Mobile XMPP and VoIP

Context

• External identity management
• No Roster: contacts based on phone address book
• Conversation Index
• Initial restriction: single resource
• Multi-region: federation
• Design to scale up

Conversation Index

Contacts

Contact Discovery

• No roster, so no explicitly stored contacts
• Push contacts from phone book
• Matches by User Service
• Cached in Redis
• Auto-expires
• Cache miss:
  • Ask IDM
  • Ask other regions

Contact Discovery Request

<iq from='romeo@montague.lit/orchard' id='uw72g179'
    to='contacts.montague.lit' type='get'>
  <contacts xmlns='urn:xmpp:contact-disco:0' bid='100000'>
    <contact id='1234'>
      <address uri='tel:5550909090'/>
      <address uri='tel:5550909091'/>
      <address uri='mailto:elvis@rock.com'/>
    </contact>
    <contact id='1235'>
      <address uri='tel:5550909092'/>
      <address uri='tel:5550909094'/>
    </contact>
  </contacts>
</iq>
            

Contact Discovery Async Result (1)

<message from='contacts.montague.lit'
         to='romeo@montague.lit' type='headline'>
  <contacts xmlns='urn:xmpp:contact-disco:0' bid='100000'>
    <contact id='1234'>
      <address uri='tel:5550909090'>
        <discovery uri='xmpp:juliet@capulet.lit'/>
        <discovery uri='mailto:juliet@capulet.lit'/>
      </address>
      <address uri='tel:5550909091' >
        <discovery uri='xmpp:juliet@capulet.lit'/>
      </address>
      <address uri='mailto:elvis@rock.com'/>
    </contact>
  </contacts>
</message>
            

Contact Discovery Async Result (2)

<message from='contacts.montague.lit'
         to='romeo@montague.lit' type='headline'>
  <contacts xmlns='urn:xmpp:contact-disco:0' bid='100000'>
    <contact id='1235'>
      <address uri='tel:5550909092' >
        <discovery uri='mailto:tristan@capulet.lit'/>
      </address>
      <address uri='tel:5550909094' >
        <discovery uri='xmpp:tristan@capulet.lit'/>
      </address>
    </contact>
  </contacts>
</message>
            

Contact Metadata

Display names only:

1. Local address book
2. vCard4 iq request
3. Unknown

Service Discovery

• Old-style (pre-hash) CAPS
• Mostly used to discover voice capability

Avatars

• Fully HTTP based
• Lookup by JID

Calling

Jingle Signaling

• Use SDP directly instead of XEP-0167 (Jingle RTP Sessions)
• No SDP parsing required
• Easier to work with WebRTC library
• Similar to Jingle SDP Content (inbox) by Philipp Hancke
• session-initiate send to bare JID

TURN Authentication

• REST API For Access To TURN Services by Justin Uberti
• XMPP <iq/> instead of HTTP Rest

Call Push

• Push mechanism similar to XEP-0357 (Push Notifications)
• Initial <iq/> sent as payload
• Compression with pre-populated dictionary
• Library: Shogun

Call Records

• Call Detail Records
• Headline message stanzas
• To be part of chat history
• After Jingle session-termination
• Used to inform parties of:
  • Placed calls
  • Missed calls
  • Call Failures

CDR Example

<cdr xmlns='urn:xmpp:cdr:0'
     sid='sessionNumber1'
     initiator='northumberland@shakespeare.lit/westminster'
     responder='kingrichard@royalty.england.lit'
     answer='true'
     ring='true'
     termination-reason='success'
     duration='324'>
  <ssrc>a73sjjvkla37jfea</ssrc>
  <optional-value>a73sjjvkla37jfea</optional-value>
</cdr>  
            

CDR in Chat

Chat

• Reuse of existing standards
• Regular message stanzas
• Explicitly made <body/> fallback

Chat Markers

• Based on XEP-0333 (Chat Markers)
• Added dispatched state
• Timestamp receival by server

Archive Management

• External History component
• Message stanzas directly to Kafka
• History service indexes
• Retrieval using XEP-0313 (Message Archive Management)

Multimedia Sharing

• Upload over HTTP
• Prevent roundtrips for each upload
• Authentication like TURN auth
• XEP-0385 (Stateless Inline Media Sharing)
• XEP-0264 (Jingle Content Thumbnails)

Other Sharing

• Stickers
• News
• Offers