jeudi 19 avril 2012

WebRTC


The main parts of the WebRTC specification are now stable and are coming soon to all 200M+ Chrome users. With this blog post, we want to help developers plan for what will be introduced in this first stable release later this year.

What's in:

JSEP
JSEP (Javascript Session Establishment Protocol) is an API for signaling that allows for much more powerful apps and flexibility in choice of signaling protocols. To abstract the complexity, we provide and maintain a Javascript lib that makes browser to browser calls a few lines of Javascript.

Topologies
Our implementation will support multiple independent PeerConnections, each capable of sending and receiving multiple independent media sources.

ICE / STUN / TURN
ICE and STUN are standardized methods for establishing a peer-to-peer connection on the Internet, even if the two end points are behind private network addresses (NAT). Chrome’s current stack deviates from the official current standards. We are working to fix this.

We will also support TURN servers to allow connections through tougher firewalls, where relaying and encapsulation are needed. Exactly what type of TURN will be supported is TBD.

DTLS-SRTP 
Encryption will be mandatory for all usage of WebRTC in Chrome. For our first stable release, we will implement DTLS-SRTP.

VP8, iSAC, iLBC, G.711
The video codec support by Chrome will be VP8. We've made several major improvements inside and around VP8 to ensure it can deliver a great real time experience. On the audio side, we will initially support iSAC, iLBC, G.711, and DTMF, with iSAC being the default. It is a royalty free wideband codec optimized for speech, open sourced at webrtc.org.

What’s next?

More functionality and features will appear in future versions of Chrome. We’ll work on prioritizing them once we get the basics right:
  • Data API. Implementation will start once the network stack is ready. 
  • Screen sharing
  • PeerConnection proxying. The ability to relay a stream to a third party will not make our first version. 
  • Recording. MediaRecorder specification work has not been completed yet.

mardi 17 avril 2012

OpenFlow


OpenFlow is a communications protocol that gives access to the forwarding plane of a network switch or router over the network.[1] In simpler terms, OpenFlow allows the path of network packets through the network of switches to be determined by software running on multiple routers (minimum two of them - primary and secondary - has a role of observers). This separation of the control from the forwarding allows for more sophisticated traffic management than what is feasible using access control lists (ACL)s and routing protocols. Its inventors consider OpenFlow an enabler of "Software Defined Networking".[2]
OpenFlow has been implemented by a number of network switch and router vendors including Brocade Communications[3]Arista NetworksCiscoForce10Extreme NetworksIBMJuniper NetworksHewlett-Packard and NEC.[4] Some network control plane implementations use the protocol to manage the network forwarding elements.[5] OpenFlow is mainly used between the switch and controller on a secure channel.
Version 1.1 of the OpenFlow protocol was released on February 28, 2011 and is still maintained at openflow.org, but new development of the standard was managed by the Open Networking Foundation (ONF).[6] In December 2011, the ONF board approved OpenFlow version 1.2 and published it in February 2012. [7]
Indiana University in May 2011 launched the SDN Interoperability Lab in conjunction with the Open Networking Foundation to test how well different vendors' Software-Defined Networking and OpenFlow products work together.
In February of 2012, Big Switch Networks released an open source package for OpenFlow software. The company has released Floodlight, an Apache-licensed open source OpenFlow Controller. [8]
In February 2012 HP said it is taking its first leap into OpenFlow-enabled network equipment, supporting the standard on 16 of its Ethernet switch products as it attempts to gain a foothold in a market likely to receive significant attention. [9]
In April 2012 Google announced that its internal network was completely re-designed to run under OpenFlow over the past two years. [10]