IP178A Datasheet, PDF (20/44 Pages) List of Unclassifed Manufacturers – 8-Port 10/100 Ethernet Integrated Switch

(Advance Version)
IP178A
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
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.
X_EN
x
x
1
0
1
0
1
0
1
0
Conditions
REMOTE_IEEE UPDATE_ BK_EN
802.3X
R4_E
x
x
0
x
x
1
1
0
x
1
0
x
0
0
x
0
0
x
1
1
x
1
1
x
0
1
x
0
1
x
Result
Remote site My site Remote site My site My My back
802.3x pressure
half
X
half
half off
off
half
X
half
half off
on
full/half full/half
full
full on
off
full/half full/half
full
full off
off
full/half full/half
full
full off
off
full/half full/half
full
full off
off
full/half full/half
full
full on
off
full/half full/half half
half off
on
full/half full/half half
half off
on
full/half full/half half
half off
on
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.
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.
Preliminary, Specification subject to change without notice 20
IP178A-DS-P05
Sep. 09, 2002