Derived VLAN mapping technique
AssigneeCisco Technology, Inc.
InventorRaymond Kloth
Life of this patent
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Abstract
A derived virtual local area network (VLAN) mapping technique enables centralized control of broadcast domains by a switch capable of supporting different protocols carried within frames that are distributed throughout a computer internetwork. Associated with each incoming frame received at the switch are characteristics such as protocol type and/or subnet information, and associated with each input port of the switch are characteristics such as VLAN and/or index values. Utilizing certain of these characteristics, a derived VLAN value is generated that allows users to create arbitrary VLAN domains and reduce broadcast traffic received by stations of the domains.
Claims20
A method for controlling broadcast domains in a switch capable of supporting different protocols frames that are forwarded throughout a computer internetwork, the switch having a plurality of input ports and output ports, the method comprising the steps of:
- associating (i) each frame received at the switch with one of a protocol type value and a subnet value and (ii) each input port of the switch with one of a virtual local area network (VLAN) value and index value;
- creating a mapping address from predetermined ones of the values;
- selecting one of a plurality of entries of a translation structure using the created mapping address to generate a derived VLAN value;
- and
- accessing a forwarding database using the derived VLAN value to determine an output port for the received frame to thereby control a broadcast domain.
Apparatus adapted to control broadcast domains in a switch capable of supporting different protocols frames that are forwarded throughout a computer internetwork, the switch having a plurality of input ports for receiving the frames at the switch and a plurality of output ports, the apparatus comprising:
- a parsing engine configured to extract (i) a source network address having a subnet value from a packet header encapsulated within a received frame and (ii) a protocol type value from a header of the received frame;
- a forwarding engine coupled to the parsing engine and configured to create a mapping address from predetermined ones of the values;
- a translation structure coupled to the forwarding engine and configured to generate a derived virtual local area network (VLAN) value in response to the mapping address;
- and
- a forwarding database coupled to the forwarding engine and configured to determine an output port for the received frame in response to the derived VLAN value to thereby control a broadcast domain.
A computer readable medium containing executable program instructions for controlling broadcast domains in a switch capable of supporting different protocols frames that are forwarded throughout a computer internetwork, the switch having a plurality of input ports and output ports, the executable program instructions comprising the program instructions for:
- associating (i) each frame received at the switch with one of a protocol type value and a subnet value and (ii) each input port of the switch with one of a virtual local area network (VLAN) value and index value;
- creating a mapping address from predetermined ones of the values;
- selecting one of a plurality of entries of a translation structure using the created mapping address to generate a derived VLAN value;
- and
- accessing a forwarding database using the derived VLAN value to determine an output port for the received frame to thereby control a broadcast domain.
Dependencies are inferred from the claim text.