Dynamic trunk protocol
AssigneeCisco Technology, Inc.
InventorsAlagu Annaamalai, Umesh Mahajan
Life of this patent
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Abstract
A dynamic trunk protocol enables dynamic negotiation of trunk encapsulation types between ports connecting intermediate stations in a computer network. The stations are preferably interconnected by a point-to-point link. Negotiation between a local port and a neighbor port of the switches results in synchronization of the port configurations to a common trunk encapsulation type, such as an Interswitch Link (ISL), IEEE 802.1Q or non-trunk port configuration.
Claims37
Apparatus for dynamically negotiating trunk encapsulation types of trunk capable ports within intermediate stations interconnected by a link in a computer network, the apparatus comprising:
- a processor;
- a memory coupled to the processor, the memory storing a process that executes on the processor to administer a dynamic trunk protocol (DTP) for exchanging DTP messages between the intermediate stations, each DTP message containing trunk status and type information that enables dynamic negotiation of the trunk encapsulation types, the memory further storing and maintaining DTP port state information relating to the trunk and status type information;
- and
- port interface circuitry of each trunk capable port, the port interface circuitry coupled between the processor and the link to receive the DTP messages from the link and forward the messages to the processor for servicing by the process, the port interface circuitry responsive to the DTP port state information to thereby configure the trunk capable port in accordance with the negotiated trunk encapsulation type.
A method for dynamically negotiating trunk encapsulation types of a first port and a second port of respective first and second intermediate stations in a computer network, the stations interconnected via a link, the method comprising the steps of:
- transmitting a dynamic trunking protocol (DTP) packet from the first port over the link to the second port, the DTP packet containing configuration information representative of a status and type of first port interface circuitry of the first port;
- comparing the configuration information contained in the DTP packet with configuration information representative of a status and type of second port interface circuitry of the second port;
- if the compared information differs, forwarding a return DTP packet having configuration information representative of an agreeable status and type based on the configuration information contained in the first DTP packet;
- examining the returned agreeable status and type information at the first port;
- and
- if the returned agreeable status and type information is mutually agreeable to the ports, configuring the first and second port interface circuitry to the agreeable status and type.
A method for dynamically negotiating trunk encapsulation types of a port at an intermediate station, the method comprising the steps of:
- transmitting a dynamic trunking protocol (DTP) packet from the intermediate station to a second intermediate station, the DTP packet containing configuration information representative of a status and type of port interface circuitry of the port;
- receiving a return DTP packet from the second intermediate station, the return DTP packet containing configuration information representative of an agreeable status and type based on the configuration information contained in the first DTP packet;
- examining the returned agreeable status and type information;
- and
- determining if the returned agreeable status and type information is mutually agreeable and if so, configuring the port interface circuitry to the agreeable status and type.
A method for dynamically negotiating trunk encapsulation types of a first port at an intermediate station, the method comprising the steps of:
- receiving a dynamic trunking protocol (DTP) packet from a second intermediate station, the DTP packet containing configuration information representative of a status and type of port interface circuitry of a second port;
- comparing the configuration information contained in the DTP packet with configuration information representative of a status and type of port interface circuitry of the first port;
- and
- if the compared information differs, forwarding to the second intermediate station, a return DTP packet having configuration information representative of an agreeable status and type based on the configuration information contained in the first DTP packet.
A computer network comprising a first port of a first intermediate station and a second port of a second intermediate station, the network comprising:
- means for transmitting a dynamic trunking protocol (DTP) packet from the first port over the link to the second port, the DTP packet containing configuration information representative of a status and type of first port interface circuitry of the first port;
- means for comparing the configuration information contained in the DTP packet with configuration information representative of a status and type of second port interface circuitry of the second port;
- means for determining if the compared information differs and if so, forwarding a return DTP packet having configuration information representative of an agreeable status and type based on the configuration information contained in the first DTP packet;
- means for examining the returned agreeable status and type information at the first port;
- and
- means for determining if the returned agreeable status and type information is mutually agreeable to the ports and if so, configuring the first and second port interface circuitry to the agreeable status and type.
Dependencies are inferred from the claim text.