Clock synchronization system and method for use in a scalable access node
First Claim
1. A clock synchronization system for use in an access network element having a primary bank and a plurality of secondary banks interlinked via an interbank communication link, comprising:
- a central master timing and frame alignment control block disposed in said primary bank, said central master timing and frame alignment control block operating based on a master reference clock to determine a delay preset with respect to a slave timing and frame alignment control block disposed in a first level secondary bank coupled to said primary bank;
a local counter coupled to said slave timing and frame alignment control block disposed in said first level secondary bank, wherein said local counter is operable to generate an adjusted local clock based on said delay preset received from said central master timing and frame alignment control block; and
a local master timing and frame alignment control block disposed in said first level secondary bank, said local master timing and frame alignment control block operating responsive to said adjusted local clock to determine a delay preset with respect to a slave timing and frame alignment control block disposed in an adjacent secondary bank immediately below said first level secondary bank, wherein a local counter coupled to said slave timing and frame alignment control block disposed in said adjacent secondary bank is operable to generate an adjusted local clock based on said delay preset received from said first level secondary bank.
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Accused Products
Abstract
A clock synchronization scheme for use with an access network element having scalable architecture. A point-to-point, high-speed communication link provided between two adjacent banks of the access network element logically interconnects a plurality of banks in a linear stack, thereby creating a stackplane hierarchy for local traffic. A primary bank includes a central master timing and frame alignment control block operable based on a master reference clock. A secondary bank immediately coupled to the primary bank is operable to synchronize its local clock based on a delay preset signal provided by the primary bank. Each remaining secondary bank is operable to synchronize its local clock based on the delay preset signal provided by a local master timing control block disposed in the secondary bank immediately above it.
42 Citations
18 Claims
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1. A clock synchronization system for use in an access network element having a primary bank and a plurality of secondary banks interlinked via an interbank communication link, comprising:
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a central master timing and frame alignment control block disposed in said primary bank, said central master timing and frame alignment control block operating based on a master reference clock to determine a delay preset with respect to a slave timing and frame alignment control block disposed in a first level secondary bank coupled to said primary bank; a local counter coupled to said slave timing and frame alignment control block disposed in said first level secondary bank, wherein said local counter is operable to generate an adjusted local clock based on said delay preset received from said central master timing and frame alignment control block; and a local master timing and frame alignment control block disposed in said first level secondary bank, said local master timing and frame alignment control block operating responsive to said adjusted local clock to determine a delay preset with respect to a slave timing and frame alignment control block disposed in an adjacent secondary bank immediately below said first level secondary bank, wherein a local counter coupled to said slave timing and frame alignment control block disposed in said adjacent secondary bank is operable to generate an adjusted local clock based on said delay preset received from said first level secondary bank. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A clock synchronization method for use in an access network element having a primary bank and a plurality of secondary banks interlinked via an interbank communication link, comprising the steps:
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providing a delay preset by a central master timing and frame alignment control block disposed in said primary bank to a slave timing and frame alignment control block disposed in a first level secondary bank coupled to said primary bank; adjusting a local clock generated by a local counter that is coupled to said slave timing and frame alignment control block disposed in said first level secondary bank, wherein said local clock is operable to be adjusted based on said delay preset received from said central master timing and frame alignment control block; synchronizing a local master timing and frame alignment control block disposed in said first level secondary bank based on said adjusted local clock; and providing a delay preset by said local master timing and frame alignment control block operating responsive to said adjusted local clock to a slave timing and frame alignment control block disposed in an adjacent secondary bank immediately below said first level secondary bank, wherein a local counter coupled to said slave timing and frame alignment control block disposed in said adjacent secondary bank is operable to generate an adjusted local clock based on said delay preset received from said first level secondary bank, said adjusted local clock in said adjacent secondary bank operating to synchronize a local master timing and frame alignment control block disposed therein. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification