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Call Server Configuration

If you have special configuration needs and want to modify the dial plan, be aware that some of the default dial rules are necessary for “normal” operation. Removing or modifying them takes the system out of compliance with ITU and IEEE standards.

Here are some suggestions and guidelines for modifying the dial plan:

●To add an MCU, ISDN gateway, SBC, neighbor gatekeeper, SIP peer, or simplified dialing service that can be dialed by prefix, configure the prefix range of the new service on the appropriate page. No dial plan change is necessary, since Rule Dial services by prefix of the default dial plan takes care of dialing by prefix.

●You can remove or disable a default dial rule if you don't want the associated functionality.

But note that Rule Dial endpoints by IP address (Dial endpoints by IP address) is used in several scenarios where calls are received from neighbor gatekeepers or SBCs. Removing it breaks these scenarios.

●If certain dial strings are matching on the wrong dial rule, you may need to re-order the rules.

●In some circumstances (depending on the dial plan and the network topology and configuration), dial rules using the Resolve to external address action (like Rule 5 of the default dial plan) or the Resolve to IP address action (like Rule 6) can enable dialing loops to develop, especially if servers reference each other either directly or via DNS.

Common ways to avoid dialing loops include:

Use domain restrictions to ensure that the RealPresence DMA system and its peers are each responsible for specific domains (see Add External SIP Peer Dialog and Domains).

Use a preliminary script like the sample script “SUBSTITUTE DOMAIN (SIP)” (see Sample Preliminary and Postliminary Scripts) to change the domain of a SIP URI dial string to something that won’t create a dialing loop.

Use a postliminary script to similarly change the domain before sending to a peer.

Use configuration options on the peers to prevent loops.

Create a dial rule that uses the Block action and a preliminary script to enhance the system’s ability to prevent dialing loops for specific types of calls. The preliminary script ensures that the dial rule only matches the types of calls you want to block. This dial rule should be ordered after other dial rules that are expected to resolve the intended call requests.

For example, a dial rule with the Block action using the following preliminary script blocks all call requests that use a prefix of “44” if they have not been resolved by previous dial rules: println("DIAL_STRING=" + DIAL_STRING);

var prefix='44'

var re = RegExp('^(sip:sips:h323:tel:)?'+ prefix +'.*') if(! DIAL_STRING.match(re))

{

println("NEXT_RULE"); return NEXT_RULE;

}

println("ACCEPT and terminate 44 prefix calls if they were not resolved by previous dial rules");

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