S-Series Debugging and Diagnostics | 363Table 14-5 describes the type and number of ASICs per platform.You can tune buffers at three locations, as shown in Figure 14-8.1. CSF – Output queues going from the CSF.2. FP Uplink—Output queues going from the FP to the CSF IDP links.3. Front-End Link—Output queues going from the FP to the front-end PHY.All ports support eight queues, 4 for data traffic and 4 for control traffic. All 8 queues are tunable.Physical memory is organized into cells of 128 bytes. The cells are organized into two buffer pools—dedicated buffer and dynamic buffer.• Dedicated buffer is reserved memory that cannot be used by other interfaces on the same ASIC or byother queues on the same interface. This buffer is always allocated, and no dynamic recarving takesplace based on changes in interface status. Dedicated buffers introduce a trade-off. They provide eachinterface with a guaranteed minimum buffer to prevent an overused and congested interface fromstarving all other interfaces. However, this minimum guarantee means the buffer manager does notreallocate the buffer to an adjacent congested interface, which means that in some cases, memory isunderused.• Dynamic buffer is shared memory that is allocated as needed, up to a configured limit. Using dynamicbuffers provides the benefit of statistical buffer sharing. An interface requests dynamic buffers whenits dedicated buffer pool is exhausted. The buffer manager grants the request based on threeconditions:• 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 uniquepacket 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 cellsTable 14-5. ASICS by PlatformHardware FP CSFS50N, S50V 2 0S25V, S25P, S25N 1 0
