> # Buffer Pools

> In the architecture of Generation 2, Generation 3, and Generation 4 modules, receive buffers shared by a set of ports are called buffer groups. The receive buffer groups are organized into global and local buffer pools.

> The receive buffers allocated from the global buffer pool to be shared by a port group are called a global receive buffer pool. Global receive buffer pools include the following buffer groups:

> - Reserved internal buffers
> - Allocated BB_credit buffers for each Fibre Channel interface (user configured or assigned by default)
> - Common unallocated buffer pool for BB_credits, if any, to be used for additional BB_credits as needed
> - Performance buffers (only used on 12-port 4-Gbps and 4-port 10-Gbps switching modules)

> Note The 48-port and 24-port 8-Gbps modules have dual global buffer pools. Each buffer pool in the 48-port modules support 24 ports and in the 24-port modules each buffer pool supports 12 ports.

> Note The default BB_credit buffer allocation is the same for all port speeds.

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