Method and system for effective use of internal and external memory for packet buffering within a network device

A network node configured to route network packets from an ingress network to one or more egress networks, the network node comprising:

• a first network interface, coupled to the ingress network, and configured to receive a plurality of network packets from the ingress network;
• a second network interface, coupled to a first egress network of the one or more egress networks, and configured to transmit a network packet of the plurality of network packets to the first egress network;
• an internal memory, coupled to a packet processor, and configured to store network packet data from the plurality of network packets in one or more egress packet queues;
• an internal memory unit manager (IMU manager), coupled to the internal memory, and configured to detect depletion of available memory space in the internal memory;
• an eviction dispatcher module, coupled to the IMU manager and a queue manager module, and configured to
• select, in response to the IMU manager detecting depletion of available memory space, an egress packet queue from which to evict one or more associated packets from the internal memory, wherein said selecting the egress packet queue is performed in communication with the queue manager module, and
• select one or more packets associated with the selected egress packet queue for evicting from the internal memory, wherein said selecting the one or more packets is performed in communication with the queue manager module;
• and
• an eviction engine module, coupled to the internal memory and the eviction dispatcher module, and configured to
• receive identification of the selected one or more packets associated with the selected egress packet queue from the eviction dispatcher,
• copy the selected one or more packets to an external memory coupled to the eviction engine and the packet processor, and
• release internal memory resources associated with the copied packets subsequent to said copying to the external memory, wherein
• the second network interface accesses an entry from an egress packet queue, and packet data for the entry is retrieved from one of the internal memory or the external memory in response to previously copying the selected packets to the external memory.

A non-transitory, computer-readable storage medium embodying computer program code, the computer program code comprising instructions executable by one or more modules of a network device configured to route network packets from an ingress network to one or more egress networks, the instructions configured for:

• detecting depletion of available memory space in an internal memory of the network device, wherein
• the internal memory is associated with a packet processor,
• the internal memory stores network packet data from a plurality of network packets, and
• the network packet data is stored as entries of one or more egress packet queues;
• selecting, in response to detecting depletion of available memory space, an egress packet queue from which to evict one or more associated packets from the internal memory;
• selecting one or more packets associated with the selected egress packet queue for evicting from the internal memory;
• copying the selected one or more packets to an external memory coupled to the packet processor;
• releasing internal memory resources associated with the copied packets;
• and
• accessing an entry from an egress packet queue, wherein
• packet data for the entry is retrieved from one of the internal memory or external memory in response to previously copying the selected packets to the external memory.