Verifying Congestion Isolation - Cisco MDS 9000 Series Configuration Manual

Congestion Detection, Avoidance, and Isolation
Note For 16-Gbps modules, 32-Gbps modules, and Cisco MDS 9700, 9148S, 9250i, and 9396S switches, if
no-credit-drop timeout is configured, the maximum value of tx-slowport-oper-delay as shown in slow-port
monitor events is limited by the no-credit-drop timeout. So, the maximum value for tx-slowport-oper-delay
can reach the level of the no-credit-drop timeout even if the actual slow-port delay from the device is higher
because the frames are forcefully dropped by the hardware when tx-slowport-oper-delay reaches the level
of the no-credit-drop timeout.

Verifying Congestion Isolation

Note TxWait on FCoE ethernet or Virtual Fibre Channels (VFC) interfaces is the amount of time a port cannot
transmit because of the received Priority Flow Control (PFC) pause frames.
RxWait on FCoE ethernet or VFCs is the amount of time a port cannot receive because of the port transmitting
PFC pause frames.
Both TxWait and RxWait are in units of 2.5us and are converted to seconds in some command outputs. To
convert to seconds multiple the TxWait or RxWait value by 2.5 and divide by 1,000,000.
This example displays the status and statistics of priority-flow-control on all interfaces:
switch# show interface priority-flow-control
RxPause: No. of pause frames received
TxPause: No. of pause frames transmitted
TxWait: Time in 2.5uSec a link is not transmitting data[received pause]
RxWait: Time in 2.5uSec a link is not receiving data[transmitted pause]
===================================================================================
Interface
====================================================================================
port-channel1
port-channel350
port-channel351
port-channel552
port-channel700
Ethernet2/17
Ethernet2/18
Ethernet2/19
Ethernet2/20
Ethernet2/25
Ethernet2/26
This example displays the detailed configuration and statistics of a specified virtual Fibre Channel interface:
switch# show interface vfc 9/11 counters details
vfc9/11
Admin Oper (VL bmap) VL
Auto NA
Auto NA
Auto NA
Auto NA
Auto NA
Auto Off
Auto Off
Auto Off
Auto Off
Auto On
Auto On
3108091433 fcoe in packets
6564116595616 fcoe in octets
30676987 fcoe out packets
2553913687 fcoe out octets
0 2.5us TxWait due to pause frames (VL3)
RxPause TxPause RxWait-
(8) 3 0
(8) 3 0
(8) 3 0
(8) 3 111506
(8) 3 0
(8) 3 0
(8) 3 0
Cisco MDS 9000 Series Interfaces Configuration Guide, Release 8.x
Verifying Congestion Isolation
TxWait-
2.5us(sec) 2.5us(sec)
0 0(0) 0(0)
0 0(0) 0(0)
0 0(0) 0(0)
0 0(0) 5014944(12)
0 0(0) 0(0)
0 0(0) 0(0)
0 0(0) 0(0)
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