SIP Client Requirements

The client is written in Tcl/Tk.

Listed roughly in order of importance:

• re-INVITE to allow users to change, add and delete media during a call;
• application sharing using the AT&T screen sharing software vnc;
• interface with address book (LDIF);
• add sip handler to Netscape browser, so that sip URLs automatically invoke sipc;
• invocation from IE URLs;
• speed-dial buttons, configured via REGISTER response;
• "visual abbreviated dialing" - add small image to quick-dial button, with right-click menu to remove;
• intercom mode, with emergency broadcast system features;
• Features

  Caller        Priority From   To    Action
  -----------------------------------------------------------
  *             any      anytime      ring "short long long"
  sweetheart@   high     anytime      ring "song.au"
  *             urgent   10pm   8am   forward to voicemail
  hgs@cs.       any      anytime      busy
  

  The user interface could be similar to the email filter in Netscape, for example. The user credentials are stored in the address book, not in the rule. Any parameters for a rule are made visible only if the action is selected. Ringing should allow selection of an audio file via a file browser ("browse" button), while forwarding should allow selection of an address from the address book.

  Later, this can then move to CPL generation.

• Upload call processing scripts into sipd Internet telephony server (see Internet Draft);
• Handle syntax issues like continuation lines;
• Display headers like Organization;
• Support Route and Record-Route SIP headers;
• configurable invocation of external programs, with %s for destination address, %p for port, %t for ttl and %e for encoding
• allow storing of configurations to disk;
• handling of advanced Contact header options, with class, service, etc.; allow choosing of one or more of the offered locations when redirecting;
• multiple simultaneous calls;
• add/drop users to/from existing calls, with third-party call control;
• hold, mute (for each media) by setting the destination IP address for a media type to zero;
• change of media during a phone call
• call transfer
• configuration similar to Netscape (tabbed notebook) including list of acceptable encodings and preference for quality or bandwidth; this configuration is then used to construct the SDP message.
• user interface similar to browser URL window, with list of recently visited sites;
• user-oriented logging of incoming and outgoing calls ("history"), with possibly automatic addition to address book and ability to call back users
• ability to invoke external script (as in cgi-bin) for sophisticated call processing; SIP headers are translated to SIP_*. Where they make sense, the environment variables of cgi-bin 1.2 should be used. The message body is sent to the standard input.
• rendering of HTML for responses (error messages, IVR), with ability to click on SIP URLs; may be done by invoking external browser, Tcl HTML renderer or HotJava HTML component

  What: HTML display
  Where:
  
  Description: A simple HTML parsing and display library.  Supports
          all HTML/2.0 features, including forms.
  Updated: 10/1996
  Contact:  (Stephen Uhler)
  

• XML parser for Tcl, for parsing CPL
• Uploading of CPL scripts according to the spec. Then, design a mechanism to embed prompts into CPL in order to allow user customization. One simple approach is to use the C preprocessor, but there must be better approaches. Thus, users should be able to take existing CPL scripts, sipc finds the embedded prompts and then substitutes the result of the user input into the script. The script is then uploaded to the server via REGISTER.
• integration of presence notification (SUBSCRIBE and NOTIFY)
• Via restriction to force calls to come through proxy (to avoid callers circumventing call filtering); redirect via 3xx.

Last updated by Henning Schulzrinne