09-05-2007 07:25 AM - edited 03-05-2019 06:17 PM
Hi
Please brief me what is Output flow-control and input flow contron options from "Sh int fa0/0" output.
Thanks
09-05-2007 08:29 AM
I suspect you're looking at Ethernet full-duplex flow control. This feature allows the receiver to tell the sender to suspend (or pause) its transmission. This allows the receiver to process the received data avoiding drops.
Not all Ethernet duplex devices support this capability. Often you need to tell the device to negotiate the option.
Some Ethernet devices can provide a similar capability when using half duplex. What happens is the receiver makes the wire appear busy to the sender.
09-05-2007 08:55 AM
GigabitEthernet1/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is xxxx.xxxx.xxxx
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
input flow-control is on, output flow-control is on
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 2000 bits/sec, 3 packets/sec
38 packets input, 3556 bytes, 0 no buffer
Received 14 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
41369 packets output, 3254019 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
from the above output you can see
"input flow-control is on, output flow-control is on"
Please let me know what is this means and how to turn it off?
Thanks
09-05-2007 09:29 AM
Standards are slightly different for gig Ethernet. Not sure flow control can be disabled on gig.
Why do you want to disable it?
What type of box is this, and what image are you using?
09-06-2007 06:58 AM
Cisco 4006
the switch port is connected to Unix server.
when that flow control is on I couldn't ping the server even from switch itself. engineer had did something after that server was reachable. then I checked I noticied only that flow control was turned off.
The engineer told just turned off the speed negotiation. I dont understand what is that. Can you please shed a light on this for me.
Thanks
09-06-2007 11:24 AM
"the switch port is connected to Unix server. " Using fiber? ("media type is 1000BaseSX " under your original post.)
"Cisco 4006" A 4006 or a 4506? Assuming the latter, you can start here, for flow control and speed commands:
http://www.cisco.com/en/US/products/hw/switches/ps4324/tsd_products_support_series_home.html
or with the command references for the software image you're using, here:
http://www.cisco.com/en/US/products/hw/switches/ps4324/prod_command_reference_list.html
Then look for the command "flowcontrol", to control flow control settings, and/or "speed" to control speed settings.
"The engineer told just turned off the speed negotiation. I dont understand what is that. Can you please shed a light on this for me."
Speed negotiation is how a multi-speed Ethernet interface, e.g. 10/100 or 10/100/1000, attempts to find the best matching speed with the interface on the other side of the link.
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