Dear Extreme community experts,
our Extreme network switches (x450e,x670,x650,BD8810's) have Flow Control (802.3x) enabled by default, rx-pause only, in all their ports as far as I know. Our servers have RX-pause & TX-pause enabled.
802.3x was designed to avoid congestion in half-duplex links, @ hubs times. My question is how does Flow Control behave in nowadays full-duplex 1-10GbE world, specifically in std Extreme multiple switch environment.
My questions about Flow Control are very simple, but maybe tricky.
As an example: We have N servers A,B,C & D, using TCP ( A<->B,C,D) and connected to the same vlan, and another servers E,& F not talking with A. 'A' ethernet is getting colapsed (ex: running out of RX buffer), because of incoming B,C,& D traffic.
TX-PAUSE frames have the 'A' server mac-address origin, and as target a std. 'mac multicast' 01:80:C2:00:00:01 (if I'm not wrong). The payload is simple, type 0x0001 (TX-PAUSE frame) and just a number (1-65535), indicating the number of ethernet slot times to stop sending data, as far as I know.
My question is what exactly does the Extreme switch/port where A is connected to, with just rx-pause enabled, when a TX-PAUSE frame arrives?.
Does TX-PAUSE, from A, arrive to all vlan servers, even to unrelated ones, E&F? Or only to those B,C&D?
TX-PAUSE frames did only affect the switch where A is connected to?
If servers B,C &D are connected to other switches (rx-pause world) and the same vlan, do they receive those TX-PAUSE coming from 'A', or not?
Let's twist it a bit. What happens when server A it's in vlan A, and B,C,D are in their respective vlans B,C & D, maybe switches away? (always within all ports in a rx-pause enabled world)
Does matter the link/uplink type( 1GbE or 10GbE )???