This specification defines the smpte Section 3. The header may also contain a time parameter in UTC, specifying the time at which the operation is to be made effective. The Range response header indicates what range of time is actually being played or recorded. If the Range header is given in a time format that is not understood, the recipient should return " Not Implemented". Ranges are half-open intervals, including the lower point, but excluding the upper point.
In other words, a range of a-b starts exactly at time a, but stops just before b. Only the start time of a media unit such as a video or audio frame is relevant. As an example, assume that video frames are generated every 40 ms. A range of It allows clients to select an excerpt from the media object, and to play from a given point to the end as well as from the current location to a given point.
The start of playback can be scheduled for any time in the future, although a server may refuse to keep server resources for extended idle periods. This is to make sure that the client-server interaction will proceed without delay when all options are understood by both sides, and only slow down if options are not understood as in the case above. For a well-matched client-server pair, the interaction proceeds quickly, saving a round-trip often required by negotiation mechanisms. In addition, it also removes state ambiguity when the client requires features that the server does not understand.
The relationship between "funky-feature" and Funky-Parameter is not communicated via the RTSP exchange, since that relationship is an immutable property of "funky-feature" and thus should not be transmitted with every exchange. If a particular extension requires that intermediate devices support it, the extension should be tagged in the Proxy-Require field instead see Section This allows clients to gracefully deal with packets when seeking.
The client uses this value to differentiate packets that originated before the seek from packets that originated after the seek. Note: For aggregate control, a particular stream may not actually generate a packet for the Range time value returned or implied. Thus, there is no guarantee that the packet with the sequence number indicated by seq actually has the timestamp indicated by rtptime. Furthermore, in order to ensure that this information is available at the necessary time immediately at startup or after a seek , and that it is delivered reliably, this mapping is placed in the RTSP control channel.
If not 1, the value corresponds to the rate with respect to normal viewing rate. For example, a ratio of 2 indicates twice the normal viewing rate "fast forward" and a ratio of 0. In other words, a ratio of 2 has normal play time increase at twice the wallclock rate. For every second of elapsed wallclock time, 2 seconds of content will be delivered.
A negative value indicates reverse direction. Implementation of scale changes depends on the server and media type. For video, a server may, for example, deliver only key frames or selected key frames. For audio, it may time-scale the audio while preserving pitch or, less desirably, deliver fragments of audio. The server should try to approximate the viewing rate, but may restrict the range of scale values that it supports.
The response MUST contain the actual scale value chosen by the server. If the request contains a Range parameter, the new scale value will take effect at that time. The default is the bit rate of the stream. The parameter value is expressed as a decimal ratio, e. A speed of zero is invalid. If the request contains a Range parameter, the new speed value will take effect at that time. It is meant for use in specific circumstances where preview of the presentation at a higher or lower rate is necessary.
Implementors should keep in mind that bandwidth for the session may be negotiated beforehand by means other than RTSP , and therefore re-negotiation may be necessary.
The session identifier is chosen by the media server see Section 3. Once a client receives a Session identifier, it MUST return it for any request related to that session. A server does not have to set up a session identifier if it has other means of identifying a session, such as dynamically generated URLs. The server uses it to indicate to the client how long the server is prepared to wait between RTSP commands before closing the session due to lack of activity see Section A.
The timeout is measured in Schulzrinne, et. Note that a session identifier identifies a RTSP session across transport sessions or connections. Hence, it is possible that clients use the same session for controlling many streams constituting a presentation, as long as all the streams come from the same server.
See example in Section The session identifier is needed to distinguish several delivery requests for the same URL coming from the same client. The response Session Not Found is returned if the session identifier is invalid. The value of the timestamp is of significance only to the client and may use any timescale. The server MUST echo the exact same value and MAY, if it has accurate information about this, add a floating point number indicating the number of seconds that has elapsed since it has received the request.
The timestamp is used by the client to compute the round-trip time to the server so that it can adjust the timeout value for retransmissions. It sets those values not already determined by a presentation description.
Transports are comma separated, listed in order of preference. Parameters may be added to each transport, separated by a semicolon. The Transport header MAY also be used to change certain transport parameters. A server MAY refuse to change parameters of an existing stream.
The server MAY return a Transport response header in the response to indicate the values actually chosen. In that case, the server MUST return a single option which was actually chosen. The default value for the "lower-transport" parameters is specific to the profile. Below are the configuration parameters associated with transport: General parameters: unicast multicast: mutually exclusive indication of whether unicast or multicast delivery will be attempted.
Default value is multicast. Clients that are capable of handling both unicast and multicast transmission MUST indicate such capability by including two full transport-specs with separate parameters for each. The client may specify the multicast address with the destination parameter. To avoid becoming the unwitting perpetrator of a remote- controlled denial-of-service attack, a server SHOULD authenticate the client and SHOULD log such attempts before allowing the client to direct a media stream to an address not chosen by the server.
A server SHOULD not allow a client to direct media streams to an address that differs from the address commands are coming from. This information may also be available through SDP. However, since this is more a feature of transport than media initialization, the authoritative source for this information should be in the SETUP response.
The layers are sent to consecutive addresses starting at the destination address. If not provided, the default is PLAY. If appending is requested and the server does not support this, it MUST refuse the request rather than overwrite the resource identified by the URI. This parameter may be specified as a range, e. It is specified as a range, e. This parameter is only valid for unicast transmission. It identifies the synchronization source to be associated with the media stream.
RTSP can also control multiple streams as a single entity. Making it part of RTSP rather than relying on a multitude of session description formats greatly simplifies designs of firewalls. In the case where the feature was specified via the Proxy-Require field Section RTSP differs significantly in that respect. However, it is desirable for the continuous media data, typically delivered out-of-band with respect to RTSP, to be cached, as well as the session description.
If the copy is not up-to-date, it modifies the SETUP transport parameters as appropriate and forwards the request to the origin server. The proxy delivers the continuous media data to the client, while possibly making a local copy for later reuse. The exact behavior allowed to the cache is given by the cache-response directives Schulzrinne, et.
Rather than retrieving the whole resource from the origin server, the cache simply copies the streaming data as it passes by on its way to the client. Thus, it does not introduce additional latency. To the client, an RTSP proxy cache appears like a regular media server, to the media origin server like a client. Just as an HTTP cache has to store the content type, content language, and so on for the objects it caches, a media cache has to store the presentation description.
Typically, a cache eliminates all transport-references that is, multicast information from the presentation description, since these are independent of the data delivery from the cache to the client. Information on the encodings remains the same. If the cache is able to translate the cached media data, it would create a new presentation description with all the encoding possibilities it can offer. The following examples are not to be used as a reference for those formats.
The media description is stored on a web server W. The media description contains descriptions of the presentation and all its streams, including the codecs that are available, dynamic RTP payload types, the protocol stack, and content information such as language or copyright restrictions. It may also give an indication about the timeline of the movie.
In this example, the client is only interested in the last part of the movie. Container files are a widely used means to store such presentations. While the components are transported as independent streams, it is desirable to maintain a common context for those streams at the server end. This enables the server to keep a single storage handle open easily.
It also allows treating all the streams equally in case of any prioritization of streams by the server. It is also possible that the presentation author may wish to prevent selective retrieval of the streams by the client in order to preserve the artistic effect of the combined media presentation. Similarly, in such a tightly bound presentation, it is desirable to be able to control all the streams via a single control message using an aggregate URL. The following is an example of using a single RTSP session to control multiple streams.
It also illustrates the use of aggregate URLs. The movie is stored in a container file. This is disallowed for that presentation by the server. This keeps the syntax of the Transport header simple and allows easy parsing of transport information by firewalls. This makes complete sense when there are multiple streams with aggregate control, but is less than intuitive in the special case where the number of streams is one. Here, we assume that the web server only contains a pointer to the full description, while the media server M maintains the full description.
C indicates to the media server that the network addresses and encryption keys are already given by the conference, so they should not be chosen by the server. The example omits the simple ACK responses. Specifically, please note the following: Authentication Mechanisms: RTSP and HTTP share common authentication schemes, and thus should follow the same prescriptions with regards to authentication. Abuse of Server Log Information: RTSP and HTTP servers will presumably have similar logging mechanisms, and thus should be equally guarded in protecting the contents of those logs, thus protecting the privacy of the Schulzrinne, et.
Therefore, all of the precautions regarding the protection of data privacy and user privacy apply to implementors of RTSP clients, servers, and proxies. Nonetheless, the recommendations provided in [H Location Headers and Spoofing: If a single server supports multiple organizations that do not trust one another, then it must check the values of Location and Content-Location headers in responses that are generated under control of said organizations to make sure that they do not attempt to invalidate resources over which they have no authority.
Concentrated denial-of-service attack: The protocol offers the opportunity for a remote-controlled denial-of-service attack. While the attacker's IP address may be known in this case, this is not always useful in prevention of more attacks or ascertaining the attackers identity. Session hijacking: Since there is no relation between a transport layer connection and an RTSP session, it is possible for a malicious client to issue requests with random session identifiers which would affect unsuspecting clients.
The server SHOULD use a large, random and non-sequential session identifier to minimize the possibility of this kind of attack. In environments requiring tighter security for the control messages, the RTSP control stream may be encrypted. Stream issues: RTSP only provides for stream control. Stream delivery issues are not covered in this section, nor in the rest of this memo. RTSP servers SHOULD also be aware of attempts to probe the server for weaknesses and entry points and MAY arbitrarily disconnect and ignore further requests clients which are deemed to be in violation of local security policy.
State is defined on a per object basis. This example does not imply a standard way to represent streams in URLs or a relation to the filesystem. See Section 3. Note that some requests are effective at a future time or position such as a PAUSE , and state also changes accordingly.
This document defines a list of operational security requirements for the infrastructure of large Internet Service Provider ISP IP networks routers and switches. A framework is defined for specifying "profiles", which are collections of requirements applicable to certain network topology contexts all, core-only, edge-only The goal is to provide network operators a clear, concise way of communicating their security requirements to vendors.
This memo defines a portion of the Management Information Base MIB module for use with network management protocols in the Internet community. It is designed to transport public switched telephone network PSTN signaling messages over the connectionless packet network, but is capable of broader applications. This document specifies a bit one-way hash function, calledSHA SHA is based on SHA, but it uses a different initial value and the result is truncated to bits.
The Common Gateway Interface CGI is a simple interface for running external programs, software or gateways under an information server in a platform-independent manner. Currently, the supported information servers are HTTP servers. NationalCentre for Supercomputing Applications.
This document describes a control for the Lightweight DirectoryAccess Protocol version 3 that is used to return a subset of attribute values from an entry. Specifically, only those values that match a "values return" filter. Without support for this control, a client must retrieve all of an attribute's values and search for specific values locally. In particular, it describes management objects used for modelling and storing alarms.
In particular, it defines objects for controlling the reporting of alarm conditions. This document describes the issues surrounding the use of IPv6 site- local unicast addresses in their original form, and formally deprecates them. This deprecation does not prevent their continued use until a replacement has been standardized and implemented. It is designed to be implementable on either network servers or user agents. It is meant to be simple, extensible, easily edited by graphical clients, and independent of operating system or signalling protocol.
It is suitable for running on a server where users may not be allowed to execute arbitrary programs, as it has no variables, loops, or ability to run external programs. This document defines the format of data to be collected and minimum set of attributes that need to be captured for security auditing in healthcare application systems. The format is defined as an XML schema, which is intended as a reference for healthcare standards developers and application designers.
It consolidates several previous documents on security auditing of healthcare data. This document describes an operational technique that uses BGP communities to remotely trigger black-holing of a particular destination network to block denial-of-service attacks.
Black-holing can be applied on a selection of routers rather than all BGP-speaking routers in the network. The document also describes a sinkhole tunnel technique using BGP communities and tunnels to pull traffic into a sinkhole router for analysis. This technique allows a demand circuit to go down when no interesting traffic is going through the link.
However, it also introduces a problem, where it becomes impossible to detect an OSPF-inactive neighbor over such a link. This memo introduces a new mechanism called "neighbor probing" to address the above problem.
IPsec can secure the links of a multihop network to protect communication between trusted components, e. Virtual links established by IPsec tunnel mode can conflict with routing and forwarding inside VNs because IP routing depends on references to interfaces and next-hop IP addresses. The IPsec tunnel mode specification is ambiguous on this issue, so even compliant implementations cannot be trusted to avoid conflicts.
IPIP encapsulation occurs as a separate initial step, as the result of a forwarding lookup of theVN packet. IPsec transport mode processes the resulting tunneled IP packet with an SA determined through a security association database SAD match on the tunnel header. IIPtran demonstrates how to configure any compliant IPsec implementation to avoid the aforementioned conflicts. This memo defines an extension to the SMTP service whereby a client may mark a message for future tracking.
Message Tracking is expected to be used to determine the status of undelivered e-mail upon request. It is to be issued upon a request as described in "Message Tracking Query Protocol". This memo defines only the format of the status information. An extension to SMTP to label messages for further tracking and request tracking status is defined in a separate memo. Customers buying enterprise message systems often ask: Can I track the messages? Message tracking is the ability to find out the path that a particular message has taken through a messaging system and the current routing status of that message.
This document describes the Message Tracking Query Protocol that is used in conjunction with extensions to the ESMTP protocol to provide a complete message tracking solution for the Internet. This document provides a model of message tracking that can be used for understanding theInternet-wide message infrastructure and to further enhance those capabilities to include message tracking, as well as requirements for proposed message tracking solutions.
The transport independent bit-rate value together with the maximum packet rate can then be used to calculate the real bit-rate over the transport actually used. The existing SDP bandwidth modifiers and their values include the bandwidth needed for the transport and IP layers. This document defines a new header for use with Session InitiationProtocol SIP multi-party applications and call control. Citation Context Protocol can be used as an enabling platform for delivering communication and providing event-based services.
We present a mobile workforce management solution which integrates fleet management with presence-based communication to show how presence technology can be used to realize location-based co Abstract - Cited by 1 1 self - Add to MetaCart Protocol can be used as an enabling platform for delivering communication and providing event-based services.
We present a mobile workforce management solution which integrates fleet management with presence-based communication to show how presence technology can be used to realize location-based communication services. Our solution can provide services for both consumer residential and an enterprise scenario, for example, E, rental car management, delivery companies e.
A prototype system and its realization is presented to show the main concepts, feasibility and usefulness of such a solution. Schulzrinne, V. Singh, H. Tschofenig, M. Thomson , XML format for carrying geographical information of a presentity.
Elements are defined that enable expression of spatial orientation, speed, and heading of the presentity. It represents the consensus of the IETF community. It has received public review and has been approved for publication by the. The MultiService Forum MSF is responsible for developing Implementation Agreements or Architectural Frameworks which can be used by developers and network operators to ensure interoperability between components from different vendors.
Abstract - Add to MetaCart The MultiService Forum MSF is responsible for developing Implementation Agreements or Architectural Frameworks which can be used by developers and network operators to ensure interoperability between components from different vendors.
The presence document compliant to this specification MUST have the namespace 'urn:ietf:params:xml:ns:pidf:'. Tuples provide a way of segmenting presence information. Protocols or applications may choose to segment the presence information associated with a presentity for any number of reasons - for example, because components of the full presence information for a presentity have come from distinct devices or different applications on the same device, or have been generated at different times.
Tuples should be preferred over other manners of segmenting presence information such as creating multiple PIDF instances. See Section 4. Other status values may be included using the standard extensibility framework see Section 4. They also indicate general availability for other communication means, but this memo does not specify these in detail. It optionally has a 'priority' attribute, whose value means a relative priority of this contact address over the others.
The value of the Sugano, et al. Higher values indicate higher priority. Examples of priority values are 0, 0. If the 'priority' attribute is omitted, applications MUST assign the contact address the lowest priority. If the 'priority' value is out of the range, applications just SHOULD ignore the value and process it as if the attribute was not present. How they are actually treated is beyond this specification.
Also, how to handle contacts with the same priority is up to implementations. The value of this attribute is the language identifier as defined by [ RFC ]. It MAY be omitted when the language used is implied by the larger context such as the encoding information of the contents, such as an xml:lang attribute on an enclosing XML element, or a Content-language header [ RFC ] on an enclosing MIME wrapper. For security guidelines for watchers receiving presence information with timestamps, see the Security Considerations.
These extensions merely allow protocols and applications to define richer presence data. Any developer can introduce their own element names, avoiding conflict by choosing an appropriate namespace URI. Within the presence data, element or attribute names are associated with a particular namespace by a namespace prefix, which is a leading part of the name, followed by a colon ":" ; e. Note that the choice of 'prefix' is quite arbitrary; it is the corresponding URI that defines the naming scope.
Two different prefixes associated with the same namespace URI refer to the same namespace. A default namespace can be declared for XML elements without a namespace prefix. The default namespace does NOT apply to attribute names, but interpretation of an unprefixed attribute can be determined by the containing element. A namespace is identified by a URI. In this usage, the URI is used simply as a globally unique identifier, and there is no requirement that it can be used to retrieve a web resource, or for any other purpose.
By "globally unique", we mean constructed according to some set of rules so that it is reasonable to expect that nobody else will use the same URI for a different purpose. This includes all of the element content, even if it appears to contain elements with recognized names. However, in order to understand a complex extension, nested elements within an extension element might need to be marked as mandatory.
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