Cisco MDS 9000 Series Configuration Manual page 126

Buffer Pools
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Table 4-7
BB_Credit Buffer Allocation Type
Total number of BB_credit buffers per module
Total number of performance buffers per module
1. ISL = E port or TE port.
The following considerations apply to BB_credit buffers on 12-port 4-Gbps switching modules:
BB_credit buffers for ISL connections can be configured from a minimum of 2 buffers to a
•
maximum of 250 buffers.
BB_credit buffers for Fx port mode connections can be configured from a minimum of 2 buffers to
•
a maximum of 250 buffers.
By default, 512 performance buffers are preallocated and are shared by all the ports. These buffers
•
are configurable and the buffers are assigned to the port based on the availability of the buffers in
the shared pool.
• There are 2488 extra buffers available as extended BB_credit buffers after allocating all the default
BB_credit buffers for all the ports in ISL mode (5488 - (250 * 12)).
Note
Note By default, the ports in the 12-port 4-Gbps switching modules come up in 4-Gbps dedicated rate mode
but can be configured as 1-Gbps and 2-Gbps dedicated rate mode. Shared mode is not supported.
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
4-14
12-Port 4-Gbps Switching Module BB_Credit Buffer Allocation
Extended BB_credits are allocated across all ports on the switch. That is, they are not allocated
by port group.
Chapter 4 Configuring Interface Buffers
BB_Credit Buffers Per Port
Dedicated Rate Mode
4-Gbps Speed
1
ISL Fx Port
5488
512 (shared)
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)