Method and apparatus for encoding bridging/switching information within a routing information filed in a token ring environment
AssigneeCisco Technology, Inc.
InventorsJayaraman Iyer, Kushal A. Patel
Life of this patent
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Abstract
A technique increases the efficiency of functions performed by an intermediate device of a computer network by encoding a portion of a routing information field (RIF) of a token ring frame transported over the network with information for use by the device. The maximum number of route descriptor (RD) hops in the network is altered to provide a predetermined portion of the RIF for storing encoded information. Each intermediate device configured in accordance with the technique identifies this predetermined portion as that portion of the RIF immediately following its matching RD.
Claims28
A method for operating an intermediate device of a computer network, the method comprising the steps of:
- receiving a token ring (TR) frame transported over the computer network at the intermediate device, the TR frame transmitted by a source host, the TR frame including a routing information field (RIF), the RIF including a plurality of route descriptors (RDs);
- using a RD to designate the intermediate device;
- modifying a predetermined portion of the RIF of the TR frame;
- and
- transmitting a second TR frame to the source host to enable the modified RIF to be incorporated into a plurality of subsequent data frames of a session, the predetermined portion of the RIF used by the intermediate device in processing the subsequent data frames.
An intermediate device of a computer network, comprising:
- means for receiving a token ring (TR) frame transported over the computer network at the intermediate device, the TR frame transmitted by a source host, the TR frame including a routing information field (RIF), the RIF including a plurality of route descriptors (RDs);
- means for using a RD to designate the intermediate device;
- means for modifying a predetermined portion of the RIF of the TR frame;
- and
- means for transmitting a second TR frame to the source host to enable the modified RIF to be incorporated into a plurality of subsequent data frames of a session, the predetermined portion of the RIF used by the intermediate device in processing the subsequent data frames.
A method for operating an intermediate device of a computer network, the method comprising the steps of:
- receiving an I-can-reach explorer frame (ICR_ex) at the intermediate device, the ICR_ex frame transmitted by a peer intermediate device in response to a can-u-reach explorer frame (CUR_ex) transmitted by the intermediate device, the CUR_ex frame transmitted in response to the intermediate device receiving a first token ring (TR) frame from a host;
- the first TR frame including a routing information field (RIF), the RIF including a plurality of route descriptors (RDs);
- incorporating into a RIF of a second TR frame a RD corresponding to the intermediate device and an INFO field, the INFO field storing an index into a switching table of the intermediate device;
- and
- transmitting, in response to receiving the ICR_ex frame, the second TR frame to the host to enable the host to transmit a further TR frame incorporating the INFO field in a RIF field of the further TR frame.
An intermediate device of a computer network, the apparatus comprising:
- means for receiving an I-can-reach explorer frame (ICR_ex) at the intermediate device, the ICR_ex frame transmitted by a peer intermediate device in response to a can-u-reach explorer frame (CUR_ex) transmitted by the intermediate device, the CUR_ex frame transmitted in response to the intermediate device receiving a first token ring (TR) frame from a host;
- the first TR frame including a routing information field (RIF), the RIF including a plurality of route descriptors (RDs);
- means for incorporating into a RIF of a second TR frame a RD corresponding to the intermediate device and an INFO field, the INFO field storing an index into a switching table of the intermediate device;
- and
- means for transmitting, in response to receiving the ICR_ex frame, the second TR frame to the host to enable the host to transmit a further TR frame incorporating the INFO field in a RIF field of the further TR frame.
Dependencies are inferred from the claim text.