Core Networking

Core Networking

Multi-core networking

6Wind has ported its Linux-based multi-core networking stack to a new PowerPC-based networking system-on-chip (SoC) from Freescale Semiconductor. The 6WindGate stack now supports Freescale's upcoming QorIQ P4080, having been ported to the platform using Virtutech's Simics simulation environment, the company says.

The 6WindGate stack is aimed at telecommunications, security, and networking equipment manufacturers, says the company. It includes routing, security, QoS (quality-of-service), mobility, and IPv4-6 support, along with an XML-based management system for integration with UTM (unified threat management) software. Other features include standard-compliant IPsec cryptography hardware, and "fast-path" modules said to support the OpenBSD Cryptographic Framework (OCF).

6WindGate EDS architecture

The 6WindGate stack comes in a symmetrical multiprocessing version called ADS, as well as a fast-path enabled SDS version that is said to offer a fast data path by dedicating some cores specifically to data plane processing via its real-time MCEE (Multi-Core Executive Environment) operating system. In this configuration, it assigns other cores to control plane tasks running Linux.

6WindGate's ADS, EDS, and SDS versions

6Wind also offers an EDS version that manages to accomplish fast-path performance without MCEE. Instead, it implements fast path as a Linux kernel module sitting between the Linux networking stack and the interface drivers (see diagram above).

QorIQ on the horizon

Announced in June, QorIQ is a pin- and software-compatible successor to Freescale's Linux-compatible PowerQUICC line of network processors. Based on one to eight e500 cores clocked from 400MHz to 1.5GHz, QorIQ is fabricated with 45nm process technology, leading to greater claimed power efficiency.


QorIQ P4 block diagram

The QorIQ P4080 is not expected to sample until mid 2009. However, Freescale collaborated with Virtutech in order to provide virtualized "Simics" simluation models for the chips. Using technology similar to processor virtualization, the Simics models mimic the QorIQ chips at the instruction-set level, enabling both hardware and software developers to get started in advance of hardware availability, the companies say.

6Wind provides its IP stack running on the Virtutech Simics Hybrid Virtual simulation platform, it says. Other companies touting early support for QorIQ, based on ports to Simics, include carrier-grade Linux distributors MontaVista and Wind River. 

The Linux-compatible QorIQ SoCs range from the single-core P1010, clocked at 400MHz and consuming only four Watts, to the eight-core P4 clocked at 1.5Ghz and requiring 30 Watts, says Freescale. QorIQ uses the same e500 Power Architecture core used by PowerQUICC. Each e500 is said to offer 36-bit physical addressing, double-precision floating-point support, a 32KB L1 instruction cache, and a 32KB L1 data cache. Other touted features include one private backside cache per core, tri-level cache hierarchy, datapath acceleration architecture (DPAA), and a CoreNet coherency fabric on-chip, high-speed, interconnect between e500 cores, says the company.

Stated Eric Carmes, CEO of 6Wind, "Adding Freescale Semiconductor to our large list of technology partners essentially defines 6WIND as a reference solution for L2/L3 embedded networking software specifically designed for multicore."

The 6WindGate stack has been validated on x86, IXP4xx, IXP2xxx, and multi-core MIPS64 processors from Cavium and Raza, 6Wind Says. Additionally, last week, the company announced a reference design aimed at 4G wireless base stations and smart media gateway equipment. The design combines 6WindGate with VirtualLogix's VLX-NI (network infrastructure) virtualization technology, running on Texas Instruments's C6000 multi-core digital signal processors (DSPs).

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Current Protocols Essential Laboratory Techniques (CPET)

Current Protocols Launches Current Protocols Essential Laboratory Techniques

Current Protocols Essential Laboratory Techniques (CPET) provides every researcher with the skills and understanding of fundamental laboratory procedures needed to ensure greater success at the bench. CPET takes the novice researcher from very basic skills like weight and volume measurement, through reagent preparation and the use of routine instrumentation, and finally into advanced topics such as real-time PCR and bioinformatics. In addition CPET:

  • Teaches new investigators how to formulate basic research questions and plan the experiments needed to answer them
  • Describes solution chemistry and preparation
  • Covers basic laboratory safety
  • Provides instruction on the care and use of common equipment such as pH meters, spectrophotometers, centrifuges, and microscopes
  • Teaches how to manage information from lab notebooks, images, and literature references, as well as manuscript preparation
  • Details modern bioinformatics techniques
  • Provides practical guides to outsourcing tasks such as sequencing and oligonucleotide synthesis
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Modulation Techniques for Wireless

Introduction
The purpose of analog modulation is to impress an
information-bearing analog waveform onto a carrier for
transmission.
The purpose of digital modulation is to convert an
information-bearing discrete-time symbol sequence into a
continuous-time waveform (perhaps impressed on a carrier).
Key concerns | bandwidth efficiency and implementation
complexity.

These are aected by:
  • base band pulse shape
  • phase transition characteristics
  • envelope
uctuations (channel non-linearity?)
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FREE Wi-Fi

Find and Use FREE Wi-Fi INTERNET

VISIT

Anchor Free

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How To Setup Wireless Connection (APPLY SAFETY SETTINGS FIRST)

"Don't ever connect a wireless router without doing the above safety settings. By default they are setup "loose" so that they get the fewest tech support calls. A central location of where you are most likely to use your wireless devices is desirable."

Ø Make sure your internet connection is working directly from your internet connection modem prior to connecting your router.

Ø Hook your router up as per instructions. Any wired computers will plug into the LAN connections and one cable will go to the modem.

Ø Log into the router using a wired computer with the ip address that is provided in the manual. Most are 192.168.0.1. Inputting this address in your browser's address window should get you there. Default login is "admin" , passwords vary, so check your book.

Ø Turn on WPA-PSK encryption so that the data from your computer is encrypted and not visible by your neighbor.

Ø Change the default router access password so that only you can logon.

Ø Turn off SSID broadcasting as this tells anyone passing by with a wireless device that you have a connection available; also name SSID what you want. You will use this name when connecting from your wireless device.

Ø Mac address filtering allows only your computer(s) to connect to your network so enable this as well. Finding your Mac address of your network device(s) is done by starting a command prompt window and typing "ipconfig/all" without the quotes. A typical Mac address is 00-06-5B-04-B4.

Ø Click enable Mac address filtering, then type your computer's Mac addresses in and save.

Ø WAN connection type will most likely be set to DHCP and should work fine at this setting for most applications.

Ø Fire up your computer with the wireless device installed....You did type the Mac address for this device, right?

Ø Start wireless setup wizard in Windows XP and it will walk you through connecting to your router. Use manual settings and check the box for wpa at the bottom. Remember that WPA-PSK key/password you made earlier? You will input it here. SSID name will also be entered here.

Ø If you have more than 1 computer and you would like to enable share files, click start>my network places then if you are using a Windows XP, on the side toolbar click "set up a home or small office network" and follow the steps with every computer.

Ø If all went smoothly you will now be able to safely connect wirelessly.
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GPRS Core Network

The GPRS Core Network is the centralised part of the GPRS system and also provides support for WCDMA based 3G networks. The GPRS core network is an integrated part of the GSM core network.                            

The GPRS Core Network (GPRS stands for General Packet Radio Services) provides mobility management, session management and transport for Internet Protocol packet services in GSM and WCDMA networks. The core network also provides support for other additional functions such as billing and lawful interception.

  • GPRS Tunnelling Protocol (GTP)

GPRS Tunnelling Protocol is the defining IP protocol of the GPRS core network. It is the protocol which allows end users of a GSM or WCDMA network to move from place to place while continuing to connect to the internet as if from one location at the Gateway GPRS Support Node (GGSN). It does this by carrying the subscriber's data from the subscriber's current Serving GPRS Support Node (SGSN) to the GGSN which is handling the subscriber's session. The forms of GTP used by the GPRS core network 
GTP-U: for transfer of user data
in separated tunnels for each PDP context
GTP-C: for control reasons

  • GPRS Support Nodes (GSN)  

A GSN is a network node which supports the use of GPRS in the GSM core network. All GSNs should have a Gn interface and support the GPRS Tunnelling Protocol.

There are two key variants of the GSN;

 GGSN and the SGSN 

  • Access Point

An access point is:
An IP network to which a mobile can be connected
A set of settings which are used for that connection
A particular option in a set of settings in a mobile phone

When a GPRS mobile phone sets up a PDP context, the access point is selected.

  • PDP Context

The PDP (Packet Data Protocol, e.g. IP, X.25, FrameRelay) context is a data structure present on both the SGSN and the GGSN which contains the subscriber's session information when the subscriber has an active session. When a mobile wants to use GPRS, it must first attach and then activate a PDP context. This allocates a PDP context data structure in the SGSN that the subscriber is currently visiting and the GGSN serving the subscribers access point. The data recorded includes:
Subscriber's IP address
Subscriber's IMSI
Subscriber's 
Tunnel Endpoint ID (TEID) at the GGSN
Tunnel Endpoint ID (TEID) at the SGSN

The Tunnel Endpoint ID (TEID) is a number allocated by the GSN which identifies the tunnelled data related to a particular PDP context.

There are two kinds of PDP contexts:

Primary PDP Context :  Has a unique IP address associated with it
Secondary PDP Context :  Shares an IP address with another PDP context

A total of 11 PDP contexts (with any combination of Primary and Secondary) can co-exist.

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