Study Guide Flashcards
What are the two types of packets routers use?
Data packets and route update packets.
What is a window?
A window defines the amount of data a transmitting device can send before it has to stop and wait for an acknowledgement. It’s a layer 2 concept. A smaller window can better ensure data integrity but it will result in a slower, more laborious transmission of data.
Why is it that routers “break up broadcast domains” but switches don’t?
Because routers, by default, block broadcasts and multicasts. Switches flood them.
On what layer of the OSI reference model does a hub act?
The physical layer only - it merely repeats the signals it receives.
What are the three things to remember about full duplex mode?
• There are NO collisions in full
duplex mode
• A dedicated switch port is required
for each full duplex node
• Both the NIC and the switch port
must be capable of running full
duplex mode
What is the highest-order bit in a MAC address when used in Ethernet addressing?
Is the Individual/Group bit (I/G). If it’s turned off it means that the MAC address belongs to a single device and can be used for a unicast. If it’s on, the following address is a broadcast address.
What is the second-highest-order bit?
The global/local (g/l) bit
What’s the IEEE standard for all 10 Mbps cabling? What’s the standard for 100 Mpbs (fast Ethernet) physical media?
- 3
802. 3u
What are the three types of cable that can be created from an Ethernet cable? What are they used to connect?
• straight-through - used to connect a
PC to a switch or a switch to a router
• crossover - used to connect a switch
to a switch, PC to PC, hub to hub or
hub to switch
• rolled - used for a console connection
between a PC and a switch or router
ICMP functions on what layer?
Layer 3
What’s the only difference between Ethernet and Ethernet_II headers?
The Ethernet_II header uses a Type field instead of a Length field.
RARP
Reverse Address Resolution Protocol
RARP translates a MAC address into an IP address. Diskless devices initially don't know their
Which layer 4 protocol(s) and port number(s) does DHCP use?
UDP 67, 68
Which layer 4 protocol(s) and port number(s) does telnet use?
TCP 23
Which layer 4 protocol(s) and port number(s) does FTP use?
TCP 21