Cisco Systems DSC9148D8G48PK9 manual Default BBcredit buffers 250 Maximum BBcredit buffers 500

Chapter 4 Configuring Interface Buffers

Information About Interface Buffers

•Two ports with dedicated rate mode and 8-Gbps speed plus four ports with shared rate mode and 8-Gbps speed (2:1 oversubscription) .

•One port with dedicated rate mode and 8-Gbps speed plus three ports with dedicated rate mode and 4-Gbps speed plus two ports with shared rate mode and 8-Gbps speed (1.33:1 oversubscription).

•Six ports with dedicated rate mode and 8-Gbps speed.

48-Port 8-Gbps Fibre Channel Module BB_Credit Buffers

Table 4-2lists the BB_credit buffer allocation for the 48-port 8-Gbps Fibre Channel switching module.

Table 4-2	48-Port 8-Gbps Switching Module BB_Credit Buffer Allocation
		BB_Credit Buffers Per Port
		Dedicated Rate Mode		Shared Rate Mode
		8-Gbps Speed		8-Gbps Speed
BB_Credit Buffer Allocation		ISL	Fx Port	Fx Port
Default BB_credit buffers		250	32	32
Maximum BB_credit buffers		500	500	32
Total Number of BB_Credit Buffers per Module
Ports 1 through 24		6000
Ports 25 through 48		6000

The following guidelines apply to BB_credit buffers on 48-port 8-Gbps Fibre Channel switching modules:

•BB_credit buffers allocated for ports 1 through 24 and 25 through 48 can be a maximum of 6000 each so that the load is distributed.

•BB_credit buffers for ISL connections can be configured from a minimum of 2 buffers to a maximum of 500 buffers for dedicated rate mode.

•BB_credit buffers for Fx port mode connections can be configured. The minimum is 2 buffers and the maximum of 500 buffers for dedicated rate mode or 32 buffers for shared rate mode.

•Performance buffers are not supported on this module.

•The buffers should not be allocated automatically.

Each port group on the 48-port 8-Gbps Fibre Channel switching module consists of six ports. The ports in shared rate mode in a port group can have a maximum bandwidth oversubscription of 10:1 considering that each port group has 12.8-Gbps bandwidth.

The following example configurations are supported by the 48-port 8-Gbps Fibre Channel switching modules:

•Six ports with shared rate mode and 8-Gbps speed (4:1 oversubscription) (default)

•One port with dedicated rate mode and 8-Gbps speed plus

five ports with shared rate mode and 8-Gbps speed (10:1 oversubscription)

•Two ports with dedicated rate mode and 4-Gbps speed plus

four ports with shared rate mode and 4-Gbps speed (4:1 oversubscription)

	Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x		4-7