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ROM:- Used to store the routers bootstrap details, operating SYSTEM software.

Flash memory: - holds the operating systems images. The content is retained when the router is restarted.

RAM: - Used to store the Routing TABLES, configuration files, caching and BUFFERING details. Content is lost when lost router is switched off or restarted.

NVRAM:- Stores the routers STARTUP config files. Data is non volatile.

Network interfaces to connect router to network.

ROM:- Used to store the routers bootstrap details, operating system software.

Flash memory: - holds the operating systems images. The content is retained when the router is restarted.

RAM: - Used to store the Routing tables, configuration files, caching and buffering details. Content is lost when lost router is switched off or restarted.

NVRAM:- Stores the routers startup config files. Data is non volatile.

Network interfaces to connect router to network.

A routing table stores the routes of the various nodes in a network. Nodes can be any electronic device connected to the network. The table is usually stored in a router or the network computer as a database or file. This information helps to fond the BEST possible path. The routing table has at least 3 FIELDS: the destination network ID, cost of the path, next hop or address to SEND the PACKET.

A routing table stores the routes of the various nodes in a network. Nodes can be any electronic device connected to the network. The table is usually stored in a router or the network computer as a database or file. This information helps to fond the best possible path. The routing table has at least 3 fields: the destination network id, cost of the path, next hop or address to send the packet.

The MAIN goal of Distance Vector ROUTING PROTOCOLS Is to find out the best path for he data packet to reach the destination. Distance here could be the hops. The three different types of Distance Vector routing protocols include:- Routing Information Protocol (RIP v1 and v2) and Interior Gateway Routing Protocol. The protocol is easy to manage however not WELL scalable.

The Distance Vector protocol initially prepares a Routing table which is shared with other routers. This routing table is shared between routers PRESENT in the same network. A new routing table is prepared when some new information is received from some other router. Now, the bad routing paths are removed keeping only the smallest hop paths. This new table is then communicated to other routers.

The main goal of Distance Vector Routing Protocols Is to find out the best path for he data packet to reach the destination. Distance here could be the hops. The three different types of Distance Vector routing protocols include:- Routing Information Protocol (RIP v1 and v2) and Interior Gateway Routing Protocol. The protocol is easy to manage however not well scalable.

The Distance Vector protocol initially prepares a Routing table which is shared with other routers. This routing table is shared between routers present in the same network. A new routing table is prepared when some new information is received from some other router. Now, the bad routing paths are removed keeping only the smallest hop paths. This new table is then communicated to other routers.

ROUTING PROTOCOL INTERACTS and informs the hardware that is needed to TRANSMIT the data between transmitter and the receiver for transmission over NETWORK.

Routing protocol interacts and informs the hardware that is needed to transmit the data between transmitter and the receiver for transmission over network.

Routing PROTOCOL specifies how the ROUTERS communicate, disseminating the information which enables the routers to be SELECTED between two nodes in a network.

Routing protocol specifies how the routers communicate, disseminating the information which enables the routers to be selected between two nodes in a network.

VIRTUAL terminals: For ACCESSING routers 

NETWORK management STATIONS.

Virtual terminals: For accessing routers 

Network management stations.

The INTERNATIONAL ORGANIZATION for STANDARDIZATION (ISO) developed the Open Systems Interconnection (OSI) Reference Model to describe how information is TRANSFERRED from one machine to another.

The International Organization for Standardization (ISO) developed the Open Systems Interconnection (OSI) Reference Model to describe how information is transferred from one machine to another.

Micro segmentation is a TERM used with switches when each networking DEVICE has its own dedicated port on a SWITCH.

Micro segmentation is a term used with switches when each networking device has its own dedicated port on a switch.

A cooperative TRADE association responsible for the "Commercial BUILDING Telecommunication Cabling Standard," also KNOWN as EIA/TIA 568, which specifies how NETWORK cables should be installed in a commercial site.

A cooperative trade association responsible for the "Commercial Building Telecommunication Cabling Standard," also known as EIA/TIA 568, which specifies how network cables should be installed in a commercial site.

ARP, or Address Resolution Protocol can be likened to DNS for MAC ADDRESSES. Standard DNS ALLOWS for the mapping of human-friendly URLs to IP addresses, while ARP allows for the mapping of IP addresses to MAC addresses. In this way it lets SYSTEMS go from a regular domain name down to the actual piece of hardware it resides upon.

ARP, or Address Resolution Protocol can be likened to DNS for MAC Addresses. Standard DNS allows for the mapping of human-friendly URLs to IP addresses, while ARP allows for the mapping of IP addresses to MAC addresses. In this way it lets systems go from a regular domain name down to the actual piece of hardware it resides upon.

A type of signal interference caused by signals TRANSMITTED on ONE pair of WIRES bleeding over into the other pairs. Crosstalk can cause network signals to degrade, eventually rendering them UNVIABLE.

A type of signal interference caused by signals transmitted on one pair of wires bleeding over into the other pairs. Crosstalk can cause network signals to degrade, eventually rendering them unviable.

Boot to LAN is most OFTEN used when you are doing a fresh install on a system. What you would do is setup a network-based installer CAPABLE of network-booting VIA PXE. Boot to LAN enables this by allowing a pre-boot environment to look for a DHCP server and connect to the broadcasting network installation server. Environments that have very large NUMBERS of systems more often than not have the capability of pushing out images via the network. This reduces the amount of hands-on time that is required on each system, and keeps the installs more consistent.

Boot to LAN is most often used when you are doing a fresh install on a system. What you would do is setup a network-based installer capable of network-booting via PXE. Boot to LAN enables this by allowing a pre-boot environment to look for a DHCP server and connect to the broadcasting network installation server. Environments that have very large numbers of systems more often than not have the capability of pushing out images via the network. This reduces the amount of hands-on time that is required on each system, and keeps the installs more consistent.

Sticky ports are one of the network admin's BEST friends and WORST headaches. They allow you to set up your network so that each port on a switch only permits one (or a number that you SPECIFY) computer to connect on that port by locking it to a particular MAC address. If any other computer plugs into that port, the port shuts down and you receive a call that they can't connect anymore. If you were the one that originally ran all the network connections then this isn't a BIG issue, and likewise if it is a PREDICTABLE pattern then it also isn't an issue. However if you're working in a hand-me-down network where chaos is the norm then you might end up spending a while toning out exactly what they are connecting to.

Sticky ports are one of the network admin's best friends and worst headaches. They allow you to set up your network so that each port on a switch only permits one (or a number that you specify) computer to connect on that port by locking it to a particular MAC address. If any other computer plugs into that port, the port shuts down and you receive a call that they can't connect anymore. If you were the one that originally ran all the network connections then this isn't a big issue, and likewise if it is a predictable pattern then it also isn't an issue. However if you're working in a hand-me-down network where chaos is the norm then you might end up spending a while toning out exactly what they are connecting to.

Routing is a PROCESS of FINDING a path to TRANSFER data from SOURCE to destination.

Routing is a process of finding a path to transfer data from source to destination.

TIA/EIA-568-B

TIA/EIA-568-B

VoIP is FAR better than traditional telephony but it has some drawbacks as LISTED below:

• Some VoIP services don't work during power outages and the service PROVIDER may not offer BACKUP power.
• Not all VoIP services connect directly to emergency services through 9-1-1.
• VoIP providers may or may not offer directory assistance/white PAGE listings.

VoIP is far better than traditional telephony but it has some drawbacks as listed below:

The simple answer is that Multimode is cheaper but can't transmit as far. Single Mode has a smaller core (the part that HANDLES light) than Multimode, but is better at keeping the light INTACT. This allows it to travel greater DISTANCES and at higher bandwidths than Multimode. The problem is that the requirements for Single Mode are very specific and as a RESULT it usually is more expensive than Multimode. Therefore for applications, you will usually see Multimode in the datacenter with Single Mode for long-haul connections.

The simple answer is that Multimode is cheaper but can't transmit as far. Single Mode has a smaller core (the part that handles light) than Multimode, but is better at keeping the light intact. This allows it to travel greater distances and at higher bandwidths than Multimode. The problem is that the requirements for Single Mode are very specific and as a result it usually is more expensive than Multimode. Therefore for applications, you will usually see Multimode in the datacenter with Single Mode for long-haul connections.

A workgroup is a collection of systems each with their own rules and local user logins tied to that particular system. A Domain is a collection of systems with a centralized authentication server that tells them what the rules are. While workgroups work effectively in small numbers, once you pass a relatively low threshold (usually anything more than say 5 systems), it becomes increasingly difficult to manage permissions and sharing effectively. To put this another way, a workgroup is very similar to a P2P network- each member is its own ISLAND and chooses what it decides to share with the rest of the network. Domains on the other HAND are MUCH more like a STANDARD client/server relationship- the individual MEMBERS of the domain connect to a central server which handles the heavy lifting and standardization of sharing and access permissions.

A workgroup is a collection of systems each with their own rules and local user logins tied to that particular system. A Domain is a collection of systems with a centralized authentication server that tells them what the rules are. While workgroups work effectively in small numbers, once you pass a relatively low threshold (usually anything more than say 5 systems), it becomes increasingly difficult to manage permissions and sharing effectively. To put this another way, a workgroup is very similar to a P2P network- each member is its own island and chooses what it decides to share with the rest of the network. Domains on the other hand are much more like a standard client/server relationship- the individual members of the domain connect to a central server which handles the heavy lifting and standardization of sharing and access permissions.

ICMP is the Internet Control Message PROTOCOL. Most USERS will RECOGNIZE the name through the use of tools such as ping and traceroute, as this is the protocol that these services run over among other things. Its primary purpose is to tell systems when they are trying to connect remotely if the other end is available. Like TCP and UDP, it is a part of the IP suite and uses IP port number 1. Please note, this is not TCP port 1 or UDP port 1 as this is a DIFFERENT numbering scheme that for reference can be located here (For your reference, TCP uses IP port 6, while UDP uses IP port 17). That being said, different functions of ICMP use specific ports on TCP and UDP. For example, the 'echo' portion of ping (the part where someone else is able to ping you) uses TCP port 7.

ICMP is the Internet Control Message Protocol. Most users will recognize the name through the use of tools such as ping and traceroute, as this is the protocol that these services run over among other things. Its primary purpose is to tell systems when they are trying to connect remotely if the other end is available. Like TCP and UDP, it is a part of the IP suite and uses IP port number 1. Please note, this is not TCP port 1 or UDP port 1 as this is a different numbering scheme that for reference can be located here (For your reference, TCP uses IP port 6, while UDP uses IP port 17). That being said, different functions of ICMP use specific ports on TCP and UDP. For example, the 'echo' portion of ping (the part where someone else is able to ping you) uses TCP port 7.

• RJ-11 ( Registered Jack-11) a four- or six-wire connector primarily used to connect telephone equipment.
• RJ-45 (Registered Jack-45) connector is an eight-wire connector that is commonly used to connect COMPUTERS to a LOCAL area network (LAN), PARTICULARLY Ethernet LANs.
• AUI( Attachment Unit Interface.) is the part of the Ethernet standard that specifies how a Thicknet cable is to be CONNECTED to an Ethernet card. AUI specifies a coaxial cable connected to a transceiver that plugs into a 15-pin socket on the network interface card (NIC).
• BNC stand for British Naval Connector (or Bayonet Nut Connector or Bayonet Neill Concelman)a type of connector used with coaxial cables such as RG-58.BNC connectors are used on both Thicknet and Thinnet.

In VoIP, phone conversations are CONVERTED to packets that flit all over the Internet or PRIVATE networks, just like e-mails or Web pages, though voice packets get priority status. The packets get reassembled and converted to sound on the other end of the call but in TRADITIONAL phone service, a phone conversation is converted into electronic signals that traverse an elaborate NETWORK of SWITCHES, in a dedicated circuit that lasts the duration of a call.

In VoIP, phone conversations are converted to packets that flit all over the Internet or private networks, just like e-mails or Web pages, though voice packets get priority status. The packets get reassembled and converted to sound on the other end of the call but in traditional phone service, a phone conversation is converted into electronic signals that traverse an elaborate network of switches, in a dedicated circuit that lasts the duration of a call.

The main PURPOSE of data link layer is to CHECK that WHETHER messages are sent to the RIGHT devices. Another FUNCTION of data link layer is framing.

The main purpose of data link layer is to check that whether messages are sent to the right devices. Another function of data link layer is framing.

If you as a Linux admin "What is root", you may very well get the response "root, god, what's the difference?" Essentially root is THE admin, but in a Linux environment it is IMPORTANT to remember that unlike in a WINDOWS environment, you spend very little time in a "privileged" mode. Many Windows programs over the years have required that the user be a LOCAL admin in order to function properly and have caused huge security issues as a result. This has changed some over the years, but it can still be difficult to remove all of the programs asking for top level permissions.

A Linux user remains as a standard user nearly all the time, and only when necessary do they change their permissions to that of root or the superuser (su). sudo (literally- superuser do …) is the main way used to run one-off commands as root, or it is ALSO possible to temporarily have a root-level bash prompt. UAC (User Account Control) is similar in theme to sudo, and like Windows Firewall can be a pain in the neck but it does do a lot of GOOD. Both programs allow the user to engage higher-level permissions without having to log out of their current user session- a massive time saver.

If you as a Linux admin "What is root", you may very well get the response "root, god, what's the difference?" Essentially root is THE admin, but in a Linux environment it is important to remember that unlike in a Windows environment, you spend very little time in a "privileged" mode. Many Windows programs over the years have required that the user be a local admin in order to function properly and have caused huge security issues as a result. This has changed some over the years, but it can still be difficult to remove all of the programs asking for top level permissions.

A Linux user remains as a standard user nearly all the time, and only when necessary do they change their permissions to that of root or the superuser (su). sudo (literally- superuser do …) is the main way used to run one-off commands as root, or it is also possible to temporarily have a root-level bash prompt. UAC (User Account Control) is similar in theme to sudo, and like Windows Firewall can be a pain in the neck but it does do a lot of good. Both programs allow the user to engage higher-level permissions without having to log out of their current user session- a massive time saver.

Transport layer assigns a unique set of numbers for each CONNECTION. These numbers are called port or socket numbers TCP, and UDP, provide a multiplexing function for a device: This allows multiple APPLICATIONS to SIMULTANEOUSLY SEND and receive data.

Transport layer assigns a unique set of numbers for each connection. These numbers are called port or socket numbers TCP, and UDP, provide a multiplexing function for a device: This allows multiple applications to simultaneously send and receive data.

A straight-through cable is used for DTE-to-DCE connections.

• A HUB to a router, PC, or FILE SERVER
• A switch to a router, PC, or file server

Crossover cables should by used when you CONNECT a DTE to another DTE or a DCE to another DCE.

• A hub to another hub
• A switch to another switch
• A hub to a switch
• A PC, router, or file server to another PC, router, or file server

A straight-through cable is used for DTE-to-DCE connections.

Crossover cables should by used when you connect a DTE to another DTE or a DCE to another DCE.

When trying to communicate with systems on the inside of a secured network, it can be very difficult to do so from the outside- and with good reason. Therefore, the use of a port forwarding table within the router itself or other connection management device, can allow for SPECIFIC traffic to be automatically forwarded on to a PARTICULAR DESTINATION. For example, if you had a web server running on your network and you wanted ACCESS to be granted to it from the outside, you would setup port forwarding to port 80 on the server in question. This would mean that anyone putting in your IP ADDRESS in a web browser would be connected up to the server's website immediately. Please note, this is usually not recommended to allow access to a server from the outside directly into your network.

When trying to communicate with systems on the inside of a secured network, it can be very difficult to do so from the outside- and with good reason. Therefore, the use of a port forwarding table within the router itself or other connection management device, can allow for specific traffic to be automatically forwarded on to a particular destination. For example, if you had a web server running on your network and you wanted access to be granted to it from the outside, you would setup port forwarding to port 80 on the server in question. This would mean that anyone putting in your IP address in a web browser would be connected up to the server's website immediately. Please note, this is usually not recommended to allow access to a server from the outside directly into your network.

In plain English, DNS is the Internet's phone book. The Domain Name System is what makes it possible to only have to remember something like "cnn.com" instead of (at this particular moment) "157.166.226.26". IP address change all the time however, although less so for mega-level servers. Human friendly names ALLOW users to remember a something much easier and less likely to change frequently, and DNS makes it possible to map to those new addresses under the hood. If you were to look in a standard phone book and you know the name of the person or business you're looking for, it will then show you the number for that person.

DNS servers do exactly the same THING but with updates on a daily or hourly basis. The TIERED nature of DNS also makes it possible to have repeat queries responded to very quickly, although it may take a few moments to discover where a brand new address is that you haven't been to before. From your home, say that you wanted to go to the InfoSec Institute's home page. You know the address for it, so you punch it in and wait. Your computer will first talk to your local DNS server (likely your home ROUTER) to see if it KNOWS where it is. If it doesn't know, it will talk to your ISP's DNS server and ask it if it knows. If the ISP doesn't know, it will keep going up the chain asking questions until it reaches one of the 13 Root DNS Servers. The responding DNS server will send the appropriate address back down the pipe, caching it in each location as it does so to make any repeat requests much faster.

In plain English, DNS is the Internet's phone book. The Domain Name System is what makes it possible to only have to remember something like "cnn.com" instead of (at this particular moment) "157.166.226.26". IP address change all the time however, although less so for mega-level servers. Human friendly names allow users to remember a something much easier and less likely to change frequently, and DNS makes it possible to map to those new addresses under the hood. If you were to look in a standard phone book and you know the name of the person or business you're looking for, it will then show you the number for that person.

DNS servers do exactly the same thing but with updates on a daily or hourly basis. The tiered nature of DNS also makes it possible to have repeat queries responded to very quickly, although it may take a few moments to discover where a brand new address is that you haven't been to before. From your home, say that you wanted to go to the InfoSec Institute's home page. You know the address for it, so you punch it in and wait. Your computer will first talk to your local DNS server (likely your home router) to see if it knows where it is. If it doesn't know, it will talk to your ISP's DNS server and ask it if it knows. If the ISP doesn't know, it will keep going up the chain asking questions until it reaches one of the 13 Root DNS Servers. The responding DNS server will send the appropriate address back down the pipe, caching it in each location as it does so to make any repeat requests much faster.

Dynamic Host Configuration Protocol is the default way for connecting up to a network. The implementation varies ACROSS Operating Systems, but the simple explanation is that there is a server on the network that hands out IP addresses when requested. Upon connecting to a network, a DHCP request will be sent out from a NEW member system. The DHCP server will respond and issue an address lease for a varying amount of time. If the system connects to another network, it will be ISSUED a new address by that server but if it re-connects to the original network before the lease is up- it will be re-issued that same address that it had before.

To illustrate this point, say you have your phone SET to wifi at your home. It will pick up a DHCP address from your router, before you head to work and connect to your CORPORATE network. It will be issued a new address by your DHCP server before you go to starbucks for your mid-morning coffee where you'll get another address there, then at the local restaurant where you get lunch, then at the grocery store, and so on and so on.

Dynamic Host Configuration Protocol is the default way for connecting up to a network. The implementation varies across Operating Systems, but the simple explanation is that there is a server on the network that hands out IP addresses when requested. Upon connecting to a network, a DHCP request will be sent out from a new member system. The DHCP server will respond and issue an address lease for a varying amount of time. If the system connects to another network, it will be issued a new address by that server but if it re-connects to the original network before the lease is up- it will be re-issued that same address that it had before.

To illustrate this point, say you have your phone set to wifi at your home. It will pick up a DHCP address from your router, before you head to work and connect to your corporate network. It will be issued a new address by your DHCP server before you go to starbucks for your mid-morning coffee where you'll get another address there, then at the local restaurant where you get lunch, then at the grocery store, and so on and so on.

UTP cable comes in a variety of DIFFERENT grades, called "categories" by the Electronics Industry ASSOCIATION (EIA) and the Telecommunications Industry Association (TIA), the combination being referred to as EIA/TIA.

• Cat 1 :- USED for voice-grade telephone networks only; not for data transmissions
• Cat 2 :- Used for voice-grade telephone networks
• Cat 3 :-Used for voice-grade telephone networks, 10 Mbps ETHERNET, 4 Mbps TOKEN Ring,
• Cat 4 :-Used for 16 Mbps Token Ring networks
• Cat 5 :-Used for 100BaseTX Fast Ethernet, SONet, and OC-3 ATM
• Cat 5e:- Used for Gigabit (1000 Mbps) Ethernet protocols

UTP cable comes in a variety of different grades, called "categories" by the Electronics Industry Association (EIA) and the Telecommunications Industry Association (TIA), the combination being referred to as EIA/TIA.

SWITCH

• Switches are used at data link layer.
• Switches create SEPARATE collision DOMAIN and a single broadcast domain.
• Address learning
• Forward/filter decision using mac address.

Hub

• HUBS are used at physical layer.
• Hubs create single collision domain and a single broadcast domain.
• No addressing.
• No filtering.

Switch

Hub

External Media has been used for backups for a very long time, but has started to fall out of favor in the past few years due to its speed limitations. As capacities CONTINUE to climb higher and higher, the amount of time it takes to not only perform a backup but also a restore skyrockets. Tapes have been particularly hit hard in this regard, primarily because they were quite sluggish even before the jump to the terabyte era.

Removable hard disks have been able to pick up on this trend however, as capacity and price have GIVEN them a solid lead in front of other options. But this takes us back to the question- why use EXTERNAL media? Internal media usually is able to connect faster, and is more reliable correct? Yes and no. While the ESTIMATED lifetime of storage devices has been steadily going up, there is always the chance for user error, data corruption, or hiccups on the hard disk. As a result, having regular backups to external media is still one of the best bang-for-buck methods available. Removable hard disks now have the CAPABILITY to connect very rapidly, even without the use of a dedicated hot-swap drive bay. Through eSATA or USB3, these connections are nearly as FAST as if they were plugged directly into the motherboard.

External Media has been used for backups for a very long time, but has started to fall out of favor in the past few years due to its speed limitations. As capacities continue to climb higher and higher, the amount of time it takes to not only perform a backup but also a restore skyrockets. Tapes have been particularly hit hard in this regard, primarily because they were quite sluggish even before the jump to the terabyte era.

Removable hard disks have been able to pick up on this trend however, as capacity and price have given them a solid lead in front of other options. But this takes us back to the question- why use EXTERNAL media? Internal media usually is able to connect faster, and is more reliable correct? Yes and no. While the estimated lifetime of storage devices has been steadily going up, there is always the chance for user error, data corruption, or hiccups on the hard disk. As a result, having regular backups to external media is still one of the best bang-for-buck methods available. Removable hard disks now have the capability to connect very rapidly, even without the use of a dedicated hot-swap drive bay. Through eSATA or USB3, these connections are nearly as fast as if they were plugged directly into the motherboard.

If you were to ask a Microsoft Sales Rep this question, they would no doubt have hundreds of TWEAKS and performance boosts from system to system. In reality however there are two main differences between the Windows HOME edition and Windows Professional: Joining a DOMAIN and built-in encryption. Both features are active in Professional only, as joining a domain is nearly a mandatory requirement for businesses. EFS (Encrypted File System) in and its successor Bitlocker are both ALSO only present in Pro. While there are workarounds for both of these items, they do present a nice quality-of-life boost as well as allow easier standardization across multiple systems. That being said, the jump from Windows Pro to Windows Server is a monumental paradigm shift.

While we could go through all of the bells and whistles of what makes Windows Server…Windows Server, it can be summed up very briefly as this: Windows Home and Pro are designed to connect outwards by default and are optimized as such. Windows Server is designed to have other objects connect to it, and as a result it is optimized severely for this purpose. Windows Server 2012 has taken this to a new extreme with being able to perform an installation style very similar to that of a Unix/Linux system with no GUI whatsoever. As a result, they claim that the attack vector of the Operating System has been reduced massively (when installing it in that mode)

If you were to ask a Microsoft Sales Rep this question, they would no doubt have hundreds of tweaks and performance boosts from system to system. In reality however there are two main differences between the Windows Home edition and Windows Professional: Joining a domain and built-in encryption. Both features are active in Professional only, as joining a domain is nearly a mandatory requirement for businesses. EFS (Encrypted File System) in and its successor Bitlocker are both also only present in Pro. While there are workarounds for both of these items, they do present a nice quality-of-life boost as well as allow easier standardization across multiple systems. That being said, the jump from Windows Pro to Windows Server is a monumental paradigm shift.

While we could go through all of the bells and whistles of what makes Windows Server…Windows Server, it can be summed up very briefly as this: Windows Home and Pro are designed to connect outwards by default and are optimized as such. Windows Server is designed to have other objects connect to it, and as a result it is optimized severely for this purpose. Windows Server 2012 has taken this to a new extreme with being able to perform an installation style very similar to that of a Unix/Linux system with no GUI whatsoever. As a result, they claim that the attack vector of the Operating System has been reduced massively (when installing it in that mode)

Even if you don't recognize anything else on this list, you like have heard of TCP/IP before. Contrary to popular believe, TCP/IP is not actually a protocol, but rather TCP is a member of the IP protocol suite. TCP stands for Transmission Control Protocol and is one of the big big mindbogglingly massively used protocols in use today. Almost every major protocol that we use on a daily basis- HTTP, FTP and SSH among a large list of others- utilizes TCP. The big benefit to TCP is that it has to establish the connection on both ends before any data begins to flow. It is also able to sync up this data flow so that if packets arrive out of order, the receiving system is able to FIGURE out what the puzzle of packets is supposed to look like- that this packet goes before this one, this one goes here, this one doesn't belong at all and looks sort of like a FISH, etc. Because the list of ports for TCP is so massive, charts are commonplace to show what uses what, and Wikipedia's which can be found here is excellent for a desk REFERENCE.

Even if you don't recognize anything else on this list, you like have heard of TCP/IP before. Contrary to popular believe, TCP/IP is not actually a protocol, but rather TCP is a member of the IP protocol suite. TCP stands for Transmission Control Protocol and is one of the big big mindbogglingly massively used protocols in use today. Almost every major protocol that we use on a daily basis- HTTP, FTP and SSH among a large list of others- utilizes TCP. The big benefit to TCP is that it has to establish the connection on both ends before any data begins to flow. It is also able to sync up this data flow so that if packets arrive out of order, the receiving system is able to figure out what the puzzle of packets is supposed to look like- that this packet goes before this one, this one goes here, this one doesn't belong at all and looks sort of like a fish, etc. Because the list of ports for TCP is so massive, charts are commonplace to show what uses what, and Wikipedia's which can be found here is excellent for a desk reference.

To make a baseband network practical for many computers to share, the data transmitted by each system is broken up into separate units called packets. When your computer transmits data it might be broken up into many packets, and the computer transmits each packet SEPARATELY. When all of the packets constituting a particular transmission reach their destination, the receiving computer reassembles them back into original data. This is the basis for a packet-switching network.

Circuit-switching means that the two systems wanting to communicate establish a circuit before they transmit any INFORMATION. That circuit remains open throughout the life of the EXCHANGE, and is only broken when the two systems are FINISHED communicating. Circuit switching is more common in environments like the public switched telephone network (PSTN), in which the connection between your telephone and that of the person you're CALLING remains open for the entire duration of the call.

To make a baseband network practical for many computers to share, the data transmitted by each system is broken up into separate units called packets. When your computer transmits data it might be broken up into many packets, and the computer transmits each packet separately. When all of the packets constituting a particular transmission reach their destination, the receiving computer reassembles them back into original data. This is the basis for a packet-switching network.

Circuit-switching means that the two systems wanting to communicate establish a circuit before they transmit any information. That circuit remains open throughout the life of the exchange, and is only broken when the two systems are finished communicating. Circuit switching is more common in environments like the public switched telephone network (PSTN), in which the connection between your telephone and that of the person you're calling remains open for the entire duration of the call.

COMMUNICATION is a process of SENDING and receiving data by an externally CONNECTED data cable whereas transmission is a process of sending data from source to DESTINATION.

Communication is a process of sending and receiving data by an externally connected data cable whereas transmission is a process of sending data from source to destination.

For general VOIP set up we require the following things:

• BROADBAND connection
• VoIP phone
• Nexton soft-switches
• Router
• Audiocodec
• Astric SERVER

For general VoIP set up we require the following things:

HTTP or HyperText Transfer Protocol, is the MAIN protocol responsible for shiny content on the Web. Most webpages still use this protocol to TRANSMIT their basic website content and allows for the display and NAVIGATION of 'hypertext' or links. While HTTP can use a NUMBER of different CARRIER protocols to go from system to system, the primary protocol and port used is TCP port 80.

HTTP or HyperText Transfer Protocol, is the main protocol responsible for shiny content on the Web. Most webpages still use this protocol to transmit their basic website content and allows for the display and navigation of 'hypertext' or links. While HTTP can use a number of different carrier protocols to go from system to system, the primary protocol and port used is TCP port 80.

In half-duplex communication DATA TRAVELS in only ONE direction at a time.

In full-duplex MODE TWO systems that can communicate in both directions simultaneously are operating.

In half-duplex communication data travels in only one direction at a time.

In full-duplex mode two systems that can communicate in both directions simultaneously are operating.

The process of ROUTING is done by the DEVICES known as ROUTERS. Routers are the NETWORK LAYER devices.

The process of routing is done by the devices known as Routers. Routers are the network layer devices.

Voice over Internet Protocol (VOIP) is the technology to send your voice (analog DATA) over the internet (DIGITAL data) to an end user. It enables users to use the Internet as the transmission medium for voice CALLS at a very low cost.

Voice over Internet Protocol (VoIP) is the technology to send your voice (analog data) over the internet (digital data) to an end user. It enables users to use the Internet as the transmission medium for voice calls at a very low cost.

/etc/passwd is the primary file in Unix/Linux operating system that stores information about USER accounts and can be read by all users. /etc/shadow many times is used by the operating system instead due to SECURITY CONCERNS and increased HASHING capabilities. /etc/shadow more often than not is HIGHLY restricted to privileged users.

/etc/passwd is the primary file in Unix/Linux operating system that stores information about user accounts and can be read by all users. /etc/shadow many times is used by the operating system instead due to security concerns and increased hashing capabilities. /etc/shadow more often than not is highly restricted to privileged users.

SHADOW copies are a versioning system in place on Windows operating systems. This allows for users to go back to a previously available version of a file without the need for restoring the file from a standard backup- ALTHOUGH the specific features of shadow copies vary from version to version of the OS. While it is not NECESSARY to use a backup function in CONJUNCTION with Shadow Copies, it is recommended due to the additional stability and reliability it provides. Please note- Shadow Copies are not Delta Files. Delta files allow for easy comparison between versions of files, while Shadow Copies STORE entire previous versions of the files.

Shadow copies are a versioning system in place on Windows operating systems. This allows for users to go back to a previously available version of a file without the need for restoring the file from a standard backup- although the specific features of shadow copies vary from version to version of the OS. While it is not necessary to use a backup function in conjunction with Shadow Copies, it is recommended due to the additional stability and reliability it provides. Please note- Shadow Copies are not Delta Files. Delta files allow for easy comparison between versions of files, while Shadow Copies store entire previous versions of the files.

Also known as the program that can give your admin nightmares, telnet is a very SMALL and versatile utility that ALLOWS for connections on nearly any port. Telnet would allow the admin to connect into REMOTE devices and administer them via a command prompt. In many cases this has been replaced by SSH, as telnet transmits its data in cleartext (like ftp). Telnet can and does however get used in cases where the user is trying to SEE if a program is LISTENING on a particular port, but they want to keep a low profile or if the connection type pre-dates standard network connectivity methods.

Also known as the program that can give your admin nightmares, telnet is a very small and versatile utility that allows for connections on nearly any port. Telnet would allow the admin to connect into remote devices and administer them via a command prompt. In many cases this has been replaced by SSH, as telnet transmits its data in cleartext (like ftp). Telnet can and does however get used in cases where the user is trying to see if a program is listening on a particular port, but they want to keep a low profile or if the connection type pre-dates standard network connectivity methods.

A subnet MASK tells the network how BIG it is. When an ADDRESS is inside the mask, it will be handled internally as a part of the local network. When it is outside, it will be handled DIFFERENTLY as it is not part of the local network. The proper use and calculation of a subnet mask can be a great benefit when designing a network as well as for gauging future growth.

A subnet mask tells the network how big it is. When an address is inside the mask, it will be handled internally as a part of the local network. When it is outside, it will be handled differently as it is not part of the local network. The proper use and calculation of a subnet mask can be a great benefit when designing a network as well as for gauging future growth.

The twin to TCP is UDP- User Datagram Protocol. Where TCP has a lot of additional under-the-hood features to make sure that everybody stays on the same page, UDP can broadcast 'into the dark'- not really caring if somebody on the other end is listening (and thus is often called a 'connectionless' protocol). As a result, the extra heavy lifting that TCP needs to do in order to create and maintain its connection isn't required so UDP oftentimes has a faster transmission SPEED than TCP.

An EASY way to picture the DIFFERENCES between these two protocols is like this: TCP is like a CB radio, the PERSON transmitting is always waiting for confirmation from the person on the other end that they received the message. UDP on the other hand is like a standard television broadcast signal. The transmitter doesn't know or care about the person on the other end, all it does care about is that its signal is going out correctly. UDP is used primarily for 'small' bursts of information such as DNS requests where speed matters above nearly everything else. The above listing for TCP also contains counterparts for UDP, so it can be used as a REFERENCE for both.

The twin to TCP is UDP- User Datagram Protocol. Where TCP has a lot of additional under-the-hood features to make sure that everybody stays on the same page, UDP can broadcast 'into the dark'- not really caring if somebody on the other end is listening (and thus is often called a 'connectionless' protocol). As a result, the extra heavy lifting that TCP needs to do in order to create and maintain its connection isn't required so UDP oftentimes has a faster transmission speed than TCP.

An easy way to picture the differences between these two protocols is like this: TCP is like a CB radio, the person transmitting is always waiting for confirmation from the person on the other end that they received the message. UDP on the other hand is like a standard television broadcast signal. The transmitter doesn't know or care about the person on the other end, all it does care about is that its signal is going out correctly. UDP is used primarily for 'small' bursts of information such as DNS requests where speed matters above nearly everything else. The above listing for TCP also contains counterparts for UDP, so it can be used as a reference for both.

• Defines the process for connecting two layers, promoting INTEROPERABILITY between vendors.
• Separates a complex function into simpler components.
• Allows vendors to compartmentalize their DESIGN EFFORTS to FIT a modular design, which EASES implementations and simplifies troubleshooting

The progressive weakening of a signal as it travels over a CABLE or other medium. The LONGER the DISTANCE a signal travels, the weaker the signal gets, until it becomes unreadable by the RECEIVING SYSTEM 

The progressive weakening of a signal as it travels over a cable or other medium. The longer the distance a signal travels, the weaker the signal gets, until it becomes unreadable by the receiving system