Dell PowerEdge FX2/FX2s - Manual (Page 277)

manager does not reallocate the buffer to an adjacent congested interface, which means that in some
cases, memory is under-used.
• Dynamic buffer — this pool is shared memory that is allocated as needed, up to a configured limit.
Using dynamic buffers provides the benefit of statistical buffer sharing. An interface requests dynamic
buffers when its dedicated buffer pool is exhausted. The buffer manager grants the request based on
three conditions:
– The number of used and available dynamic buffers.
– The maximum number of cells that an interface can occupy.
– Available packet pointers (2k per interface). Each packet is managed in the buffer using a unique
packet pointer. Thus, each interface can manage up to 2k packets.
You can configure dynamic buffers per port on both 1G and 10G FPs and per queue on CSFs. By default,
the FP dynamic buffer allocation is 10 times oversubscribed. For the 48-port 1G card:
• Dynamic Pool= Total Available Pool(16384 cells) — Total Dedicated Pool = 5904 cells
• Oversubscription ratio = 10
• Dynamic Cell Limit Per port = 59040/29 = 2036 cells
Figure 31. Buffer Tuning Points
Debugging and Diagnostics 277