Initial published version.
Clarified order of events to be consistent with raw-udp and ice-udp.
Add additional text to use NAT assisting protocols and allow the responder to also send <streamhost/> information. This change required the introduction of streamhost-used and streamhost-error.
Rough draft.
&xep0166; defines a framework for negotiating and managing data sessions over XMPP. In order to provide a flexible framework, the base Jingle specification defines neither data transport methods nor application formats, leaving that up to separate specifications. The current document defines a transport method for establishing and managing data exchanges between XMPP entities using the existing SOCKS5 Bytestreams (S5B) protocol specified in &xep0065;. This "jingle-s5b" method results in a streaming transport method suitable for use in Jingle application types where packet loss cannot be tolerated (e.g., file transfer).
+It is RECOMMENDED that a client offers as much <streamhost/> elements with itself as StreamHost as possible. This includes opening the TCP port on all available interfaces the user wants to use (e.g. maybe not an expensive UMTS link), both the IPv4 and IPv6 of that interface (if available), and using an assisting NAT protocol if possible. If the client knows it is behind and the router announces UPnP IGD or NAT-PMP support, the client SHOULD map the open port to the external interface of the router and include the public IP address and port information in the <streamhost/> offers. To increase the chance of success without using a proxy, this specification allows the responder to also send offers.
+|
+ | ack |
+ |<---------------------------------|
+ | session-accept |
+ | (with S5B info) |
+ |<---------------------------------|
+ | ack |
+ |--------------------------------->|
+ | streamhost transport-info |
+ |<---------------------------------|
+ | ack |
+ |--------------------------------->|
+ | streamhost-used transport-info |
+ |--------------------------------->|
+ | ack |
+ |<---------------------------------|
+ | S5B "SESSION" |
+ |<================================>|
+ | session-terminate |
+ |<---------------------------------|
+ | ack |
+ |--------------------------------->|
+ | |
+ ]]>
+ This flow is illustrated in the following examples (to prevent confusion these use a "stub" transport instead of a real application type).
+First the initiator sends a Jingle session-initiate request that contains one or more transport candidates, which in jingle-s5b are XEP-0065 streamhosts.
+The responder immediately acknowledges receipt.
+Depending on the application type, a user agent controlled by a human user might need to wait for the user to affirm a desire to proceed with the session before continuing. When the user agent has received such affirmation (or if the user agent can automatically proceed for any reason, e.g. because no human intervention is expected or because a human user has configured the user agent to automatically accept sessions with a given entity), it returns a Jingle session-accept message. This message MUST contain a &TRANSPORT; element qualified by the 'urn:xmpp:jingle:transports:s5b:0' namespace, which SHOULD in turn contain one <streamhost/> element for each SOCKS5 Bytestreams candidate generated by or known to the responder, but MAY instead be empty if the responder does not wish to offer any streamhosts or wishes to send each candidate as the payload of a transport-info message.
+Note: If the responder sends streamhost candidates, the chances of a successful connection are increased. For example, the initiator might be behind a NAT or might have no access to a proxy, whereas the responder might have a public IP address, might know about a streamhost proxy, or might have NAT penetration support like NAT-PMP in the router.
+In the following example, Juliet's client is the StreamHost and opens one port. The provided <streamhost/> elements are the (private) IPv4 address of the interface, a (public) IPv6 address, and the public IPv4 address created by mapping the private IP address/port using NAT-PMP.
+The initiator acknowledges receipt and tries to connect to the offered StreamHosts.
+Once one client has successfully created a connection with a StreamHost, it sends the <streamhost-used/> element defined in XEP-0065 to the peer; as a result, both clients will stop trying to connect to other candidates.
The peer immediately acknowledges receipt.
+The initiator can then immediately begin sending data over the SOCKS5 bytestream as described in XEP-0065 (in fact the streamhost is bidirectional, so the responder can use it as well).
+Once the parties have finished using the bytestream (e.g., because a complete file has been sent), either party can send a Jingle session-terminate action.
+The other party then acknowledges the session-terminate and the Jingle session is finished.
+The session flow is as follows.
+|
+ | ack |
+ |<---------------------------------|
+ | session-accept |
+ | (with S5B info) |
+ |<---------------------------------|
+ | [ SOCKS5 failure! ] |
+ |x--------------------------------x|
+ | transport-replace (IBB) |
+ |--------------------------------->|
+ | ack |
+ |<---------------------------------|
+ | IBB "SESSION" |
+ |=================================>|
+ | terminate |
+ |<---------------------------------|
+ | ack |
+ |--------------------------------->|
+ | |
+ ]]>
+ The protocol flow is as follows.
+First the initiator sends a Jingle session-initiate, in this case with a transport of SOCKS5 Bytestreams.
+The responder acknowledges receipt of the session-initiate and sends a session-accept.
+The initiator acknowledges receipt and tries to connect to the offered StreamHosts.
+If initiator or responder is unable to connect to any of the StreamHosts, it MUST send a <streamhost-error/> transport-info to the peer.
+The peer immediately acknowledges receipt.
+If the initiator receives such an error message from the responder and was also unable to connect to any StreamHosts (or did not receive any from the responder), it MUST either terminate the Jingle session with a Jingle reason of <connectivity-error/> or replace the transport by something else using the transport-replace action. Typically the fallback option is &xep0047;. Therefore the initiator sends a transport-replace action including a transport of IBB.
+The responder then acknowledges the transport-replace action.
+If the transport replacement is acceptable, the responder then sends a transport-accept action to the initiator (if not, the responder sends a transport-reject action).
+The initiator acknowledges the Jingle transport-accept action.
+Now the initiator sends data using In-Band Bytestreams as defined in XEP-0047.
+The same processing rules and usage guidelines defined in XEP-0065 apply to the Jingle S5B Transport Method. Additional implementation suggestions are:
+The same security considerations defined in XEP-0065 apply to the Jingle S5B Transport Method.
+This document requires no interaction with &IANA;.
+The XMPP Registrar shall add to its registry of Jingle transport methods a definition for the "jingle-s5b" transport method. The registry submission is as follows:
+
+ s5b
+ A method for exchanging data over SOCKS5 Bytestreams.
+ streaming
+ XEP-0260
+
+ ]]>
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+ ]]>
+Initial published version.
&xep0166; defines a framework for negotiating and managing data sessions over XMPP. In order to provide a flexible framework, the base Jingle specification defines neither data transport methods nor application formats, leaving that up to separate specifications. The current document defines a transport method for establishing and managing data exchanges between XMPP entities using the existing In-Band Bytestreams (IBB) protocol specified in &xep0047;. This "jingle-ibb" method results in a streaming transport method suitable for use in Jingle application types where packet loss cannot be tolerated (e.g., file transfer); however, because the "jingle-ibb" transport method sends data over the XMPP channel itself (albeit not the Jingle signalling channel), it is intended as a transport of last resort when other streaming transports cannot be negotiated.
+The approach taken in this specification is to use the existing IBB mechanisms described in XEP-0047 for transporting the data, and to define Jingle-specific methods only to start and end the in-band bytestream.
+|
+ | ack |
+ |<---------------------------|
+ | session-accept |
+ |<---------------------------|
+ | ack |
+ |--------------------------->|
+ | IBB "SESSION" |
+ |<==========================>|
+ | session-terminate |
+ |<---------------------------|
+ | ack |
+ |--------------------------->|
+ | |
+ ]]>
+ This flow is illustrated in the following examples (to prevent confusion these use a "stub" transport instead of a real application type).
+First the initiator sends a Jingle session-initiate request.
+Note: The Jingle IBB Transport Method defines one attribute in addition to those defined in XEP-0047: the 'stanza' attribute. This attribute specifies whether the initiator intends to send IBB data using &MESSAGE; or &IQ; stanzas, but is purely advisory. The default value is "iq", and it is RECOMMENDED to send IBB data using IQ stanzas instead of message stanzas because IQ stanzas provide feedback to the sender regarding delivery to the recipient (e.g., if the recipient is on a small pipe and cannot handle a large volume of IBB packets in quick succession).
+The responder immediately acknowledges receipt (but does not yet accept the session).
+If the offer is acceptable, the responder returns a Jingle session-accept and the initiator acknowledges the session-accept.
+The initiator then immediately begins sending IBB packets using an IQ-set for each chunk as described in XEP-0047, and the responder acknowledges each IQ-set.
+Once the parties have finished using the bytestream (e.g., because a complete file has been sent), either party can send a Jingle session-terminate action.
+The other party then acknowledges the session-terminate and the Jingle session is finished.
+As IBB is defined in XEP-0047, there is one session per bytestream (which can be used in both directions). To extend this idea, it might be useful to run multiple sessions over a single bytestream. This can be done by sending a transport-info message that authorizes an additional session, as shown in the following example.
+Here the Jingle Session ID is the same ("a73sjjvkla37jfea") but the new IBB Session ID ("bt8a71h6") is different from the old IBB Session ID that is already in use ("ch3d9s71").
+The same processing rules and usage guidelines defined in XEP-0047 apply to the Jingle IBB Transport Method.
+The same security considerations defined in XEP-0047 apply to the Jingle IBB Transport Method.
+This document requires no interaction with &IANA;.
+This specification defines the following XML namespace:
+Upon advancement of this specification from a status of Experimental to a status of Draft, the ®ISTRAR; shall add the foregoing namespace to the registry located at &NAMESPACES;, as described in Section 4 of &xep0053;.
+The XMPP Registrar shall add to its registry of Jingle transport methods a definition for the "jingle-ibb" transport method. The registry submission is as follows:
+
+ ibb
+ A method for exchanging data over In-Band Bytestreams.
+ streaming
+ XEP-0261
+
+ ]]>
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