ENUM architecture assigns a temporary ENUM at call time. For an originated communication requiring routing to a party which needs a particular callback format not supported, the TempENUM provides consistency with the specific format required by the receiving party. The TempENUM is assigned for the duration of the call or communication, or for a given amount of time thereafter. The TempENUM service gateway includes a TempENUM database, a module that assigns a suitable TempENUM at the time of call routing, and a module that handles a lookup in the TempENUM database, and maps the assigned TempENUM to a calling party identifier (CgPID). The TempENUM database stores a TempENUM from a coordinator system and relates the actual calling party identifier (CgPID) for use in callback attempts. Either during the initial call or communication, or shortly thereafter, the receiving party uses the TempENUM number to return communication the initial caller.

Abstract: In a first aspect, a first method is provided for creating a media access control (MAC) address for a device. The first method includes the steps of (1) obtaining one or more identifiers; (2) obtaining a first MAC address; and (3) creating at least a second MAC address based on the one or more identifiers and the first MAC address. Numerous other aspects are provided.

Abstract: A monitoring program contains a method for detecting a load imbalance in a group of servers and providing notification so that corrections can be made. An embodiment of the invention reads from the address resolution protocol (ARP) cache to determine which server addresses are present, then clears the ARP cache. The address resolution protocol will repopulate the cache from traffic it snoops and from new requests. By performing this query and clear operation periodically, the tracking program can form a picture of the activity levels of the servers. When a significant imbalance exists, the program notifies a control console for human intervention to solve the problem. The tracking program will periodically write its results to a log file, allowing reports for various time periods to be produced as needed. By this mechanism, not only can an imbalance be quickly detected, but underutilization can be picked up by comparing known capability of a resource to its actual usage.

Abstract: An MPOA system for establishing communication by using layer 3 protocol on an ATM network, in which data about the layer 3 address of a source of data packets is added to an address resolution request packet which is transmitted in order to establish a shortcut VCC toward a destination of the data packets in each communication node and hence transmitted to the destination, and in the case of accepting the address resolution request packets to be transmitted in order to establish the respective shortcut VCCs toward the destination of the data packets, as for the same communication, from a plurality of the communication nodes, a shortcut VCC is established only between the destination and the communication node remotest from the destination on the network.

Abstract: Systems and methods consistent with embodiments of the present invention provide a method for forwarding packets between VLAN groups served by segmented ports on a network switching device. A request from a source in a VLAN group to a destination in another VLAN group is identified. Information needed to route packets to the destination is obtained by re-broadcasting the request for destination information to all VLAN groups, which do not include the source, that are served by the network switching device. Information needed to route packets to the source is also obtained. In some embodiments, source and destination routing information obtained, is stored in tables in a memory cache on the network switching device. Information stored in the tables is used to relay additional packets between the segmented ports on the device serving the source and destination.

Abstract: A network switch and a method thereof for network communications include a first data port interface and a second data port interface supporting a data port transmitting and receiving data at a first data rate and a second data rate, respectively. The switch has a CPU interface to communicate with a CPU and a memory management unit to communicate data from at least one of the first and second data port interfaces and a memory. The switch includes a communication channel communicating data and messaging information between the first and second data port interfaces and the memory management unit and lookup tables, including an address resolution lookup table and a VLAN table. The first or second data port interfaces determine an egress port for an incoming data packet from a search of the address resolution lookup table and the VLAN table using a VLAN ID from the incoming data packet.

Abstract: Method and system for providing access layer satellite architecture in a data network including receiving a data packet from an access layer network device, the data packet including a Virtual Local Area Network (VLAN) identifier associated with a port on the access layer network device, performing a route lookup procedure based on the received data packet to determine a destination of the data packet, updating an ARP table with a Media Access Control (MAC) address associated with the VLAN identifier and the port of the received data packet, and transmitting the data packet to a destination network device, is disclosed.

Abstract: An MPOA system for establishing communication by using layer 3 protocol on an ATM network, in which data about the layer 3 address of a source of data packets is added to an address resolution request packet which is transmitted in order to establish a shortcut VCC toward a destination of the data packets in each communication node and hence transmitted to the destination, and in the case of accepting the address resolution request packets to be transmitted in order to establish the respective shortcut VCCs toward the destination of the data packets, as for the same communication, from a plurality of the communication nodes, a shortcut VCC is established only between the destination and the communication node remotest from the destination on the network.

Abstract: A radio bridging device is used for a communications network. If a source host transmits a communications request directed to a destination host, the radio bridging device records an IP address and a MAC address of the source host and an IP address of the destination host in a local table. A state of the source host is set as “LOCAL” if the source host belongs to a segment where the radio bridging device belongs, and set as “AIR” if otherwise. Further, a state of the destination host is set as “SEARCH”, and an ARP request directed to the destination host is broadcast. If an ARP response is received from the destination host, the state of the destination host is changed from “SEARCH” to “LOCAL” or “AIR” to be recorded in the local table together with a MAC address of the destination address.

Abstract: The relay device, comprising an address correspondence holding section which holds, for each of the terminals, the IP address and real MAC address of the terminal and a virtual MAC address being a MAC address that is virtual; a proxy reply section which, when a first ARP request frame that seeks the acquisition of the virtual MAC address from the terminal is received, reads the virtual MAC address of the corresponding terminal from the address correspondence holding section and sends back the virtual MAC address to the terminal; a MAC address conversion section which receives a first frame addressed to the virtual MAC address when the first frame is sent and received between the terminals, performs conversion of the virtual MAC address and real MAC address for the MAC address of the first frame, and sends back a converted second frame; and a security check section.

Abstract: A local network is interfaced with one or more external network elements via a gateway that implements an address substitution mechanism for ensuring that communications between devices attached to the local network are not routed through an external network as a result of, e.g., disparity in their remotely-assigned Internet protocol (IP) addresses. In accordance with the invention, the gateway is configured to intercept communications from devices on the local network in order to determine remotely-assigned IP address information for those devices. After such information is determined for a given device, the gateway creates a set of address substitution information that includes sub-network compatible addresses for use by other devices on the local network when communicating with the given device.

Abstract: The present invention provides a method and apparatus for network address translation (NAT) based on pure hardware architecture. The method includes that when receiving a packet, the first MAC circuit will translate the address of the packet directly and store the address-translated packet into the storage, and that the first MAC circuit informs the second MAC circuit to access the address-translated packets from the storage so as to output. Because address translation requires lots of operating resource, the present invention using the first and the second MAC circuits instead of the CPU to obtain the aforesaid functions only needs a simple, low-speed and low-power CPU to setup the parameters of the first and the second MAC circuits or process few special packets, thus getting the biggest bandwidth under the restriction, the zero wastage of the smallest packet, followed the stipulation of IEEE802.3 in the environment of 100 MHz Ethernet.

Abstract: One embodiment of the present invention provides a system that detects a non-compliant router that incorrectly responds to all address-resolution-protocol (ARP) requests, including ARP requests and ARP probes for link-local IP addresses. This is accomplished by sending an ARP request asking for an Ethernet address associated with a link-local IP address, wherein the link-local IP address is a reserved link-local IP address, which should not be assigned to any device. If a response is received to the ARP request, the system determines that the response was sent by a non-compliant router that incorrectly responds to all ARP requests, including ARP requests for link-local IP addresses.

Abstract: In a first aspect, a first method is provided for creating a media access control (MAC) address for a device. The first method includes the steps of (1) obtaining one or more identifiers; (2) obtaining a first MAC address; and (3) creating at least a second MAC address based on the one or more identifiers and the first MAC address. Numerous other aspects are provided.

Abstract: A method and system for data link layer address classification. Data link layer address information is received from a device over a local area network (LAN), wherein the LAN is partitioned into a plurality of domains. The data link layer address information is classified as being associated with a domain of the plurality of domains based on a source address of the device. The data link layer address information is assigned to the domain.

Abstract: A packet communication method and a packet communication system capable of making an IPv4-compatible application operating on an information processing apparatus communicate with another information processing apparatus connected to an IPv6 network without using an address translation router. In the information processing apparatus connected to the IPv6 network, an IPv4-to-IPv6 protocol conversion control function is incorporated in a LAN driver. A protocol conversion control module receives an IPv4 packet from a protocol control module. When a send destination IPv4 address contained in a header of the packet is registered in an address translation table incorporated in the protocol conversion control module, an IPv6 address is generated to be sent onto a LAN. Unless the send destination IPv4 address contained in the packet header is registered in the address translation table incorporated in the protocol conversion control module, the IPv4 packet as received is intactly sent onto the LAN.

Abstract: A network switch includes a look-up engine for obtaining associated data in response to a header portion of a packet and an interlinked network processor such as a RISC for performing a processing function on the header portion or the associated data. Both look-up engine and the network processor may modify a destination port bitmask. The network processor may implement additional packet header processing required for replication or server load balancing.

Abstract: A method and apparatus that routes packets in a network is disclosed. The method may include receiving a packet from a first communication device in the network requesting an IP address, determining if another communication device owns the requested IP address, wherein if another communication device does not own the requested IP address, giving the IP address to the first communication device, otherwise, if it is determined that a second communication device is claiming ownership of the IP address, determining whether the first communication device or the second communication device owns the IP address using an address request authority percentage protocol (ARAPP) function, wherein based on the results of the ARAPP function, the first communication device is given the IP address, otherwise the IP address request from the first communication device is denied.

Abstract: A system, method, and program product are provided that gather a plurality of IP addresses that each correspond to a common domain name. A list of domain names is provided for gathering corresponding IP addresses. For each of the received domain names, IP addresses are retrieved from a number of DNS tables. The unique IP addresses are identified from the gathered IP addresses retrieved for each of the domain names. The domain names and their associated IP addresses are stored in a domain name repository.

Abstract: The present invention discloses a high-capacity broadband access method, comprising: a broadband subscriber initiating an access request to an access unit; the access unit sending the subscriber authentication information to a control unit via a route switching unit; the control unit authenticating the subscriber with an internal or external authentication, authorization and accounting server, returning the authentication result to the access unit via the route switching unit, and sending the configuration information to the accessed subscriber; the route switching unit and the access unit accomplishing configuration of the subscriber information, allocating corresponding resource to the subscriber, and establishing a data channel for network access of the subscriber. The present invention also discloses a high-capacity broadband access device and a system thereof.

Abstract: There is provided a device connected to a network to which nodes are connected. The device is provided with a first storage unit in which information is registered, a request unit configured to transmit a request for device information concerning a name and an address of a node to the nodes, a reception unit configured to receive device information transmitted from the nodes as responses to the request, and a registration unit configured to register the device information received by the reception unit into the first storage unit.

Abstract: The present invention provides methods and apparatuses for interfacing high-layer applications to Link Capacity Adjustment Scheme (LCAS) on Synchronous Optical Network/Synchronous Digital Hierarchy (SONET/SDH) edge nodes. These applications include high-level control protocols, such as Generalized Multiprotocol Label Switching (GMPLS) and Optical Switching and Routing Protocol (OSRP), and user-initiated cross-connect creation and termination. The present invention provides a mechanism that is capable of mapping SONET/SDH connections to Virtual Concatenated Groups (VCGs), thus enabling an efficient interface for operators to control and manage the connections via LCAS. As part of the mechanism, the existing LCAS protocol state machine is enhanced such that the operators can shut down bi-directional SONET/SDH flows from a single edge node, as opposed to from both source and sink nodes, as provided for by existing specifications.

Abstract: A technique is performed within a DNS server to respond to a DNS message. The technique includes receiving the DNS message from a requesting device (e.g., a DHCP server), and generating a search result based on a search of a portion of the DNS message for a request to delete a specific record (i.e., a specific, predefined record which is not expected to exist in the DNS). The technique further includes selectively providing and not providing current state information (or other information) to the requesting device depending on whether the search result indicates that the request to delete the specific record resides within the portion of the DNS message. Such operation allows for augmented operation with augmented DNS clients, as well as non-augmented operation with legacy equipment.

Abstract: A method is presented for address resolution mapping in a wireless multihop communication network wherein the network is built up by client devices and/or infrastructure devices, network traffic is based on using ARP forwarding and rebroadcasting to locate devices in such a network architecture. The invention also includes devices for such a network and the complete communication system is described.

Abstract: Preventing duplicate sources on a protocol connection that uses network addresses, protocols and port numbers to identify source applications that are served by a NAPT. If an arriving packet encapsulates an encrypted packet and has passed through an NAPT en route to the destination host, the encapsulated packet is decrypted to obtain an original source port number and original packet protocol from the decrypted packet. A source port mapping table (SPMT) is searched for an association between the NAPT source address, the original source port, and the original packet protocol associated with the NAPT source address and port number. If an incorrect association is found, the packet is rejected as representing an illegal duplicate source; that is, a second packet from a different host served by a NAPT that is USING the same SOURCE port and protocol.

Abstract: A network system includes a first device and a second device separated by a network having asymmetric routes in which traffic forwarded in a first direction from the first device to the second device may travel a different route than traffic forwarded in a second direction from the second device to the first device. At least three intermediate processing devices are located between the first device and the second device, wherein at least two of the intermediate processing devices are located along different asymmetric routes. The intermediate processing devices intercept a communication flow between the first device and the second device, and encapsulate the communication flow within network tunnels so that communications associated with the communication flow in the first direction and the second direction are forwarded between a same set of at least two of the intermediate processing devices.

Abstract: Disclosed is an apparatus and method of client device roaming from a home subnet to a foreign subnet of a network. The method includes the client device accessing the network through a first access node of the home subnet, and the client device roaming to a second access node of the foreign subnet, the client device accessing the network through the second access node, the client device maintaining a fixed client IP address, default gateway IP address and IP subnet attachment as the client device roams from the first access node to the second access node.

Abstract: A computer system of a federation coupled to a network including a server having an internal address associated with a first subnet and a network abstraction and isolation layer rules-based federation and masquerading (NAIL RBFM) interface that interfaces the server with the network. The NAIL RBFM interface transforms the internal address between the first subnet and a second subnet for intra-federation communications. The NAIL RBFM interface performs transform and inverse transform operations to convert between internal and external addresses of intra-federation network traffic. The operations may be performed on source and destination addresses, and may be configured in any of several manners, such as modifying at least one bit of an address, replacing at least one octet of an IP address, substituting a prefix of an address, replacing an entire address, etc.

Abstract: The present invention has an object to provide a relay device capable of performing dynamic port forward setting to open a port even if performing a connection in two stages and being connected to a network and a port forward setting method, and relates to a router for relaying a data packet which has such a structure as to comprise a control portion for giving a port forward setting request to an upper router 2 to perform the port forward setting of the upper router 2 and to relate port forward setting for a CP4 to port forward setting of a router upon receipt of the port forward setting request from the CP4 when a WAN side I/F portion is connected to an internet 1 through the upper router 2 and a LAN side I/F portion is connected to the CP4.

Abstract: A method for burning MAC address is used to burn a MAC address into a network card in the course of making a network card. The method includes the following steps: Stores a plurality of MAC addresses in a burning platform. The burning platform sends a MAC address to a burning device, and then burns the MAC address to a network card through the burning device. When the burning process finishes, the burning platform reads the contents of the network card, and compares the reading contents to the burning contents. If the result is correct, the burning platform sends the MAC address and a serial number of the network card to a server, and compares them to serial numbers and MAC addresses being stored in the server to prevent the MAC address being reused.

Abstract: A system and method are provided for forwarding packets through a fully meshed communication network when the destination MAC address may not be known. Each network element maintains a mapping of MAC addresses and IP addresses, each MAC address having an associated IP address which indicates to where packets are to be forwarded. If a network element receives a packet but has not yet associated an IP address with the destination MAC address of the packet, then the network element forwards the packet along a tree. If a network element receives a packet and has associated an IP address with the destination MAC address, in other words has learned of the IP address for the MAC address, the network element sends the packet directly to the IP address unless a direct link to the IP address is not available. If a direct link is not available, the network element forwards the packet along the tree.

Abstract: A protocol is provided for backing up ATM network devices should they fail. The protocol is implemented in a system running ATMARP and supporting IP over ATM. In the protocol, multiple ATM network devices are combined in a “standby group” and share a common IP address. When an active member of the standby group fails, one of the other members of the standby group takes over ATM responsibility for the functions of the failed device. An ATMARP Server determines which member of a standby group should handle IP packets destined for that group.

Abstract: A system and method maps Virtual Local Area Network (VLAN) designations to Internet Protocol version 6 (IPv6) site identifiers (IDs), and embeds site IDs into scoped internet addresses in such a way as to facilitate processing by primarily hardware-oriented forwarding tables. A router has a plurality of interfaces for receiving and forwarding packets, and a route processor for making forwarding decisions for received packets. The route processor includes a routing engine, a routing table, a forwarding information base (FIB), a VLAN store and a site ID store. At least some of the router's interfaces are associated with corresponding VLAN IDs, and the site ID store is preconfigured with a mapping of VLAN IDs to site IDs.

Abstract: Methods and apparatus for optimizing NAT traversal in Mobile IP are disclosed. Various mechanisms may performed independently or in combination with one another. A first mechanism enables one-way keep alive messaging to the Home Agent, while a second mechanism enables two-way keep alive messaging to the Home Agent, thereby enabling an entry in a NAT translation table to be maintained. The two-way keep alive messaging requires that the Home Agent send an acknowledgement message, while the one-way keep alive messaging does not. Keep alive messaging may be performed at the Mobile Node or the Foreign Agent. A third mechanism enables a Foreign Agent to encapsulate a registration request packet with the Foreign Agent care-of address in the source IP address field rather than an egress interface of the Foreign Agent. A fourth mechanism enables a Mobile Node to force a Home Agent to perform UDP tunneling.

Abstract: The distribution of traffic flows in a load-sharing redundancy group that includes a first gateway device and a second gateway device includes assigning a first set of forwarding addresses to the first gateway device and a second set of forwarding addresses to the second gateway device. The redundancy group distributes forwarding addresses to hosts which in turn use the distributed forwarding addresses to send packets to the redundancy group. The traffic flow for each of the assigned forwarding addresses is measured and may be compared to a target traffic flow. The traffic flow is adjusted to close in on the target traffic flow. Adjustment of the traffic flow can be accomplished either by changing the existing measured traffic flow by re-assigning a forwarding address originally assigned to one gateway device to a different gateway device or by altering future distribution of forwarding addresses so that additional traffic is sent to one or more forwarding addresses having lower measured traffic.

Abstract: Provided are a method, system, and program for transferring data between an initiator node and target node. A request is received conforming to a first data transfer protocol at the initiator node to transmit to the target node. A reference to a memory location is obtained to use to transfer the request to the target node. At least one function is called that executes in a user address space of the initiator node, wherein the initiator node includes a kernel address space and the user address space. The at least one function executing in the user address space interfaces with an adaptor to transmit the request and reference to the memory location to the target node using a second data transfer protocol.

Abstract: A client to utilize a translator without changing the DNS server specification, when a service targeted at general clients is provided. An IPv6/IPv4 translator which reciprocally translates packets between IPv6 and IPv4 protocols and is configured so that a DNS query from a client reaches a translator DNS proxy using a dedicated domain effective as a specific DNS domain, the translator DNS proxy specifying an operation by entering a defined character string in FQDN.

Abstract: L2 switch 1 accommodates a plurality of subscriber lines and is connected to an upper side of an internet including service/management device 5 to exchange data packet. L2 switch 1 transmits broadcast packet of DHCP and ARP among the exchanged data packets to not the side of subscriber line but the upper side of the internet. When L2 packet transfer device 2 transfers the broadcast packet of ARP request to IP address managing device 3, L2 packet transfer device 2 determines whether the ARP request is transmitted from a user terminal connected to the subscriber line or from service/management device 5 or packet transfer device 4.