Label handling in packet networks
First Claim
1. A switch for transferring data packets, each data packet having a label including a first part and a second part, comprising:
- pluralities of input ports and output ports, wherein each input port has a list of internal labels including a first sublist and a second sublist; and
a switch core for transferring data packets that have arrived at an input port to a selected output port;
wherein each input port performs, for a data packet that has arrived at the input port, a first table look-up in the first sublist based on the first part of the label of the arrived data packet, whereby an internal label is obtained, to determine whether a second table look-up should be performed;
when the second table look-up should not be performed, the input port substitutes the internal, label obtained by the first table look-up for the first part of the label of the arrived data packet; and
when the second table look-up should be performed, the input port performs the second table look-up in the second sublist based on the second part of the label of the arrived data packet, whereby an internal label is obtained, and substitutes the internal label obtained by the second table look-up for the label of the arrived data packet.
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Accused Products
Abstract
In a packet network for electronic transfer of data packets from one end station to another end station, there are, in the conventional way, a number of switch units. Each end station is connected to a switch unit, and the switch units perform the transfer of data packets along an established connection. The switch units are provided with switch ports on all of their connections. In these switch ports, a substitution is performed of labels of the data packets, both for data packets arriving to the switch unit and for data packets forwarded from the switch unit. The substitution prevents data packets belonging to different connections from having the same label and also offers distributed services in the data network. The data packet labels are constructed of a VPI field and a VCI field and, for data packets that arrive directly from or are sent directly to an end station, a GFC-field. In the substitution of the label of a data packet arriving to a switch unit, a table look-up is first performed in the associated switch port by way of the contents of the VPI field of the data packet. The result of the table look-up gives a direct information if the data packet belongs to a connection having a label comprising only a VPI field (VP connection), and then its contents are replaced by a record obtained in the table look-up. If the data packet has both a VPI field and a VCI field (VC connection), its VPI and VCI fields are replaced by new label portions obtained from a second table look-up.
38 Citations
27 Claims
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1. A switch for transferring data packets, each data packet having a label including a first part and a second part, comprising:
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pluralities of input ports and output ports, wherein each input port has a list of internal labels including a first sublist and a second sublist; and a switch core for transferring data packets that have arrived at an input port to a selected output port; wherein each input port performs, for a data packet that has arrived at the input port, a first table look-up in the first sublist based on the first part of the label of the arrived data packet, whereby an internal label is obtained, to determine whether a second table look-up should be performed;
when the second table look-up should not be performed, the input port substitutes the internal, label obtained by the first table look-up for the first part of the label of the arrived data packet; and
when the second table look-up should be performed, the input port performs the second table look-up in the second sublist based on the second part of the label of the arrived data packet, whereby an internal label is obtained, and substitutes the internal label obtained by the second table look-up for the label of the arrived data packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A network for transferring data packets belonging to logical connections having either a first type or a second type, each data packet having a label including a first part and a second part and identifying the logical connection to which a data packet belongs, comprising:
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a plurality of end stations, each end station being either a start point or an end point for a data packet; a plurality of switch units, each switch unit having a plurality of input ports and output ports allows transferring of a, between which ports a data packet; and a connection line from each end station to one of an input port and an output port of a respective switch unit associated with each end station, and a plurality of connection lines between the input ports and output ports of the switch units, which are not connected to an end station; wherein each switch unit establishes, when a data packet arrives from an end station associated with that switch unit, a logical connection to another end station, logical connection being established through that switch unit and in the network in cooperation with other switch units, and determines an internal label having a first part and a second part for the logical connection; each input port has a list of internal labels including a first sublist and a second sublist and substitutes an internal label for the label of a data packet arrived at that input port on a connection line which is established for the logical connection to which the data packet belongs; when a data packet belongs to the first type of logical connection, the input port at which the data packet arrives performs a first table look-up in the first sublist based on the first part of the label of the arrived data packet to obtain an internal label, and substitutes that internal label for only the first part of the label of the arrived data packet; and when a data packet belongs to the second type of logical connection, the input port at which the data packet arrives performs a second table look-up in the second sublist based on the second part of the label of the arrived data packet to obtain an internal label, and substitutes that internal label for the label of the arrived data packet. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification