ASSIGNMENT ON NETWORKING
Q.1 Identify the five components of a data communication system.
Ans. The five components are:
- Message - It is the information to be communicated. Popular forms of information include text, pictures, audio, video etc. Text is converted to binary, number doesn’t converted, image is converted to pixels, etc.
- Sender - It is the device which sends the data messages. It can be a computer, workstation, telephone handset etc.
- Receiver - It is the device which receives the data messages. It can be a computer, workstation, telephone handset etc.
- Transmission Medium - It is the physical path by which a message travels from sender to receiver. Some examples include twisted-pair wire, coaxial cable, radio waves etc.
- Protocol - It is a set of rules that governs the data communications. It represents an agreement between the communicating devices. Without a protocol, two devices may be connected but not communicating.
Q.2 what are the various popular communication tools? Solve by www.solvezone.in
Ans. Mail – Slow and costly as it is, traditional mail is still very effective for delivering invitations and personal messages. It is also more impactful for communicating with legislators and is often the only way to contact people who are not computer users.
Website – Establishing a website for your grassroots coalition will allow you to post alerts, events, group membership, mission, and a host of other information in a place that is accessible to members and non-members alike. Because building an engaging and easy to navigate website can be complicated, some groups may choose not to have one. Also, a useful website must be updated regularly. However, if you decide to go this route there are a myriad of services that will host your website for free and many tools available to make development and maintenance much easier.
Email – The workhorse of grassroots advocacy, it is cheap and allows you to deliver longer more dynamic messages that other messages. Because of the shear bulk of email most people receive, it is important to use it wisely. Also consider putting your email address list in the ‘blind copy’ field. This keeps member addresses private and avoids the messy “Reply to All” email conversations that can happen with large groups.
Listserv – An email listserv allows anyone with access to send an email to an entire group of email addresses by sending it to one listserv address. Like using ‘blind copy,’ a listserv also keeps member email addresses private from other people on the list. While it is tempting to allow all members access to the listserv so that they can engage each other, this leads to a lot of email and turns members off. Consider limiting listserv access to group leadership.
Texting – Rather like the phone trees of old, test messages allow you to personally communicate directly and instantly with your coalition members. Because most phones allow you to create contact groups, you can also usually send a message to your entire network at once. This is particularly useful for urgent or time-sensitive messages, though it is not free and can be seen as intrusive. This is a high-power tool, so use it sparingly. Also, since many people do not text, consider asking people beforehand if they would like to be added to your list.
Legislative Action Center – MASA’s Legislative Action Center is not only for MASA members, but anyone who wants to advocate on behalf of public education. MASA Government Relations frequently puts out notification to members about relevant and timely legislative issues and gives them an opportunity to weigh in with their local legislators and media through email, phone calls, and letters to the editor. Consider forwarding our action alerts along to your grassroots coalition. You can also link to them through your website, Facebook, and Twitter! The convenient Tell-A-Friend feature also allows activists to quickly send the alerts along to their contacts, further expanding the circle of influence.
Q.3 What is the difference between local and remote log-in in TELNET?
Ans. Local login command is used to ensure the secure remote login by telnet and it is also used to store the information about that remote user in the database. While creating the users with previlage with login local command the TACACS or RADIUS protocol is used for authentication and accounting purpose.
Telnet permits a user to connect to an account on a remote machine. A client program running on the user’s machine communicates using the Telnet protocol with a server program running on the remote machine.
Remote log and Telnet are two very similar protocols as they both allow a user to remotely connect to another computer and then send commands that are executed on that computer. They both allow a person to manipulate and extract data from a computer even without being physically in contact with it. But, there are a couple of major differences between Remote log and telnet. The most major difference between Remote log and telnet is in the way that Remote log allows the credentials of the client to be stored in a local remote hosts file so that the just needs to access the remote server and he is connected automatically. The client program passes the credentials automatically. This can be both for password and username or password only. The problem with this is that leaving a terminal unattended leaves not only that terminal vulnerable but also all the other remote computers that has entries in the local remote hosts file. It is not implemented in telnet, thus there is no risk of exposing the server to unnecessary risk.
The first one is the ability to pass settings and environment variables as parameters. Of course, you can also change the settings and environment variables by entering commands after the session is established, but for many, it is an unnecessary step. It was later discovered though that this feature exposes the server to security risks. Thus, many servers disable the use of this feature even if it slightly inconveniences the client.
But the most important thing about these two is the same with both and not actually a difference. Both Remote log and telnet are not secure protocols that send messages in plain text; a form that is easily readable when intercepted. So, the use of both is not advisable when routing through public networks like the internet. Even when restricted to a local private network, the use of either Remote log or telnet is still discouraged. For security reasons, Remote log and telnet are no longer being used. Other protocols like SSH has largely taken over for these two protocols.
Q.4 Explain why ftp does not have a message format?
Ans. FTP allows a user to copy files to and from a remote machine. The client program also sends commands to the server program to coordinate the copying of files between the two machines on behalf of the user. The FTP client connects to the remote machine which prompts the user to enter a login identifier and a password. However, some users may not have their own accounts on the remote machine. To grant access to a broad set of users, many FTP servers have a special account (e.g. anonymous) that does not require password information. Instead, the user logs in using guest or his email address as password. The FTP server coordinates access to a collection of files in various directories.
FTP does not have a message format because of security reasons. It is not safe for FTP, also known as file transfer protocol, source code to be shared openly. The specification of FTP includes more than 30 different commands, which are transmitted over the control connection in NVT ASCII format. The commands are not case-sensitive and may have arguments; each command ends with a two character sequence of a carriage return (CR) followed by a line feed (LF). It must be emphasized here that these commands are different from the commands typed by the user at the interface provided by the client. Transferring a single file for instance requires only a single user-level command (e.g., put or get), but this single command triggers the client to send a set of FTP commands to the server. The FTP server responds to each command with a three-digit reply code (for the FTP client) and an optional text message (for the user). The control connection persists over a sequence of FTP commands, as the client and the server continue their dialogue. The typical interaction starts with a command that identifies the user on the server machine followed by another command to send the user password. The arguments for these commands are gleaned from the user’s input (his account name and password). The server uses this information to verify whether the user has an authorized account on the remote machine, and in the case of anonymous FTP decides on the set of directories to which the anonymous guest has access. The next set of commands depends on the user request to send, receive, or view the files in a present Directory.
Q.5 The following is a dump of a TCP header in hexadecimal format.
05320017 00000001 00000000 500207FF 00000000
- What is the source port number?
Ans. Source port is 2 bytes take 05 32 = 1330
- What is the destination port number?
Ans. 2 bytes as destination address 00 17 == 23 (default TCP port)
- What is the sequence number?
Ans. 4 bytes as sequence number 00 00 00 01 = 1
- What is the acknowledgment number?
Ans. 4 bytes as acknowledgment number 00 00 00 00 = 0
- What is the length of the header?
Ans. 4 bits as HLEN 5 =5, this indicates number of sets of 4 bytes which makes the header length = 20bytes.
- What is the type of the segment?
Ans. 6 bits are reserved i.e.0 =0000and 2 bits from hex 0 next 6 bits are control bits = remaining 2 bits from hex 0 and 4 bits of 2
- What is the window size?
Ans. 2 bytes indicate the window length 07 FF = 2047 byte
Q.1) Explain why most of the addresses in class A are wasted. Explain why a medium size or large size corporation does not want a block of class C addresses.
Ans. IP addresses are classified into 3 classes’ (groups) depending on the decimal equivalent of the 1st octet in the address as below:
0-255.xxx.xxx.xxx = all address´s
Intended for a small number of networks that had a large number of computers (hosts) attached. Class A IP Address have a value in the range 1...126 as the first octet. The values 0 and 127 are not available because they have special uses. Class A addresses use the first octet to identify the network which means that 126 addresses are usable, each of which can support 16,777,216 computers (hosts).
Intended for some networks that had an intermediate number of computers (hosts) attached. Class B IP Addresses have a value in the range 128...191 as the first octet. Class B addresses use the first two octets to identify the network which means that 16,320 addresses are usable, each of which can support 65,536 computers (hosts).
Intended for a large number of networks that would have a small (relatively) number of computers (hosts) attached. Class C IP Addresses have a value in the range 192...223 as the first octet. Class C addresses use the first three octets to identify the network which means that 2,080,800 addresses (networks) are possible, each of which can support 254 computers (hosts). A class A subnet has 24 bits worth of addressing, which is enough for almost 17 million individual devices. Most entities have only a small fraction of this number of devices, so most of the addresses are not used, that’s why most of the address in class A are wasted or it can be said as A block in Class A address is too large for almost any organization. A single Class A block has 16,777,216 unique hosts. A large part of this addresses are never used, even by the largest organizations where they are assigned.
An IP consist of 4 parts AAA.BBB.CCC.xxx - the first part is called A-class, the second part B-class and the third part C-class. So any IP under the last part will be in the same C-class. So for example:
220.127.116.11 and 18.104.22.168 are in the same C-class but
22.214.171.124 and 126.96.36.199 is in two different C-classes
Many smaller host only mange one single or very few C-classes and therefore makes it difficult to get multiple IPs in different C-classes if you host all your sites the same place. Larger hosts have many C-classes (I believe some even have almost full B-classes but unless you specifically request your various sites to be on different C-class IPs you still could end up on the same
Now, due to how the classes of the older system were designed, there are over 2 million Class C address blocks, but only 16,384 Class Bs. While 16,384 seems like a lot at first glance, there are millions of organizations and corporations around the world. Class B allocations were being consumed at a rapid pace, while the smaller Class C networks were relatively unused. A Class B address block contains a very large number of addresses (65,534) but a Class C block has only a relatively small number (254). There are many thousands of “medium-sized” organizations who need more than 254 IP addresses, but a small percentage of these needs 65,534 or anything even close to it. When setting up their networks, these companies and groups would tend to request Class B address blocks and not Class C blocks because they need more than 254, without considering how many of the 65,000-odd addresses they really would use.
Q.2) How many multicast addresses can be supported for the IPv4 protocol in Ethernet. How many multicast addresses can be supported for the IPv4 protocol. What is the size of address space lost when we transform a multicast IPv4 address to an Ethernet multicast address?
Ans. A multicast address is a logical identifier for a group of hosts in a computer network, that are available to process datagrams or frames intended to be multicast for a designated network service. Multicast addressing can be used in the Link Layer (Layer 2 in the OSI model), such as Ethernet multicast, and at the Internet Layer(Layer 3 for OSI) for Internet Protocol Version 4 (IPv4) or Version 6 (IPv6) multicast.
Multicast Address for the IPv4 protocol in Ethernet-
Ethernet frames with a value of 1 in the least-significant bit of the first octet [note 2] of the destination address are treated as multicast frames and are flooded to all points on the network. While frames with ones in all bits of the destination address (FF:FF:FF:FF:FF:FF) are sometimes referred to as broadcasts, Ethernet network equipment generally does not distinguish between multicast and broadcast frames. Modern Ethernet controllers filter received packets to reduce CPU load, by looking up the hash of a multicast destination address in a table, initialized by software, which controls whether a multicast packet is dropped or fully received.
Some well-known Ethernet multicast addresses
Ethernet multicast address
CDP (Cisco Discovery Protocol), VTP (VLAN Trunking Protocol)
Cisco Shared Spanning Tree Protocol Address
Spanning Tree Protocol (for bridges) IEEE 802.1D
01:80:C2:00:00:03, or 01:80:C2:00:00:0E
Link Layer Discovery Protocol
Spanning Tree Protocol (for provider bridges) IEEE 802.1AD
Ethernet flow control (Pause frame) IEEE 802.3x
Ethernet OAM Protocol IEEE 802.3ah (A.K.A. "slow protocols")
01:00:5E:00:00:00 - 01:00:5E:7F:FF:FF
IPv4 Multicast (RFC 1112), insert the low 23 Bits of the multicast IPv4 Address into the Ethernet Address (RFC 7042 2.1.1.)
IPv6 Multicast (RFC 2464), insert the low 32 Bits of the multicast IPv6 Address into the Ethernet Address (RFC 7042 2.3.1.)
Multicast Address for the IPv4 protocal-
IPv4 multicast addresses are defined by the leading address bits of 1110, originating from the classful network design of the early Internet when this group of addresses was designated as Class D. The Classless Inter-Domain Routing (CIDR) prefix of this group is 188.8.131.52/4. The group includes the addresses from 184.108.40.206 to 220.127.116.11. Address assignments from within this range are specified in RFC 5771, an Internet Engineering Task Force (IETF) Best Current Practice document (BCP 51).
The following table is a list of notable well-known IPv4 addresses that are reserved for IP multicasting and that are registered with the Internet Assigned Numbers Authority (IANA).
Ethernet layer acts as an imperfect filter and the IP layer will have to decide whether to accept the datagram’s the data-link layer passed to it. The IP layer acts as a definitive perfect filter. Both Ethernet and FDDI frames have a 48 bit destination address field. In order to avoid a kind of multicast ARP to map multicast IP addresses to Ethernet/FDDI ones, the IANA reserved a range of addresses for multicast: every Ethernet/FDDI frame with its destination in the range 01-00-5e-00-00-00 to 01-00-5e-ff-ff-ff (hex) contains data for a multicast group. The prefix 01-00-5e identifies the frame as multicast; the next bit is always 0and so only 23 bits are left to the multicast address. As IP multicast groups are 28 bits long, the mapping cannot be one-to-one. Only the 23 least significant bits of the IP multicast group are placed in the frame. The remaining 5 high-order bits are ignored, resulting in 32 different multicast groups being mapped to the same Ethernet/FDDI address
Q.3) Name the advantages of optical fiber over twisted-pair and coaxial cable.
Ans. The biggest is less attenuation (degradation) of signal, so that a message can travel significantly further over an optical fibre than over a copper (twisted pair of coax) cable before it becomes too garbled to understand. In addition, fibre optic cables are generally immune to electromagnetic interference (such as strong electrical or magnetic fields) nearby, while copper cables can have such interference reduce or completely destroy their ability to carry signals. Finally, it is much easier to transmit on multiple channels (frequencies) over fibre than over copper, so a fibre optic cable can handle many more simultaneous message streams than twisted pair or coax.
fibre allows hugely greater distances between endpoints, is practically immune to outside interference, and can handle hundreds or thousands of times more signal channels than twisted pair or coaxial cable. Coaxial cable is used predominantly for video and not used much at all anymore for enterprise networks, so I would not worry about that one unless you are looking for legacy information. As for fiber and twisted pair, we will address your questions one at a time and compare the two.
This will vary with the electronics, category of fiber or copper and distances spanned. Category 5e is supposed to be capable of providing gigabit performance. However it is estimated that 50% of all Category 5e UTP is not really 5e and can´t perform to 5e as it was installed prior to the standards. The standards recommend recertification of all 5e channels prior to moving to gigabit. Cat 6 is generally what is being installed today. Work is ongoing at the IEEE for 10GBASE-T (10 gigabits per second) over Category 6 or an augmented 6 that is characterized out to 625 MHz. Today´s category 6 is 250 MHz, 5e is 100 MHz. You will also notice that many vendors have cabling and connectivity that are in excess of these numbers. This is because they have "margin and headroom" which basically is a forgiveness factor for what can happen over a cable channel, such as interference, etc.
Fiber transmission rates depend on distance, diameter of the fiber and the light source used to move the light over the fiber. This can be done via laser, VCSEL, etc.
Fiber is more expensive than copper due to the light emitting equipment and cost. Copper comes in two varieties, shielded and non-shielded. In the U.S., most companies use non-shielded copper. PC´s come with copper ports in them already, so that is also a benefit. Fiber to the desktop can be very expensive when you have to add fiber NICs and fiber switches. For instance – 10G fiber is supposed to settle at around 10x the cost of gigabit, while the copper alternative should settle at around 3x.
Ease of Installation
If properly trained, none of them are hard to install. However, proper training should include the entire channel, not just the termination. It does take a bit longer to terminate fiber than copper.
Lengths are in the table above for fiber and copper is 100m as a standard although most are not that long.
One problem with UTP is that it can be "snooped" or eavesdropped. Interference is also not an issue with shielded systems or fiber. They key to controlling interference with UTP (unshielded) is to have it properly installed by someone that understands all of the channel specifications including proper distances from any source of interference.
Q.4) How does sky propagation differ from line-of-sight propagation?
Ans. Sky propagation is not limited to send signals to receivers, line-of-sight is dependent on direction, range and objects which may occur between sender and receiver.
Sky propagation is not limited in sense of distance of source and destination and not restricted by being in range or in direction with antennas. In this case, signals are sent towards space and then signals have vast range to reach receivers back to the earth. We should consider this thing, Sky is the beyond the troposphere and ionosphere. When signals gone beyond these spheres so when satellite will reflect those signals back, they will have much vast access to receivers.
On other hand line-of-sight propagation is limited because of earth curvature. If antennas (source and target) are not directional, not facing each other or something preventing to establish the connection so communication won’t be made.
Electromagnetic waves - radio waves propagate through the air and vacuum by altering the electro-magnetic (EM) properties of space. They will be reflected whenever the EM properties of the space change. Incoming radiation from the sun partly ionizes some of the air molecules in the upper atmosphere and, for some frequencies, this will reflect (or refract) the EM signal.
This allows the EM signal to be reflected over long distances - even around the world - multiple hops. This effect is only true for HF radio - frequencies up to 10MHz or so. And varies naturally, day and night.
A related phenomenon affecting the upper atmosphere is that incoming meteorites may give temporary ionization tracks. These have been used for burst transmissions but are not suitable for broadcast communications.
Higher frequencies, 100 MHz or so, use line - of - sight transmission, for these high frequencies are not affected by the ionized layers. there are various layers on the atmosphere.. D - E - F1 and F2 layers. The F1 layer is opaque to low frequency radio waves (HF).
(AM is just a modulation type). The medium frequency wave will propagate to the F2 layer and be reflected by excited Nitrogen atoms in this region, as does the F1 for the lower frequencies.
E layer propagation works much the same way but reflects VHF and UHF (90 -800 Mhz). VHF is really 30 Mhz up to 300Mhz, but above 90 Mhz the E layer reflects the signals better. Sporadic E is a densely ionized layer of Nitrogen atoms that are ionizezed by high energy particles from the solar wind. Excited Oxygen Helium and Hydrogen atoms also plasmate too. These pasmated atoms (highly excited atoms) propagate UHF and microwaves, too.
Modulation types have no bearing on propagation, though Single Sideband (SSB) suppressed carrier with a bandwidth of 3khz and CW (Continuous Wave - 200 - 800Hz) and a narrow band with a narrow IF pass-band will be detected by the envelope modulation detector before any other modulation types at further distances.
The D layer will break down when the sun falls below the horizon, and medium wave signals will bounce of the F1 and F2 layers and travel further.
1) Put the following in the correct order, from high to low: session (a), presentation (b), physical (c), data link (d), network (e), application (f), transport (g).
- a) c, d, e, g, a, b, f
- b) f, a, b, g, d, e, c
- c) f, b, g, a, e, d, c
- d) f, b, a, g, e, d, c
Ans- d) f, b, a, g, e, d, c
2) The _________ layer provides for hardware addressing.
- a) Transport
- b) Network
- c) Data link
- d) Physical
Ans- c) Data link
3) Which component of the data link layer for IEEE specifies network protocols?
- a) LLC
- b) MAC
- c) 802.5
- d) 802.3
Ans- a) LLC
4) The network layer solves all of the following problems except ___________.
- a) Broadcast problems
- b) Conversion between media types
- c) Hierarchy through the use of physical addresses
- d) Collision problems
Ans- c) Hierarchy through the use of physical addresses
5) Connection multiplexing is done through the use of a ________ number.
- a) Socket
- b) Hardware
- c) Network
- d) Session
Ans- a) Socket
6) Reliable connections go through a three-way handshake. Place the following in the correct order:
ACK (1), SYN, (2), SYN/ACK (3).
- a) 2, 1, 3
- b) 3, 2, 1
- c) 2, 3, 1
- d) 1, 2, 3
Ans- c) 2, 3, 1
7) _________ describe(s) users working from home.
- a) SOHO
- b) Branch office
- c) Regional office
- d) Corporate office
Ans- a) SOHO
8) _________ has a physical star topology but a logical ring topology
- a) Ethernet
- b) FDDI
- c) Token Ring
- d) FDDI and Token Ring
Ans- c) Token Ring
9) A _________ uses Gigabit Ethernet as a media type
- LAN and MAN
Ans- B. LAN
10) The TCP/IP protocol stack has ________ layers.
- a) 4
- b) 5
- c) 6
- d) 7
Ans- d) 7
11) A Class A address has _________ host bits.
- a) 8
- b) 16
- c) 20
- d) 24
Ans- d) 24
12) 18.104.22.168 is a Class __________ address.
- a) A
- b) B
- c) C
- d) None of the above
Ans- b) B
13) Which of the following is a valid subnet mask value?
- a) 255.0.255.255
- b) 0.0.0.255
- c) 255.255.254.0
- d) 255.255.255.256
Ans- c) 255.255.254.0
14) You are given a Class C network with 25 bits of networking. How many subnets do you have?
- a) 1
- b) 2
- c) 3
- d) 4
Ans- b) 2
15) You are given a Class B network with a subnet mask of 255.255.255.192. How many host addresses are there on each subnet?
- a) 30
- b) 62
- c) 126
- d) 254
Ans- b) 62
16) You are given the following addressing information: 192.168.37.192/25. What type of address is this?
- a) Network
- b) Directed broadcast
- c) Host
Ans- c) Host
17) When choosing a networking product, you should consider all of the following except _______.
- a) Ease of installation and support
- b) Product features and functions
- c) Backplane capacity
- d) Amount of memory
Ans- c) Backplane capacity
18) When connecting a router to a PC, use a __________ cable.
Ans- A. Crossover
19) With _________ switching, the switch reads the destination MAC address of the frame and immediately starts forwarding the frame.
Ans- B. Cut-through
20) Which type of traffic is sent to a group of devices?
Ans- A. Multicast
21) What subnet mask would you use to set up a default route?
- Depends on the type of network number
- None of these answers
Ans- A. 0.0.0.0
22) When choosing a dynamic routing protocol, which of the following should not be considered?
- Metrics used
- How routing information is shared
- How routing information is processed
- Number of PCs in the network
23) A routing protocol will use a(n) _________ to determine which path is the best path.
- Administrative distance
- Hop count
Ans- B. Metric
24) Which type of routing protocol uses the Shortest Path First algorithm?
- Distance vector
- Link state
Ans- A. Distance vector
25) What command activates the IP routing process?
- no shutdown
Ans- A. router
26) RIP has a maximum hop count of ____________ hops.
Ans- B. 15
27) Which of the following is false concerning OSPF?
- It provides a loop-free topology.
- It is a classful protocol and allows for a hierarchical design.
- It requires more memory and processing cycles than distance vector protocols.
- It is complex to configure and difficult to troubleshoot.
Ans- B. It is a classful protocol and allows for a hierarchical design.
28) The OSPF process ID is __________.
- Locally significant and is the router ID
- Globally significant and must be configured on every router
- Locally significant
- OSPF doesn’t use a process ID, but an AS number
Ans- C. Locally significant
29) An OSPF’s router ID is based on __________.
- The lowest IP address on its loopback interface, if configured, or the lowest IP address on its
- The highest IP address on its loopback interface, if configured, or the highest IP address on its
- The highest IP address on its active interfaces, if configured, or the highest IP address on its
- The lowest IP address on its active interfaces, if configured, or the lowest IP address on its
Ans- B. The highest IP address on its loopback interface, if configured, or the highest IP address on its active interfaces
30) You are given a Class C network, 192.168.1.0/24. You need one network with 120 hosts and three networks with 60 hosts. What subnet mask values would you use?
- 255.255.255.128 and 255.255.255.192
D None of these
Ans- A. 255.255.255.128 and 255.255.255.192
31) Which of the following is a private address?
Ans- D. 172.16.255.89
32) Which of the following reasons might you need to use address translation?
- You have to use public addressing because your ISP didn’t assign you enough private addresses.
- You are using private addresses but have changed ISPs, and your new ISP won’t support these
- You want to assign the same IP address to multiple machines so that users on the Internet see this
offered service as a single logical computer.
- You are merging two companies that use different address spaces.
Ans- D. You are merging two companies that use different address spaces.
33): As the data moves from the Upper to Lower Layers, headers are
Ans- a. Added
34): In communication satellite, multiple repeaters are known as
Ans- d. transponders
35): While transmitting odd-parity coded symbols, the number of zeros in each symbol is
- a and b both
Ans- d. unknown
36): Which type of network provides customers with limited access to corporate data such as inventory,Parts lists, and orders?
Ans- b. Extranet
37): An example of an analog communication method is
- laser beam
- voice grade telephone line
- all of the above
Ans- d. all of the above
38): Physical Layer is located in which layer of OSI
- Layer 5
- Layer 3
Ans- c. Layer1
39): Physical Layer can only communicate with
- Application Layer
- Data link Layer
- Transport Layer
- Network Layer
Ans- b. Data link Layer
40): The Calculated value used by the Data Link Layer for error detections is
- The Data Link layer does not implement error detection
Ans- c. CRC