Back pressure Control
The receive buffer may grow faster than it is
emptied out over the VDSL link. If in half
duplex mode (see
section General Settings
and
the section MAC Command
), back
pressure can be used to control and manage
the traffic. Back pressure is implemented by
transmitting a continuous preamble after a
standard IPG.
Truncated Back-off Algorithm - Collision
Counter Reset:
Controls the truncated back-
off algorithm. To achieve a more aggressive
transmitter behavior the collision counter can
be reset after a programmable number of
attempts. Once the counter is reset the
algorithm is reset thus allowing shorter IPGs
to be statistically inserted. Packets are not
discarded in any case.
Back pressure enable:
Enables or disables the
back pressure functionality.
Automatic Back pressure and Flow Control:
In
MAC mode, the Back Pressure and Flow
Control mechanisms are automatically
activated or deactivated according to the
speed and duplex configuration (see
General
Settings
and
MAC Command sections
) and
IEEE 802.3. If this feature is disabled, Back
Pressure and Flow Control must be manually
set.
Back pressure Method:
Select the back pressure
method:
Figure 19 Ethernet Configuration –
Back pressure Control
Append:
Append packet coming from the 10BaseS link into the transmit FIFO to the continuous
preamble of any length.
IPG Insertion:
Insert IPG before generating a legal preamble for the packet that enters the transmit
FIFO during back pressure.
Back pressure Start Level:
Back pressure is started when the level of the receive FIFO defined in this field
is exceeded. The size of ’max packet size’ is either 1518 or 1536 bytes as it was defined in the General
Settings menu (see
General Settings
).
Back pressure Stop Level:
Back pressure is stopped when the receive FIFO level drops below the limit
adjusted in this field. The size of ’max Packet size’ is either 1518 or 1536 bytes as it was defined in
the General Settings menu (see
General Settings
).
Pattern Length:
Length of preamble before IPG insertion when back pressure is activated.
Back pressure IPG Insertion:
IPG length between two consecutive patterns when back pressure is
activated.
Normal Operation IPG Insertion:
IPG length between two consecutive patterns while normal operation,
i.e. when back pressure is not activated.
17
Содержание Extreme Copper XC-RP300
Страница 1: ...XC RP300 VDSL Repeater Owner s Manual GDI COMMUNICATIONS LLC PO Box 130 Verdi NV 89439 ...
Страница 2: ......
Страница 38: ......
Страница 39: ......
Страница 40: ...Copyright 2006 GDI Communications LLC All Rights Reserved ...
