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802.3 flow control

Clemens Bohnenblust
Occasional Contributor

802.3 flow control

I have a pc connected to a switch 1# and the switch is connected to a second. when the second switch has a buffer overflow it sends back a 802.3x MAC Control Pause packet to switch #1. What happens with this packet ? Is it forwardet to the PC ?
3 REPLIES
Jerome Henry
Honored Contributor

Re: 802.3 flow control

Well,

This packet is received by switch 1, which then stop sending, waiting for a flag 0 on another MAC Control Pause packet from the same source.

If in between your PC continues emitting, and overflow stack on swithc 1, then switch 1 will emit MAC Control Pause packet to PC.

If PC is full duplex, it'll stop emitting, as only full duplex allow this kind of message.

Otherwise, it'll continue emitting, and switch will drop packets.

Hope you found what you needed.

You can get more detailled info in documents such as :

http://www.accessethernet.com/source_documents/ Traffic_Management_In_The_AccessEthernet_Switch.pdf

Thanks for assigning points if useful . :]

J
You can lean only on what resists you...
Clemens Bohnenblust
Occasional Contributor

Re: 802.3 flow control

thank for the answer. I cant access your document. Can you help ?
Ron Kinner
Honored Contributor

Re: 802.3 flow control

The URL got split in half by the posting program. You won't be able to just click on it since you only get half the address. You will have to copy the two pieces to your browser in order to get it to work.

Ron