Day 3

Question 1

variable length subnet masking (VLSM)

Answer 1

allows us to optimize available IP addresses by specifying a different subbnet mask for an IP network,

Question 2

VLSM rules

Answer 2

IP is always a CIDR of /24
-add two to the number of hosts needed in each network
-start with greatest # of networks first
-WAN links have a CIDR of /30
-use #line to determine # of hosts you need
-corresponding CIDR is CIDR for network ID
for WAN interface, start at the end and subtract by 4 256-4=252-4=248-4=244-4=240-4=236-4=232

Question 3

switches

Answer 3

layer 2 device
make decisions based on physical mac addresses
break up collision domains but not broadcast domains

Question 4

Content Addressable Memory (CAM)

Answer 4

locaiton where a switch stores MAC information

Question 5

MAC Addressable Table (MAT)

Answer 5

a copy of the CAM in human readable form of the CAM.

often used to describe the CAM

Question 6

spanning tree protocol (STP)

Answer 6

when multiple switches are connected, a bridge loop may occur. STP detects bridge loops and blocks redundant ports

Question 7

Ethernet

Answer 7

most popular type of lan.
IEEE 802.3
easy to install, scalable, inexpensive to implement
can operate in half or full duplex modes

Question 8

ethernet types

Answer 8

Ethernet 10 Mbps coaxial, copper
Fast Ethernet 100 Mbps copper/fiber
gigabit ethernet 1000Mbps fiber

Question 9

half duplex ethernet

Answer 9

at risk of collisions between frames

Question 10

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

Answer 10

imposes half-duplex logic which limits transmission to one station at a time. if a collision occurs, a fall back timer is invoked and the transmitting machines transmit again at different times

Question 11

full duplex ethernet

Answer 11

allows simultaneous communication between a pair of stations.
the link between the stations must be point to point using twisted pair or fiber optic

Question 12

router

Answer 12

layer 3 device

makes routing decisions based on IP addresses

Question 13

default gateway

Answer 13

required for each network that needs to communicate with a different network. the default gateway connects the LAN to the WAN.
the IP address applied to the interface is the default gateway address and is where a host sends traffic when the destination for that traffic is outside of the LAN

Question 14

Routing table

Answer 14

list of networks and paths the router references for decisions on packet forwarding.
entries are built manually (static routes), or through information from other routers (dynamic routes).
if there is no entry, a default route is used to send traffic to a gateway of last resort for forwarding

Question 15

Internet protocol

Answer 15

a protocol that allows data to be routed from one network device to another.
encapsulates data in a packet