VXLAN - Extended VLAN

The Virtual Extensible VLAN (VXLAN) standard proposed by Cisco and VMware this month will create logical networks -- or extended VLANs -- for long distance virtual machine (VM) migration across geographically dispersed data centers. VXLAN will ultimately enable the kind of long-distance segmentation necessary for multi-tenant cloud networks.
Cisco and VMware have already incorporated the proposed VXLAN standard into products, but the VXLAN draft, which was also co-authored by Cisco, VMware, Arista Networks, Broadcom Corporation, Citrix Systems and Red Hat Inc., awaits standardization by the Internet Engineering Task Force (IETF).

Why the need for the VXLAN standard?
VLANs have long been used to separate data streams, but the IEEE 802.1Q VLAN specification provides only 4,094 VLAN identifiers. A top-of-rack switch may be connected to more than 40 servers. Each server may support multiple VMs with each VM communicating on multiple VLANs. A data center may contain many racks so the total number of VLANs may exceed the 4,094 limit. In addition, VMs comprising a single application may reside in geographically different data centers. These VMs must be connected via a Layer 2 network, so VLAN identifiers must be unique across geographies.

VXLAN standard isolates application data
TheVXLAN standard, outlined in this  RFC draft, groups VLANs associated with an application into a segment defined by a 24-bit identifier called a VXLAN Network Identifier (VNI).  As many as 16 million VNIs may be defined in any administrative domain and each VNI may contain up to 4,094 VLANs. Customer data is kept separate because only VMs operating within the same VNI can communicate.
The Layer 2 network visible to VMs is carried over a Layer 3 network in UDP packets. This enables data centers to operate within different IP subnets. Only the Layer 2 network is visible to VMs, so it's possible for a VM within an application to migrate from one data center to another without the change becoming visible to the relocating VM or any of the other VMs comprising the application.

Communicating between VMs in a VXLAN environment
VM software need not be modified to operate within a VXLAN environment. VNIs are assigned to the VMs operating on a server by a Virtual Tunnel End Point (VTEP). The VTEP resides within the server hypervisor and generates the headers needed to specify the VNI and communicate across the Layer 3 network.

To communicate with other VMs in the segment, a VM creates packets identical to the packets that would be created in a non-VXLAN, non-virtual environment. Packets consist of standard MAC frames with an Ethernet header, source and destination MAC addresses, and Ethernet type. A VLAN tag is included if the VM utilizes multiple VLANs.
The VTEP supporting the VM then encapsulates the packet with an 8-byte VXLAN header. The header contains a single-bit VXLAN flag, the 24-bit VNI and a total of 39 bits reserved for future use. The resulting packet is then enclosed in a UDP packet. The destination IP address is the address of the VTEP to which the packet will be sent. The source IP is the address of the sending VTEP.
The packet is then enclosed in an outer Ethernet packet with the destination MAC of either the destination server or the router that will forward the packet.

Communication between VMs requires IP multicast
When a VM initiates communication with another VM, it operates just as it would in a non-VXLAN environment. If the destination is on the same subnet, it generates an ARP request broadcast for the destination. If they are on different subnets, it ARPs for the first hop router. The VTEP encapsulates the ARP request in VXLAN and UDP headers and sends  the broadcast packet to the IP multicast group associated with the VXLAN segment to which the communicating VMs belong. Assignment of segments to IP multicast groups is done by the management layer.
The VTEP supporting the destination VM strips off the UDP and VXLAN headers and passes the ARP request to the VM, which then responds to the request.  When the response reaches the source VTEP and VM, both VTEPs and VMs have learned the IP and MAC addresses needed to communicate.  Subsequent communication travels VTEP to VTEP without need for multicast.
In some cases, VMs will need to communicate outside the VXLAN environment. A VXLAN gateway strips off the VXLAN and UDP headers and forwards the packet to the destination MAC specified in the packet prepared by the VM. Neither the source VM nor the destination equipment needs to be modified to take part in the interchange. A VXLAN gateway could be implemented in software or in a switch or router.

credit: techtarget.com

Wordless Wednesday #1

Testing

Test

Nokia X3 Touch and Type

Design

Dimensions

• Dimensions: 106.2 x 48.4 x 9.6 mm


• Weight (with battery): 78 g


• Volume: 45.2 cc


• Additional size and shape information
  
  
  
  • Touch screen with keypad
  
  
  
  

Display and user interface

• Size: 2.4" resistive touch screen


• Resolution: 240 x 320 pixels (QVGA TFT)


• Up to 262,000 colours

Keys and input methods

• Call and end keys


• Dedicated messaging key


• Dedicated music key

Colours

• Available colours:
  
  
  
  • White silver
  
  
  • Dark metal
  
  
  • Pink
  
  
  • Lilac
  
  
  
  

Personalisation

• Customisable home screen:
  
  
  
  • widgets
  
  
  • themes
  
  
  • favourite contacts
  
  
  • shortcuts
  
  
  • menu
  
  
  
  


• Customisable profiles


• Ringtones: mp3, AAC, eAAC, eAAC+, WMA


• Video ringtones


• Themes
  
  
  
  • wallpapers
  
  
  • screensavers
  
  
  • ringtones
  
  
  • pre-installed themes
  
  
  • changeable colour themesx
  
  
  
  

Hardware

Power Management

• BL-4S 860 mAh Li-Ion battery
  
  
  
  • Talk time: up to 300 mins
  
  
  • Standby time: up to 430 hours
  
  
  • Music playback time: up to 28 hours
  
  
  • Video playback time: up to 6 hours
  
  
  
  

Operation times may vary depending on radio access technology used, operator network configuration and usage.

Memory

• MicroSD memory card slot, hot swappable, up to 16 GB


• Internal memory: 50 MB

Operating frequency

• Quad band GSM 850/900/1800/1900


• WCDMA: 850/900/1900/2100


• Automatic switching between GSM bands


• Flight mode

Data network

• GPRS class B, multislot class 33, maximum speed 107 kbps downlink/85.7 kbps uplink


• EGPRS class B, multislot class 33, maximum speed 296 kpbs downlink/236.8 kbps uplink


• HSDPA category 9, maximum speed up to 10.2 Mbps


• HSUPA category 5, maximum speed up to 2 Mbps


• Capability to serve as data modem


• WLAN 802.11 b,g,n

Requires data service. Data services may not be available in all networks. Data transmission speeds may be as high as 10.2 Mbps, but may vary based upon network capabilities and other conditions. The establishment and continuation of a data connection depends on network availability, provider support and signal strength.

Connectivity

• 2 mm charger connector


• Bluetooth version 2.1 with Enhanced Data Rate


• Stereo Bluetooth Headset support


• High-Speed USB 2.0 (micro USB connector)


• USB charging


• 3.5 mm AV connector

Software and Application

Software platform & user interface

• Series 40 6th edition


• Firmware update over the air (FOTA)


• Speech codecs: WB-AMR, HR, FR, EFR, NB-AMR

Applications

• Converter


• Size converter


• World clock


• Web Search


• Countdown timer


• Stopwatch


• World clock


• Ovi Store


• My Nokia


• Opera mini browser

Personal Information Management (PIM)

• Detailed contact information


• Favourite contacts


• Calendar


• To-do list


• Notes


• Voice Recorder


• Calculator


• Clock

And more here.

World's Tiniest Video Camera

OMER, Israel, May 3, 2011 /PRNewswire-FirstCall/ -- Medigus Ltd. (TASE: MDGS) has developed the world's smallest video camera - just 0.99 mm in diameter.

These miniature cameras are manufactured from materials suitable for human medical procedures. They are designed specifically for small-diameter disposable endoscopic devices, used in diagnostic and surgical procedures in regions of the anatomy where larger scopes are not viable. Medical fields in which such tools are required include: cardiology; orthopedics; gastroenterology; gynecology; otolaryngology, bronchoscopy and robotic surgery.

These cameras will be integrated into endoscopic devices developed and manufactured by the company, and also sold to third-party medical device manufacturers. Medigus will begin supplying camera samples in the coming weeks to US and Japanese companies which produce cardiology-related devices. The miniature cameras offered by Medigus are supported by the company's digital video processing systems.

The second generation cameras utilize advanced technology, notably the TSV (Through Silicon Via) method which enables miniaturization and reduction of mass-production costs. A dedicated 0.66x0.66 mm CMOS sensor provides high image resolution at 45,000 pixels. When manufactured and sold in large quantities, the costs are sufficiently low for the camera to be used in disposable devices, eliminating the need for costly, time-consuming and potentially hazardous device sterilization.

The global miniature camera market for disposable endoscopic devices is estimated at 4M units in 2011 and 7M in 2015.

"We are excited to release our second generation of disposable cameras to further progress the medical endoscopic field." said Dr. Elazar Sonnenschein, CEO for Medigus Ltd. "Medical procedures that have not been possible until now become possible with the world's smallest camera. The advanced technology provides the medical community and patients with safe, quality and cost-effective treatment."

Kop's new kid : Jack Robinson

After last week’s impressive debut by John Flanagan, it seems only fitting this week to take a closer look at the latest young player getting a chance with the first team, with an every-touch (and tackle) compilation of Jack Robinson1 against Arsenal.

It wasn’t actually Jack Robinson’s debut in the Premier League. That came two managers back, when he was only sixteen, in the final two minutes against Hull City in the final game of last season’s Premier League campaign. It made him the youngest player to ever play in the league for Liverpool, a record that he still holds though appearances by the even younger Raheem Sterling and Suso in this year’s pre-season left Robinson only the third youngest player to get any kind of run out with the first team.

Right off the top, Robinson’s introduction provides a reminder of how well Kenny Dalglish deals with the younger players from the academy, players he in many cases spent time with during the two seasons spent in an ambassadorial and player development role after Rafa Benitez brought him back to the club. It’s a connection seen again later in the match when taking John Flanagan aside after the fullback’s collision with Jamie Carragher led to the stand-in captain being stretchered off the pitch in a neck brace.

As for Robinson, though his feet perhaps gave lie to early nerves with a couple of slips on the Emirates turf, he quickly found his feet on the way to effectively shutting down England regular and exceptionally pacy headless chicken Theo Walcott. In Walcott, Arsenal have a winger whose end product may at times disappoint, but his pure pace can never be doubted, and with the significant Premier League experience that he does have it would have been entirely reasonable for fans to fear for the young Liverpool fullback’s hide.



At the other end of the field, it has to be noted that Robinson didn’t get down the pitch all that often to help provide attacking width against Arsenal. In the end that is of course one of a fullback’s more important jobs–at times his most important job, depending on the system–but for a young kid making his first major appearance on the road against the number two side in the table and with a pacy winger up against him, it’s hard to find much to fault regardless. In any case, even if he wasn’t especially adventurous, he at least looked far more comfortable on the ball than Danny Wilson has when occasion has seen the center back forced to fill in on the outside. That does suggest there’s reason to hope for the future at left back, perhaps even for the near future against less attacking sides at Anfield. Perhaps even for when Birmingham comes to visit on Saturday, with there being every chance that both of Liverpool’s new pair of fullbacks who can’t grow a beard between them will start.

For both Robinson and Flanagan, though, people would do well to remember just how young they are, and that they’re at a position that often doesn’t see players really hit their peak until they’ve been around for another entire decade. Both of them have shown huge promise, though, and shown that in a pinch they might even have it in them to do a job for the club already. Still, to expect and pressure either one of them to be able to contribute both consistently and over the long term, at the kind of level Liverpool would need to be a top-four side moving forward, would likely end up doing more harm than good to each player’s long term development.

However, that’s more a worry for the summer than for right now, so in the meantime, here’s to hoping for a few more quality performances by the youngsters before the season comes to an end.

credits:  theoffside.com

The Royal Wedding - LIVE

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