Dell N1100-ON, Reference Manual

Page: 2198 / 2332

Switch Management Commands
2198
User Guidelines
This command displays interface transmit and receive utilization in bits/sec
and packets/sec. The transmit utilization and transmit packet counts include
packets generated by the CPU.
Buffer utilization is the count of cells queued for transmission on a port. A
buffer utilization value of less than 10 generally indicates that the port is not
experiencing congestion and packets are transmitted as soon as they are
queued for output. A value above 10 that increases and decreases indicates a
port that is experiencing burstiness. A persistent value above 10 indicates a
port that is experiencing congestion (incast); if the cell count continues to
increase over time, the port begins discarding packets when reaching the tail
drop threshold.
The value of 10 cells above corresponds to one and one-half maximum length
packets queued for transmission. For the N1100-ON, N2000, N2100-ON,
N3000, N3100-ON, and N4000 switches, the cell size is 208 bytes; for the
N1500, the cell size is 128 bytes. If jumbo frames are enabled (MTU 9200),
the expected size of a single maximum length packet is 45 cells (9200/208 =
44.2). Allowing for a frame and a half to be buffered on average, a value of 75
is perhaps more appropriate to consider as the indicator for determining if
congestion exists on a port.
The clear counters command clears the underlying counters for transmit and
receive utilization values, transmit and receive packets per second values, and
the drops counter. The count of buffered packets is not a sampled counter
and cannot be cleared.
This command displays the following interface transmit and receive
utilization in bits/sec and packets/sec.
Field Description
Port The interface for which information is
displayed.
Load Interval The load interval for the interface.
Oper. Speed The operational speed, which is the
speed at which the interface is currently
operating (e.g., 1M, 10M, 100M, 1G,
10G, 40G).