4-3
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x
Chapter 4 Configuring Interface Buffers
Information About Interface Buffers
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.
Figure 4-1 shows the allocation of BB_credit buffers on line cards (24-port and 48-port 4-Gbps line
cards).
Figure 4-1 Receive Buffers for Fibre Channel Ports in a Global Buffer Pool
Figure 4-2 shows the default BB_credit buffer allocation model for 48-port 8-Gbps switching modules.
The minimum BB_credits required to bring up a port is two buffers.
Figure 4-2 BB_Credit Buffer Allocation in 48-Port 8-Gbps Switching Modules
Reserved Internal Buffers (not user configurable)
Performance Buffers (Shared Pool)
Common unallocated buffer pool for BB_credits
123 N
Allocated BB_credit buffers
for each front panel FC ports
Maximim Receive
buffers
Total BB_credit
buffers
185164
48-port module
Mixed
All ports
shared (8 Gpbs)
32 BB credits
1 Gbps
250 BB credits
2 Gbps
250 BB credits
4 Gbps
250 BB credits
All ports
dedicated (2 Gbps)
250 BB credits
Dedicated
Shared
32 BB credits
8 Gbps
250 BB credits
189048
