Internet Communications Using SIP : Delivering VoIP and Multimedia Services With Session Initiation Protocol {2Nd Ed.}

between the user agent requestor and the proxy or user agent requiring the authentication. Any SIP request can be challenged for ...

An example SIP digest authentication exchange is shown in Figure 6.13. The initial INVITEmessage has no authorization credential ...

There is also a Proxy-Requireheader that lists features that any proxies in the path must support. However, the use of this head ...

SIP user agents should also indicate which methods and features they sup- port using the Allow, Supported, Allow-Events, and Acc ...

[16] “AAA Usage for IP Telephony with QoS” by H. Sinnreich, D. Rawlins, A. Johnston, S. Donovan, and S. Thomas. Internet Draft, ...

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135 A major driver for many service providers adopting SIP is the advantages and flexibility of service creation using the proto ...

services will include integration with the World Wide Web or other databases of information. However, the first set of services ...

Figure 7.1 Call-forward, no-answer service implemented by the proxy server Called User Agent Implementation Figure 7.2 shows how ...

Figure 7.2 Call-forward, no-answer service implemented by the called user agent Calling User Agent Implementation Finally, Figur ...

The caller then sends an INVITEto the first URI. After the ring-no-answer timer expires in the calling user agent, the caller se ...

The construction of the voicemail URI also shows the method of using an “opaque” URI [1] to indicate to the voicemail server the ...

Table 7.1 (continued) SERVICE IMPLEMENTATION ADVANTAGES DISADVANTAGES Calling user agent No logic or provisioning in Requires fe ...

listing supported methods. However, other extensions, such as reliable provi- sional responses, need the Requireheader that list ...

closes the tag. There are, however, some important differences between XML and HTML. In XML, there are strict parsing rules that ...

Table 7.2 CPL Tag Summary TAG DESCRIPTION cpl Begins the CPL script incoming Defines server operation for an incoming call outgo ...

Table 7.3 CPL Switch Types SWITCH TYPE MATCHES FIELDS SUBFIELDS address is origin address-type contains destination user subdoma ...

Example of CPL Scripts The following example from the CPL RFC 3880 shows a CPL script imple- menting a call-forward, no-answer, ...

Note that CPL also can be used for service creation for outgoing calls. Con- sider the following example, also taken from the CP ...

SIP CGI is an interface, not a programming language. It allows services to be developed in familiar languages such as Perl, C, T ...