Default buffer pool exists (logically) at each port. Buffer pools cannot be created or deleted in the 7210 SAS. The egress buffer pools are created as access uplink port egress buffer pool for access-uplink ports and access port egress buffer pool for access ports. Based on the maximum number of ports to be supported for access and access-uplink, the total buffer is distributed into the access port egress buffer pool and the access uplink port egress buffer pool. The distribution of the buffers into access and access-uplink port egress pools take care of the buffer requirements at the port level for various queue shaping/ scheduling mechanisms and for various packet sizes varying from 64 bytes to jumbo frames. Each port on the system gets an equal portion of the available buffers. From the buffers allocated to a port, each queue gets its CBS amount of buffers. The remaining buffers are allocated toward the shared MBS pool per port. All the queues of the port can use the buffers from the shared MBS pool. By default, each queue on the access port and access-uplink port is associated with slope-policy default which disables the slope parameters within the pool.
On 7210 SAS-D, WRED is supported to evaluate the packet’s eligibility to be allocated a buffer based on the slope parameters configured for the queue.
On 7210 SAS-Dxp, WRED is supported to evaluate the TCP packet’s eligibility to be allocated a buffer based on the slope parameters configured for the queue. WRED is not supported for non-TCP packets.