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Archived from groups: comp.dcom.lans.ethernet (More info?)
Hi,
I have been trying to calculate how long a successful Gigabit Ethernet
auto-negotiation sequence takes and the time I have calculated seems
to be quite high. From referring to the 802.3 standard:
Time [average] between consecutive FLPs: 16ms
Gigabit Ethernet uses 4 LCWs to auto-negotiate: one Base Page, one
message Next Page and two 1000BaseT unformatted Next pages.
Time to send four FLP: 4 X 16ms = 64ms
802.3 standards specify that each LCW should be received 3 times
before acknowledgement. Therefore, 4 FLPs [3 X LCW + 1 acknowledgement
LCW] are required for exchanging 1 LCW.
Therefore, minimum time to auto-negotiate 1Gbps link speed = 64 ms X 4
= 256ms
Considering that Ethernet is a LAN protocol, this seems to be too
large a vaue. Could somebody please tell me where I have made a
mistake? Thanks!
Chamara Gunaratne
pgunarat@csee.usf.edu
University of South Florida
Hi,
I have been trying to calculate how long a successful Gigabit Ethernet
auto-negotiation sequence takes and the time I have calculated seems
to be quite high. From referring to the 802.3 standard:
Time [average] between consecutive FLPs: 16ms
Gigabit Ethernet uses 4 LCWs to auto-negotiate: one Base Page, one
message Next Page and two 1000BaseT unformatted Next pages.
Time to send four FLP: 4 X 16ms = 64ms
802.3 standards specify that each LCW should be received 3 times
before acknowledgement. Therefore, 4 FLPs [3 X LCW + 1 acknowledgement
LCW] are required for exchanging 1 LCW.
Therefore, minimum time to auto-negotiate 1Gbps link speed = 64 ms X 4
= 256ms
Considering that Ethernet is a LAN protocol, this seems to be too
large a vaue. Could somebody please tell me where I have made a
mistake? Thanks!
Chamara Gunaratne
pgunarat@csee.usf.edu
University of South Florida