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NAT definition NAT (Network Address Translation) is the translation of an Internet Protocol add ress (IP address) used within one network to a different IP address known within another network. One network is designated the inside network and the other is the outside. Typically, a compan y maps its local inside network addresses to one or more global outside IP addresses and unmaps the global IP addresses on incoming packets back into local IP addresses. This helps ensure s ecurity since each outgoing or incoming request must go through a translation process that al so offers the opportunity to qualify or authenticate the request or match it to a previous req uest. NAT also conserves on the number of global IP addresses that a company needs and it lets the company use a single IP address in its communication with the world.

Definition - What does Variable Length Subnet Mask (VLSM) mean? A Variable Length Subnet Mask (VLSM) is a numerical masking sequence, or IP addr ess subset, based on overall network requirements. A VLSM allows a network administrator to use long masks for networks with few hosts and short masks for networks with multiple hosts. A VLSM is used with a VLSM router and must have routing protocol support. A VLSM is also known as a classless Internet Protocol (IP) address. Techopedia explains Variable Length Subnet Mask (VLSM) Key VLSM features include: Simple network configuration Network IP addressing through empty subnet filling Greater efficiency than fixed-length subnet masks (FLSM) Streamlined routing, where a router functions only with a VLSM sequence, ver sus a full IP address VLAN Short for virtual LAN, a network of computers that behave as if they are connect ed to the same wire even though they may actually be physically located on different segments of a L AN. VLANs are configured through software rather than hardware, which makes them extremely fle xible. One of the biggest advantages of VLANs is that when a computer is physically moved to a nother location, it can stay on the same VLAN without any hardware reconfiguration.

Variable Length Subnet Masking - VLSM - is a technique that allows network admi nistrators to divide an IP address space into subnets of different sizes, unlike simple same-s

ize Subnetting. Variable Length Subnet Mask (VLSM) in a way, means subnetting a subnet. To simp lify further, VLSM is the breaking down of IP addresses into subnets (multiple levels) and all ocating it according to the individual need on a network. It can also be called a classless IP addres sing. A classful addressing follows the general rule that has been proven to amount to IP address wastage.

Features of RIP v2 To help today's IP internetworks minimize broadcast traffic, use variable length subnetting to conserve IP addresses, and secure their routing environment from misconfigured or malicious routers, se veral key features were added to RIP v2.

Difference between Dynamic and Static Routing? Answer The difference between dynamic and static routing are that static routing manual ly written into routing tables. This is done through a configuration file to set up the optimal path between the source and destination computers. Dynamic routi ng uses dynamic protocols to update the routing table and find the optimal path between the source and destination computers.

Static routes are manually entered into your routing table. With dynamic routing you have algorithms which calculate "the best" possible routes and it happens a utomatically. Most commonly used dynamic algorithms are RIP and OSPF. So basically with static routes you explicitly say how do you want traffic route d and with dynamic protocols are used to determine the shortest paths or the pat hs with best link width (or both).

Flat vs. Hierarchichal Routing Protocols Last Updated: Wednesday, 03-Apr-2013 12:52:56 MDT | By InetDaemon FLAT Flat routing protocols distribute information as needed to any router that can b e reached or receive information. No effort is made to organize the network or i ts traffic, only to discover the best route hop by hop to a destination by any p ath. Think of this as all routers sitting on a flat geometric plane. Routing Inf ormation Protocol (RIP) is an example of a flat routing protocol. HIERARCHICAL

Heirarchical routing protocols often group routers together by function into a h ierarchy. A heirarchical protocol allows an administrator to make best use of hi s fast powerful routers as backbone routers, and the slower, lower powered route rs may be used for access purposes. In this way, the access routers form the fir st tier of the hierarchy, and the backbone routers form the second tier. Hierarc hichal protocols make an effort to keep local traffic local, that is, they will not forward traffic to the backbone if it is not necessary to reach a destinatio n. Some hierearchichal protocols also perform route aggregation to reduce the nu mber of routes advertised (only summary routes are advertised). - See more at: ierarchical.shtml#sthash.bq3w6YvG.dpuf

ll IP addresses have a network and host portion. In classful addressing, the net work portion ends on one of the separating dots in the address (on an octet boun dary). Classful addressing divides an IP address into the Network and Host porti ons along octet boundaries.In the classful addressing system all the IP addresse s that are available are divided into the five classes A,B,C,D and E, in which c lass A,B and C address are frequently used because class D is for Multicast and is rarely used and class E is reserved and is not currently used. Each of the IP address belongs to a particular class that's why they are classfu l addresses.Earlier this addressing system did not have any name,but when classl ess addressing system came into existence then it is named as Classful addressin g system.The main disadvantage of classful addressing is that it limited the fle xibility and number of addresses that can be assigned to any device.One of the m ajor disadvantage of classful addressing is that it does not send subnet informa tion but it will send the complete network address. The router will supply its o wn subnet mask based on its locally configured subnets. As long as you have the same subnet mask and the network is contiguous, you can use subnets of a classfu l network address. Classless Addressing: Classless addressing uses a variable number of bits for the network and host por tions of the address. Classless addressing treats the IP address as a 32 bit stream of ones and zeroes , where the boundary between network and host portions can fall anywhere between bit 0 and bit 31.Classless addressing system is also known as CIDR(Classless In ter-Domain Routing).Classless addressing is a way to allocate and specify the In ternet addresses used in inter-domain routing more flexibly than with the origin al system of Internet Protocol (IP) address classes.CIDR (Classless Internet Dom ain Routing), defines arbitrarily-sized subnets solely by base address and numbe r of significant bits in the address. A CIDR address of defines a block of addresses in the range through, while 192.16 8.0.0/20 would define a network 16 times as large - from through 192 .168.15.255.

What Is a Subnet Mask? A subnet mask is a number that looks like an IP address. It shows TCP/IP how man y bits are used for the network portion of the IP address by covering up, or masking, the IP address s network portion.

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