Monday TECHtionary.com TECH-Tip – Backhaul Options Via Wireless – Disaster Recovery Solution
The animated TECH-Tip tutorial is available at http://www.techtionary.com
Summary
Single and multi-hop backhaul is no panacea but is something to seriously consider.
Details
This TECHtionary TECH-Tips focuses on network backhaul or sometimes referred to as a CAN-Community Access Network.
Here are some of the services provided by CAN cluster of AP-Access Points:
- Self-organizing - AP-Access Points communicate status traffic, build and optimize a "network inside" the network
- Auto-configuring - called auto-discovery as new AP-Access Points are added the network automatically adds them and dynamically updates authentication and authorization access privileges
- Multi-hop backhaul - AP-Access Points can be used to support both user device access or connect traffic back to a wireline point.This reduces unnecessary or inaccessible wireline installations.
- Integrated security for authentication and authorization as well as traffic prioritization for special users such as law enforcement.
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Tuesday TECHtionary.com TECH-Tip – Alien Wavelengths – Optical Switching
The animated TECH-Tip tutorial available at http://www.techtionary.com
Summary
Alien wavelength refers to optical signals being generated by devices other than original ROADM/OADM such as a transponder, ethernet switch or router. Integration of third-party wavelengths reduces losses from optical-to-optical wavelength translation.
Details
Parallel OADM’s are easy to manage but often have a high insertion (add-delete) loss.Serial OADM’s have a lower pass through loss but often have a higher add/drop insertion loss also known as grooming for wavelength and sub-wavelength control or routing.Grooming is the process of adding, deleting, changing routes of optical links.Optical Transponders add photonic or electronic switch to avoid wavelength blocking found in Serial and Parallel switches and add grooming (add/drop) features, scalability to thousands of wavelengths and other emerging benefits.In a 10 Gigabit and 40 Gigabit working system, there will likely be both OOO-All Optical cross connect and OEO-Optical Transponder cross connects.Eventually bit rate photonic switches will replace any electronic cross connects.This concept is also referred to as ROADM-Reconfigurable OADM.OVPN-Optical Virtual Private Network distributes bandwidth to customers in the form of optical bandwidth rather than electrical signals.Optical Couplers are send to multiplex (mix) optical fiber energy
- FBTC-Fused Biconical Tapered Coupler
- Two inputs/outputs
- Star coupler or optical crossconnect
- X (variable) inputs/outputs
Optical Multiplexers are called by many names from OXC-Optical X=cross Connect, Lambda MUX - wavelength multiplexer, Tunable Transponder and other names.Check with manufacturers for specific naming conventions and product names.
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Wednesday TECHtionary.com TECH-Tip – Detecting “Unvoices” - VoIP VAD-Voice Activity Detection
The animated TECH-Tip tutorial is available at http://www.techtionary.com
The archive animated TECH-Tip tutorial is available at http://www.techtionary.com/members/slides/j/jitter.swf
Summary
A key part of the formula in VoIP Planning that is an additional factor is VAD-Voice Activity Detection.
Details
VAD systems determine the difference between human voice, tones, unvoice, "white noise" (similar in concept to white light (composed of equal amounts of all visible light frequencies) - a sound composed of an equal mix of all audible frequencies), comfort noise (noise generated to let the user know the call has not been disconnected) and other sources.
Intel recommends the formula shown above in planning a full-duplex (simultaneous two-way) voice network.Examples are always useful.Here the assumption is a RD or RTP byte size of 10 milliseconds with 4 FFP-voice Frames Per Packet in a 100 BaseT (100 megabit Baseband over Twisted pair) LAN-Local Area Network using a VAD-Voice Activity Detector.As explained in detail elsewhere, the basic recommendation is to use the fastest voice CODEC in relation to the bandwidth of the WAN-Wide Area Network (internet) and the LAN-Local Area Network.What is really means in all too many situations is an upgrade in LAN speeds, LAN switches, routers and bandwidth.
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Thursday TECHtionary.com TECH-Tip – Proxy Servers – Choking Up In the DMZ
The animated TECH-Tip tutorial is available at http://www.techtionary.com
Summary
Choke Routers are IP-Internet Protocol packet-filtering gateways (protocol converter from IP-to-Ethernet) and an application gateway combined and are typically located on the internal side of the router.
Details
Choke Routers are IP-Internet Protocol packet-filtering gateways (protocol converter from IP-to-Ethernet) and an application gateway combined and are typically located on the internal side of the router.The other function of the Choke Router is to reduce/limit/control access to improve performance for mission-critical transactions.
Reverse Hosting (Server) allows the firewall to redirect Applications (Layer 7) specific proxy such as HTTP-Hyper-Text Transfer Protocol requests to multiple internal Web servers.
Server Proxy provides the same functionality as reverse proxy and reverse server hosting, but unlike these features, it works with protocols other than HTTP to provide secure access from the Internet to internal resources such as SMTP-Simple Mail Transfer Protocol or SQL-Structured Query Language (database) server.
Another option is to place the server in a DMZ-De-Militarized Zone (separate security areas) and use the server proxy functionality of the firewall to query (search) the database.The DMZ provides another level of security but access (such as database) performance may be reduced.
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Friday TECHtionary.com TECH-Tip – Search Engines Explained – Searching Recursive “Running Backward” and Iterative “Running Blind”
Summary
Each Search Engine searches data from web sites and other online services but each has their own proprietary (secret) algorithms (rule-of-thumb or step-by-step problem-solving procedure/practices.
Details
Users login (connect or create a session) to a mainframe (shown on the left).Since there was no GUI-Graphical User Interface (such as the "green screen") of an IBM 3270 "dumb" terminal (show above), computer programmers would create programs to retrieve these lists of data files and place them in a Menu.Programs such as Archie, Veronica, WAIS-Wide Area Information Server and Gopher (University mascot) not just "go-fer" (fetch/retrieve) were the first search engines.The term "Spider" comes from the concept of crawling (Crawler) across other locations. Bot comes from robot an automated process.That is, the robot crosses other networks and retrieves data.Since large "dumb terminals" were replaced with multi-application PC-Personal Computers running DOS-Disk Operating System programs, new types of search engines emerged. DOS operating systems have been largely replaced with GUI-Graphical User Interface OS-Operating Systems such as Apple, Microsoft and Linux.WEB browsers and new multi-media applications accelerated the growth and need for search engines.
Each Search Engine searches data from web sites and other online services but each has their own proprietary (secret) algorithms (rule-of-thumb or step-by-step problem-solving procedure/practices).There are two primary search algorithms; Recursive “Running Backward” – searching up from the root, trunk, branch to the lead and Iterative Searching “Running Blind” or continually modifying the search until query found as to the way data is retrieved, organized, rated/ranked and other features/factors.
SEO-Search Engine Optimization is performed by different search engines often very differently.Since Google, Yahoo, MSN, Lycos and the hundreds of other Search Engines are all in competition with one another, each company attempts (though generally poorly) to execute/process your search.In order to improve rating/ranking of your web site and accessibility by Search Engines there is universal agreement that the web site should be designed for easy access by search engine spiders to META TAGS.When users type in the URL-Uniform Resource Locator, the browser looks for a file(s) called index.html.This file is the main web directory.Using a HTML-HyperText Markup Language software editor, the following is one type of coding/format used by Spiders to "login and retrieve" information about your web site.
Page title here UP TO 60 CHARACTERS - Recommended Limit
UP TO 100-150 CHARACTERS - Recommended Limit
UP TO 864 CHARACTERS - Recommended Limit
NOTE:This is not the only information that is in the index.html file but it is the information most retrieved by Search Engine Spiders.
RIGHT CLICK - By right clicking on your mouse on any web page, you can call up the source HTML code.Before building your own index.html, go see how others have written the code.Since there are no absolute rules, this can certainly give you some ideas.
Spiders, crawlers and bots search and retrieve META tags from web sites.SEO-Search Engine Optimization is based on retrieving data that is made available to the public directories (folders).Password protected, internally accessible data is not available to the spiders.