CCNA 1 Chapter 3 Network Protocols and Communications Questions
What are the 3 parts of a packet?
Each packet consists of three distinct parts, each of which each part contains some of the components listed above: Header: typically includes an alert signal to indicate that the data is being transmitted, source and destination addresses and clock information to synchronise the transmission. Data: The actual data being sent. It can vary (depending on the network) from 48 bytes to 4 kilobytes. Trailer: The contents of the trailer (or even its existence) can vary among network types, but it normally includes a Cyclic Redundancy Checksum (CRC) which lets the network determine whether or not a packet has been damaged in transmission.
What are the three major network protocols?
In this model, there are four layers, including: Ethernet (Physical/Data Link Layers) IP/IPX (Network Layer) TCP/SPX (Transport Layer) HTTP, FTP, Telnet, SMTP, and DNS(combined Session/Presentation/Application Layers)
What does ICMP do?
Internet Control Message Protocol (ICMP) is a TCP/IP network layer protocol that provides troubleshooting, control and error message services. ICMP is most frequently used in operating systems for networked computers, where it transmits error messages. ICMP is a protocol for sending various messages to report network conditions—it is not ping. ... An ICMP packet is therefore an IP packet with ICMP in the IP data portion. Every ICMP message will also contain the entire IP header from the original message, so that the end system will know which packet actually failed. it is ip support
What does IMAP stand for and what does it do?
Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by RFC 3501. it is a email protocol
Which protocol stack does Internet use?
Internet Protocol stack in Internet protocol suite (TCP/IP) The Internet protocol suite is set of communications protocols used on the Internet. It is commonly known as TCP/IP because the foundational protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP).
What are the different layers of TCP IP protocol stack?
It stands for Transmission Control Protocol/Internet Protocol. The TCP/IP model is a concise version of the OSI model. It contains four layers, unlike seven layers in the OSI model.
What does Domain Name System DNS do?
It translates web addresses that people use into addresses the Internet uses. it is part of application layer and is a naming system it is a host config protocol
Layer 3 - Network
Layer 3 provides switching and routing technologies, creating logical paths, known as virtual circuits, for transmitting data from node to node. Routing and forwarding are functions of this layer, as well as addressing, internetworking, error handling, congestion control and packet sequencing. Layer 3 Network examples include AppleTalk DDP, IP, IPX.
What are the 7 layers of the OSI model?
1. Physical 2. Data Link 3. Network 4. Transport 5. Session 6. Presentation 7. Application
What does ARP do?
1. sends out a broadcast message with an ARP request packet and IP address of the system it's trying to find 2. the system it's trying to find replies with physical address 3. stores address in ARP cache
What are the sizes of the packets?
A packet is a block of data with length that can vary between successive packets, ranging from 7 to 65,542 bytes, including the packet header. Packetized data is transmitted via frames, which are fixed-length data blocks. The size of a frame, including frame header and control information, can range up to 2048 bytes.
What is a protocol stack and why is it layered?
A protocol stack is layers of protocols that build and rely on each other. Protocols are layered so that new protocols can be developed without abandoning fundamental aspects of lower levels.
The development of TCP/IP occurred during the ________ era. A) cloud and mobile computing B) general-purpose mainframe and minicomputer C) enterprise computing D) personal computer E) enterprise computing
E) enterprise computing
Data Link Addresses
The data link, or Layer 2, physical address has a different role. The purpose of the data link address is to deliver the data link frame from one network interface to another network interface on the same network. Before an IP packet can be sent over a wired or wireless network, it must be encapsulated in a data link frame so it can be transmitted over the physical medium. As the IP packet travels from host-to-router, router-to-router, and finally router-to-host, at each point along the way the IP packet is encapsulated in a new data link frame. Each data link frame contains the source data link address of the NIC card sending the frame, and the destination data link address of the NIC card receiving the frame. The Layer 2, data link protocol is only used to deliver the packet from NIC-to-NIC on the same network. The router removes the Layer 2 information as it is received on one NIC and adds new data link information before forwarding out the exit NIC on its way towards the final destination. The IP packet is encapsulated in a data link frame that contains data link information, including a: Source data link address - The physical address of the device's NIC that is sending the data link frame. Destination data link address - The physical address of the NIC that is receiving the data link frame. This address is either the next hop router or of the final destination device. Example 1A-23-F9-CD-06-9B
Development of TCP/IP
The first packet switching network and predecessor to today's Internet was the Advanced Research Projects Agency Network (ARPANET), which came to life in 1969 by connecting mainframe computers at four locations. ARPANET was funded by the U.S. Department of Defense for use by universities and research laboratories.
Layer 6 - Presentation Layer
This layer provides independence from differences in data representation (e.g., encryption) by translating from application to network format, and vice versa. The presentation layer works to transform data into the form that the application layer can accept. This layer formats and encrypts data to be sent across a network, providing freedom from compatibility problems. It is sometimes called the syntax layer. Layer 6 Presentation examples include encryption, ASCII, EBCDIC, TIFF, GIF, PICT, JPEG, MPEG, MIDI.
de-encapsulation
This process is reversed at the receiving host, and is known as de-encapsulation. De-encapsulation is the process used by a receiving device to remove one or more of the protocol headers. The data is de-encapsulated as it moves up the stack toward the end-user application.
What does TFTP do?
Trivial File Transfer Protocol (TFTP) is an Internet software utility for transferring files that is simpler to use than the File Transfer Protocol (FTP) but less capable. It is used where user authentication and directory visibility are not required. its a file transfer protocol
What does UDP do?
UDP (User Datagram Protocol) is an alternative communications protocol to Transmission Control Protocol (TCP) used primarily for establishing low-latency and loss-tolerating connections between applications on the internet. part of transport layer Following implementations uses UDP as a transport layer protocol: NTP (Network Time Protocol) DNS (Domain Name Service) BOOTP, DHCP. NNP (Network News Protocol) Quote of the day protocol. TFTP, RTSP, RIP, OSPF.
what are the Message Delivery Options?
Unicast, Multicast & Broadcast
What is upper layer protocol?
Upper Layer Protocol. ... (ULP, or upper-layer protocol) Any protocol residing in OSI layers five or above. The Internet protocol suite includes many upper layer protocols representing a wide variety of applications e.g. FTP, NFS, RPC, and SMTP.
Encapsulation
When sending messages on a network, the encapsulation process works from top to bottom. At each layer, the upper layer information is considered data within the encapsulated protocol. For example, the TCP segment is considered data within the IP packet.
What are the 4 layers of the TCP IP model?
application, transport, internet, network access
What does a DHCP do?
automatically assigns IP addresses Allows addresses to be reused when no longer needed. it is a host config protocol
What is OSI reference model in networking?
OSI (Open Systems Interconnection) is a reference model for how applications communicate over a network. A reference model is a conceptual framework for understanding relationships. The OSI model provides an extensive list of functions and services that can occur at each layer. It also describes the interaction of each layer with the layers directly above and below. The TCP/IP protocols discussed in this course are structured around both the OSI and TCP/IP models. Click each layer of the OSI model to view the details. The functionality of each layer and the relationship between layers will become more evident throughout this course as the protocols are discussed in more detail.
Layer 1 - Physical
OSI Model, Layer 1 conveys the bit stream - electrical impulse, light or radio signal — through the network at the electrical and mechanical level. It provides the hardware means of sending and receiving data on a carrier, including defining cables, cards and physical aspects. Fast Ethernet, RS232, and ATM are protocols with physical layer components. Layer 1 Physical examples include Ethernet, FDDI, B8ZS, V.35, V.24, RJ45.
Layer 4 - Transport
OSI Model, Layer 4, provides transparent transfer of data between end systems, or hosts, and is responsible for end-to-end error recovery and flow control. It ensures complete data transfer. Layer 4 Transport examples include SPX, TCP, UDP.
Layer 7 - Application Layer
OSI Model, Layer 7, supports application and end-user processes. Communication partners are identified, quality of service is identified, user authentication and privacy are considered, and any constraints on data syntax are identified. Everything at this layer is application-specific. This layer provides application services for file transfers, e-mail, and other network software services. Telnet and FTP are applications that exist entirely in the application level. Tiered application architectures are part of this layer. Layer 7 Application examples include WWW browsers, NFS, SNMP, Telnet, HTTP, FTP
Is OSPF better than Eigrp?
OSPF can only summarize between areas. OSPF is link state so it has a better view of the entire network than EIGRP before it runs the SPF algorithm. Network administrators will usually be more comfortable with OSPF because it's more commonly deployed. Both protocols have advantages and disadvantages.
Why BGP is used over OSPF?
OSPF requires intensive use of memory and CPU resources. As against, in BGP the need of device resources relies on the size of the routing table. BGP is more flexible and scalable than OSPF and used on a larger network, unlike OSPF. The primary objective of the OSPF is to determine the best route, i.e., fastest.
What does OFPF do?
Open Shortest Path First (OSPF) is a routing protocol for Internet Protocol (IP) networks. It uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). It means dividing routers inside a single autonomous system running OSPF, into areas where each area consists of a group of connected routers. ... Having many routers exchange the link state database could flood the network and reduce its efficiency - this was the need that led to the creation of concept Areas.
Role of the Network Layer Addresses
Role of the Network Layer Addresses The network layer addresses, or IP addresses, indicate the original source and final destination. An IP address contains two parts: Network portion - The left-most part of the address that indicates which network the IP address is a member. All devices on the same network will have the same network portion of the address. Host portion - The remaining part of the address that identifies a specific device on the network. The host portion is unique for each device on the network.
What does IP do?
Routes packets through various networks The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet.
What is the function of ARP?
The Address Resolution Protocol (ARP) feature performs a required function in IP routing. ARP finds the hardware address, also known as Media Access Control (MAC) address, of a host from its known IP address. ARP maintains a cache (table) in which MAC addresses are mapped to IP addresses.
Why is ARP important?
The Address Resolution Protocol (or ARP) is a very important part of IP networking. ... For most of us, that means that ARP is used to link our IP addressing to our Ethernet addressing (MAC Addressing). For you to communicate with any device on your network, you must have the Ethernet MAC address for that device.
What does Bootstrap Protocol do?
The Bootstrap Protocol (BOOTP) is a computer networking protocol used in Internet Protocol networks to automatically assign an IP address to network devices from a configuration server. The BOOTP was originally defined in RFC 951. part of application layer and host configuring system
What does FTP stand for and what does it do?
The File Transfer Protocol (FTP) is a standard network protocol used for the transfer of computer files between a client and server on a computer network. its a file transfer protocol
What is the difference between Ethernet and Internet?
The Internet is a world wide packet switching network. Since it is based on packets, and Ethernet delivers packets, the carrier for the Internet that most people encounter is Ethernet. Within one building , the Internet is often carried by Ethernet. But over longer distances, others technologies are used.
Why is TCP IP called a protocol stack?
The OSI Reference Model that defines seven protocol layers is often called a stack, as is the set of TCP/IP protocols that define communication over the internet. ... Another common phrase is binding a stack, which refers to linking a set of network protocols to a network interface card (NIC).
Why do we need OSPF?
The OSPF protocol is a link-state routing protocol, which means that the routers exchange topology information with their nearest neighbors. The topology information is flooded throughout the AS, so that every router within the AS has a complete picture of the topology of the AS.
when was the first message transmitted?
october 29th 1969 from SDS 7 sigma mainframe at university of California los Angeles to a SDS 940 mainframe at Stanford research institute
what are the two basic types of networking models?
protocol models and reference models
What is the maximum size of a message inside an ipv4 Packet?
referred to as the Packet Length, this 16-bit field defines the entire packet (fragment) size, including header and data, in bytes. The minimum length packet is 20 bytes (20-byte header + 0 bytes data) and the maximum is 65,535 bytes. The 16-bit field is used for error checking of the IP header.
Protocol Data Units
As application data is passed down the protocol stack on its way to be transmitted across the network media, various protocol information is added at each level. This is known as the encapsulation process. The form that a piece of data takes at any layer is called a protocol data unit (PDU). During encapsulation, each succeeding layer encapsulates the PDU that it receives from the layer above in accordance with the protocol being used. At each stage of the process, a PDU has a different name to reflect its new functions. Although there is no universal naming convention for PDUs, in this course, the PDUs are named according to the protocols of the TCP/IP suite, as shown in the figure. Click each PDU in the figure for more information.
Benefits of Using a Layered Model
Assists in protocol design, because protocols that operate at a specific layer have defined information that they act upon and a defined interface to the layers above and below. Fosters competition because products from different vendors can work together. Prevents technology or capability changes in one layer from affecting other layers above and below. Provides a common language to describe networking functions and capabilities.
Layer 2 - Data Link
At OSI Model, Layer 2, data packets are encoded and decoded into bits. It furnishes transmission protocol knowledge and management and handles errors in the physical layer, flow control and frame synchronization. The data link layer is divided into two sub layers: The Media Access Control (MAC) layer and the Logical Link Control (LLC) layer. The MAC sub layer controls how a computer on the network gains access to the data and permission to transmit it. The LLC layer controls frame synchronization, flow control and error checking. Layer 2 Data Link examples include PPP, FDDI, ATM, IEEE 802.5/ 802.2, IEEE 802.3/802.2, HDLC,
What is difference between OSPF and Eigrp?
Difference Between EIGRP and OSPF. Enhanced Interior Gateway Routing Protocol (also known as EIGRP) is a proprietary routing protocol developed by Cisco. ... These routers accomplish this by converting 32 bit EIGRP metric to 24 bit IGRP metric. Open Shortest Path First (also known as OSPF) is a dynamic routing protocol.
Network Protocols
At the human level, some communication rules are formal and others are simply understood based on custom and practice. For devices to successfully communicate, a network protocol suite must describe precise requirements and interactions. Networking protocols define a common format and set of rules for exchanging messages between devices. Some common networking protocols are Hypertext Transfer Protocol (HTTP), Transmission Control Protocol (TCP), and Internet Protocol (IP). networking protocols that describe the following processes: How the message is formatted or structured. The process by which networking devices share information about pathways with other networks. How and when error and system messages are passed between devices. The setup and termination of data transfer sessions.
what does TCP do?
Breaks messages into packets and reassembles them at their destination
What is the difference between OSPF and BGP?
Difference Between OSPF and BGP. The major difference between OSPF and BGP is that the OSPF is an intradomain routing protocol while BGP is the interdomain routing protocol. The OSPF protocol uses link state routing. On the other hand, BGP protocol uses path vector routing.
What is difference between IMAP and SMTP?
Difference Between SMTP and IMAP. SMTP, which stands for Simple Mail Transfer Protocol, along with IMAP (Internet Access Message Protocol) are the two mechanisms that are used in sending and receiving email messages. The main difference between the two is the function that they play.
Protocol Interaction
Communication between a web server and web client is an example of an interaction between several protocols. T HTTP - is an application protocol that governs the way a web server and a web client interact. HTTP defines the content and formatting of the requests and responses that are exchanged between the client and server. Both the client and the web server software implement HTTP as part of the application. HTTP relies on other protocols to govern how the messages are transported between the client and server. TCP - is the transport protocol that manages the individual conversations. TCP divides the HTTP messages into smaller pieces, called segments. These segments are sent between the web server and client processes running at the destination host. TCP is also responsible for controlling the size and rate at which messages are exchanged between the server and the client. IP - is responsible for taking the formatted segments from TCP, encapsulating them into packets, assigning them the appropriate addresses, and delivering them to the destination host. Ethernet - is a network access protocol that describes two primary functions: communication over a data link and the physical transmission of data on the network media. Network access protocols are responsible for taking the packets from IP and formatting them to be transmitted over the media.
Message Encoding
Encoding is the process of converting information into another acceptable form, for transmission. Decoding reverses this process in order to interpret the information. Encoding between hosts must be in an appropriate format for the medium. Messages sent across the network are first converted into bits by the sending host. Each bit is encoded into a pattern of sounds, light waves, or electrical impulses depending on the network media over which the bits are transmitted. The destination host receives and decodes the signals in order to interpret the message.
What are the advantages of Eigrp other routing protocol?
Enhanced Interior Gateway Routing Protocol (EIGRP) is a unique Cisco innovation. Highly valued for its ease of deployment and fast convergence, EIGRP is commonly used in many large Enterprise networks. EIGRP maintains all of the advantages of distance-vector protocols, while avoiding the concurrent disadvantages.
What does EIGRP Do?
Enhanced Interior Gateway Routing Protocol (EIGRP) is an advanced distance-vector routing protocol that is used on a computer network for automating routing decisions and configuration. The protocol was designed by Cisco Systems as a proprietary protocol, available only on Cisco routers.
Message Formatting and Encapsulation
For centuries, the agreed format for personal letters has not changed. In many cultures, a personal letter contains the following elements: An identifier of the recipient A salutation or greeting The message content A closing phrase An identifier of the sender A message that is sent over a computer network follows specific format rules for it to be delivered and processed. Just as a letter is encapsulated in an envelope for delivery, so too are computer messages. Each computer message is encapsulated in a specific format, called a frame, before it is sent over the network. A frame acts like an envelope; it provides the address of the destination and the address of the source host..
What does HTTP do?
HTTP means HyperText Transfer Protocol. HTTP is the underlying protocol used by the World Wide Web and this protocol defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. HTTP (Hypertext Transfer Protocol) is the set of rules for transferring files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. As soon as a Web user opens their Web browser, the user is indirectly making use of HTTP. it is web based protocol
What does Small Mail Transfer Protocol (SMTP) do?
Handles outgoing mail it is a email protocol
What does NAT do?
NAT translates the IP addresses of computers in a local network to a single IP address. This address is often used by the router that connects the computers to the Internet.
What are network protocols and standards?
Network protocols are formal standards and policies comprised of rules, procedures and formats that define communication between two or more devices over a network. Network protocols govern the end-to-end processes of timely, secure and managed data or network communication.
What does POP do?
POP is short for Post Office Protocol, a protocol used to retrieve e-mail from a mail server. Most e-mail applications (sometimes called an e-mail client) use the POP protocol, although some can use the newer IMAP (Internet Message Access Protocol). There are two versions of POP. it is a email protocol
What does PPP do?
Point-to-Point Protocol (PPP) is a data link layer (layer 2) communications protocol used to establish a direct connection between two nodes. It connects two routers directly without any host or any other networking device in between. Point-to-Point Protocol (PPP) is a data link layer (layer 2) communications protocol used to establish a direct connection between two nodes. It connects two routers directly without any host or any other networking device in between. Point To Point Protocol (PPP) ... PPP can be encapsulated in a number of data link layer protocols, including Ethernet (PPPoE) and Asynchronous Transfer Mode (PPPoA). PPP uses Link Control Protocol (LCP) to establish a session between a user's computer and an ISP.
Role of the Data Link Layer Addresses
Role of the Data Link Layer Addresses When the sender and receiver of the IP packet are on the same network, the data link frame is sent directly to the receiving device. On an Ethernet network, the data link addresses are known as Ethernet (Media Access Control) addresses. MAC addresses are physically embedded on the Ethernet NIC. Source MAC address - This is the data link address, or the Ethernet MAC address, of the device that sends the data link frame with the encapsulated IP packet. The MAC address of the Ethernet NIC of PC1 is AA-AA-AA-AA-AA-AA, written in hexadecimal notation. Destination MAC address - When the receiving device is on the same network as the sending device, this is the data link address of the receiving device. In this example, the destination MAC address is the MAC address of the FTP server: CC-CC-CC-CC-CC-CC, written in hexadecimal notation. The frame with the encapsulated IP packet can now be transmitted from PC1 directly to the FTP server.
difference between TCP and IP
TCP is for transport layer in OSI model. ... The difference is that TCP is responsible for the data delivery of a packet , it guarantees that packets will be delivered in the same order in which they were sent. and IP is responsible for the logical(IP) addressing, IP protocol deals only with packets.
What are Protocol Suites and Industry Standards
TCP/IP Application: HTTP, DNS, DHOP, FTP Transport: TCP/UDP Internet IPV4, IPV6 , ICMPv4, ICMP6 Network Assess Ethernet, PPP, Freme Relay, ATM, WLAN ISO Application: acse, Rose, TRSE, AFP Transport: TP0, TP1, TP2, TP3, TP4 Internet: CONP/CMNS, CLNP/CLNS Network Assess: Ethernet, PPP, Freme Relay, ATM, WLAN Apple Talk Application: AFP Transport: ATP, AEP, NBP, RTMP Internet: AARP Network Assess: Ethernet, PPP, Freme Relay, ATM, WLAN Novell Netware Application: NDS Transport: SPX Internet: IPX Network Assess: Ethernet, PPP, Freme Relay, ATM, WLAN
What is TCP IP layer protocol model?
TCP/IP Protocol Architecture Model. The OSI model describes an idealized network communications protocol family. TCP/IP does not correspond to this model directly, as it either combines several OSI layers into a single layer, or does not use certain layers at all.
Network Addresses
The network and data link layers are responsible for delivering the data from the source device to the destination device. protocols at both layers contain a source and destination address, but their addresses have different purposes. Network layer source and destination addresses - Responsible for delivering the IP packet from the original source to the final destination, either on the same network or to a remote network. Data link layer source and destination addresses - Responsible for delivering the data link frame from one network interface card (NIC) to another NIC on the same network. An IP address is the network layer, or Layer 3, logical address used to deliver the IP packet from the original source to the final destination. The IP packet contains two IP addresses: Source IP address - The IP address of the sending device, the original source of the packet. Destination IP address - The IP address of the receiving device, the final destination of the packet.
What does Ethernet do?
This cable connects wired devices together to the local network for file sharing and Internet access. Linksys routers use Ethernet cables to connect to the modem via its Internet or WAN port and get Internet access for wired and wireless devices connected behind the router. Ethernet Network - The Role of Ethernet in Computer Networks. An ethernet network is a situation in which multiple computers are connected to one another and share the same Internet protocol address. ... The benefit in this is that multiple networks do not need to be created.
Layer 5 - Session
This layer establishes, manages and terminates connections between applications. The session layer sets up, coordinates, and terminates conversations, exchanges, and dialogues between the applications at each end. It deals with session and connection coordination. Layer 5 Session examples include NFS, NetBios names, RPC, SQL.
