Network Connection Device Facts

Question 1

Hub

Answer 1

• The central connecting point of a physical star, logical bus topology
• *** Hubs are layer 1 devices they simply repeat incoming frames without examining the MAC address in the frame **

Question 2

Hub communication method

Answer 2

• Host sends frame to another host through the hub
• Hub duplicates the frame ∧ sends it to every host connected to the hub
• The host to which the frame is addressed accepts the frame. Every other host ignores the frame.

Question 3

Bridge

Answer 3

• Is a device that connects two (or more) media segments on the same subnet, and it filters traffic between both segments based on the MAC address in the frame

Question 4

Bridge builds a database based on MAC addresses to make these forwarding decisions

Answer 4

• Begins by examining the sources MAC address of an incoming frame
• If the source address is not in the forwarding database an entry for the address is made in the database, associating the MAC address with the media segment

Question 5

Destination address then examined

Part 2

Answer 5

• If the destination address is in the database, the frame is sent out on all segments except for the one on which it was received
• If the destination address is in the database, the frame is forwarded to the appropriate segment if the segment is different from the one on which it was received
• Broadcast frames are forwarded to all segments except the one on which they were received

Question 6

Be aware of the following regarding bridges

Answer 6

• Bridges are used to separate one part of a subnet from another. (This eliminates unnecessary traffic between segments and keeps the network from wasting bandwith)
• All segments connected to a bridge are on the same subnet and share a common subnet address
• Bridges can connect two segments that use different types of network architecture. EX. a bridge can connect a segment using Ethernet to a segment using 802.11 wireless
• Bridges are Layer 2 devices, they read the MAC address contained in a frame to make forwarding decisions
• Frame forwarding happens independently of the upper-layer protocols (such as TCP/IP)

Question 7

Switch

Answer 7

• Is a multiport bridge that performs filtering based on MAC addresses, in addition to providing additional features not found in a bridge

Question 8

Switch Features

Answer 8

• Bridges can process only a single frame at a time, switches can process multiple frames simultaneously
• Switches offer guaranteed bandwidth to each switch port
• Switches can make additional forward decisions based on the MAC address, EX a switch can be configured to accept frames from specific MAC addresses
• Like bridges switched operate at Layer 2

Question 9

Unmanaged Switches

Answer 9

• Are autonomous in their function, requiring no port management or configuration

Question 10

Managed Switches

Answer 10

• Allow administrators to change the port configurations, including the following:
• *** Port Speed
• *** Duplexing
• *** Filters based on a network adapter MAC addresses
• *** VLAN assignment