Jingle: Cutting Edge VoIP

Jingle: Cutting Edge Open Source VoIP

Matt Tucker

CTO, Jive Software

I like XMPP

The Vision:

People wouldn’t stop asking for voice chat to be added to XMPP.

or

Worldwide federated network that combines messaging, presence and voice. Ensure there are Open Source tools for all of it.

Current approaches don’t work

Skype

Closed network

Proprietary protocol

SIP

Poor protocol for IM and presence

Very little world-wide federation

Most implementations don’t do Skype-type p2p

In this talk

XMPP Overview

All about Jingle

Protocol flow

NAT traversal (ICE)

Open Source implementations

Others uses for Jingle

XMPP

eXtensible Messaging and Presence Protocol

Open standard approved by the IETF as RFC 3920 and 3921, maintained and extended by the XMPP Standards Foundation

Countless servers and clients deployed in an open federation.

XMPP already won as the open standard for IM

XMPP Protocol Basics

XML based, making it very easy to use and extend

Strong security (TLS) and identity protection built-in Secure Communications with Jabber Peter Saint-Andre Time: 11:35AM - 12:20PM Location: D137-138

Major packet types: Message, Presence and IQ

Sample XMPP Message

<message to='matt@jivesoftware.com'

from='gato@igniterealtime.org' type='chat'>

<thread>thread1</thread>

<body>How's that presentation going?</body>

</message>

XEPs: XMPP Extension Protocols

Core RFC’s are extended through an open process by the XSF

Key extensions cover multi-user chat, file transfer, avatars, publish-subscribe

Jingle is a set of XEPs

Example packet extension

<message to='player@igniterealtime.org'

from='dealer@igniterealtime.org'>

<body>Blackjack!</body>

<gameData xmlns='casino:blackjack'>

<card1 rank='ace' suit='diamonds'/>

<card2 rank='jack' suit='spades'/>

</gameData>

</message>

Jingle

Many attempts at VoIP were tried – stream initiation, TINS, etc. None of them worked very well.

Google launched their XMPP network with voice support, then joined the standards effort to define Jingle.

Covered by several XMPP extensions: XEP-166: Jingle XEP-167: Jingle Audio via RTP XEP-176: Jingle ICE Transport XEP-177: Jingle Raw UDP Transport XEP-180: Jingle Video via RTP XEP-181: Jingle DTMF XEP-183: Jingle Telepathy Transport Method XEP-208: Bootstrapping Implementation of Jingle XEP-215: STUN Server Discovery for Jingle

Acronym soup: ICE, STUN, TURN

Jingle in three easy steps

Do you want a session? Session Negotiation

What kind of session do you want to negotiate? (voice, video, file transfer?) Content Negotiation

How are we going to make this session work? (direct connect, ICE, media proxy?) Transport Negotiation

<iq from='romeo@montague.net/orchard‘ to='juliet@capulet.com/balcony‘ id='jingle1‘ type='set'> <jingle xmlns='http://www.xmpp.org/extensions/xep-0166.html#ns‘ action='session-initiate‘ initiator='romeo@montague.net/orchard‘ sid='a73sjjvkla37jfea‘> <content creator='romeo@montague.net‘ name='this-is-the-audio-content'> <description xmlns='http://www.xmpp.org/extensions/xep-0167.html#ns'> <payload-type id='96' name='speex' clockrate='16000'/> <payload-type id='97' name='speex' clockrate='8000'/> </description> <transport xmlns='http://www.xmpp.org/extensions/xep-0177.html#ns'> <candidate .../> <candidate ip='10.1.1.104' port='13540' generation='0'/> </transport> </content> </jingle>

</iq>

Jingle packet example

SIP packet example

INVITE sip:bob@biloxi.example.com SIP/2.0 Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 Max-Forwards: 70 From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl To: Bob <sip:bob@biloxi.example.com> Call-ID: 3848276298220188511@atlanta.example.com CSeq: 2 INVITE Proxy-Authorization: Digest username="alice", realm="atlanta.example.com", nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", uri="sip:bob@biloxi.example.com", response="42ce3cef44b22f50c6a6071bc8“ Contact: <sip:alice@client.atlanta.example.com;transport=tcp> Content-Type: application/sdp Content-Length: 151 v=0 o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com s=- c=IN IP4 192.0.2.101 t=0 0 m=audio 49172 RTP/AVP 0 a=rtpmap:0 PCMU/8000

Transport approaches

Always use the server to transport media

Pro: always works (we’re using the server to send XMPP packets already)

Con: overloads the server, may be too slow for real-time protocols like voice/video. (~2000 concurrent users max)

Try to go peer to peer

Pro: scales forever. Best way to build a worldwide network.

Con: gets really complicated with firewalls and NATs.

Making peer to peer work

Step 1: try direct connect between IP addresses. (typically only works inside a local network)

Step 2: if #1 fails, the parties are probably behind a firewall or NAT. Do some “crazy stuff” to punch through. (can work up to 90% of the time)

Step 3: if #2 fails, there’s a pretty strict firewall in place so failover to using the server (media relay) (catch the other 10% or so)

The sum of these techniques is ICE, at the cutting edge of VoIP connectivity

Jingle connection architecture

What is NAT?

Problem: the internet was running out of IPv4 addresses Whoops. In the same category as the fake Bill Gates quote: ”640K ought to be enough for anybody”

Solution: group a bunch of computers behind a single IP address using Network Address Translation You don’t know your public IP when behind a NAT. The NAT device dynamically assigns ports to internal hosts to keep all the network traffic going to the right places

Better Solution: IPv6 – bigger addresses (not being adopted worldwide anytime soon) 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses, or enough to give multiple IP addresses to every grain of sand on the planet. Could run into problems when humans conquer multiple galaxies?

“ Crazy stuff”: punching through NATs

Step 1: use a STUN server to find your public IP address

Me: Hey STUN server, I don’t know my IP Address. Can you help? NUTS (the STUN server): Looking at the packet you sent me, I see that the IP address of your NAT device is AAA.BBB.CCC.DDD Me: Sweet!

Step 2: figure out more stuff using the STUN server

Me: Ok, now I want to check to see what my NAT device does with ports. Does the public port change when I connect to different IP addresses? NUTS: Well, good question. I have another IP address you can connect to in order to try that. Me: Awesome, I tried that out and now I know more about my NAT device. Based on my local addresses, what you told me, plus what the other guy told me, I now have have a bunch of address/port options I can try with the other party. NUTS: No problem, glad to help! Buh-bye.

Step 3: connectivity checking to try to create a hole

Me: Can you hear me on this IP/port? You: … [Silence] Me: Hmm, the last one didn’t work. How about this one? You: … [Silence] Me: This is taking awhile… arg! How about this one? You: I hear you, I hear you! Yay, we found a hole.

(Punching holes works better with UDP vs. TCP)

Jingle Client Libraries

libjingle from Google -- http://code.google.com/apis/talk/libjingle/index.html

Telepathy -- http://telepathy.freedesktop.org

Smack – http://www.igniterealtime.org

Jingle server support

Openfire: an Open Source XMPP server with enhancements for Jingle.

Built-in media relay

Without it, P2P calls won’t always complete

Built-in STUN server

Without it, you’ll have to use public STUN servers

Jingle: not just for voice

File transfer

Screen sharing

Video

Whiteboard

Anything else that uses a lot of bandwidth or that does streaming

Jingle: what’s missing

Haven’t defined a way to do VoIP conferencing

Advanced call controls are missing (hold, transfer, etc). There’s a general consensus that this stuff shouldn’t be added to Jingle. Leave it to SIP.

Other Jingle content types (besides audio) are either not defined or immature

Current Jingle status

Standards work on the fundamentals and audio content profile is wrapping up.

Waiting for Google to switch to official Jingle protocol.

Need interop work between different implementations.

Jingle is poised to fulfill its promise as an open standard for a federated, world-wide VoIP network.

Questions?

Contact me via IM or email:

[email_address]

Resources

http://www.xmpp.org

http://www.igniterealtime.org

Secure Communications with Jabber Peter Saint-Andre Time: 11:35AM - 12:20PM Location: D137-138

Jingle: Cutting Edge VoIP

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