Cisco Systems DSC9148D8G48PK9 manual BBCredit Buffers for Switching Modules

Chapter 4 Configuring Interface Buffers

Information About Interface Buffers

Figure 4-5shows the default BB_credit buffer allocation model for 24-port 4-Gbps switching modules. The minimum BB_credits required to bring up a port is two buffers.

Figure 4-5 BB_Credit Buffer Allocation in 24-Port 4-Gbps Switching Modules

All ports

shared (4 Gpbs)

16 BB credits

24-port module

Mixed

All ports

dedicated (2 Gbps)

250 BB credits

1Gbps

250 BB credits

Dedicated

2Gbps

250 BB credits

Shared

16 BB credits

4Gbps

250 BB credits

144856

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

BB_Credit Buffers for Switching Modules

This section describes how buffer credits are allocated to Cisco MDS 9000 switching modules, and includes the following topics:

•Configuring Buffer Credits on a Generation 2, Generation 3 or Generation 4 Module, page 4-5

•48-Port8-Gbps Advanced Fibre Channel Module BB_Credit Buffers, page 4-6

•48-Port8-Gbps Fibre Channel Module BB_Credit Buffers, page 4-7

•24-Port8-Gbps Fibre Channel Module BB_Credit Buffers, page 4-8

•4/44-Port8-GbpsHost-Optimized Fibre Channel Module BB_Credit Buffers, page 4-9

•48-Port4-Gbps Fibre Channel Module BB_Credit Buffers, page 4-10

•24-Port4-Gbps Fibre Channel Module BB_Credit Buffers, page 4-12

•18-Port Fibre Channel/4-Port Gigabit Ethernet Multiservice Module BB_Credit Buffers, page 4-13

•4-Port10-Gbps Switching Module BB_Credit Buffers, page 4-15

Configuring Buffer Credits on a Generation 2, Generation 3 or Generation 4 Module

When you configure port mode to auto or E on a Generation 2 module, one of the ports will not come up for the following configuration:

•Port Mode: auto or E for all of the ports

•Rate Mode: dedicated

•Buffer Credits: default value

	Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x		4-5