CCNA 2 v6.0 Final Exam Answers 2018 – Routing & Switching Essentials

IP addresses used for peerings

CCNA Routing & Switching 200-120
See All Related Articles. Become a member to interact with all questions and read all tutorials, labs! The number is the count of leading 1 bits in the subnet mask. The number of available subnets is 2 n , where n is the number of bits used for the network portion of the address. CIDR is principally a bitwise, prefix-based standard for the representation of IP addresses and their routing properties. Which characteristic describes cut-through switching? ExpressRoute cannot be configured as transit routers.

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Networking 101: Understanding Subnets and CIDR

This connectivity allows the network to react quickly when it must route data flow from a downed link to another path. For a small core with a limited number of divisions, this core layer design provides robust connectivity. However, a fully meshed core layer design is very expensive for a corporation with many divisions. As the number of routers increases, the cost of full-mesh connectivity might become prohibitive. As a network grows, fully meshing all the core routers can become difficult.

At that point, consolidation into geographically separate data centers might be appropriate. For example, in many companies, data travels to a centralized headquarters where the corporate databases and network services reside.

To reflect this corporate centralization, the core layer hub-and-spoke configuration establishes a focal point for the data flow at a key site. The hub-and-spoke design, illustrated in Figure , supports the traffic flow through the corporation. A partial-mesh design is also possible, including some nodes connected in a full mesh and some connected in hub-and-spoke fashion.

Remote sites are points of entry to the network for end users and customers. Within the network, remote sites gain access to network services through the access layer. The distribution layer consolidates the services and devices that the access layer needs to process the activity that is generated by the remote sites.

Figure illustrates this process. Frame Relay, shown in Figure , is a WAN access protocol commonly used to interconnect geographically dispersed sites.

Services should be placed in the distribution layer when there is no benefit to having duplicated services at the remote sites. You can fully mesh connectivity between remote sites at the access layer. However, using a hub-and-spoke configuration by connecting remote sites to at least two distribution layer devices provides redundancy and is relatively easy to administer.

An effective network design accommodates unexpected growth and quick changes in the corporate environment. The network design can be adapted to accommodate mergers with other companies, corporate restructuring, and downsizing with minimal impact on the portions of the network that do not change. The following are characteristics of a good IP addressing plan implemented in a well-designed network:. Private addresses are reserved IPv4 addresses to be used only internally within a company's network.

These private addresses are not to be used on the Internet, so they must be mapped to a company's external registered address when you send anything to a recipient on the Internet. The current proliferation of corporate mergers emphasizes the design issues inherent in private IPv4 addressing. For example, if two companies merge, and both use network A scalable network that integrates private addressing with a good IP addressing plan minimizes the impact of additions or reorganizations of divisions to a network.

A scalable network allows companies that merge to connect at the core layer. Implementing NAT on routers allows the network administrator to translate overlapping network numbers to an unused address space as a temporary solution.

Good network design also facilitates the process of adding routers to an existing network. For example, in Figure , two companies have merged. Both companies were using network One correct way to merge the two networks would be as follows:. Routers B and E each have two best paths to the networks behind router X: Both have two hops through either routers A or D.

If router D fails, routers B and E do not need to discover alternative routes because the preferred route exists in the routing table. Thus, if router D fails, the routes to X in router C's routing table do not change.

If a routing protocol that uses bandwidth in its calculation is used for example, Interior Gateway Routing Protocol [IGRP] , the bandwidth should be configured equally on all interfaces within a layer at each site.

For example, in Figure , routers B and E are consolidation points for the access layer routers G, C, and F in the example. The paths between routers B and E and routers A and D need larger-bandwidth pipes to consolidate the traffic between corporate divisions.

The result is a predictable traffic pattern. This level of network behavior predictability is a direct benefit of a scalable network design. A scalable network also needs to be flexible. For example, corporate reorganizations can have minimal impact on the rest of the network when implemented in a scalable network.

In the sample network shown in Figure , assume that Frame Relay is used at the remote sites and that Division Beta is sold and merged with another company, except for remote site H, which becomes part of Division Alpha.

The network administrator in this sample network could accommodate the corporate reorganization with the following process:. Perhaps the best-known addressing hierarchy is the telephone network. The telephone network uses a hierarchical numbering scheme that includes country codes, area codes, and local exchange numbers.

For example, if you are in San Jose, California, and you call someone else in San Jose, you dial the San Jose local exchange number, , and the person's four digit number.

Upon seeing the number , the central office recognizes that the destination telephone is within its area, so it looks up the four digit number and transfers the call. In many places in North America now, the area code must also be dialed for local calls. This is because of changes in the use of specific digits for area codes and local exchange numbers. The telephone network is suffering from address exhaustion , just like the IP network.

Outside MCI's network, the Within MCI's network, Only within the ARS corporate network would the In common usage, the first address in a subnet, all binary zero in the host identifier, is reserved for referring to the network itself, while the last address, all binary one in the host identifier, is used as a broadcast address for the network; this reduces the number of addresses available for hosts by 2.

The large address size used in IPv6 permitted implementation of worldwide route summarization and guaranteed sufficient address pools at each site. This IPv6 subnetting reference lists the sizes for IPv6 subnetworks. Different types of network links may require different subnet sizes. Selecting a smaller prefix size results in fewer number of networks covered, but with more addresses within those networks. CIDR provides fine-grained routing prefix aggregation. This reduces the number of routes that have to be advertised.

From Wikipedia, the free encyclopedia. Redirected from IPv4 subnetting reference. For other uses, see CIDR disambiguation. Internet Standard Subnetting Procedure. Broadcasting Internet Datagrams in the Presence of Subnets. Requirements for IP Version 4 Routers. Retrieved from " https: Webarchive template wayback links. Views Read Edit View history. This page was last edited on 7 September , at By using this site, you agree to the Terms of Use and Privacy Policy.

Largest IANA block allocation. Actually the first available one is the subnet-zero which we explicitly note. The following table provides all the calculated information. Don't get discouraged if you didn't understand every little detail I went over in this article. Subnetting is not really that difficult, but it does require a bit of practice. Start with testing your knowledge of subnets and make sure you feel confident about this before you move on to designing your own subnets.

But remember, if you're on the Cisco Networking track you will have to deal with subnetting sooner or later, so grab this opportunity and start testing yourself. Go ahead and subnet the network address Find the valid subnets, host ranges and broadcast addresses per subnet. If you want to double-check your answer, feel free to leave me a comment and I will provide you with the correct solution.

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Simplify Routing with Subnetting: The Subnetting Concept You will be surprised how easy the concept of Subnetting really is. Subnetting a Class C Address Using the Binary Method We will use a Class C address which takes 5 bits from the Host field for subnetting and leaves 3 bits for defining hosts as shown in figure 1 below.

The following diagram clearly illustrates this process: Calculate the Total Number of Subnets and Hosts Per Subnet Knowing the number of Subnet and Host bits we can now calculate the total number of possible subnets and the total number of hosts per subnet. The steps to perform this task are the following: Note that our IP address Get our content first.

CCNA 200-125