| Basic Info | |
|---|---|
| Media Type | audio |
| subtype | vnd.cisco.nse |
| Registered? | Yes |
| See also | Kumar |
| Extensions | |
Tags: (none)
File Formats: (none)
Name : Rajesh Kumar E-mail : [email protected] MIME media type name : Audio MIME subtype name : Vendor Tree - vnd.cisco.com Required parameters : The "events" parameter lists the Cisco NSEs (Named Signaling Events) supported by the implementation. Events are listed as one or more comma-separated elements. Each element can either be a single integer or two integers separated by a hyphen. The range of these integers is 0-255. No white space is allowed in the argument. The integers designate the Cisco NSE numbers supported by the implementation. Thus, events="192,194,200-202" indicates that the Cisco NSEs supported by the implementation are 192, 194, 200, 201 and 202. The "events" parameter can be represented in the Session Description Protocol (SDP, rfc2327) and in ITU-T recommendation H.323/H.245 by the "fmtp" attribute and the non-standard capability field in the capability table respectively. When this is done, its value is represented in a format that is identical in format to the "events" MIME parameter. The encoding name used in conjunction with this MIME is "X-NSE". The "X-" prefix results from the fact that this encoding name is not defined in a standard. Since the "events" parameter is mandatory with this vendor MIME and encoding name, there is no default list of events that can be assumed when this MIME subtype is supported for a session or connection. Optional parameters : The "rate" parameter describes the sampling rate, in Hertz. The number is written as an integer. If omitted, the default value is 8000 Hz. The rate parameter can be represented in the Session Description Protocol (SDP, rfc2327) as one of the fields in the "rtpmap" attribute line. Encoding considerations : This MIME subtype is only defined for transfer via the Real Time Protocol (RTP) as defined in rfc1889. As such, it consists of packets of binary data. The packet format is the same as that for telephone events in rfc2833. The difference from rfc2833 events is that this MIME subtype uses a separate name space for event numbers, with semantics defined by Cisco. Security considerations : RTP packets using the payload format used for Cisco NSEs defined in this specification are subject to the security considerations discussed in the RTP specification (RFC 1889) and any appropriate RTP profile (for example RFC 1890). This implies that confidentiality of the media streams is achieved by encryption. Because the data compression used with this payload format is applied end-to-end, encryption may be performed after compression so there is no conflict between the two operations. This payload type does not exhibit any significant non-uniformity in the receiver side computational complexity for packet processing to cause a potential denial-of-service threat. This MIME subtype contains no executable content. Interoperability considerations : For interoperability, the use of the Cisco NSE MIME subtype must comply with internal Cisco documentation. For this the Cisco NSE MIME subtype, Cisco reserves the right to control and change the assignment of event numbers to events. When used in conjunction with rfc2833 telephone events, Cisco NSEs are assigned a dynamic payload type that is different from that of the rfc2833 telephone events. > > Published specification : > > None at this time. Cisco internal documentation available to > partners > > and customers. Contact name below. Applications which use this media : Voice over IP applications with value-adds provided by Cisco solutions. Additional information : 1. Magic number(s) : N/A 2. File extension(s) : N/A 3. Macintosh file type code : N/A 4. Object Identifiers: N/A The volume and duration fields are generally set to 0. This is because Cisco NSEs are generally used for state change signaling. In this case, the volume and duration fields are not meaningful. Redundant transmission of Cisco NSEs is along the lines of telephone events as described in rfc2833. It is optional. Person to contact for further information : 1. Name : Rajesh Kumar 2. E-mail : [email protected] Intended usage : Limited Use Cisco NSEs are meant to be a value-add in applications that use Cisco equipment. These are meant to SUPPLEMENT not SUPPLANT the rfc2833 events. These are used for state change signaling along the lines of the AAL2 type 3 packets. Examples of the use of Cisco NSEs are: Cisco NSE Number :: Semantics 192 :: Shift to voiceband data mode 193 :: Disable echo cancellation 194 :: Shift to voice mode 200 :: Shift to fax relay mode 201 :: Positive acknowledgement of Cisco NSE 202 :: Negative acknowledgement of Cisco NSE Author/Change controller : Rajesh Kumar [email protected] Cisco Systems 170 West Tasman Drive San Jose, CA 95134-1706 (created 2001 August 23) []