ip178a ETC-unknow, ip178a Datasheet - Page 20

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

Capability Changing
If the remote station does not support IEEE802.3x and
has full duplex capability, IP178A supports a private
mechanism to handle flow control to prevent packet loss.
It is called capability changing and is controlled by the
parameter Update_r4_en. This function prevents the
packet loss due to no IEEE802.3x.
When the remote station does not support IEEE802.3x
and has full duplex capability and Update_r4_en is
turned on, the port changes its ability to half duplex to
make the remote station link at half duplex after Nway.
IP178A handles the data flow of segment by
X_EN
Aging
IP178A supports address aging. If the address aging is
enabled (Agetime≠0), the learned SA will be cleared if it
is not refreshed within the specified aging time.
Preliminary, Specification subject to change without notice
IP178A-DS-P05
Sep. 09, 2002
x
x
1
0
1
0
1
0
1
0
REMOTE_IEEE
802.3X
x
x
1
1
0
0
1
1
0
0
UPDATE_
R4_E
Conditions
x
x
0
0
0
0
1
1
1
1
BK_EN Remote site My site
0
1
x
x
x
x
x
x
x
x
20
full/half
full/half
full/half
full/half
full/half
full/half
full/half
full/half
half
half
backpressure. To do this, the port keeps silence to force
the remote node link failure and changes its capability to
half duplex then restarts Nway. Both side of the segment
will be link at half duplex.
When the remote station does not support IEEE802.3x
and has full duplex capability and Update_r4_en is
turned off, the port turns off its IEEE802.3x capability and
is link at full duplex after Nway. There is no flow control
between these two nodes in this application. The detail
operation is illustrated in the following table.
Broadcast Storm Protection
IP178A is able to prevent receiving too many broadcast
packets to waste the switch resource. IP178A discards
the incoming broadcast packets depending on the setting
of Bf_stm_en if the number of broadcast packets from a
port exceeds threshold.
full/half
full/half
full/half
full/half
full/half
full/half
full/half
full/half
X
X
Remote site My site My
half
half
half
half
half
full
full
full
full
full
half
half
half
half
half
full
full
full
full
full
Result
(Advance Version)
802.3x
off
off
on
off
off
off
on
off
off
off
IP178A
My back
pressure
off
on
off
off
off
off
off
on
on
on