Buffer Tuning - Dell Z9000 Configuration Manual

OID String
Hardware MIB Buffer Statistics
.1.3.6.1.4.1.6027.3.16.1.1.4
.1.3.6.1.4.1.6027.3.16.1.1.5
.1.3.6.1.4.1.6027.3.16.1.1.6

Buffer Tuning

Buffer tuning allows you to modify the way your switch allocates buffers from its available memory and
helps prevent packet drops during a temporary burst of traffic.
The application-specific integrated circuits (ASICs) implement the key functions of queuing, feature
lookups, and forwarding lookups in hardware.
Forwarding processor (FP) ASICs provide Ethernet MAC functions, queueing and buffering, as well as
store feature and forwarding tables for hardware-based lookup and forwarding decisions. The 1G and
10G interfaces use different FPs.
You can tune buffers at three locations.
1. CSF — Output queues going from the CSF.
2. FP Uplink — Output queues going from the FP to the CSF IDP links.
3. Front-End Link — Output queues going from the FP to the front-end PHY.
All ports support eight queues — four for data traffic and four for control traffic. All eight queues are
tunable.
Physical memory is organized into cells of 128 bytes. The cells are organized into two buffer pools —
dedicated buffer and dynamic buffer.
• Dedicated buffer — is reserved memory that cannot be used by other interfaces on the same ASIC or
by other queues on the same interface. This buffer is always allocated, and no dynamic re-carving
takes place based on changes in interface status. Dedicated buffers introduce a trade-off. They
provide each interface with a guaranteed minimum buffer to prevent an overused and congested
interface from starving all other interfaces. However, this minimum guarantee means the buffer
manager does not reallocate the buffer to an adjacent congested interface, which means that in some
cases, memory is underused.
Z-Series Debugging and Diagnostics
OID Name
fpPacketBufferTable
fpStatsPerPortTable
fpStatsPerCOSTable
Description
NOTE: These OIDs are only
generated if you enable the
enable optic-info-
update-interval
command.
View the modular packet buffers
details per stack unit and the
mode of allocation.
View the forwarding plane
statistics containing the packet
buffer usage per port per stack
unit.
View the forwarding plane
statistics containing the packet
buffer statistics per COS per port.
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