Quiz X - IP Addressing & Routing (Ch. 7-8, 13) - (CANCELLED Quiz 3) Flashcards
1
Q
2
Q
What is the origin of the term internet?
A
- A short form of the technical term internetwork
- the result of interconnecting computer networks
3
Q
What is The Internet?
A
- A network of networks
- consists of millions of private, public, academic, business, and government networks
- local to global scope
- linked by a broad array of electronic, wireless and optical networking technologies
4
Q
Does the Internet have a centralized governance?
A
- No, The Internet has no centralized governance in either technological implementation or policies for access and usage
5
Q
Is there an overarching standard for the Internet?
A
- No, each constituent network sets its own standards
6
Q
What body maintains IP address space and DNS definitions?
A
- ICANN
- Internet Corporation for Assigned Names and Numbers (ICANN)
- Only the overarching definitions of the Internet Protocol (IP) address space and the Domain Name System (DNS), are directed by a maintainer organization
7
Q
What agency controls the technical standards of the internet?
A
- IETF
- The technical underpinning and standardization of the core protocols is an activity of the Internet Engineering Task Force (IETF),
- a non-profit organization of loosely affiliated international participants that anyone may associate with by contributing technical expertise.
8
Q
How do you access the Internet?
A
you need an…
- Internet Service Provider (ISP) and an
- access line to your ISP
9
Q
What does the ISP do?
A
Your ISP…
- gives you access and
- carries your packets
10
Q
Do organizations also need to use an ISP?
A
- Yes, organizations also need ISPs
11
Q
What comprises the Internet backbone?
A
- ISPs collectively comprise the Internet backbone
12
Q
How do ISPs connect to each other?
A
- They interconnect at Network Access Points (NAPs)
13
Q
How are ISPs classified?
A
- Tier-1 ISPs : national/international coverage
- Tier-2 ISPs : smaller, often regional coverage
- Tier-3 & Local ISPs : last hop (“access”) network (closest to end systems)
14
Q
What are the relationships among different tiers of ISPs?
A
- Tier-2 ISP is customer of Tier-1 provider
- Local and Tier- 3 ISPs are customers of higher tier ISPs connecting them to rest of Internet
15
Q
A data packet typically passes through only one network. True or False
A
- False, a packet passes through many networks!
16
Q
How do the Network and Transport layers function in regard to the Internet?
A
[insert slide 9 image here]
17
Q
How does the Network layer “create” the Internet?
A
- The network layer facilitates the interconnection of local networks establishing the Internet
18
Q
What is TCP/IP?
A
- A set of protocols used for the Internet and other similar networks
19
Q
What do TCP and IP stand for?
A
- TCP: Transmission Control Protocol
- IP: Internet Protocol
20
Q
What types of networks does TCP/IP support?
A
- Supports both simple and complex networks
- Small LAN
- Multiple LANs interconnected into a WAN
21
Q
What is the primary transmission responsibility of the Network layer?
A
- hop-by-hop
22
Q
What is the primary transmission responsibility of the Transport layer?
A
- end-to-end
23
Q
TCP operates on what OSI layer?
A
- TCP is the Transport layer protocol
24
Q
IP operates on what OSI layer?
A
- IP is the Network layer protocol
25
When and where was TCP/IP created?
Created in the...
* ***1970s*** at
* ***DARPA***
26
Who created TCP/IP?
* ***Vint Cerf***
* ***Bob Kahn***
* (called “the fathers of the Internet”)
27
What is DARPA?
* ***Defense Advanced Research Projects Agency***
28
What is an IP address?
* IP (Internet Protocol) address
* assigned to each device (e.g., computer, printer, router) participating in a computer network that uses the Internet Protocol
29
What versions of Internet Protocol are currently in use?
* IP Version 4: 32 bits
* IP Version 6: 128 bits
30
What is the length of an IPv4 address?
* 32 bits
31
What is the length of an IPv6 address?
* 128 bits
32
What is the maximum decimal number in an IPv4 address?
* 255
33
What is the format of IPv4?
* dotted decimal
* ***four decimal numbers separated by dots***
* Each of the four parts represents a byte (8 bits)
34
Convert 129.174.1.38 into dotted decimal.
* 129.174.1.38 = 10000001.10101110.00000001.00100110
35
What is a static IP address?
* ***Manually*** type in all IP information (in the station)
* Every IP address must be unique
36
What is a dynamic IP address?
* Dynamically get address from a server using DHCP
* ***Automatically*** assigns an IP address whenever a computer connects to the network
37
What is the difference between static and dynamic addresses?
* static addresses do not change
* dynamic addresses are assigned when a host connects to the network
38
What does DHCP stand for?
* Dynamic Host Configuration Protocol
39
What is DHCP used for?
* Assigning IP addresses to hosts joining a network that need an IP address
40
How does DHCP work?
* Client requests IP address from DHCP server
* DHCP server provides address and other info
41
What is the difference between the network address and the physical address?
* **Physical address**—refers to a particular device
* The physical address ***doesn’t change*** when the device is moved
* **Network address**—refers only to the network in which the device resides
* The network address ***changes*** when the device is moved
42
How can a device be reached by using an IP address?
* To reach a device, there must be a ***mapping of its IP address to its physical address***
43
What does ARP stand for?
* ***Address Resolution Protocol***
44
What is ARP used for?
* ARP is used to
* ***determine the MAC address*** of the destination computer
* based on its IP address
45
What are the steps in ARP?
* **ARP broadcast** by the originating router is used to determine the MAC address of the destination computer based on its IP address
* The destination computer **replies with its MAC** address
* The originating router records IP-Ethernet address pair in **ARP cache** and uses it to send future frames to the host without using ARP
46
What does ICMP stand for?
* **Internet Control Message Protocol**
47
What is ICMP?
* one of the core protocols of the Internet Protocol (IP) Suite
* chiefly used by the operating systems of networked computers to **send error messages**
* indicating, for example, that a requested service is not available or that a host or router could not be reached.
48
How are ICMP messages transmitted?
* ICMP messages are ***embedded in IP packets***
* **Type number**—indicates kind of message problem
* **Code number**—specific details within type
49
What are subnets?
* ***logical networks*** with their own IP addresses
50
How are subnets created?
* created by ***assigning hosts to groups*** with their own subnet addresses
51
Routers are used within subnets to connect hosts
* **No**, hosts can physically reach each other without an intervening router
52
How are subnets logically defined?
* organized many ways—by building, floor, department
53
Can an entire subnet connect to the Internet with a single IP address?
* **Yes**, a single IP address can connect a whole subnet to the Internet
54
How are the IP addresses of subnets organized?
* IP addresses are ***hierarchical*** in a subnet
55
What are the first and second segments (part 1) of the IP address used for?
* **Network** (not always 16 bits)
* "nnn.nnn"
56
What is the third segment (part 2) of the IP address used for?
* **Subnet** (not always 8 bits)
* "nnn"
57
What is the fourth segment (part 3) of the IP address used for?
* **Host** (not always 8 bits)
* "nnn"
58
Can an IP address be less than 32 bits?
* **No**, the total of an IP address is always 32 bits
59
How many parts does an IP address have?
* An IP address usually has ***three parts***
60
What is classful addressing?
...
61
How many bits are used for the network/subnet+host parts of a Class A network?
* Class A: **8/24**
62
What is Class A addressing used for?
* For ***few organizations*** needing ***many host*** addresses
* Few bits for network addresses, many for hosts
63
How many bits are used for the network/subnet+host parts of a Class B network?
* Class B: **16/16**
64
What is Class B addressing used for?
* For ***many companies*** with ***many hosts***
* Many bits for network addresses, but also many for hosts
65
How many bits are used for the network/subnet+host parts of a Class C network?
* Class C: **24/8**
66
What is Class C addressing used for?
* For the ***great many organizations*** with ***very few hosts***
* Many bits for network addresses, few for hosts
67
What about other classes?
* Classes D & E are ***not important*** for individual computers
68
How are network classes identified in an IP address?
* **Class identifier bits** (prefixes) are
* included in the network address part of the split
69
What is the classful addressing prefix for a Class A network?
* Class A (8/24) is **0**
70
What is the classful addressing prefix for a Class B network?
* Class B (16/16) is **10**
71
What is the classful addressing prefix for a Class C network?
* Class C (24/8) is **110**
72
Classful addressing diagram
Classful Addressing
73
What is the main limitation of classful addressing?
* Classful addressing ***wastes a lot of addresses***
74
How does classful addressing waste addresses?
An organization that applies for an IPv4 address...
* Receives a network address with a block of host addresses
* The size of this block is determined by class
* If the organization can handle more addresses than it actually uses,
* the other addresses associated with the company’s block ***go unused***
75
What is the main advantage of classless addressing?
* Theoretically, ***all of 32 bits of address space would be available*** without restriction
* Twice as many addresses could be created
76
What does CIDR stand for?
* CIDR: **Classless Inter-Domain Routing**
77
What is CIDR?
* Allows ***any number of leftmost bits*** to be assigned as a network address
* ***no class designation***--addresses assigned based on the number of hosts a network can support
* ***not limited to 8,16,or 24 bit*** network addresses
* network address assignments can be ***more in line with an organization's needs***
78
Does CIDR waste any IP addresses?
* Still wastes addresses,
* just ***not as many*** as classful addressing
79
With classful addressing, if an organization requires 600 IP addresses, what class of IP addresses would the organization require? How many addresses will be wasted?
* **Class B**
* 2^16 - 2 = 65534 - 600 = **64,934 wasted** IP addresses
80
With classless addressing, if an organization requires 600 IP addresses, how many host bits would the organization require?
* Need **10 bits** (2^10 - 2 = 1022)
* **422 wasted** IP addresses
81
Why are subnet masks used?
* Problem: IP must give each computer a way to ***understand when a packet destination is local or on the WAN***
* Sending to host on same network: broadcast for MAC address
* Sending to host on another network: send to default gateway
* Solution: Subnet masks
* Sending computer uses subnet mask to determine where to send packet
82
What is a subnet mask?
* A mask is ***a series of initial ones followed by series of final zeros***, for a total of 32 bits
* e.g., 11111111.11111111.11111111.00000000
* (i.e., 255.255.255.0)
* The ***bit patterns*** are applied to entire addresses to isolate their components
* ***Used to separate network, subnet, and host addresses***
83
Subnet mask example
Subnet Mask
84
What is the shorthand for subnet masks?
11111111111111111111111100000000 = **/24** (24 ones) 11111111111111110000000000000000 = **/16** (16 ones) 11111111000000000000000000000000 = **/8** (8 ones)
85
How can an IP address and a subnet mask be described in a single compact statement?
* An ***IP address followed by the / and a number*** describes the IP and the address in one statement
* 201.23.45.123/24 denotes IP address plus subnet mask
* IP address = 201.23.45.123
* Subnet mask = 255.255.255.0
* 184.222.4.36/16 denotes IP address plus subnet mask
* IP address = 184.222.4.36
* Subnet mask = 255.255.0.0
86
The length of a subnet mask is the same as that of an IP address.
True or False?
* **True**
87
The subnet mask in the notation 201.23.45.123/24 is \_\_\_\_\_\_
A. 201.23.45.123
B. 255.0.255.0
C. 255.255.0.0
D. 255.255.255.0
* **C. 255.255.255.0**
88
The host ID of the address 130.57.110.128/22 consists of ______ bits.
A. 5
B. 10
C. 15
D. 20
E. 22
* **B. 10**
* (32 bits - 22 bits = 10 bits)
89
The subnet mask ______ is an example of classless subnetting?
A. /8
B. /12
C. /16
D. /24
* **B. /12**
* (/8, /16, /24 are all classful)
90
How many bits long is an IPv4 address?
* **32 bits**
91
How many possible addresses are available under IPv4?
* **≈ 4.3 billion** (232) possible addresses
92
Why is the shift to IPv6 from IPv4 necessary?
* address space ***soon to be completely allocated***
* developed in the 1980s, did not anticipate the enormous growth of the Internet
93
How many bits long is an IPv6 address?
* **128 bits**
94
How many possible addresses are available under IPv6?
* **2128** possible addresses
95
What are the advantages of IPv6 over IP v4?
* increases the number of available IP addresses
* improves security by making the Internet Protocol Security (IPSec) protocol support a standard
* improves routing efficiency
96
How are binary IPv6 addresses divided?
* The address is divided along ***eight 16-bit boundaries***
* 0010000111011010 0000000011010011 0000000000000000 0010111100111011 0000001010101010 0000000011111111 1111111000101000 1001110001011010
97
How are binary IPv6 addresses represented in hexadecimal?
* Each 16-bit block in the address is converted to hexadecimal and
* delimited with colons (called colon-hexadecimal)
* 21DA:00D3:0000:2F3B:02AA:00FF:FE28:9C5A
98
How can the hexadecimal IPv6 address be further simplified?
The address can be further simplified by...
* ***removing the leading zeros*** within each 16-bit block
* However, each block must have at least a single digit
* 21DA:D3:0:2F3B:2AA:FF:FE28:9C5A
99
Can the Internet switch immediately from IPv4 to IPv6?
* **No**,
* since the differences between IPv4 and IPv6 are substantial,
* the Internet cannot be changed from one to the other overnight
100
How is the transition from IPv4 to IPv6 being accomplished?
To permit gradual cutover and to allow for variations in timing,
* **three methods** have been developed that permit functioning in mixed IPv4/IPv6 environments.
101
What are the methods that allow functioning in mixed IPv4/IPv6 environments?
* Dual stack
* Translation
* Tunneling
102
Briefly describe the Dual Stack method of operating mixed IPv4/IPv6 environments.
* Dual stack = nodes contain the stacks for ***both IP versions***
103
Briefly describe the Translation method of operating mixed IPv4/IPv6 environments.
* Translation = the ***edge router translates*** the IPv6 header into an IPv4 header
104
What is the most popular method for operating mixed IPv4/IPv6 environments?
* **Tunneling**
105
Why is the tunneling method used?
* A packet from an IPv6 node or region of nodes (a cloud) may have to ***travel across an IPv4 cloud*** to reach another IPv6 node
106
How does the tunneling method work?
* An IPv4 tunnel is created for it to travel through
* First it needs an IPv4 address from the IPv6 edge router at the IPv4/IPv6 border
* The IPv6 router will ***encapsulate it into an IPv4 packet***
* At the other border, the IPv4 edge router will then ***decapsulate this packet***
107
What is the primary advantage of the tunneling method?
* Avoids having to assign IPv4 addresses to IPv6-only nodes within a capsule
108
What is the primary disadvantage of the tunneling method?
* ***Additional processing*** at the borders
109
Tunneling diagram
Tunneling
110
IPv6 has ______ bits.
* **128**
111
In tunneling ______ packets are encapsulated within ______ packets.
A. IPv4; IPv6
B. IPv6; IPv4
* **B. IPv6; IPv4**
112
What is the purpose of a router?
* forward traffic between networks
* is connected to two or more data lines from different networks
* forwards packets based on their destination IP address
113
In which layer do routers operate?
* network layer (layer 3)
114
What are the main functions that a router performs?
Routing involves two basic activities:
1. ***determining the optimal path*** a packet should take while traveling from source to destination
2. ***processing an individual packet and transporting it*** through an internetwork based on its IP address
115
How does a router determine how to send packets?
* Determining optimal paths can be very complex
* Each router comes with a ***routing table***
116
What does a routing table do?
* Routing tables ***indicate where to send packets*** next
117
What are the types of routing tables?
* **Static**
* **Dynamic**
118
Briefly describe a static routing table.
* Static—table entries are ***entered manually***, and ***do not change***
119
Briefly describe a dynamic routing table.
* Dynamic—entries are ***automatically updated***
120
How are switches organized, and how does this affect switching tables?
* Ethernet switches are organized in a ***hierarchy***
* only one possible port to send a frame out
* only ***one row per address ***in a switcing table
121
How are routers organized, and how does this affect routing tables?
* Routers are arranged in ***meshes***
* ***multiple alternative routes between hosts***
* a router may send a packet out more than one interface (port) and still get the packet to its destination host
122
Can a routing table contain conflicting information about where to send a packet?
* **Yes**, multiple rows may give conflicting information about what to do with a packet
123
How does a router resolve conflicting information in a routing table?
Whenever a packet arrives, the router looks at the destination IP address, then…
* Step 1: Finds all row matches
* Step 2: Finds the ***best-match row***
* Step 3: Sends the packet back out based on the best-match row
124
By what general method do routers determine how to route a packet?
* Optimal path determination
125
Describe *optimal path determination.*
* Routing protocols ***use metrics*** to evaluate what path will be the best for a packet to travel:
* Path length
* Reliability
* Delay
* Bandwidth
* Load
* Communication cost
* Routing algorithms initialize and maintain routing tables, which contain route information
* Route information ***varies depending on the routing algorithm used***
126
Routers work at the ______ layer.
* network (layer 3)
127
The two main functions of an Internet router are ______ and ______ .
* ***determine optimal path*** for the packet
* ***send the packet*** along that path
128
The path a packet takes may depend on the routing algorithm used by the router.
True or False?
* **True**
