ip178a ETC-unknow, ip178a Datasheet - Page 19

• Manufacturer Part Number: ip178a
• Description: 8-port 10/100 Ethernet Integrated Switch
• Manufacturer: ETC-unknow

IEEE 802.3x
The IEEE 802.3x is used for flow control in full duplex
mode if both IP178A (X_en=1) and the remote station
have IEEE802.3x capability. When the level of occupied
buffer of a port is over set threshold, it will send a
PAUSE frame with maximum delay FFFF. The remote
station will stop to transmit the next packet after
receiving the PAUSE frame. After level of the occupied
buffer is below release threshold, the port sends out a
PAUSE frame with zero delay to resume receiving the
incoming packets. The remote station is re-enable to
transmit packets after receiving the PAUSE frame with
zero delay. While level of the occupied buffer of a port is
over set threshold, IP178A re-transmits the PAUSE
PAUSE Frame Format
Preliminary, Specification
IP178A-DS-P05
Sep. 09, 2002
01-80-C2-00-00-01
Destination
6 bytes
subject to change without notice
Source
6 bytes
SA
2 bytes
Type
8808
19
Opcode
2bytes
0001
frame with maximum delay to ensure the pause timer of
the remote station does not expire and begins
transmission. The IPG between PAUSE frames is
42ms(100M) or 420ms(10M).
When an incoming PAUSE frame with non-zero delay is
received, the port stops the next frame transmission and
starts its pause timer. It is re-enabled transmission
function either the pause timer is expired or a PAUSE
frame with zero delay is received. If another pause frame
is received before the timer expires, the timer will be
updated with the new value. During this period, only
PAUSE frame from IP178A will be transmitted.
Pause Timer
FFFF(0000)
2 bytes
PAD with zero
42 bytes
Pad
(Advance Version)
4 bytes
IP178A
CRC
CRC