VT6516 ETC, VT6516 Datasheet - Page 61

• Manufacturer Part Number: VT6516
• Description: 16/12 PORT 10/1000 ASE T/TX
• Manufacturer: ETC

02H
Backoff configuration
bit 0: CAP mode , mild solution for Capture effect
bit 1: MBA mode , aggressive solution for Capture
effect
bit 2: EEFAST mode , drop the 2
for testing
bit 3: CRANDOM mode , use another random
algorithm
bit 4: OFSET , parameter for backoff timer
For that CAP mode is enabled, the TMAC module
will select the backoff time as b’10 or b’11 for the
2
is 2 or 3 slot times, where a slot time is 512 bits time
duration.
For that MBA mode is enabled, the TMAC will
select
backoff time for 10
collision
backoff time for 11
collision
backoff time for 12
collision
backoff time for 13
collision
backoff time for 14
collision
backoff time for 15
For that EEFAST mode is enabled, the Output
Control will drop the packet immediately as the
second collision happens.
For that CRANDOM mode is enabled, the TMAC
will select the backoff time by using the alternative
random algorithm that calculates the backoff time as
that for 10
For OFSET=1, the TMAC will follow the 802.3
standard backoff algorithm. For OFSET=0, the
TMAC will select the backoff time for the 1
collision as that of the 3
the backoff time for the 1
from 0 to 7 in unit of slot time.
nd
VIA Technologies, Inc.
collision, i.e. the backoff time for the 2
th
collision.
purpose, accelerate the drop event
th
th
th
th
th
th
collision just as that for 5
collision just as that for 4
collision just as that for 3
collision just as that for 2
collision just as that for 1
collision as 0.
rd
st
collision, i.e. the possible
and 2
nd
collision is ranged
nd
-61-
collided packet
nd
st
collision
and 2
th
th
rd
nd
st
Preliminary VT6516 Datarsheet
nd
BOFFCFG [4:0] 5’b10
000
R/
W