Network traffic metering credit distribution in network device having multiple processing units

A method comprising:

• maintaining a plurality of meters management of which is distributed among a plurality of processing units of a network device, wherein each meter of the plurality of meters is implemented in a form of a master entry managed by one of the plurality of processing units and a slave entry managed by each processing unit of the plurality of processing units;
• receiving, by a first processing unit of the plurality of processing units, a credit request message relating to a slave entry associated with a first meter of the plurality of meters and corresponding to a particular master entry of a plurality of master entries managed by the first processing unit;
• responsive to the credit request message:
• calculating, by the first processing unit, a number of credits to be granted to the slave entry based on an available credit of the particular master entry;
• deducting, by the first processing unit, the number of credits from the available credit;
• granting, by the first processing unit, the number of credits to the slave entry by sending a credit grant message indicating the number of credits to a processing unit of the plurality of processing units managing the slave entry.

A network device comprising:

• a memory;
• a plurality of network processors (NPs) coupled to the memory;
• a processing resource;
• and
• a non-transitory computer-readable medium, coupled to the processing resource, having stored therein instructions that when executed by the processing resource cause the processing resource to:
• distribute management of a plurality of meters among the plurality of NPs, wherein each meter of the plurality of meters is implemented in a form of a master entry managed by one of the plurality of NPs and a slave entry managed by each NP of the plurality of NPs;
• causing a packet that is subject to rate-limiting by a first meter of the plurality of meters to be directed to a first NP of the plurality of NPs, wherein the first NP:
• determines with reference to a slave entry of a plurality of slave entries managed by the first NP unit and corresponding to the first meter whether the packet is to be passed or dropped based on available credit of the slave entry, wherein the slave entries are stored in the memory;
• when the packet is to be dropped, the first NP drops the packet;
• when the packet is to be passed, the first NP:
• deducts an amount of credit associated with passing the packet from the available credit;
• and
• allows the packet to be passed to a subsequent stage of packet processing.