Method and apparatus for enabling LCAS-like feature through embedded software
AssigneeCisco Technology, Inc.
InventorsDavid E. Chisholm, Ji Wen, Charles A. Carriker, Jr., Jim P. Ervin, Sanjeev D. Rampal
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Abstract
A technique controls the capacity of a virtual concatenation group (VCG) carried on a SONET path of a data network. Efficient control of VCG capacity is provided by emulating aspects of a Link Capacity Adjustment Scheme (LCAS) protocol in software. A hardware poller facility is employed to manage the status and state of the VCG, as well as members belonging to the VCG. The hardware poller contains one or more VCG state machines (VSMs) and member state machines (MSMs) configured to maintain the status and states of the VCGs and their members.
Claims20
A method for controlling capacity associated with a virtual concatenation group (VCG) comprising the steps of:
- adding a plurality of member virtual tributaries (VTs) to the VCG by an intermediate node whose hardware does not support Link Capacity Adjustment Scheme (LCAS) protocol running at hardware level on the hardware;
- retrieving, by software at the intermediate node, Synchronous Optical Network (SONET) and virtual concatenation (VCAT) information from the hardware in the intermediate node;
- determining in software at the intermediate node if a SONET frame associated with a member VT added to the VCG indicates a SONET defect;
- if the SONET frame associated with the member VT added to the VCG indicates a SONET defect, removing the member VT from the VCG until the SONET defect clears;
- determining in software at the intermediate node if a SONET frame associated with the VCG has an H4 byte that is corrupt;
- and
- if the SONET frame associated with the VCG has an H4 byte that is corrupt, removing all of the plurality of added member VTs from the VCG and placing the VCG in a down state until H4 byte corruption clears.
An intermediate node that utilizes a virtual concatenation group (VCG) that includes a plurality of member virtual tributaries (VTs), the intermediate node comprising:
- a processor configured to emulate the Link Capacity Adjustment Scheme (LCAS) protocol in software, the processor further configured to determine in software if a Synchronous Optical Network (SONET) frame associated with a member VT of the VCG indicates a SONET defect, and, if so, remove the member VT from the VCG until the SONET defect clears, and to determine in software if a SONET frame associated with the VCG has an H4 byte that is corrupt, and, if so, remove all of the plurality member VTs from the VCG and place the VCG in a down state until H4 byte corruption clears,
- wherein LCAS-compatible hardware that supports running LCAS running at hardware level is not available in the intermediate node.
An apparatus that utilizes a virtual concatenation group (VCG) that includes a plurality of member virtual tributaries (VTs), the apparatus comprising:
- a memory configured to store a virtual concatenation group state machine (VSM) associated with the VCG wherein the VSM comprises a normal state and a down state;
- and
- a processor configured to execute software to:
- monitor Synchronous Optical Network (SONET) frames associated with member VT associated with the VCG to determine if a frame associated with a member VCG indicates a SONET defect,
- remove the member VT from the VCG until the SONET defect clears,
- monitor SONET frames associated with the VCG to determine if an H4 byte of the frames is corrupt, and
- transition the VSM from the normal state to the down state for the VCG if a SONET frame associated with the VCG has an H4 byte that is corrupt, until H4 byte corruption clears,
- wherein the apparatus does not support Link Capacity Adjustment Scheme (LCAS) protocol running at hardware level on hardware of the apparatus.
An apparatus for controlling capacity of one or more data links in a data network, the apparatus comprising:
- means for generating a virtual concatenation group (VCG);
- means for generating a plurality of member virtual tributaries (VTs);
- means for adding the plurality of member VTs to the VCG;
- means for determining in software at the apparatus if a Synchronous Optical Network (SONET) frame associated with a member VT added to the VCG indicates a SONET defect;
- means for removing the member VT from the VCG until the SONET defect clears, if the SONET frame associated with the member VT added to the VCG indicates a SONET defect;
- means for determining in software at the apparatus if a Synchronous Optical Network (SONET) frame associated with the VCG has an H4 byte that is corrupt;
- and
- means for removing all the plurality of added member VTs from the VCG and placing the VCG in a down state if a SONET frame associated with the VCG has an H4 byte that is corrupt, until H4 byte corruption clears,
- wherein the apparatus does not support Link Capacity Adjustment Scheme (LCAS) protocol running at hardware level on hardware of the apparatus.
A non-transitory computer readable storage medium containing computer executable instructions for:
- adding a plurality of member virtual tributaries (VTs) to a virtual concatenation group (VCG);
- determining in software if a Synchronous Optical Network (SONET) frame associated with a member VT added to the VCG indicates a SONET defect;
- removing the member VT from the VCG until the SONET defect clears, if the SONET frame associated with the member VT added to the VCG indicates a SONET defect;
- determining in software if a Synchronous Optical Network (SONET) frame associated with the VCG has an H4 byte that is corrupt;
- and
- if so, removing all the plurality of added member VTs from the VCG and placing the VCG in a down state until H4 byte corruption clears.
Dependencies are inferred from the claim text.