Fastlink Mode (Flm) - R&S M3SR 4100 Series Operating Manual

M3SR Series 4100

5.3.2 FastLink Mode (FLM)

The main purpose of the FastLink Mode (FLM) feature is to allow an application to establish
exclusive point-to-point connections and thus to avoid concurrent connections on the radio
network. IPoA itself provides appropriate mechanisms on the link layer to reduce the collision
probability for concurrent connections, the efficiency will suffer with increasing amount of
parallel connections.
Especially multiple long-lasting TCP (Transmission Control Protocol) connections will benefit
from FLM, since the TCP protocol does not scale well with increasing amount of concurrent
connections over a slow radio link (see sect. 5.3 IP over Air (IPoA)).
If the typical use case consists of many (e.g. more than 5) concurrent and long-lasting con-
nections, FLM will greatly improve performance and reliability of such data transfers. Al-
though the FLM feature uses some lower layer (link layer) services, there is no influence of
these layers by FLM. FLM can be seen as a stand-alone state machine on application level
that sits on top of the transport and link layer. It is the responsibility of the application to use
FLM appropriately, e.g. to send only FLM assigned data when an FLM connection is estab-
lished if exclusive channel access (only one connection at a time) shall be guaranteed net-
work-wide.
5.42
FastLink Mode (FLM)
Operating Manual 6175.4760.02 – 01