Legacy Data System Reference - Comtech EF Data

SNA/SDLC Support
• SNA/SDLC port (either primary or secondary),
• LAN interface,
• WAN port,
• Boundary Node Network (BNN) connection (Routed SNA Over Frame Relay),
• Boundary Access Network (BAN) connection (Bridged SNA Over Frame Relay)
The PU operating mode is determined from these two logical connections.
6.1.4 Session Timeout Control
NOTE: For the SDLC-SDLC mode, the logical connections require one primary and
one secondary SNA/SDLC port.
SNA, like other delay-sensitive protocols, operates as though a dedicated set of resources
exists between any pair of communications devices in the network. Without the
NetPerformer in a LAN/WAN internetwork, SNA transmissions may not be completed
before the session timer expires, due to competition with traffic from the LANs. In
addition to severe network delays, users may be faced with session timeouts.
Protocol spoofing reduces the risk of session timeouts. In addition, the protocol
prioritization capability of the NetPerformer guarantees session safety even in high traffic
conditions. Two sets of configurable parameters can be used to prioritize SNA data (or any
other data type that must be prioritized):
• FILTERS, using the Setup Filters menu
• CLASSES, using the Setup Classes menu.
For details, refer to the Quality of Service (QoS) module of this document series.
6.1.5 Connection Types
An SDLC port connection may have a point-to-point or multipoint configuration. In
addition, point-to-point connections can be switched or non-switched. Data may be sent
simultaneously in both directions, called two-way simultaneous transmission.
Alternatively, data may be sent in one direction at a time, which is called two-way
alternate transmission.
Multipoint Connection
Several PUs can be connected to a single user port on the NetPerformer. Simply attach a
line-sharing device or connect to a multipoint line. The NetPerformer automatically
establishes and maintains a link session with every device on the drop.
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