Ethernet Pause Frames allow for a temporary stop in data transmission. A situation may arise where a sending device may transmit data faster than a destination device can accept it. The destination sends a PAUSE frame back to the source, stopping the sender's transmission for a period of time .
The PAUSE frame is defined by IEEE 802.3x and uses MAC Control frames to carry the PAUSE commands. Ethernet pause frames are supported on full duplex only.
If a port is over-subscribed, Ethernet Pause Frame flow control does not ensure no-loss behavior.
You can view the current count of throttles since the last time the counters were cleared with this command:throttles. as pause framesDell Networking Force10 switches report
Dell#show interface te 0/1
TenGigabitEthernet 0/1 is down, line protocol is down
Hardware is DellEth, address is 00:01:e8:8b:18:bb
Current address is 00:01:e8:8b:18:bb
Pluggable media not present
Interface index is 1048708
Internet address is not set
Mode of IPv4 Address Assignment : NONE
DHCP Client-ID :0001e88b18bb
MTU 1554 bytes, IP MTU 1500 bytes
LineSpeed auto
Flowcontrol rx off tx off
ARP type: ARPA, ARP Timeout 04:00:00
Last clearing of "show interface" counters 16:48:20
Queueing strategy: fifo
Input Statistics:
0 packets, 0 bytes
0 64-byte pkts, 0 over 64-byte pkts, 0 over 127-byte pkts
0 over 255-byte pkts, 0 over 511-byte pkts, 0 over 1023-byte pkts
0 Multicasts, 0 Broadcasts, 0 Unicasts
0 runts, 0 giants, 0 throttles
0 CRC, 0 overrun, 0 discarded
Output Statistics:
0 packets, 0 bytes, 0 underruns
0 64-byte pkts, 0 over 64-byte pkts, 0 over 127-byte pkts
0 over 255-byte pkts, 0 over 511-byte pkts, 0 over 1023-byte pkts
0 Multicasts, 0 Broadcasts, 0 Unicasts
0 throttles, 0 discarded, 0 collisions, 0 wreddrops
Rate info (interval 299 seconds):
Input 00.00 Mbits/sec, 0 packets/sec, 0.00% of line-rate
Output 00.00 Mbits/sec, 0 packets/sec, 0.00% of line-rate
Time since last interface status change: 16:46:37