Filter
Top Products
̈ Chapter 9: Quality of Service LANCOM Reference Manual LCOS 3.50
169
Quality of Service
desired data transfer, certain data packets must be treated preferentially. It is
necessary for this, that at first a LANCOM recognizes which data packets
should be preferred at all.
There are two possibilities to signal the need for a preferential treatment of
data packets in the LANCOM:
̈ The application, as e.g. the software of certain IP telephones, is itself able
to mark the data packets appropriately. This marking, the “tag”, is set
within the header of the IP packets. The two different variants of this
marking “ToS” and “DiffServ” can simply described assume the following
states:
୴ ToS “Low Delay“
୴ ToS “High Reliability“
୴ DiffServ “Expedited Forwarding“
୴ DiffServ “Assured Forwarding“
The IP header bits of the ToS resp. DiffServ field are copied in case of
a VPN route also into the enclosing IP header of the IPSec VPN packet.
Thus QoS is available also for VPN routes over the Internet, as long as
your provider treats according packets preferentially also in the WAN.
̈ When the application itself has no possibility to mark the data packets
appropriately, the LANCOM can ensure the correct treatment. For this, it
uses the existing functions of the firewall, which can classify e.g. data
packets according to subnets or services (applications). Due to these func-
tions it is e. g. possible to treat individually data packets of a FTP connec-
tion or those of a certain department (in a separate subnet).
For treatment of data packets classified by the firewall the following two
possibilities can be chosen:
୴ Guaranteed minimum bandwidth