The Bits and Bytes of Computer Networking - Week 2

Calculate how many decimal numbers a 4-bit number can represent. 256, 4, 16, 8

- 16 Review the videos in the "Network Layer" module for a refresher.

How many IP addresses does a class C network have? - 1 address - 65,536 addresses - 254 addresses - 16,777,216 addresses

- 254 addresses

What is the maximum decimal number possible to represent with 16 bits? 256, 1600, 16, 65536

- 65536

What can represent all decimal numbers from 0 to 255?

- 8 bits of data or a single octet

Select examples of routing protocols. Check all that apply. - Transmission Control Protocol - Border Gateway Protocol - User Datagram Protocol - Routing Information Protocol - Hypertext Transfer Protocol

- Border Gateway Protocol - Routing Information Protocol

Which company owns every single IP that has the number 9 as the first octet?

- IBM

What is the most common routing protocol?

- RIP (Routing Information Protocol) is one of the oldest routing protocols still in service. Hop count is the metric that RIP uses and the hop limit limits the network size that RIP can support. - OSPF (Open Shortest Path First) is the most widely used IGP (Interior Gateway Protocol) large enterprise networks.

How many bits long is an IP address?

32 bits; IP addresses are 32-bit-long numbers made up of four octets, and each octet is normally described in decimal numbers.

Which number cannot be represented by eight bits of data?

436; Eight bits of data, or a single octet, can represent all decimal numbers from 0-255. 436 is beyond this limit.

What is a subnet mask?

A subnet mask is a way for a computer to use and operators to determine if an IP address exists on the same network.

What protocol is used to discover the hardware address of a node with a certain IP address?

ARP table; An ARP table is just a list of IP addresses and the MAC addresses associated with them.

What is the correct term for the list of IP addresses and the MAC addresses associated with them?

Address Resolution Protocol (ARP)

What is an IP address (internet protocol address)?

An IP address (internet protocol address) is a numerical representation that uniquely identifies a specific interface on the network.

Who is permitted to use non-routable address space? - The IANA - It's for testing purposes only - Anyone - The IETF

Anyone; Anyone can use non-routable address space.

Which IP address is Class A?

Class A addresses are those where the first octet is used for the network ID and the last three are used for the host ID.

An ARP broadcast is sent to the special MAC address ________.

FF:FF:FF:term-36FF:FF:FF; ARP broadcasts are used to ask all devices on a local area network if they're associated with a specific IP address.

Who are dynamic IP addresses are reserved for?

In most cases, dynamic IP addresses are reserved for clients.

Who are static IP addresses reserved for?

In most cases, static IP addresses are reserved for servers and network devices.

Which protocols are Exterior Gateway Protocols?

Interior and Exterior Gateway Protocols Border Gateway Protocol (BGP) for IP. Exterior Gateway Protocol (EGP) for IP (yes, an EGP named EGP) The ISO's InterDomain Routing Protocol (IDRP)

What do IP addresses belong to?

It's important to call out that IP addresses belong to the networks, not the devices attached to those networks.

What is the Total Length Field used for?

It's used to indicate the total length of the IP datagram it's attached to.

What is similar between an IP datagram and an Ethernet frame header?

Just like any Ethernet frame, an IP datagram is a highly structured series of fields that are strictly defined.

In binary, 1 +1 = _____. 2, 10, 1, 0

Not 1

If the total amount of data that needs to be sent is larger than what can fit in a single datagram what does the IP layer need to do?

The IP layer needs to split this data up into many individual packets.

What does the IP (IPv4) packet header consist of?

The IPv4 packet header consists of 14 fields, of which 13 are required. The 14th field is optional and aptly named: options.

What is the specific name of the data packets at the Ethernet layer?

The data packets at the Ethernet layer have a specific name, it is Ethernet frames.

What is the most common version of IP?

The most common version of IP is version four or IPv4. It is also a four bit field that declares how long the entire header is. It is almost always 20 bytes in length when dealing with IPv4.

The exact opposite of a dynamic IP address is known as?

The opposite of a dynamic IP address is known as a static IP address, and this must be configured on a node manually.

A router is performing basic routing functions. What will be the third step in the transmission of a packet?

The router looks up the destination network in its routing table; The router looks up the destination network of the IP address in its routing table in the third step.

What is Service Type Field?

These eight bits can be used to specify details about quality of service or QoS technologies.

What is the Time to Live (TTL) Field?

This field is an 8-bit field that indicates how many routers hops a datagram can traverse before it's thrown away. IP header consists of a field called as Time to live field. This value indicates how long a packet can survive.

What is Header Length Field?

This is almost always 20 bytes in length when dealing with IPv4.

What is the IP Options Field?

This is an optional field and is used to set special characteristics for datagrams primarily used for testing purposes.

Interior gateway protocols are used by routers in order to share information within a single ________.

autonomous system

Ranges of IP address that anyone can use for their internal networks are known as ______.

non-routable address space

What is the difference between an IP datagram and an Ethernet frame header?

An IP datagram header contains a lot more data than an Ethernet frame header.

What is an IP datagram?

An IP datagram is a highly structured series of fields that are strictly defined.

Which routing protocol is used today?

Border Gateway Protocol (BGP) The Border Gateway Protocol (BGP) is the only currently viable EGP and is the official routing protocol used by the Internet. Exterior Gateway Protocols (EGP): Used for routing between autonomous systems. It is also referred to as inter-AS routing. Service providers and large companies may interconnect using an EGP.

What is the Header Checksum Field?

This field is a checksum of the contents of the entire IP datagram header. It is used to check the packet for its quality. It has to be calculated on each hop(router) and if it does not match then the packet has to be discarded.

Please select all of the valid IP addresses. Check all that apply. 8.8.8.8, 123.456.123.456, 192.168.1.1, 257.70.312.49

- 8.8.8.8, - 192.168.1.1 are both valid IP addresses.

A typical routing table may contain which of the following? Check all that apply. - Total hops - TTL - Destination address - Destination network

- Total hops - A routing table entry needs to know how many hops away a destination network is. - Destination network - A routing table entry has to be tied to a specific destination network.

An IP address assigned via dynamic host configuration protocol are known as _____________________________________.

- a dynamic IP address

Many modern networks you can connect a new device and an IP address will be assigned to it automatically through a technology known as ________________________ .

- dynamic host configuration protocol

Name the IP datagram header Fields?

1. Version Field 2. Header Length Field 3. Service Type Field 4. Total Length Field 5. Identification Field 6. Flag Field 7. Fragmentation Offset Field 8. Time to Live (TTL) Field 9. Protocol Field 10. Header Checksum Field 11. Source IP Address Field 12. Destination IP Address Field 13. Options Field 14. Padding Field

What is a correct form of CIDR notation? 192.168.1.0/24 192.168.1.0:24 192.168.1.0\24 192.168.1.0 + 255.255.255.0

192.168.1.0/24; CIDR notation uses a forward slash and then lists the numbers of bits in the subnet mask.

When dealing with IPv4, what is the minimum IP header length?

20 bytes The minimum size is 20 bytes (header without data) and the maximum is 65,535 bytes. All hosts are required to be able to reassemble datagrams of size up to 576 bytes, but most modern hosts handle much larger packets.

How many possible host IDs do you always lose per network?

2; - You always lose two host IDs per network. So, if a /24 network has 2^8 or 256 potential hosts, you really only have 256 - 2 = 254 available IPs to assign.

How many octets does a subnet mask have? 1 2 3 4

4; A subnet mask is the same length as an IP address.

What is Address Resolution Protocol (ARP)?

Address Resolution Protocol (ARP) is a procedure for mapping a dynamic Internet Protocol address (IP address) to a permanent physical machine address in a local area network (LAN).

What is an Identification Field?

An identification field is a 16-bit number that's used to group messages together.

What is Border Gateway Protocol (BGP)?

Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet.[1] BGP is classified as a path-vector routing protocol,[2] and it makes routing decisions based on paths, network policies, or rule-sets configured by a network administrator.

Which IP address is Class B?

Class B addresses are where the first two octets are used for the network ID, and the second two are used for the host ID.

Which IP address is Class C?

Class C addresses, as you might have guessed, are those where the first three octets are used for the network ID, and only the final octet is used for the host ID.

What is the term for the place one network ends and another begins?

Demarcation point can also be referred as demarc extension, or point of demarcation, or simply demarc.

What are the two main types of interior gateway protocols?

Distance-vector routing protocols Link-state routing protocols.

As an IT support specialist, what is a common problem you might run into with subnetting?

Incorrect subnetting setups are a common problem you might run into as an IT support specialist, so it's important to have a strong understanding of how this works.

What does CIDR stand for? Classless Inter-Domain Routing Classful Identification Routing Classless Internet Destination Routing Classful Inter-Destination Routing

It means - Classless Inter-Domain Routing

Which are a type of interior gateway protocol? (Check all that apply)

Link state routing protocols; Link state protocols get their name because each router advertises the state of the links of each of its interfaces. This information about each router is propagated to every other router on an autonomous system. Distance-vector protocols; A router using a distance vector protocol basically just takes its routing table, which is a list of every network known to it and how far away these networks are in terms of hops. Then the router sends this list to every neighboring router, which is basically every router directly connected to it.

Ranges of IP addresses that anyone can use for their internal networks are known as ______.

Non-routable address space; Non-routable address space can be used by anyone.

What are the types of routing protocols?

Router protocols include: - Routing Information Protocol (RIP) - Interior Gateway Protocol (IGRP) - Open Shortest Path First (OSPF) - Exterior Gateway Protocol (EGP) - Enhanced Interior Gateway Routing Protocol (EIGRP) - Border Gateway Protocol (BGP) - Intermediate System-to-Intermediate System (IS-IS)

What is the Padding Field?

Since the IP options field is both optional and variable in length, the padding field is just a series of zeros used to ensure the header is the correct total size.

What is the process of taking a large network and splitting it up into many individual and smaller subnetworks called?

Subnetting

The process of taking a large network and splitting it up into many individual and smaller subnetworks is known as ________.

Subnetting; Subnetting allows for much finer-grained controls of network sizes than the old class system could support.

What is the process of taking a large network and splitting it up into many individual and smaller subnetworks called?

Subnetting; Subnetting is the process of taking a large network and splitting it up into many individual and smaller subnetworks, or subnets.

What is the maximum size of a single datagram and the largest number you can represent with 16 bits?

The Total Length field is 16 bits, and this field indicates the size of an individual datagram. The maximum size of a single datagram is the largest number you can represent with 16 bits: 65,535.

What is a Flag Field used for?

The flag field is used to indicate if a datagram is allowed to be fragmented, or to indicate that the datagram has already been fragmented.

What are different types of routing?

There are 3 types of routing: - Static routing - Static routing is a process in which we have to manually add routes in the routing table. - Default Routing - This is the method where the router is configured to send all packets towards a single router (next hop). - Dynamic Routing - This is also called Adaptive Routing, which is a process where a router can forward data via a different route or given destination based on the current conditions of the communication circuits within a system.

How many classes of available IP ranges are there, and name them?

There are five classes of available IP ranges: - Class A - 1.0.0.1 to 126.255.255.254 - Supports 16 million hosts on each of 127 networks. - Class B - 128.1.0.1 to 191.255.255.254 - Supports 65,000 hosts on each of 16,000 networks. - Class C - 192.0.1.1 to 223.255.254.254 - Supports 254 hosts on each of 2 million networks. - Class D - 224.0.0.0 to 239.255.255.255 - Reserved for multicast groups. - Class E - 240.0.0.0 to 254.255.255.254 - Reserved for future use, or research and development purposes. This class system has mostly been replaced by a system known as CIDR or Classless Inter-Domain Routing.

What is the Protocol Field?

This is another 8-bit field that contains data about what transport layer protocol is being used. The protocol field in the IP header is an 8-bit number that defines what protocol is used inside the IP packet. TCP and UDP are only two of the possible protocols that can be filtered on, although they are most common.

TTL stands for _______.

Time to Live; TTL is used to make sure that an undeliverable packet doesn't spend all of eternity waiting for delivery.