Routing and Switching Essentials. Companion Guide. Cisco Networking Academy. Cisco Press. East 96th Street. Indianapolis, Indiana USA. Routing and Switching Essentials Companion Guide CCNA Routing and Switching Complete Study Guide Exam , Exam , Exam Routing and Switching Essentials Companion Guide - Ebook download as PDF File .pdf), Text File .txt) or read book online. Routing and Switching Essentials.

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Routing and switching essentials companion guide By Cisco answers to the Reflection questions on the PDF contained in the online course. Ebook [site] ROUTING & SWITCHING ESSENTIALS (Companion Guide) PDF Ebook Full Series. DETAIL Author: Cisco Networking. 34 Routing and Switching Essentials Companion Guide brute force password Reflection questions on the PDF contained in the online course. Save your work .

This results in substantial savings over the installation and management of separate voice, video, and data networks. Such a converged network solution integrates IT management so that any moves, additions, and changes are completed with an intuitive management interface.

A converged network solution also provides PC softphone application support, as well as point-to-point video so that users can enjoy personal communications with the same ease of administration and use as a voice call.

Chapter 1: Introduction to Switched Networks 39 Figure Network Traffic Convergence The convergence of services onto the network has resulted in an evolution in networks from a traditional data transport role, to a super-highway for data, voice, and video communication. This one physical network must be properly designed and implemented to allow the reliable handling of the various types of information that it must carry. A structured design is required to allow management of this complex environment.

Play the online video to view a few of the collaboration services in action. Video Video 1. Click on the second graphic, and play the video to see how people can work more efficiently with collaboration tools.

Borderless Switched Networks 1. One of the more recent developments in network design is illustrated by the Cisco Borderless Network architecture illustrated in Figure The Cisco Borderless Network is a network architecture that combines several innovations and design considerations to allow organizations to connect anyone, anywhere, anytime, and on any device securely, reliably, and seamlessly.

This architecture is designed to address IT and business challenges, such as supporting the converged network and changing work patterns. It enables different elements, from access switches to wireless access points, to work together and allow users to access resources from any place at any time, providing optimization, scalability, and security to collaboration and virtualization.

It was not long ago that flat Layer 2 switched networks were the norm. Activity 1. Flat Layer 2 data networks relied on the basic properties of Ethernet and the widespread use of hub repeaters to propagate LAN traffic throughout an organization.

As shown in Figure It is important to deploy the appropriate types of switches based on network requirements. Table highlights some common business considerations when selecting. This is important for switches that are mounted in a rack. Features and options are limited to those that originally come with the switch.

For example. In addition to PoE considerations. Power It is now common to power access points. Port density Network switches must support the appropriate number of devices on the network.

Figure Fixed Configuration Switches. Reliability The switch should provide continuous access to the network. Frame buffers Scalability The capability of the switch to store frames is important in a network where there may be congested ports to servers or other areas of the network.

Routing and Switching Essentials v6 Companion Guide

Port speed The speed of the network connection is of primary concern to the end users. When selecting the type of switch. These options are sometimes referred to as switch form factors.

The number of users on a network typically grows over time. Another consideration is the thickness of the switch. IP phones. Figure Modular Configuration Switches Stackable Configuration Switches Stackable configuration switches can be interconnected using a special cable that provides high-bandwidth throughput between the switches Figure Stackable switches are desirable where fault tolerance and bandwidth availability are critical and a modular switch is too costly to implement.

Switches can be stacked one on top of the other with cables connecting the switches in a daisy chain fashion.

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The stacked switches effectively operate as a single larger switch. Cisco StackWise technology allows the interconnection of up to nine switches. The line card fits into the switch chassis the way that expansion cards fit into a PC. Modular configuration switches typically come with different sized chassis that allow for the installation of different numbers of modular line cards Figure The particular model determines the features and options available.

There can be many different chassis sizes to choose from. The larger the chassis. A modular switch with a port line card supports an additional port line card.

The line cards actually contain the ports. There are typically different configuration choices that vary in how many and what types of ports are included with a fixed configuration switch. Modular Configuration Switches Modular configuration switches offer more flexibility in their configuration.

Various types of switches are used in LANs. The Switched Environment 1. Identify Switch Interactive Graphic Hardware Go to the online course to match the term to the switch selection criteria. Introduction to Switched Networks 49 cross-connected connections.

Learning how switches operate is important to someone entering the networking profession. Stackable switches use a special port for interconnections. Frame Forwarding 1. Switches receive a frame from the source device and quickly forward it toward the destination device.

Many Cisco stackable switches also support StackPower technology. Figure Stackable Configuration Switches Activity 1. The term egress is used to describe frames leaving the device through a particular port. Interactive Graphic Activity 1. A LAN switch maintains a table that it uses to determine how to forward traffic through the switch. Click the Play button to begin. In the animated example: The fundamental concept of switching refers to a device making a decision based on two criteria: The term ingress is used to describe a frame entering a device on a specific port.

A switch is made up of. When a switch makes a decision.

With a LAN switch. The only intelligence of the LAN switch is its capability to use its table to forward traffic based on the ingress port and the destination address of a message. CAM is a special type of memory used in high-speed searching applications. Introduction to Switched Networks 51 integrated circuits and accompanying software that controls the data paths through the switch.

In networks with multiple interconnected switches. The switch uses the information in the MAC address table to send frames destined for a specific device out the port. An easy way to remember how a switch operates is the following saying: For a switch to know which port to use to transmit a frame. As frames enter the switch. The following steps describe the process of building the MAC address table: How To Step 1.

To forward the frame. The switch receives a frame from PC 1 on Port 1 Figure As the switch learns the relationship of ports to devices. If the address is in the table. After the switch has recorded the source address information. MAC Table: Pnrt 1: Empty Port 3: S1 Broadcasts the Frame. Port 1: An entry for a MAC address is typically kept for five minutes. The switch can now forward frames between these source and destination devices without flooding because it has entries in the address table that identify the associated ports Figure Introduction to Switched Networks 53 Step 4.

The switch enters the source MAC address of PC 3 and the port number of the ingress port into the address table.

The destination address of the frame and its associated egress port is found in the MAC address table Figure Ethernet bridges an early version of a switch were added to networks to limit the size of the collision domains. This term distinguished it from cut-through switching. Video Video 1. This method of forwarding data frames at Layer 2 was referred to as store-and-forward switching. ASICs reduce the packet-handling time within the device.

Store-and-Forward Switching Go to the course online to see an animation of how a store-and-forward switch works. In the s. As shown in the online video. By contrast. Figure Store-and-Forward Switching Automatic Buffering The ingress port buffering process used by store-and-forward switches provides the flexibility to support any mix of Ethernet speeds. The FCS is an error checking process that helps to ensure that the frame is free of physical and data-link errors.

Introduction to Switched Networks 55 Video Video 1. Click on the second graphic to see an animation of how a cutthrough switch works. After receiving the entire frame on the ingress port. If the frame is error-free. Cut-Through Switching Go to the course online. Store-and-Forward Switching 1. Error Checking A switch using store-and-forward switching performs an error check on an incoming frame.

With any mismatch in speeds between the ingress and egress ports. A store-and-forward switch drops frames that do not pass the FCS check. Cut-Through Switching 1. There are two primary characteristics of cut-through switching: Rapid Frame Forwarding As indicated in Figure The switch does not have to wait for the rest of the frame to enter the ingress port before making its forwarding decision.

This means each frame will be checked into the data field to make sure no fragmentation has occurred. Fragment Free Fragment free switching is a modified form of cut-through switching in which the switch waits for the collision window 64 bytes to pass before forwarding the frame. If there is a high error rate invalid frames in the network. The network segments that share the same bandwidth between devices are known as collision domains. With a lower latency speed advantage of cut-through switching.

Switch It! Go to the course outline to perform this practice activity where you have multiple scenarios of frames going through a switch.

This section tries to explain these two important concepts that affect LAN performance. Frame Forwarding Methods Go to the online course to indicate whether each given action is performed by storeand-forward or cut-through switching. Select how the switch will handle the frame. Use the online curriculum to check your answer. Fragment free mode provides better error checking than cut-through.

Introduction to Switched Networks 57 The cut-through switching method does not drop most invalid frames. Interactive Graphic Interactive Graphic Activity 1. Switching Domains 1. Collision Domains 1. Frames with errors are forwarded to other segments of the network. For other switches on the LAN to receive broadcast frames. Figure Collision Domains Broadcast Domains 1. More bandwidth is available to the devices on a segment. A frame with a destination MAC address of all binary ones is received by all devices in the broadcast domain.

A collection of interconnected switches forms a single broadcast domain. When a device sends a Layer 2 broadcast.

Routers are used to segment both collision and broadcast domains. This is also known as microsegmentation. The result is that each port represents a new collision domain.

A network layer device. Each port on a switch is a new segment because the devices plugged into the ports do not compete with each other for bandwidth. As shown in the Figure Network bandwidth is used to propagate the broadcast traffic. Watch how a switch broadcasts a frame out all ports except the port that received the frame. Broadcasts are sometimes necessary for initially locating other devices and network services. The frame is then also propagated to all devices connected to switch S2.

In this case. Broadcast Domains Go to the online curriculum. When a switch receives a broadcast frame. Too many broadcasts and a heavy traffic load on a network can result in congestion: Each device connected to the switch receives a copy of the broadcast frame and processes it.

Switch S1 is connected to switch S2. Fast internal switching Having fast internal forwarding capabilities allows high performance. Each port of the switch represents a separate collision domain and provides the full bandwidth to the device or devices that are connected to that port.

A full-duplex connection can carry transmitted and received signals at the same time. Large frame buffers The ability to store more received frames before having to start dropping them is useful. The method that is used may be a fast internal bus or shared memory. For this reason. LAN switches can accommodate network designs featuring fewer users per segment.

Circle the Domain Go to the online course to view nine network topologies. Table shows some important characteristics of switches that contribute to alleviating network congestion. Low per-port cost Switches provide high-port density at a lower cost. Switches interconnect LAN segments collision domains. Large enterprise switches may support hundreds of ports. Port speed Depending on the cost of a switch. On each graphic. Save your work and be ready to justify your device decisions and layout to your instructor and the class.

Introduction to Switched Networks 61 Summary 1. Work with a classmate to create two network designs to accommodate the following scenarios: Scenario 1.

All intermediary devices should be labeled with the switch model or name and the router model or name. Go to the course outline to perform this practice activity. Your tasks include configuring initial settings on two switches using the Cisco IOS and configuring IP address parameters on host devices to provide end-to-end connectivity. Internet connectivity is not required in this design. This Syntax Checker activity reviews basic switch configurations from the first course. Before this can be accomplished.

Store-and-forward reads the entire frame into a buffer and checks the CRC before forwarding the frame.

In these networks. If the destination MAC address is contained in this table. Every port on a switch forms a separate collision domain allowing for extremely highspeed full-duplex communication.

The traditional three-layer hierarchical design model divides the network into core. Resources must now be seamlessly available anytime and anywhere. In some networks. Switch ports do not block broadcasts. Although this is extremely fast. In addition. Switches use either store-and-forward or cut-through switching. Practice The following activities provide practice with the topics introduced in this chapter.

No longer are employees constrained to physical offices or by geographic boundaries.

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The Cisco Borderless Network architecture enables different elements. It provides modularity. Cut-through switching only reads the first portion of the frame and starts forwarding it as soon as the destination address is read.

Sent or Received Instructions Class Activity 1. Which hierarchical network design goal is to provide a way for the network to always be accessible? Skills Integration Challenge Check Your Understanding Questions Complete all the review questions listed here to test your understanding of the topics and concepts in this chapter. Which three options correctly associate a layer of the hierarchical design model with the function of that layer?

Choose three. The appendix. Which two layers of the hierarchical network design model are commonly combined into a single layer in a small-to-medium sized network architecture? Choose two. Implementation of an access-distribution-core layer design model for all sites in a corporation. What is convergence as it relates to network design? PC2 connects to port 2. Network design is simplified. Designing a network in such a way that each tier has a specific function and upgrade path 5.

Modular configuration switch. The switch forwards the frame to all switch ports including ports 1 and 2. The combining of voice and video with traditional network traffic D. Layer 3 D. Which two terms are correctly defined? PC1 connects to port 1. A centralized point in the network design where all traffic aggregates before transmission to the destination C. What function is most likely to be provided by a Cisco access layer switch? Voice and data support staff are combined.

A switch has just been powered on. Internal switching rate. What are three benefits of a converged network?

Rack unit. Network moves. Layer 1 B. Layer 2 C. Port density. Network configuration is simplified. Cut-through switching.

Maintenance is simpler than hierarchical networks. If PC1 sends data to PC2. Layer 4 8. Forward the data out all ports. Forward the data to port 5. Fault isolation Routing C. Forward the data out all ports except for port 4. When the switch receives the data. Introduction to Switched Networks 65 A. PoE B. Link aggregation D. You can find the definitions in the Glossary. In a properly designed network. Cisco switches are self-configuring and no additional configurations are necessary for them to function out of the box.

Scenario 3: Students with the number C should stand. Switches need to be configured to be resilient to attacks of all types while they are protecting user data and allowing for high speed connections.

Record the number of the standing student. This includes adjusting port speed and bandwidth. This chapter examines some of the basic switch configuration settings required to maintain a secure. The access layer is one of the most vulnerable areas of the network because it is so exposed to the user.

Stand by Me Scenario When you arrived to class today. Port security is one of the security features Cisco managed switches provide. Record the numbers of the standing students.

Chapter 2: Basic Switching Concepts and Configuration 35 Introduction 2. Cisco switches run Cisco IOS. When class begins. Scenario 1: Students with numbers starting with the number 5 should stand. Cisco switches can be managed both locally and remotely. Switches operate at the access layer where client network devices connect directly to the network and IT departments want uncomplicated network access for the users.

LAN switches are responsible for directing and controlling the data flow at the access layer to networked resources. Scenario 2: Students with numbers ending in B should stand.

At the end of this activity. These are just two of the configurations discussed in this chapter. To remotely manage a switch. Save your work and be prepared to share it with another student or the entire class. If this variable is not set. Configuring them can be fun and challenging. The boot loader finds the Cisco IOS image on the switch using the following process: The switch attempts to automatically boot by using information in the BOOT environment variable. On Catalyst Series switches.

Step 5. Knowing how switches normally boot and load an operating system is also important. Step 2. It initializes the CPU registers that control where physical memory is mapped. Step 3. Step 4. The boot loader performs low-level CPU initialization. The boot loader initializes the flash file system on the system board.

In Figure It tests the CPU. In a depth-first search of a directory. Reconnect the power cord to the switch and within 15 seconds press and hold down the Mode button while the System LED is still flashing green. The boot loader command line supports commands to format the flash file system.

The boot loader switch: The boot loader can be accessed through a console connection using these steps: The boot loader has a command line that provides access to files stored in flash memory.

Configure terminal emulation software to connect to the switch. Unplug the switch power cord. Connect a console cable from the PC to the switch console port. You can use the switch LEDs to quickly monitor switch activity and its performance. The Mode button is used to toggle through port status. Switches of different models and feature sets will have different LEDs. If the port LED is green. If the LED is blinking amber. If the LED is off. If the port LED is alternating green-amber. If the LED is amber.

If the LED is green. PoE is off due to a fault. When selected. PoE is off. If the LED is blinking green. If the port LED is off. This is the default mode. PoE is denied because providing power to the powered device will exceed the switch power capacity. PoE is being provided to a device. Power over Ethernet If PoE is supported.

PoE for the port has been disabled. If the LED is alternating green-amber. The SVI is a virtual interface. All ports are assigned to VLAN 1 by default. This is very similar to configuring the IP address information on host devices. VLANs are numbered logical groups to which physical ports can be assigned. Keep in mind that to manage the switch from a remote network. For security purposes. By default.

Note These IP settings are only for remote management access to the switch. The no shutdown command enables the interface. Sl config-if ip address Sl config interface vlan 99 Configure address. Sl config-if end Save the running config to the startup config. Sl copy running-config startup-config In this example.

Routing and Switching Essentials v6 Companion Guide by Cisco Networking Academy

S1 configure terminal Enter interface configuration mode for the SVI. As shown in Table The ip address command is used to configure the IP address. Configure the Management Interface. This address is the default gateway address for S1.

As shown in Table and Figure The interface on R1 connected to the switch has IP address The default gateway is the first Layer 3 device such as a router on the same management VLAN network to which the switch connects. Configure the Default Gateway. R1 is the default gateway for S1. Sl config ip default-gateway Enter the IP address of the default gateway.

Sl config end Save the running config to the startup config. Verify the Configuration. The default gateway is the IP address of the router interface to which the switch connects. Use the following command to backup the configuration: S1 configure terminal Configure the switch default gateway.

The switch will forward IP packets with destination IP addresses outside the local network to the default gateway. Basic Switch Configuration mr In this lab. This results in a micro size collision domain of a single device. Sometimes switch ports must manually have their duplex mode and speed manually configured. Sending and receiving data does not occur at the same time.

There are also times when things go awry and there are issues. In full-duplex mode. This method of optimizing network performance requires micro-segmentation. Full-duplex communication has replaced half-duplex in most hardware. A micro-segmented LAN is created when a switch port has only one device connected and is operating at full-duplex.

Unlike full-duplex communication.

Because there is only one device connected. This section helps you with these basic concepts. Most of the time the technician simply connects a cable and lets the network device and switch automatically negotiate these parameters. Frames that are sent by the two connected devices cannot collide because the devices use two separate circuits in the network cable. Half-duplex communication creates performance issues because data can flow in only one direction at a time.

Half-duplex connections are typically seen in older hardware. This is also known as bidirectional communication. Full-duplex connections require a switch that supports full-duplex configuration. This results in a percent potential use of the stated bandwidth.

Use the duplex interface configuration mode command to manually specify the duplex mode for a switch port. Configure Switch Ports at the Physical Layer 2. Full-duplex offers percent efficiency in both directions transmitting and receiving. Duplex and Speed Switch ports can be manually configured with specific duplex and speed settings. This section examines how to configure specific parameters on a Cisco switch port and introduces auto-MDIX.

In Figure and Table Use the speed interface configuration mode command to manually specify the speed for a switch port. Basic Switching Concepts and Configuration 45 of the stated bandwidth. Figure Manually Configure Duplex and Speed. Auto negotiation failure creates mismatched settings. When connecting to switches without the auto-MDIX feature. S1 configure terminal Enter interface configuration mode.

When auto-MDIX is enabled. All fiber optic ports. Switch-to-switch or switch-to-router connections required using different Ethernet cables. When troubleshooting switch port issues. Cisco recommends using the auto command for duplex and manually configuring interface speed using the speed command in order to avoid connectivity issues between devices.

Note Mismatched settings for the duplex mode and speed of switch ports can cause connectivity issues. Auto-MDIX 2. Using the automatic medium-dependent interface crossover auto-MDIX feature on an interface eliminates this problem. Interactive Graphic Activity 2. Sl config-if duplex full Configure the interface speed.

Sl copy running-config startup-config The default setting for both duplex and speed for switch ports on Cisco Catalyst and switches is auto. Basic Switching Concepts and Configuration 47 workstations. To limit the output to lines referencing auto-MDIX. Sl copy running-config startup-config Note The auto-MDIX feature is enabled by default on Catalyst and Catalyst switches but is not available on the older Catalyst and Catalyst switches.

On newer Cisco routers and switches. With auto-MDIX enabled. Crossover cables must be used to connect a switch to another switch or repeater.

Figure shows the topology. When using auto-MDIX on an interface. To examine the auto-MDIX setting for a specific interface. Sl config-if duplex auto Configure the interface to automatically negotiate speed with the connected device. S1 show startup-config Display current operating configuration. S1 show flash: Display status of system hardware and software. As seen in the output for S1. Table Switch Verification Commands Display interface status and configuration.

Verifying Switch Port Configuration 2. S1 show ip [infdre-id-ed] Display the MAC address table. S1 show history Display IP information about an interface.

S1 show version Display a history of commands entered.

Use this command to verify that the switch has been correctly configured. S1 show interfaces [interface-id] Display current startup configuration. S1 show mac-address-table OR S1 show mac address-table Look at the sample abbreviated output from the show running-config command.

S1 show running-config Display information about the flash file system. The show interfaces command is frequently used when configuring and monitoring network devices. Total output drops: DLY usec. Current configuration: ARP Timeout The following output and Table indicate the summary line to check the status of an interface. One of the most important parts of this output is the display of the line and data link protocol status.

Based on the output of the show interfaces command. The second parameter line protocol is up refers to the data link layer and reflects whether the data link layer protocol keepalives are being received.

There could be an encapsulation type mismatch. Runts Packets that are discarded because they are smaller than the minimum packet size for the medium. Giants Packets that are discarded because they exceed the maximum packet size for the medium. Output Errors The sum of all errors that prevented the final transmission of datagrams out of the interface that is being examined. Table explains some of these common errors that can be detected using the show interfaces command.

It includes runts. Late Collisions A collision that occurs after bits of the frame have been transmitted. BW Kbit. Collisions The number of messages retransmitted because of an Ethernet collision. For instance. The following output shows an example of show interfaces command.

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In that case. Giants are caused by the same issues as those that cause runts. Malfunctioning NICs are the usual cause of excessive runt frames. Troubleshooting Network Access Layer Issues 2. On Ethernet and serial interfaces. You should also search for and eliminate noise sources. To troubleshoot these issues when you have no connection or a bad connection between a switch and another device.

The reported input errors from the show interfaces command include the following: Ethernet frames that are shorter than the byte minimum allowed length are called runts. Ethernet frames that are longer than the maximum allowed length are called giants. You would see late collisions on the interface that is configured for half-duplex. A late collision refers to a collision that occurs after bits of the frame the preamble have been transmitted. This includes runts. Common causes include electrical interference.

Another common cause is duplex misconfiguration. CRC errors usually indicate a media or cable error.

Excessive cable lengths are the most common cause of late collisions. Ongoing maintenance and troubleshooting of the network infrastructure is required. If you see many CRC errors. It is highly recommended that you use full-duplex unless you have older or legacy equipment that requires half-duplex. The reported output errors from the show interfaces command include the following: Collisions in half-duplex operations are completely normal. A properly designed and configured network should never have late collisions.

The speed of an interface is typically auto-negotiated. If there does appear to be a duplex mismatch. It is recommended to use full-duplex if both sides support it. Indications may include an increase in the counters for runts.

If a bad or incorrect cable is suspected. If the interface is down: If a speed mismatch does occur through miscon. Much like the speed setting. For copper cable. If there is excessive noise.

If the interface is up. Manually set the same speed on both connection ends if an auto negotiation problem is suspected. If there are collisions or late collisions. In the following output BBoobb Password: Learning the different methods used to secure a switch is important.

SSH should replace Telnet for management connections. A Telnet stream can be targeted to capture the username and password.. SSH provides security for remote connections by providing strong encryption when a device is authenticated username and password and also for the transmitted data between the communicating devices. Management and Implementation By understanding the attacks and the available tools and countermeasures.. Telnet has already been covered.. Telnet is an older protocol that uses insecure plaintext transmission of both the login authentication username and password and the data transmitted between the communicating devices.

Secure Remote Access The attacker can track the session using the IP address of the administrator device.

Also important is learning the types of attacks that can be launched on. Telnet is assigned to TCP port Look at the online course. User Access verification username: SI configure terminal Sl config ip domain-nama cisco. A longer modulus length is more secure. If the switch is not running an IOS that supports cryptographic features.

Use the show ip ssh command to verify that the switch supports SSH. When generating RSA keys. Configure the IP domain name of the network using the ip domainname domain-name global configuration mode command.

Cisco recommends a minimum modulus size of bits refer to the sample configuration in Figure After the RSA key pair is deleted. In the following output. Note To delete the RSA key pair. Use the crypto key generate rsa global configuration mode command to enable the SSH server on the switch and generate an RSA key pair. Version Using the configuration from the previous example. Use the line vty global configuration mode command and then the login local line configuration mode command to require local authentication for SSH connections from the local username database.

The SSH server can authenticate users locally or using an authentication server. For the examples in Figures to The Catalyst has vty lines ranging from 0 to To use the local authentication method. In the example. Verifying SSH 2. After entering the correct combination. Enable the SSH protocol on the vty lines using the transport input ssh line configuration mode command. SSH version 2 is enabled.

To check the SSH connections to the device. Common Security Attacks: With this information an attacker can launch further attacks or even insert a rogue device. By examining downloaded frames. This section introduces the types of attacks and countermeasures to be performed on a wired LAN.

The more aware networking professionals within an organization are. In this activity. SSH provides security for remote connections by providing strong encryption of all transmitted data between devices. Security is a layered process that is essentially never complete. Telnet uses insecure plaintext communications.Switch config-if transport input ssh.

Figure shows a two-tier campus network design example for an enterprise campus where the distribution and core layers are collapsed into a single layer. With any mismatch in speeds between the ingress and egress ports.

If the system is configured as an NTP master and no stratum number is specified. Verifying Routing 5. Introduction to Switched Networks 51 integrated circuits and accompanying software that controls the data paths through the switch. An interface can be configured for one of three violation modes.

Each layer can be seen as a well-defined, structured module with specific roles and functions in the campus network.

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