
About XON and XOFF thresholds
An 802.3x PAUSE frame is generated when the buffer limit at the ingress port reaches or exceeds the
port’s upper watermark threshold (XOFF limit). The PAUSE frame requests that the sender stop
transmitting traffic for a period of time. The time allotted enables the egress and ingress queues to be
cleared. When the ingress queue falls below the port’s lower watermark threshold (XON limit), an
802.3x PAUSE frame with a quanta of 0 (zero) is generated. The PAUSE frame requests that the
sender resume sending traffic normally.
Each 1G, 10G, and 40G port is configured with a default total number of buffers as well as a default
XOFF and XON threshold. The defaults are different for 1G ports versus 10G or 40G ports. Also, the
default XOFF and XON thresholds are different for jumbo mode versus non-jumbo mode. The defaults
are shown in
About XON and XOFF thresholds
.
XON and XOFF default thresholds
TABLE 8
Limit when Jumbo disabled / % of buffer limit Limit when Jumbo enabled / % of buffer limit
1G ports
Total buffers 272
272
XOFF
240 / 91%
216 / 82%
XON
200 / 75%
184 / 70%
10G ports
Total buffers 416
416
XOFF
376 / 91%
336 / 82%
XON
312 / 75%
288 / 70%
40G ports
Total buffers 960
960
XOFF
832 (87%)
832 (87%)
XON
720 (75%)
720 (75%)
If necessary, you can change the total buffer limits and the XON and XOFF default thresholds. Refer
to
Changing the total buffer limits
on page 70 and
Changing the XON and XOFF thresholds
on page
69, respectively.
Configuration notes and feature limitations for symmetric flow control
Note the following configuration notes and feature limitations before enabling symmetric flow control.
• Symmetric flow control is supported on FCX and ICX devices only. It is not supported on other
FastIron models.
• Symmetric flow control is supported on all 1G,10G, and 40G data ports on FCX and ICX devices.
• Symmetric flow control is not supported on stacking ports or across units in a stack.
About XON and XOFF thresholds
68
FastIron Ethernet Switch Administration Guide
53-1003625-01
Содержание FastIron
Страница 28: ...Displaying management VRF information 28 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 146: ...Displaying interface level IPv6 settings 146 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 162: ...Example 2 162 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 172: ...Clearing CDP information 172 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 216: ...Clearing cached LLDP neighbor information 216 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 228: ...FastIron Fiber optic Transceivers 228 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 284: ...show sysmon system sfm 284 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 296: ...Syslog messages for hardware errors 296 FastIron Ethernet Switch Administration Guide 53 1003625 01...
Страница 384: ...Displaying information for breakout ports 384 FastIron Ethernet Switch Administration Guide 53 1003625 01...