Chapter 7 ( Key Points )

c. Port Fast Ethernet 0/5 is in a connected state.

A Cisco Catalyst switch has 24 10/100 ports, numbered 0/1 through 0/24. Ten PCs connect to the ten lowest numbered ports, with those PCs working and sending data over the network. The other ports are not connected to any device. Which of the following answers lists facts displayed by the show interface status command? a. Port Ethernet 0/1 is in a connected state. b. Port Fast Ethernet 0/11 is in the connected state c. Port Fast Ethernet 0/5 is in a connected state. d. Port Ethernet 0/15 is in a notconnected state.

The fastest speed that port supports.

Cisco Catalyst switches name their ports based on what?

Each switch makes its own independent forwarding decision based on its own MAC address table.

How are decisions made in a LAN that has multiple switches?

By listening to incoming frames and examining the source MAC address in the frame.

How do switches learn MAC addresses to build their MAC address tables?

By blocking some ports from forwarding frames so that only on active path exists between any pair of LAN segments.

How does STP prevent looping frames?

VLAN

LAN switches forward Ethernet frames inside a ____.

flood

Switches ____ unknown unicast frames.

2

Switches use Layer ____ logic, examining the Ethernet data-link header to choose how to process frames.

Forward

To send a frame received in one interface out another interface toward its ultimate destination.

1. To make decisions to forward or filter frames 2. To Learn MAC Addresses 3. To use STP to avoid loops

What are the three main functions of a LAN switch?

show mac address-table dynamic

What command would you use if you only want to see the dynamically learned MAC addresses in a switches MAC address table?

show interfaces status

What command would you use to check if a switches interfaces are working?

show mac address-table

What command would you use to see a switches all of the MAC address in a switches MAC address table?

The switch forwards the frame out all interfaces except the incoming interface. (a process called flooding.)

What happens when a switch gets a frame that is doesnt have a matching entry for in its mac table?

To decide whether to forward a frame or ignore a frame.

What is the primary mission of a switch once it receives an Ethernet frame?

1. The switch receives a frame 2. The switch compares the frames destination MAC address to its Mac address table. 3. If the destination Mac address matches an address in the table it forwards it. If the destination Mac address does not match an address in the table it does not forward it.

What is the process a switch takes to forward a known unicast frame?

b. It compares the unicast source address to the bridging, or MAC address table.

Which of the following comparisons does a switch make when deciding whether a new MAC address should be added to its MAC address table? a. It compares the unicast destination address to the bridging, or MAC address, table. b. It compares the unicast source address to the bridging, or MAC address table. c. It compares the VLAN ID to the bridging, or MAC address, table. d. It compares the destination IP address's ARP cache entry to the bridging or MAC address table.

a.It forwards out all interfaces in the same VLAN except for the incoming interface.

Which of the following statements best describes what a switch does with a frame destined for an unknown unicast address? a.It forwards out all interfaces in the same VLAN except for the incoming interface. b. It forwards the frame out the one interface identified by the matching entry in the MAC address table. c. It compares the destination IP address to the destination MAC address. e. It compares the frame's incoming interface to the source MAC entry in the MAC address table.

c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface.

Which of the following statements describes part of the process of how a LAN switch decides to forward a frame destined for a broadcast MAC address? a.It compares the unicast destination address to the bridging, or MAC address, table. b. It compa.It compares the unicast destination address to the bridging, or MAC address, table. b. It compares the unicast source address to the bridging, or MAC address table. c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface. d. It compares the destination IP address to the destination MAC address. e. It compares the frame's incoming interface to the source MAC entry in the MAC address table.ares the unicast source address to the bridging, or MAC address table. c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface. d. It compares the destination IP address to the destination MAC address. e. It compares the frame's incoming interface to the source MAC entry in the MAC address table.

a. It compares the unicast destination address to the bridging or MAC address table.

Which of the following statements describes part of the process of how a switch decides to forward a frame destined for a known unicast MAC address? a. It compares the unicast destination address to the bridging or MAC address table. b. It compares the unicast source address to the bridging, or MAC address table. c. It forwards the frame out all interfaces in the same VLAN except for the incoming interface. d. It compares the destination IP address to the destination MAC address. e. It compares the frame's incoming interface to the source MAC entry int he MAC address table.

STP (Spanning Tree Protocol)

With out ____ , any flooded frames would loop for an indefinite period of time in Ethernet networks with physically redundant links.

Spanning Tree Protocol (STP)

____ a protocol that uses an algorithm that allows a switch to dynamically work around loops in a network topology. It does this by having the switch exchange bridge protocol data unit messages with other switches to detect loops and then remove the loops by blocking selected switch interfaces.

Unknown Unicast Frame

____ is an ethernet frame who's destination MAC address is not listed in a switch's MAC address table, so the switch must flood the frame.

Known Unicast Frame

____ is an ethernet frame whos destination MAC address is listed in a switch's MAC address table, so the switch will forward the frame out the one port associated with the entry in MAC address table.

Flood / Flooding

____ is the result of the LAN switch forwarding process for broadcasts and unknown unicast frames. Switches forward these frames out all interfaces, except the interface in which the frame arrived.

blocking, forwarding

____ means that the interface cannot forward or receive data frames, while ___ means that the interface can send and receive data frames.

MAC Address Table

_____ _____ ____is a table of forwarding information held by a Layer 2 switch, built dynamically by listening to incoming frames and used by the switch to match frames to make decisions about where to forward the frame.

broadcast address

_____ is generally, any address that represents all devices, and can be used to send one message to all devices.