User`s guide

253
Configuration - Network > Legacy Protocols
Older protocols that existed before TCP/IP became dominant are often referred to as legacy
protocols. Examples of legacy protocols are X.25, SNA and LAPB.
Digi TransPort routers are capable of connecting to legacy networks such as X.25. They are
also capable of simulating a legacy network so that equipment that in the past would have
connected to a legacy network can connect to the Digi TransPort router instead. Thus old
equipment can be connected to modern networks such as HSUPA.
Configuration - Network > Legacy Protocols > SNA over IP
The unit is capable of sending Systems Network Architecture (SNA) traffic over TCP/IP,
using the DLSw protocol, this is often called SNAIP. The unit is also capable of sending
HDLC traffic over TCP/IP.
SNA uses Synchronous Data Link Control (SDLC) which is an unbalanced mode in which
there is one master station and 1 or more secondary stations. Each secondary station owns
a station address and can only respond when this address has just been polled by the
master. A typical scenario is shown in the diagram below: