Ccna Switching

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Wediscussed the CSMA/CD in the chapter on Ethernet, we said that the LAN networks operate using several rules. In this type of communications, devices on the same Ethernet segment usually listen to the network media to determine if they can transmit or whether they have to wait. With hubs, only one device could transmit at a time, however, with switches, multiple devices can use the media at the same time.

With unicast communication, a frame is usually sent from one node to a specific destination. In this mode, there is only one sender and one recipient. This means that the sender and the recipient as well as the switch in the middle must know about one another. In modern LANs, this is the most common form of communication especially on the internet using protocols such as HTTP, Telnet and others.

In multicast communication, the sender usually transmits a frame to a group of nodes on the Ethernet segment. The type of protocol in use can typically determine whether multicast is used. In a teleconferencing call for example, a user may need to communicate with three other users simultaneously. In this case, multicast messages will be sent.

In case a user node needs certain information and it does not know who has the specific information, it may use broadcast type of communication. In this case, a frame is usually sent to all the devices on the same LAN. This communication is also useful if the message being communicated is meant for a large audience.

In the Ethernet, the type of addressing used is the physical address which is typically the MAC address. This is the address that is used to communicate frames. When packets are received from the network layer, they are encapsulated into frames. This includes adding information such as the source and destination MAC address.

The OUI consists of the first 24 bits of the MAC address. It is usually the code that has been assigned by the IEEE to a particular vendor. In CISCO switches for example, the OUI is usually: 0009.7C

In this type of communication, transmission of data is only one way, this means a device can either send or receive frames and not both. When HUBs were common in networks this was the communication that was used. This type of communication can be likened to using a walkie-talkie where you can either talk or listen but not both. While using the half duplex communication, the likelihood of collisions is high, therefore, CSCMA/CD is used to minimize them.

Full duplex communication provides for bidirectional flow of data. This means that devices using this type of mode, can send and receive frames at the same time. In modern switches, this is usually the default mode of operation. The chances for collisions are minimal.

When we were discussing the operation of routers, we said that the forwarding decisions routers make are based on the information in the routing table. Similarly, the switches also have a database that contains addresses. This database is called the MAC-Address table and it is the basis by which switches forward frames.

We have learnt of the IOS configuration modes as well as the basic configuration in a previous chapter. We saw the different modes as the user executive mode, the privileged executive mode, the global configuration mode and various specific configuration modes such as the interface configuration. In this section, we will configure some of the basic options in a switch which include:

On more modern switches such as the CISCO 2960 switch which is the one we are using, the CISCO IOS is used, this is unlike older switches such as the catalyst switches. Therefore, most of the configuration commands we will use are similar to those used when we were configuring routers.

The banner is a message displayed when someone tries to access the switch, with a message. We discussed some of the reasons that may make an administrator want to use a banner. In our case, we will use a banner MOTD which is configured using the command:

When we were configuring routers, we noticed that to access the router remotely using the vty lines, we used an ip address. In switches, we need to configure an ip address, subnet mask and a default gateway much like a PC, the ip address is used to manage the switch.

To enable management of the switch via a management interface, we need to create a management VLAN and assign it a management ip address. In our case we will use the VLAN 99 and issue it with an ip address of 192.168.99.1, this will allow the switch to be managed remotely via telnet lines.

Step 1. Create the management VLAN interface, which is VLAN 99. Creation of VLANS will be discussed in more detail in the next chapter. However, the command we will use in this case is:

Step 3. On one of the switch interfaces, we need to link it to VLAN 99 management vlan, this is done as shown below. These concepts and commands will be discussed in part 2 of this chapter and also the chapter on VLANs.

In part 2 of this chapter, we will look at a few more concepts on switching and configure more options such as port security, we will also take a look at the various verification and troubleshooting commands that can be used on switches.

In this entry-level Cisco CCNA Routing and Switching training, Jeremy Cioara covers the objectives in the 100-105 ICND1 and 200-105 ICND2 exams, the two required exams to earn the CCNA Routing and Switching certification.

This 200-105 ICND2 course is valuable for new IT professionals with at least a year of experience with routing and switching and experienced network technicians looking to validate their Cisco skills.

Routing and Switching Pro helps you prepare students for Cisco Network Admin careers through an engaging, all-in-one training experience performing common tasks in a networked environment. Through easy-to-use technology, students will develop hands-on skills using up-to-date software to gain the knowledge and confidence needed to certify and obtain employment.

It's challenging to create a true-to-life Cisco environment in the classroom that replicates the real world. TestOut Routing and Switching Pro enables students to learn in a networked office where they can start practicing on day one.

Routing and Switching Pro features a simulated Cisco terminal integrated with networked devices. Students will perform typical network configurations to optimize, troubleshoot, and secure Cisco routing and switching devices.

Routing and Switching Pro eliminates the need to invest in physical equipment, grade screenshots, or install software. With so many features and hands-on labs, using Routing and Switching Pro is a smart choice.

Routing and Switching Pro simulates more than $200,000 in hardware and software integrated into a fully networked office campus that replicates the environments your students will experience as professionals working for large companies.

In short, TestOut Routing and Switching Pro not only saves you time and money, it will help you elevate any lesson plan and give your students the quality education that employers want, and make them stand out over all the others."

"Want to get up to your neck in Cisco software and technology for routers and switches? If so, I highly recommend the TestOut Routing and Switching Pro course. This course not only covers the content needed to earn your CCNA certification, but it gives you almost 100 different labs that simulate some of the most common network configurations you will find in the industry. Real world, in-depth labs and many practice test questions are just a couple of the reasons you should take this course. I have never seen another training program with such quality virtual labs that TestOut has, that coincide with the objectives of an industry certification, without having to buy expensive equipment to train on. This self paced course will save you time and money. What are you waiting for? Take your IT training to the next level."

Achieving your Cisco Certified Networking Associate, or CCNA, certification requires more than just studying. Instead, it takes a true in-depth understanding of network fundamentals and network security technologies covered in the CCNA material as outlined by Cisco. Our updated CCNA practice test has been redesigned to reflect the Cisco CCNA Routing and Switching 200-125 requirements found in the ICND1 and 2 version 3.0 curriculum.

With the 200-125 CCNA Routing and Switching exam that launched in mid-2016, Cisco made some much-needed changes to steer the certification away from topics covered in previous exams, such as frame relay, and focus more on modern routing and switching technologies.

A few of the major changes included an added emphasis on cloud computing and supplementary network services, such as DNS, Dynamic Host Configuration Protocol (DHCP) and Network Time Protocol (NTP). Additionally, Cisco added more Border Gateway Protocol (BGP) topics to the exam material. Lastly, you'll likely notice an increased focus on modern WAN technologies, including dynamic multipoint VPN and site-to-site VPN connectivity options.

This CCNA practice test covers the appropriate range of topics you can expect when taking the CCNA Routing and Switching exam. The practice questions are in no particular order and provide a realistic example of what you should expect.

As we learned in the previous lesson, the first step in switches' operational logic is to receive an Ethernet frame from the transmitting node. Depending on the type of switching methodology in use, the switch needs to receive and examine a different number of bytes before going to the next operational step and ultimately switch the frame to the outgoing port or ports. There are two main switching modes supported on Cisco switches:

Both switching modes base their forwarding decisions on the destination MAC address of the Ethernet frames. They also learn MAC addresses and build their MAC tables as they examine the source MAC address (SMAC) fields in the Ethernet header as frames are being forwarded. These switching modes differ in how much of the frame must be received and examined by the switch before the frame start being forwarded out the egress port.

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