Quality of Service
BAT54-Rail/F..
Release
7.54
06/08
9.7
QoS configuration
325
The differences are unveiled by looking at a FTP transfer. A client of the LAN
is connected to the Internet through a BAT.
D During an active FTP session, the client sends by the PORT command
the information to the server, on which port the DATA connection is ex-
pected. As the result, the server establishes the connection to the client
and sends the data in the same direction. In this case, the logical connec-
tion as well as the real data stream over the interface go from the server
to the client, and the BAT takes both as the receiving direction.
D Different is the case of a passive FTP session. Here the client itself estab-
lishes the connection to the server. The logical connection setup thus is
from client to server, but the data transmission over the physical interface
flows in the reverse direction from server to client.
With standard settings, a BAT assumes the sending or receiving direction de-
pending on the logical connection setup. Because such a point of view may
not be easy to follow in certain application scenarios, the point of view can
alternatively be changed to the flow of the physical data stream.
Note: The differentiation between sending and receiving direction applies
only to the installation of maximum bandwidths. For a guaranteed mini-
mum bandwidth, as well as for fragmentation and PMTU reduction always
the physical data transfer via the respective interface applies as the direc-
tion!
9.7 QoS configuration
9.7.1 Evaluating ToS and DiffServ fields
U ToS or DiffServ?
LANconfig
For configuration with LANconfig, select the configuration field 'IP router'. Ad-
just on index card 'General' whether the 'Type of service field' or alternatively
the 'DiffServ field' is to be observed for prioritization of data packets. When
both options are turned off, the ToS/DiffServ field will be ignored.