Ccna General Info

Front 1

3 Steps a computer takes to communicate with another computer on the network. (Hint: Not necessarily the 3 way handshake).

Back 1

1. Name resolution. IP address discovery.
2. Resolve IP address to MAC address.
3. Now ready to start communicating.

Front 2

What is a primary purpose of the Routing Protocols

Back 2

Build a map of the inner network.

Front 3

Define a Collision Domain and the reason they are implemented.

Back 3

A network segment with multiple hosts in which they all share the same bandwidth.
If two hosts on the same domain transmit at the same time then a collision occurs.

Front 4

Define a Broadcast Domain and what creates them.

Back 4

It is the boundary in which all devices see and participate in broadcasts sent from hosts and servers.
Broadcast Domains are created by routers.

Front 5

What is a hub?

Back 5

A "repeater" that takes a digital signal and sends it out every port (also refreshes signals).
Has 1 collision domain and 1 broadcast domain.

Front 6

What is the purpose of a Bridge?

Back 6

Break up collision domains on every port. (Creates more collision domains within a broadcast domain to avoid data collisions)
Include software that learns MAC addresses to more efficiently transfer data.
Have been replaced by switches.

Front 7

What are Switches?

Back 7

Multi-port Bridges.
Each port separates a collision domain.
Integrated the software that a bridge uses to learn MAC addresses into hardware to go through it's processes more quickly.
Logical addressing to filter the flow of data.

Front 8

What do Routers do?

Back 8

Stops broadcasts from transmitting through to other networks.
Use logical addressing.
Break up collision domains on each interface.

Front 9

What is the Application layer (OSI Model) in charge of?

Back 9

Makes sure connections can be made and that there are sufficient resources available.
File, print, message, database, and application services.

Front 10

What is the Presentation layer (OSI Model) in charge of?

Back 10

Data translation.
Presents the data in a format that can be understood by all devices.

Front 11

What is the Session layer (OSI Model) in charge of?

Back 11

Encapsulation is called Data at this layer.
Dialog control.
Maintains, tracks, and closes sessions between applications. Makes sure that the correct info is sent to the correct query.

Front 12

What is the Transportation layer (OSI Model) in charge of?

Back 12

Encapsulation is called a Segment at this layer.
End to end communication.
Multiplexes upper-layer applications.
Manages sessions, tears down virtual circuits, flow control, and data integrity.

Front 13

What is the Network layer (OSI Model) in charge of?

Back 13

Encapsulation is called a Packet at this layer.
Routing.
Transports data from one network to another by using routing tables and other methods.

Front 14

What is the Data Link layer (OSI Model) in charge of?

Back 14

Encapsulation is called a Frame at this layer.
Broken up into two sublayers, the LLC and the MAC layers.
LLC = Logical Link Control - Error control, flow control, and framing.
MAC = Media Access Control - Gives the data access depending on their MAC address.

Front 15

What is the Physical layer (OSI Model) in charge of?

Back 15

Encapsulation is converted into Bits at this layer.
The messenger, in charge of getting the information from one place to another. It is just electrical signals of 1's and 0's at this point.

Front 16

Define the Application layer (TCP/IP Model).

Back 16

Combines the top 3 layers of the OSI model into one (Application, Presentation, and Session).
Defines application protocols and how host programs interface with transport layer services to use the networks.

Front 17

Define the Transport layer (TCP/IP Model).

Back 17

Provides communication session management between host computers. Chooses TCP (safe and connection oriented) or UDP (best-effort and connectionless).

Front 18

Define the Internet layer (TCP/IP Model).

Back 18

Routes IP datagrams.
Internet Protocols (IP)
Address Resolution Protocol (ARP)
Internet Control Message Protocol (ICMP)

Front 19

Define the Physical layer (TCP/IP Model).

Back 19

Controls the hardware devices and media that make up the network.

Front 20

Address Resolution Protocol (ARP)

Back 20

A broadcast sent out over the network when one device is searching for another device within its broadcast domain.

Front 21

Internet Control Message Protocol (ICMP)

Back 21

It is in charge of error reporting. It is the protocol that the network uses to alert the network administrator that there is a problem on the network.

Front 22

When subnetting " /25 " tells you what?

Back 22

You will have the following:
1 bit on/ 7 bits off: 10000000
Subnet mask: 255.255.255.128
Increments/Block size: 128
Subnets: 2
Hosts per subnet: 126

Front 23

When subnetting " /26 " tells you what?

Back 23

You will have the following:
2 bit on/ 6 bits off: 11000000
Subnet mask: 255.255.255.192
Increments/Block size: 64
Subnets: 4
Hosts per subnet: 62

Front 24

When subnetting " /27 " tells you what?

Back 24

You will have the following:
3 bit on/ 5 bits off: 11100000
Subnet mask: 255.255.255.224
Increments/Block size: 32
Subnets: 8
Hosts per subnet: 30

Front 25

When subnetting " /28 " tells you what?

Back 25

You will have the following:
4 bit on/ 4 bits off: 11110000
Subnet mask: 255.255.255.240
Increments/Block size: 16
Subnets: 16
Hosts per subnet: 14

Front 26

When subnetting " /29 " tells you what?

Back 26

You will have the following:
5 bit on/ 3 bits off: 11111000
Subnet mask: 255.255.255.248
Increments/Block size: 8
Subnets: 32
Hosts per subnet: 6

Front 27

When subnetting " /30 " tells you what?

Back 27

You will have the following:
6 bit on/ 2 bits off: 11111100
Subnet mask: 255.255.255.252
Increments/Block size: 4
Subnets: 64
Hosts per subnet: 2

Front 28

When subnetting " /31 " tells you what?

Back 28

You will have the following:
7 bit on/ 1 bits off: 11111110
Subnet mask: 255.255.255.254
Increments/Block size: 2
Subnets: 128
Hosts per subnet: 0
Not a viable network.

Front 29

When subnetting " /32 " tells you what?

Back 29

You will have the following:
8 bit on/ 0 bits off: 11111111
Subnet mask: 255.255.255.255
Increments/Block size: 1
Not a viable network.

Front 30

What is a MTU?

Back 30

Maximum Transmission Unit - The most amount of information able to be sent at once.

Front 31

What does TCP refer to?

Back 31

A reliable connection, sets up a virtual circuit.
More network overhead since the two devices "chat" more.
Uses Syn(chronize) and Ack(nowledgements) to make sure all data is sent/received.

Front 32

What does the Transport layer use to separate data?

Back 32

Port numbers.

Front 33

What does the Network layer use to separate data?

Back 33

IP addresses

Front 34

Define Flow Control.

Back 34

It can occur at the transport layer and is a mechanism for the receiver to control the transmission speed.

Front 35

Common types of Flow Control

Back 35

Buffers - When full, some info will be dropped.
Source - Quench messages (stop and go)
Congestion avoidance - Random early detection.
Windowing (TCP) - Find exactly how much data the receiving host can accept before overloaded.

Front 36

Define TFTP.

Back 36

Trivial File Transfer Protocol
Operates on the application layer
(UDP file transfer at the transport layer)

Front 37

Define FTP.

Back 37

File Transfer Protocol
Application layer protocol
(TCP file transfer at the transport layer)

Front 38

Define NFS.

Back 38

Network File Service
Application layer protocol
(TCP file directory system)

Front 39

Define SMTP.

Back 39

Simple Mail Transfer Protocol.
Application layer protocol.
(TCP)

Front 40

Define Telnet.

Back 40

Runs programs on a remote host but does not transfer files. Makes your box a dumb terminal.
Application layer protocol.

Front 41

Define rlogin.

Back 41

Remote Login
Application layer protocol

Front 42

Define SNMP.

Back 42

Simple Network Management Protocol
Application layer protocol
(By default uses UDP - Newer versions can use TCP)

Front 43

Define DNS.

Back 43

Domain Name Service
Application layer protocol
(Resolves domain names for the internet - uses UDP - uses TCP between servers for updates)

Front 44

Define DHCP.

Back 44

Dynamic Host Configuration Protocols
Runs on top of Bootp (Bootp version 2).
Uses UDP
This is how a host can get an address on a network automatically.

Front 45

Define the DHCP process. As per CCNA Objectives. (Hint: They are not all broadcasts)

Back 45

Host --Broadcast--> Server
Discover message
"Who is out there?"
Server --Unicast--> Host
Offer message
"You are unknown, here are some credentials and [ip address] to access the network."
Host --Broadcast--> Server
Request message
"I like that info, can I associate myself with it?"
Server --Unicast--> Host
Acknowledgement message
"Ok, you are now known as [ip address] while on this network."

Front 46

Define TCP.

Back 46

Transmission Control Protocol
Connection-oriented service
Uses virtual circuits (Three-way handshake)
Enables windowing to find the optimum amount of packets that can be sent at a time.
Uses Sync/Ack.
Considered reliable.

Front 47

Define UDP.

Back 47

User Diagram Protocol
Simple connectionless service
No windowing, sequencing, or acknowledgements resulting in less overhead traffic.

Front 48

Explain Windowing.

Back 48

Uses Syn and Ack to manage data being sent. The sender tests the receiving host by sending more and more until packets begin to be dropped to find the optimum amount.
For example:
HostA --1 syn--> HostB (Sending 1)
HostA <--2 ack-- HostB (Ready for 2)
HostA --3 syn--> HostB (Sending 2 and 3)
HostA <--4 ack-- HostB (Ready for 4)
HostA --7 syn--> HostB (Sending 4, 5, 6, 7)
HostA <--7 ack-- HostB (Ready for 7 [7 dropped the first time])
HostA --9 syn--> HostB (Sent 7-9, only 3 this time since it's the max)

Front 49

What is the 3 way handshake?

Back 49

Used to set up a TCP connection.
HostA --Synchronize--> HostB
HostA <---Sync/Ack---- HostB
HostA --Acknowledge-> HostB
Both parties are ready to start reliable connection.

Front 50

What port does HTTP use?

Back 50

Port 80
TCP connection

Front 51

What port does Telnet use?

Back 51

Port 23
TCP connection

Front 52

What port does FTP use?

Back 52

Port 21
TCP connection

Front 53

What port does SMTP use?

Back 53

Port 161
TCP connection

Front 54

What port does HTTPS use?

Back 54

Port 443
TCP connection

Front 55

What port does TFTP use?

Back 55

Port 69
UDP connection

Front 56

What port does SNMP use?

Back 56

Port 161
UDP connection

Front 57

What port does DNS use?

Back 57

Port 53
UDP and TCP connection

Front 58

Define Internet Protocol (IP)

Back 58

A connectionless service that provides net addressing and routing through an inter network.

Front 59

Define RARP.

Back 59

Reverse Address Resolution Protocol
"I know my ethernet address, what is my ip?"

Front 60

What are some uses for the ICMP?

Back 60

Can provide info on network problems.
Ping (packet internet groaper). ICMP echo requests and ICMP echo replies.
ICMP Packets: Encapsulated with IP datagrams.
Traceroute: TTL (time to live) timeout, ICMP error messages.

Front 61

What does each bit mean in binary?

(For example: 10110010)

Back 61

1's are the bits turned "on"
0's are the bits turned "off"
Each bit represents the following:
128 64 32 16 8 4 2 1
From left to right:
1:128 on / 0:64 off / 1:32 on / 1:16 on / 0:8 off / 0:4 off / 1:2 on / 0:1 off
Added up this example represents 178 in binary.

Front 62

Explain Hexadecimal.

(For example: 10110010)

Back 62

Similar to binary, instead, each octet is broken up into 2 sections.
8 4 2 1 8 4 2 1
1-9 are left as-is.
10-15 are a-f (caps insensitive)
8 4 2 1 8 4 2 1
1 0 1 1 0 0 1 0
11 2
B 2
10110010 = B2 in hex.

Front 63

IP range for Class A addresses.

Back 63

10.0.0.0 - Network address (all bits off)
10.0.0.1 - First valid host
10.255.255.254 - Last valid host
10.255.255.255 - Broadcast address (all bits on)

Front 64

IP range for Class B addresses.

Back 64

172.16.0.0 - Network address (all bits off)
172.16.0.1 - First valid host
172.16.255.254 - Last valid host
172.16.255.255 - Broadcast address (all bits on)

Front 65

IP range for Class C addresses.

Back 65

192.168.10.0 - Network address (all bits off)
192.168.10.1 - First valid host
192.168.10.254 - Last valid host
192.168.10.255 - Broadcast address (all bits on)

Front 66

What does ip subnet-zero do and why is it important?

Back 66

Allows the use of the first and last address ranges in the ip range.
Without:
192.168.10.16 - First network range
192.168.10.32 - Second network range
With:
192.168.10.0 - First network range
192.168.10.16 - Second network range
Same applies to the last ranges.

Front 67

What does it mean when you see 0x2100?

Back 67

Load ROM monitor mode.

Front 68

What does it mean when you see 0x2101?

Back 68

Load mini IOS from ROM.

Front 69

What does it mean when you see 0x2102?

Back 69

Load IOS from flash and config from NVRAM. Router looks in NVRAM for boot sequence.

Front 70

What does it mean when you see 0x2142?

Back 70

Load IOS from flash and do not load startup-config.

Front 71

What is the difference between:
"enable secret ...."
and
"enable password ...."

Back 71

Enable secret will automatically encrypt your password while enable password will leave it in plain text when you do "show running-config"

Front 72

How do you encrypt all passwords at once?

Back 72

Router(config)#service password-encryption
You only need it on to setup the passwords and then you can turn it off and the passwords would still be encrypted. (Just adds to networks traffic if left running).
To turn it off...
Router(config)#no service password-encryption

Front 73

What is the default order for searching for the IOS?

Back 73

1. Check config register.
2. Parses config for the boot system command.
3. Defaults to first file in flash memory.
4. Attempts to boot from network server.
5. Boot helper image.
6. ROMMON (ROM Monitor mode)

Front 74

Define CDP.

Back 74

Cisco Discover Protocol
A cisco proprietary program that is turned on by default, runs at layer 2, and is used to gather information on its neighboring cisco devices.

Front 75

Why use SSH over Telnet?

Back 75

Even though they essentially do the same thing, you want to setup SSH and deny Telnet because SSH automatically encrypts all data being sent while Telnet sends plain text and is open to security insecurity. (Lol, flawless victory!)

Front 76

Routing Protocols

Back 76

How the routers communicate with one another to determine the path of a packet through the network.

Front 77

Routed Protocols

Back 77

IP and IPv6 are used to send user data through the inter network.

Front 78

Interior Gateway Protocols (IGP)

Back 78

Protocols such as RIP, IGRP, EIGRP, and OSPF used within an autonomous system.

Front 79

External Gateway Protocols (EGP)

Back 79

Protocols used to connect autonomous systems, BGP (Border Gateway Protocols) is the standard.

Front 80

Autonomous System

Back 80

Collection of networks under a common administrative domain.

Front 81

Classful Routing Protocols

Back 81

Do not include the subnet mask with the route advertisement. All the subnet masks need to be the same.
RIP and IGRP

Front 82

Classless Routing Protocols

Back 82

Include the subnet mask with the route advertisement. Supports Variable Length Subnet Masks (VLSM).
RIPv2, EIGRP, OSPF, and IS-IS

Front 83

What is a Distance Vector routing protocol?

Back 83

A routing protocol that periodically lets the rest of the network know about changes. Low network overhead.
RIPv1 and v2, IGRP, and EIGRP.

Front 84

What is Link State routing protocol?

Back 84

Each router is charged with creating a map of the network to calculate the best path to a destination. Considerably more network overhead than Distance Vector.
IS-IS

Front 85

What does the Hybrid Routing Protocol refer to?

Back 85

Cisco proprietary EIGRP, it is considered an advanced Distance Vector with some Link State routing protocol features.

Front 86

How does RIP figure out the best path?

Back 86

Hop count. 3 hops over 10 gigabyte lines will be seen as the same as 3 hops over a 56 kilobyte lines.

Front 87

What does IGRP use to figure out the best path through a network?

Back 87

Bandwidth, delay, load, reliability, and MTU.

Front 88

Define Split Horizon.

Back 88

The protocol implemented to avoid wrong information from a router sending and then receiving the same routing information on the same port.

Front 89

Define Route Poisoning.

Back 89

Often times due to redundant paths through a network causing routers to log bad paths to other networks.

Split Horizon - One method to prevent routing loops, it sends routing information about bad links that should be removed from routing tables.

Front 90

Default Administrative Distances

Back 90

Directly Connected: 0
Static Route: 1
RIP: 120
IGRP: 100
EIGRP: 90
OSPF: 110

Front 91

Dis-contiguous addressing is what?

Back 91

Two networks of the same classful network are separated by a different network address.

*NOTE: the command "no auto-summary" will fix that. Do not rely on that command for the CCNA exam.

Front 92

What are some important points about OSPF?

Back 92

Uses hello packets to create adjacency and maintain connectivity with neighbor routers.
Uses Multicast.
Hello packets and LSAs from other routers help build and maintain the topological database.

Front 93

What is the Router ID (RID)?

Back 93

The unique ID given to the router of an area.
It is used to properly arrange them in neighbor tables.

Front 94

What is a Designated Router (DR)?

Back 94

In an OSPF network, it is the router with the highest priority, elected by the other routers.
You want your best, most badass, router to be elected as the DR.

Front 95

What is the Backup Designated Router (BDR)?

Back 95

It is the backup to the DR in an OSPF configured network. It has the second highest priority.

Front 96

[OSPF]
Define some specifics about Broadcast Multi-Access.

Back 96

Must be full mesh, elects the DR and BDR, and uses multicast messages.

Front 97

[OSPF]
Define some specifics about Non-Broadcast Multi-Access.

Back 97

Must be full mesh, elects the DR and BDR, and uses unicast messaging.

Front 98

[OSPF]
Define some specifics about Point-to-Point.

Back 98

No DR or BDR is elected.

Front 99

A good trick to force a OSPF reelection to switch the DR and BDR.

Back 99

Raise the priority to 2 or 3 (default 1) on the DR and/or BDR and then disable the appropriate fastEthernet ports and then enable them.

Front 100

Notes on configuring Wild Card masks.

Back 100

Wildcards are always 1 less than the block size.
0.0.0.0 means that all the octets match exactly.
0.0.0.255 means the first three match exactly but the last octet can be any number.

Front 101

Spanning Tree Protocol (STP)

Back 101

Protocol to allow the ability to have redundant routes but to avoid Infinite Loops/Broadcast Storms by blocking all but one route.

Front 102

Redundant Topology

Back 102

Multiple routes through a network to help eliminate single points of failure. By itself causes broadcast storms, multiple frame copies, and MAC address table instability problems.

Front 103

STP Operations

Back 103

Designates a root bridge to funnel all traffic through. All other routers find the best path through to the root bridge for fastest convergence of the STP.

Front 104

[STP]
What is a Root Port?

Back 104

The port a router uses to get to the Root Bridge.

Front 105

[STP]
What is the Designated Port?

Back 105

This is the Root Bridge's designated port to send/receive traffic on.

Front 106

[STP]
What is the Root Bridge?

Back 106

Should be your most badass router, it is the one with the lowest Bridge ID and is in charge of funneling traffic through it.

Front 107

[STP]
How is the Bridge ID found?

Back 107

It is the Bridge Priority + Bridge MAC address.
Lowering the priority will usually make it the Root Bridge by itself.

Front 108

What are the different states of the STP?

Back 108

Blocking -> Listening -> Learning -> Forwarding (802.1d - Whole process takes about 50 seconds)

When all ports are either forwarding or blocking then all STP routes have converged.

Front 109

[STP]
What is PortFast?

Back 109

A command designed to make the STP go through its processes much quicker so you don't need to wait through the 50 seconds it takes to do its full sequence. 802.1w only take a few seconds to converge.

Front 110

What is a VLAN?

Back 110

Virtual Local Area Network
Broadcast domain
It can span across multiple switches by connecting them through their Trunked Links, in order to do this you need to assign memberships to specific ports.
(For example: VLAN 1 = Sales, sales reps can be all over the building but need to be on the same broadcast domain so you assign them to the same VLAN).

Front 111

What does the Access Link do?

Back 111

It carries information of only one VLAN.
Host to switch (connected with a straight-through cable).

Front 112

What are Trunk Links?

Back 112

These carry information about all/many VLANs.
Switch to switch (connected with a cross-over cable).
Hub to hub.

Front 113

What is 802.1q?

Back 113

Frame Tagging

Front 114

What is 802.1x?

Back 114

Port-based authentication.
This is key for bigger companies where security is very important.

Front 115

Can you get more interfaces than just the physical ones?

Back 115

Yes.
Each physical interface can be divided into virtual subinterfaces.
(For example:
FastEthernet0/0
Fa0/0.1
Fa0/0.2
Fa0/0.3
Not so good for companies, great for home use.)

Front 116

Virtual Trunk Protocol (VTP)

Back 116

Keeps the VLAN database synchronized between all switched in the internetwork by creating a "VLAN Domain."
Saved in RAM and is downloaded every time it's turned on from the VTP server.
When changes are made to the VTP server it is downloaded and the switches forward it out its ports.

Front 117

What are the VTP modes?

Back 117

Client: Accept then forward out.
Server: Host the list where changes are made.
Transparent: Do not accept the list just forward out the trunk links.

Front 118

What is one of the most Common Attacks to your network?

Back 118

Denial of Service (DoS)
Flood of packets that open sessions and do not close them, overwhelms your server and will eventually freeze it.

Front 119

What are the two main Security Appliances for your network?

Back 119

IDS - Intrusion Detection System
Detects multiple types of malicious behavior.
IPS - Intrusion Prevention System
Monitors the line for malicious packets and will deny the attacks while still letting the good traffic by.

Front 120

Access Control List (ACL)

Back 120

Allows or denies access to certain areas on a network based on permission.
(For example: Sales cannot access the IT network)

Front 121

Standard ACL

Back 121

Checks source address
Generally permits or denies entire protocol suites.

Front 122

Extended ACL

Back 122

Check the source and destination address.
Generally permits or denies specific protocols and applications.

Front 123

True or False
Pudding tastes delicious.

(FUN CARD! Change of pace, you should take a break and stretch. Go grab a glass of water or a snack.)

Back 123

Trick question!
You're right! (Assuming you answered based on whether you enjoy it or not).
It's preference.

Front 124

True or False
"Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo" is a valid sentence.

(FUN CARD! Change of pace, you should take a break and stretch. Go grab a glass of water or a snack.)

Back 124

True!
You've got to love the English language...
Look it up on wikipedia or search for it on google.

Front 125

How can you easily identify an ACL?

Back 125

Numbered Standard: 1-99, 1300-1999
Numbered Extended: 100-199, 2000-2699
Named (Std and Ext): Name

Front 126

Local Address.

Back 126

Address before translation.

Front 127

Global Address.

Back 127

Address after translation.

Front 128

Inside Local

Back 128

Inside source
IP address

Front 129

Inside Global

Back 129

Translated address
What it is on the internet (IP)

Front 130

Outside Local/Global

Back 130

Destination host...
I was told it is not really part of the CCNA objectives.

Front 131

NAT and PAT

Back 131

Network Address Translation
Port Address Translation (aka NAT overload)
Translates inside local addresses to inside global address, allowing them access to the internet.
NAT = 1 internet ip for 1 host.
PAT = 1 internet ip for many hosts.
PAT uses sockets.(IP address:Port)
Example...
UserA - 192.168.10.1:20
UserB - 192.168.10.1:21
(NOTE: Not sure if that is a valid internet address or if it's strictly a class C network address but it gets the points across).

Front 132

Are wireless routers Half or Full-Duplex?

Back 132

Half-Duplex: 802.11a, 802.11b, 802.11g
Full-Duplex: 802.11n

Front 133

What are some things to consider when setting up a wireless network?

Back 133

Interference: Microwaves, other routers (and what channels they are transmitting on), and physical barriers (concrete)
Reflection: Metallic surfaces.
Scattering: Signal hitting a lake will shoot off in all directions.
Absorption: Pine-needles and other trees will seriously reduce the strength of a signal. (Bigger problem for 2.4ghz frequency than for the 5ghz)

Front 134

What are the three unlicensed Radio Frequencies that we can use?

Back 134

900mhz
2.4ghz
5ghz

Front 135

How many channels are considered "clean" on the 2.4ghz frequency?

Back 135

Three, out of the 14 channels available, 1, 6, and 11 do not overlap with one another.
Time to use your imagination.
Imagine a circle around each number and that each number is a router using the appropriate channel, set up like this you will not need to worry about conflicting signals. (Within your network, a neighboring company or home router might be using a conflicting channel within range of your routers and you will need to either take that into account or ask them to change their channel. In both parties best interest.)
1 6 11 1 6 11
11 1 6 11 1 6
1 6 11 1 6 11

Front 136

What is the Wi-Fi Alliance?

Back 136

Global non-profit organization that certifies network devices for following an industry standard. This promotes growth and development within the industry since everyone's products work with everyone else's.

Front 137

What is the IEEE?

Back 137

Institute of Electrical and Electronic Engineers.
802.11 documentation
These guys invent all the cool stuff.

Front 138

[802.11 Topology]
Ad Hoc Mode

Back 138

Independent Basic Service Set (IBSS)
Mobile clients connect directly to one another without going through an access point.
HostA - - - - -HostB

Front 139

[802.11 Topology]
Infrastructure Mode

Back 139

Basic Service Set (BSS)
Mobile clients access one another and the network through a single access point.
HostA - - -Access Point- - - HostB

Front 140

[802.11 Topology]
Extended Service Set

Back 140

Two or more BSSs are connected by a common distribution system.
Switch
| |
HostA - - -AP AP- - - HostB

Front 141

What is a Wireless Cell?

Back 141

The area of coverage around the access point.

Front 142

How big of an wireless cell overlap do you want when setting up your network?

Back 142

10-15% overlap to not lose connectivity when you have roaming users.

Front 143

What are the data rates for 802.11b around the access point?

Back 143

11, 5.5, 2, 1mb/s DSSS (Direct Service Spread Spectrum)
The closest users get the fastest speed while on the outskirts you get only a fraction of the speed.

Front 144

What encryption types do WPA and WPA2 use?

Back 144

WPA - TKIP/MIC (Message Integrity Check)
WPA2 - AES-CCMP
AES: Advanced Encryption Scheme. A hardware encryption.

Front 145

What are some of the benefits of using IPv6?

Back 145

No need to use DHCP, NAT, or Subnet.

Front 146

What does " :: " mean in an IPv6 address?

Back 146

The octet(s) between those two semicolons are all zeros. This can only be used once in an address.
x:x:0:0:0:x:x:x = x:x::x:x:x
x:x:0:0:0:x:0:x = x:x::x:0:x
FE01:0:0:0:0:0:0:1 = FE01::1
Leading zeros are optional.
FE01:1 = 0:0:0:0:0:0:FE01:1
:: = 0:0:0:0:0:0:0:0

Front 147

What does anycast mean?

Back 147

One to nearest (from unicast address space)
More than one device shares the same address
All anycast nodes should provide uniform service
Source devices send packets to anycast address
Routers decide on closest device to get to the destination
Great for load balancing

Front 148

What is a Hot Standby Routing Protocol (HSRP)?

Back 148

When you have two default gateways setup in IPv4 one will sit on standby since you cannot have two default gateways, however in IPv6 it has been fixed so you can have multiple default gateways in one network.

Front 149

What is the difference between IPv4's and IPv6's format?

Back 149

IPv4 has 4 octets between 0 and 255 which limits the number of addresses that can be used, thankfully for NAT Overload we have been able to work around that problem.
While IPv4 only uses 4 octets, IPv6 uses 16. This gives us a phenomenal amount of variances to accommodate almost every electronic device in the world without overlap.

Front 150

How does RIP choose the best path through a network?

Back 150

With hop count.
3 jumps through 56k lines would be seen as the same as 3 jumps through 1 gigabyte lines.