When building networking
applications, you must determine how ISDN connections will be
initiated, established, and maintained. DDR creates connectivity
between ISDN sites by establishing and releasing circuit-switched
connections as needed by networking traffic. DDR can provide network
routing and directory services in numerous ways to provide the
illusion of full-time connectivity over circuit-switched
connections.
To provide total control over initial
DDR connections, you must carefully consider the following issues:
- Which sites can initiate
connections based on traffic?
- Is dial-out required to SOHO sites?
Is dial-out required for network or workstation management? Which
sites can terminate connections based on idle links?
- How are directory services and
routing tables supported across an idle connection?
- What applications need to be
supported over DDR connections? For how many users do they need
to be supported?
- What unexpected protocols might
cause DDR connections? Can they be filtered?
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