Router apparatus and frame transfer method
AssigneeKabushiki Kaisha Toshiba
InventorShigeo Matsuzawa
Life of this patent
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Abstract
A router has a function of providing a label used for transferring a datalink frame by a cut-through operation (i.e., datalink-layer switching). Whether the cut-through operation is to be performed or not is indicated by a cut-through declarator described in a prescribed portion (e.g., OUI field) within an upper-layer-protocol identifying information region (e.g., SNAP field) of a received frame or signaling message. The information described in the remaining portion (e.g., PID field) within the upper-layer-protocol identifying information region and the information described in the destination or source datalink-layer address region of the received frame or signaling message are used as the label for identifying in the datalink layer a packet flow to which a received frame belongs.
Claims21
A network interconnection apparatus comprising:
- a memory for storing an identifier for identifying a packet-flow to which a datalink frame belongs and a datalink-layer address of a next-hop node to which the datalink frame belonging to the packet-flow is to be transferred;
- a receiving unit for receiving a frame from one network;
- and
- a transfer unit for obtaining, when information in a prescribed portion within an upper-layer-protocol identifying information region of the frame received by the receiving unit indicates that A, datalink-layer switching is to be performed, a datalink-layer address of a next-hop node corresponding to a packet-flow to which the frame received by the receiving unit belongs by referring to the memory based on information in a remaining portion other than the prescribed portion within an upper-layer-protocol identifying information region, and transferring to another network the frame whose, destination address region contains the datalink-layer address obtained.
A network interconnection apparatus comprising:
- a receiving unit for receiving a signaling message for establishing a first virtual connection from a previous-hop node;
- a first registering unit for registering, when information described in a prescribed portion of a network-layer-protocol identifying information region of the signaling message received by the receiving unit indicates that a datalink-layer switching is to be performed, a first connection identifier for identifying the first virtual connection in common with the previous-hop node by extracting information described in a remaining portion other than the prescribed portion within the network-layer-protocol identifying information region;
- a second registering unit for exchanging with the previous-hop node a flow-notifying message for correlating the first connection identifier and a packet-flow to be transferred through the first virtual connection, and registering a correspondence, to provide a correspondence registered, between the first virtual connection and a second virtual connection to a next-hop node of the packet-flow indicated by the flow-notifying message;
- and
- a transfer unit for transferring a frame received from the first virtual connection onto the second virtual connection by referring to the correspondence registered.
A frame transfer method comprising the steps of:
- storing in a memory an identifier for identifying a packet-flow to which a datalink frame from one logical network belongs land a datalink-layer address of a next-hop node in another logical network to which the datalink frame belonging to the packet-flow is to be transferred;
- receiving from said one logical network a frame in which information described in a prescribed portion of an upper-layer-protocol identifying information region indicates that a datalink-layer switching is to be performed;
- writing the datalink-layer address obtained from the memory, by using information provided in a remaining portion other than the prescribed portion of the upper-layer-protocol-identifying information region as the identifier, into a destination address region of the frame received;
- and
- transmitting the frame to said another logical network.
A frame transfer method comprising the steps of:
- receiving a signaling message in which information provided in a prescribed portion of a network-layer-protocol identifying information region indicates that a datalink-layer switching is to be performed, the signaling message for establishing a first virtual connection from a previous-hop node;
- obtaining a first connection identifier for identifying the first virtual connection in common with-the-previous-hop node, by using information provided in a remaining portion other than the prescribed portion of the network-layer-protocol identifying information region;
- receiving from and/or transmitting to the previous-hop node a flow-notifying message including the first connection identifier, the flow-notifying message for notifying a packet-flow to be transferred through the first virtual connection;
- storing in a memory information for switching the first virtual connection with a second virtual connection to a next-hop node of the notified packet-flow;
- and
- transferring a frame received from the first virtual connection onto the second virtual connection in accordance with the information stored in the memory.
A computer usable medium having computer readable program code embodied therein for a computer functioning as a network interconnection device which transfers datalink frames from one network to another network, the computer readable program code includes:
- a first computer readable program code for causing said computer to register in a memory an identifier for identifying a packet-flow to which a datalink frame belongs and a datalink-layer address of a next-hop node to which the datalink frame belonging to the packet-flow is to be transferred;
- a second computer readable program code for causing said computer to receive a frame in which information in a prescribed portion of an upper-layer-protocol identifying information region indicates that a datalink-layer switching is to be performed;
- and
- third computer readable program code means for causing said computer to write the datalink-layer address retrieved from the memory according to information described in a remaining portion other than the prescribed portion of the upper-layer-protocol identifying information region, into a destination address region of the received frame to be transferred.
A computer usable medium having computer readable program code means embodied therein for a computer functioning as a network interconnection device which transfers datalink frames from a first virtual connection- onto-a second virtual connection, the computer readable program code means includes:
- first computer readable program code means for causing said computer to receive a signaling message in which information described in a prescribed portion of a network-layer-protocol identifying information region indicates that a datalink-layer switching is to be performed, the signaling message for establishing the first virtual connection from a previous-hop node;
- second computer readable program code Means for causing said computer to obtain a first connection identifier for identifying the first virtual connection in common with the previous-hop node, by using information described in a remaining portion other than the prescribed portion of the network-layer-protocol identifying information region;
- third computer readable program code means for causing said computer to exchange with the previous-hop node a flow-notifying message including the first connection identifier, the flow-notifying message for notifying a packet-flow to be transferred through the first virtual connection;
- and
- fourth computer readable program code means for causing said computer to register information for switching the first virtual connection with a second virtual connection to a next-hop node of the notified packet-flow.
Dependencies are inferred from the claim text.