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ISDN Connection Management
2-4 — Orbitor 3000 Reference Manual
Combination
A combination of the Address Connect and Auto-Call options may be configured when a semi-permanent
connection is required to one remote site and a dynamic connection is required to multiple sites. A dynamic
connection indicates that the remote site for the second ISDN call will change depending upon what
destination IP address is required for the connection. One ISDN B-channel is configured to have an Auto-
Call ISDN number and the other B-channel may be used for the Address Connect functions.
Figure 2—3 Auto-Call & Address Connect WAN Topology
Connection Process
When a LAN client requests a session with a LAN server, the client will initiate the session by sending a session
connection request to the server. If the server is located on a remote LAN, the session connection request must be
sent to that remote LAN before the server can process the session connection request and reply to it. Any of the
call establishment processes may be used to establish the ISDN call between the Orbitors in order to establish a
LAN session between the local and remote LANs.
Once the client-server session has been established, keepalive or status packets are generated by either or both
ends of the session. The keepalive packets are used to verify the status of the device at the opposite end of the
session.
When Connection Management is enabled, LAN sessions that are established across the ISDN calls are
monitored and maintained in a table. The session table may contain up to 256 entries for each supported session
type, with the Orbitor filtering all traffic for any sessions over the 256 limit of the table. The 257th and greater
LAN sessions will not be allowed by the Orbitor.
While an ISDN call is up and connected, all traffic within the sessions will be transferred to the partner Orbitor
across the ISDN call.