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4108gl flow control

John Anvari
Advisor

4108gl flow control

when does it help and when does it hinder. should I leave it as default?
3 REPLIES

Re: 4108gl flow control

generally is to say:
Our simulation-based investigations compare the throughput of TCP streams in selected network topologies when either the Ethernet flow control is disabled or enabled. In general, Ethernet's hop- by-hop flow control leads to good performance of TCP in homogenous net-works where all clients are connected to a congested switch with the same link speed. However, as soon as a network consists of clients connected with slow (e.g. 10 Mb/s) and fast (e.g. 100 Mb/s) links to the switch, the effect known as "head of Line" blocking shows up as congestion occurs and flow control is triggered. As a result of this, the throughput of data streams destined to slow clients increases because packets are no longer discarded, but the throughput of streams destined to fast clients is reduced considerably.

or further information the home page is of IEEE very helpfully.
The configuration examples are in the manage guide of the "41 xxgl" listed. See
ftp://ftp.hp.com/pub/networking/software/59905998_E1.pdf
I hope this help you unterstand flow control
regard klaus
John Anvari
Advisor

Re: 4108gl flow control

Thanks, I think I got it. So for example if I had a fully populated 4108gl with lets say 85 percent 10/100 clients connected at 100 auto negotiation and the other 15 percent being printers and old systems connected at 10 mbps this could technically cause a network performance problem?
John Anvari
Advisor

Re: 4108gl flow control

Another question. I was thinking of turning on flow control as an experiment. Do I turn on flow control on every port or just the ones connected at 10 mbps.