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Discovery 3 - Chapter 3 Reading Organizer

After completion of this chapter, the student should be able to: • Compare the types of switches used in an enterprise network. • Explain how Spanning Tree Protocol prevents switching loops. • Describe and configure VLANs on a Cisco switch • Describe and configure trunking and Inter-VLAN routing. • Maintain VLANs in an enterprise network. 3. 1 1. Explain in detail what a content addressable memory (CAM) is and how it is used by a switch.
2. How often does a switch delete entries from the MAC address table? 3. As a unicast frame enters a port, the switch finds the source MAC address in the frame. It then searches the MAC table, looking for an entry that matches the address. What happens if the source MAC address is not in the table? 4. Explain the term microsegmentation. 5. Switches can support either symmetric or asymmetric switching. Explain each term as it relates to switches. Symmetric Asymmetric A CAM is a MAC address table maintained by a switch and is recreated every time a switch is activated.

There is no set standard for how long a switch holds entries the user specifies it with an aging timer.

If the MAC address is not there it adds the address and port number to the aging timer

Microsegmentation is a division of a network into smaller segments usually with the intention of increasing aggregate bandwidth to network devices. Asymmetric is when a function on a network takes a greater length of time than the reverse function.

Symmetric is when a function on a network takes an equal length of time then the reverse function. 6. List the differences between how Layer 2 routers and switches use different Hardware Based Switching techniques for processing and Wire Speed Performance forwarding traffic. High Speed Scalability Layer 2 Switching - Low Latency a. Uses MAC addresses b. Low Cost c. d. Layer 3 e. Software based packet forwarding f. Higher Latency Layer 3 Routing - Higher per interface cost a. Uses IP addresses b. Security c. QoS 1

Discovery 3 . c.Chapter 3 Reading Organizer d. It is possible for switches in a redundant network to learn the wrong information about the location of a . How is redundancy accomplished with multiple switches? 15. b. 2 Reduces congestion Supports availability Balances load Causes duplicate frames to be sent throughout a network. b. c. What is the disadvantage of advantage of store and forward switching? 10. e. 16.forwards a frame after the first 64 bytes are received. Complete Lab Activity 3. e. A switching loop happens when there is more than one path between two switches. f. f.forwards all packets without reading the CRC value Fragment Free. d. Store and forward because the speed of today’s technology is as good as cut through switching Physically secure devices Use Secure Passwords Enable SSH Access Monitor access and traffic Disable HTTP Access Disable unused ports Enable port security Disable telnet Physically securing them limits access to authorized network staff Remember to answer lab questions!!! You can connect switches together with two wires into two ports on each 3.4 14. 2 The frame is read and stored in memory before being sent to the destination device It makes sure that frames aren’t damaged It introduces high latency Fast Forward. Explain in detail the two different cut-through methods of switching. Explain why physically securing networking devices is important and what steps can be taken to accomplish this goal. Redundancy refers to having two different pathways to a particular destination. What advantages are gained by this redundancy between switches? a. Explain the store and forward method of switching in detail. 17. 12. Very high latency. 8. h. What is the advantage of store and forward switching? 9. What basic security features should be applied to switches to ensure that only authorized people access them? a. Fast-forward – Fragment-free 11.1. Explain in detail how Multiple Frame Transmissions and MAC Database Instability can negatively affect a network. 13. g. Explain what switching loops are and how they can create problems in a redundantly switched network. Which switching method do most Cisco Switches rely on? Explain why. 7. MFT’s destination hosts can receive multiple copies of frames and can waste: bandwidth CPU time and potential duplication of transaction traffic.

If a loop exists. c.1 18. b. one switch may associate the destination MAC address with two separate ports.Chapter 3 Reading Organizer Multiple Frame Transmissions MAC Database Instability host. List what STP does to prevent switching loops. Complete Packet Tracer Activity Remember to answer lab questions!!! 3. What information is contained in a BPDU? a. the LEDs on the switch change from flashing orange to steady green. The root bridge communicates with the other switches using Bridge Protocol Data Units (BPDUs).2. 23. d. How long does it take for this cycle to complete? STP is a protocol that disables redundant links in switched networks providing redundancy without creating loops Cisco switches start looking for loops from the beginning when they start up Forces certain interfaces into a standby or blocked state Leaves other interfaces in a forwarding state Reconfigures the network by activating the appropriate standby path. As the port cycles through these states. What are BPDUs? 22. b. c. if the forwarding path becomes unavailable Network topology information sent to all other switches from another Identity of the source switch Identity of the source port Cumulative cost of path to root bridge Value of aging timers Value of the hello timer 50 seconds 3 . Explain what is required to set up Spanning Tree protocol on a Cisco switch? 20. Explain spanning tree protocol (STP)? 19. a. The Root Bridge is the primary switch or focal point in the STP topology.Discovery 3 . e. 21.

b. b. 2. indicates that the administrator has shut down the switch port. b. e.port that provides the lowest cost back to the root bridge Designated Port. to determine which ports to block and which ports to put into forwarding state. c. d. called a root bridge or root switch. STP uses this focal point. b.Chapter 3 Reading Organizer 24. A fifth state. List what takes place during each of the first four states. Forwarding – a. Explain each: Root Port 4 screen or hand in your results. c. designated ports. c. learning. e. listening. Blocking Steady Amber Receives BPDU’s Discard Data Frames Does not learn addresses Takes up to 20 seconds to change to listening state Listening Blinking Amber Listens for BPDU’s Doesn’t forward frames Doesn’t learn MAC Addresses Determines if switch has more than one turning port that might create a loop -if loop returns to the blocking state -if no loop transitions to learning state Takes 15 seconds t transition to learning also called forward delay Learning Blinking Amber Processes BPDU’s Learns MAC addresses from received traffic Does not forward frames Takes 15 seconds to transition to forwarding Blinking green Processes BPDU’s Learns MAC addresses Forwards frames 1. Learning – a. d. the switches in the network determine a switch that is the focal point in that network. each port cycles through a series of four states: blocking. STP designates three types of ports: root ports. and blocked ports. For STP to function. This information allows the network to reconfigure itself in the event of a failure. and forwarding. disabled. Blocking – a.Discovery 3 . c. As a switch powers on. 25. e.a designated port is a port that forwards traffic toward the root bridge but does not connect the least cost path . d. The bridge is chosen based on BID values plus the MAC addresses Root Port. d. The root bridge sends out BPDUs containing network topology information to all other switches. Listening – a. Complete the activity but DO NOT print 26. 27. Explain how the root bridge is chosen.

Every device that is attached to a switch can forward and receive frames from every other device on that switch. What are virtual local area networks (VLANs) created to do? 33. It allows an administrator to group together stations by logical function. b.Displays root ID. What is required to set up a static VLAN? 36.3 29. show spanning-tree summary – c. without regard to physical location of the users.2. show spanning-tree blockedports – Remember to answer lab questions!!! Every 2 seconds show spanning-tree . or by applications. VLAN’s have two major functions. Explain in detail why a network technician should plan and evaluate the network in order to select the best switch to become the root of the spanning tree. 3 . bridge ID. more broadcast traffic is generated and more bandwidth is wasted. and port states show spanning-tree summary . Contains broadcasts Groups devices A layer 3 device Assignment of ports from an administrator it requires you to be in a VMPS server to connect you to the certain VLAN and it acts like you are in a certain branch of a network It is used to access and configure the switch 3.4 31.Displays STP interface status and configuration show spanning-tree blockedports .Chapter 3 Reading Organizer Designated Port Blocked Port 28.Displays blocked ports Complete Lab Activity 3.2. What is required for traffic to move from one VLAN to another? 35. a. This arrangement poses two significant problems. List and briefly explain useful commands used to verify spanning tree operation.forwards no traffic A network technician needs to plan the order so he can allow for optimal use even when he makes the network larger Complete Lab Activity 3. show spanning-tree – b. these are: a.Displays detailed port information show spanning-tree interface . What is the purpose of the default 5 Remember to answer lab questions!!! Switches flood broadcasts out all ports.Displays a summary of port states show spanning-tree root . show spanning-tree interface – f. Hosts and servers that are connected to Layer 2 switches are part of the same network segment. Explain in detail what a Dynamic VLAN membership is and how it operates. As the number of devices connected to a switch increases. 37. show spanning-tree root – d. show spanning-tree detail – e. which consumes unnecessary bandwidth. by project teams. 38. Complete Activity.Displays the status and configuration of the root bridge show spanning-tree detail . How often does STP send out BPDUs by default? 30. 34.Discovery 3 . 32. They are: a. b. Blocked Port.

3.2 44. 41.Discovery 3 . Router Select a router interface with a minimum of a 100Mbps FastEthernet Configure subinterfaces that support 802. Switch a. List what is required o support interVLAN communication using subinterfaces on both the switch and the router. A VLAN has three major functions.4. These are: a. Configure one subinterface for each VLAN. 4 40.1 43.a port on a switch or router that connects a switch to another switch router or server Identifies the VLAN a frame belongs to Complete Lab Activity 3. Configure one pathway or subinterface for each VLAN. Explain how does Frame tagging work? Remember to answer lab questions!!! Reduce Load Logically group devices Minimize broadcast domains Access Port. Remember to answer lab questions!!! Special VLAN that accommodates untagged traffic. based on name 39.1Q trunk link.4. based on ID number show vlan name vlan_name Displays information pertaining to a specific VLAN. Trunk links carry untagged traffic over the native VLAN. . Explain in detail what a native VLAN is and how it operates. Explain the following terms: Access Port Trunk Port 42.pathway to a device that does not create loops in a switched network Trunk Port.Chapter 3 Reading Organizer VLAN1? remotely and to exchange information with other network devices show vlan Displays a detailed list of all of the VLAN numbers and names currently active on the switch. b. Complete Lab Activity 3. Subinterfaces logically divide one physical interface into multiple logical pathways. show vlan show vlan brief show vlan id id_number show vlan name vlan_name - Complete Lab Activity 3. One method for providing connectivity between different VLANs requires a feature called subinterfaces. Explain the purpose of the following commands. Router 6 Remember to answer lab questions!!! Switch Configure the switch interface as an 802.1Q encapsulation. c.2 3. along with the ports associated with each one Displays STP statistics if configured on a per VLAN basis show vlan brief Displays a summarized list showing only the active VLANs and the ports associated with each one show vlan id id_number Displays information pertaining to a specific VLAN.

3 3. VTP has three modes: server.2 7 . Transparent – a. c.Chapter 3 Reading Organizer a. Step 1: Configure VTP off-line (version 1) Step 2: Verify the VTP configuration. all switches are servers. c. c. Advertisement requests are required if the switch has been reset or the VTP domain name has been changed. VTP messages come in three varieties: summary advertisements. b. client. VLAN Trunking Protocol (VTP) is a Layer 2 messaging protocol. each switch advertises messages on its trunk ports. With VTP. c. b. c. A subset advertisement contains a list of VLAN information. What does this provide? 46. Server Creates modifies and deletes VLAN and VLAN config patterns for entire domain Saves VLAN config in NVRAM Sends VTP messages out all trunk ports Transparent Forwards VTP advertisements Ignores information contained in the VTP message Does not modify its database when receiving updates Doesn’t send out an update that includes a change of its own VLAN database Client Does not create modify or delete VLAN info Modifies its own database Sends VTP messages out all trunk ports It is good to do so to provide backup and redundancy Name Mode Revision VLANS Summary advertisements contain the current VTP domain name and the configuration revision number. Summary Advertisements Subset Advertisements – Advertisement Requests 50. Explain each in detail.5. Server – a. 49. Why is it a good practice to have at least two switches configured as servers on a network? 48. List the characteristics of each. Complete Packet Tracer Activity Remember to answer lab questions!!! 3. b. 5 45. Messages include: a. b. 47. and advertisement requests. subset advertisements. b. What are the steps involved in when adding a new switch to an existing VTP domain? Step 1: Step 2: Step 3: Remember to answer lab questions!!! provides a method for the distribution and management of the VLAN database from a centralized server in a network segment. Step 3: Reboot the switch.Discovery 3 . d. d.2. Complete Lab Activity 3. and transparent.4. By default. Client – a.

3 Complete Packet Tracer Activity Remember to answer lab questions!!! 3.2. f.Discovery 3 .5. c.5.5.3 51. Organizing server placement Disabling unused ports Configuring the management VLAN as a number other than 1 Using VLAN Trunking Protocol Configuring VTP Domains Reboot any new switch entering an established network Complete Packet Tracer Activity Remember to answer lab questions!!! 3. d. b.Chapter 3 Reading Organizer Complete Packet Remember to answer lab questions!!! Tracer Activity 3.4 8 . e. What are the recommended best practices for configuring VLANs in an enterprise network? a.