TCP/IP Addressing And Data Delivery 6 Flashcards
Two basic categories of protocols
Connection oriented and connection less protocols
Describe TCP
Transmission Control Protocol
One of the two transport 4 layer protocols.
A connection oriented guaranteed delivery Protocol used to send data packets between computers over a network like the Internet. Part of the Internet protocol suite with IP. Is responsible for breaking up data into datagrams, reassembling them at the other end, reseeding data lost in transit and resequencing data.
Describe connection oriented protocols
Require a logical connection before transfer of data.
Operates in three phases
Phase one a connection is established and the devices negotiate parameters for the connection.
Phase two the devices transfer data
Phase three the connection held by the devices is released and is torn down
Function only in bidirectional communication environments
Describe connection less protocols
Do not establish a connection between devices.
Do not have any explicit setup or release phases and are always in the data transfer phase. Data is just sent from the source to its destination without checking if the destination is prepared to receive it.
What is IP
Internet Protocol
A network layer 3 protocol responsible for routing individual datagrams and addressing.
A connectionless protocol and acts as an intermediary between higher protocol layers and the network. Makes no guarantees about packet delivery, corruption of data or lost packets.. Works in concert with TCP which establishes a connection between a source and the destination.
Describe the IP Data packet delivery process
The process of delivering a data packet by IP consists of three steps
A service establishes a connection to the receiving node at the transport layer . Resolves the name of the receiving node to that nodes IP address
the IP address is then passed from the transport layer to the Internet layer.
IP uses a subnet mask to determine if the receiving node is in the same subnet and delivers the packet
What is UDP
User Datagram Protocol
Connectionless transport layer protocol in the IP suite. Used with IP. transmits data and ensures data integrity. Lacks reliability, flow control and error recovery functions. Less complex than TCP but delivers faster service.
what is ARP
Address Resolution Protocol
Maps an IP address to a physical or MAC address recognized within a local network. Reside in the data link layer 2 of the network interface layer encapsulate by an Ethernet header.
MAC Addresses are 48 bits long and IP addresses are 32 bits long. ARP supports IP by resolving IP addresses to MAC addresses
Name the steps,ARP takes to in address resolution
ARP receives an IP address from IP
If ARP has the MAC address in its cache it returns it to IP. If not it issues a broadcast to resolve the IP address
A target node with the corresponding IP address responds with a unicast that includes its MAC address. The MAC address is added to ARPs caches and sent to the IP as requested.
What is ICMP
Internet Control Message Protocol
Used with IP to report on the condition of a connection between two nodes. Notifies sender of errors. The receiving node sends an ICMP source quench message to slow down data transmission form the sending node.
What is IGMP
Internet Group Management Protocol
In the TCP/IP suite that supports multicasting in a routed environment mused to inform all systems on a network what host currently belongs to which multicast group. Used by the router to poll its interfaces for member of the multicast group and then Forwards the multicast transmission to the group members
What is a data packet
A unit data transfer between computers that communicate over a network. Contains three parts. Header, data, footer or trailer.
Header contains the destination and source addresses
Data part contains the actual information being transmitted
The footer contains the error checking code
In OSI model frames occur at
Data link layer 2
In OSI Model packets occur at
Network layer 3
What the difference between packets and datagrams
A Datagram is a self contained independent piece of data able to move from a source to a destination.
A packet refers to any message formatted as a packet
What is a network address
A protocol specific Identifier assigned to a node. Includes two parts. Part one identifies the network part two identifies the node.
The combination of the network address and the host address is called an IP address
What is a network name
A name assigned to a node to help users and technicians recognize the device easier
A naming service maps a network name to a network address or MAC address
Making services that Mao network names to network addresses
DNS. domain name system. Used on the Internet
NetBIOS. Simple broadcast based naming service
WINS. Windows Internet Naming Service. Older
What are IP addresses
A unique 32 bit binary address assigned to a computer so that it can communicate with other devices on a TCP/IP network
Consists of two portions: network address common to all hosts and devices on a physical network and the the host address unique to the network host
Available in classful and classless
IPv4 addresses
32 bit binary addresses separated by dots into four 8 bit octets converted into a single decimal value ranging from 0 to 255
What is subnetting
The process of logically dividing a network into smaller subnetworks that each have a unique address.
What are the two main benefits of creating subsets
To improve performance and to provide a more secure network environment
What is a subnet mask
A 32 bit number assigned to each host for dividing the 32bit binary IP address into network and node portions. Uses the binary AND operation to remove the node ID from the IP address leaving the network portion. The first number must be 255. The remaining three can be any if the following : 255,254,252,248,240,224,192,128,0
What are the default subnet mask and their corresponding values of the first octet
- 0.0.0 is 1-126
- 225.0.0 is 128-191
- 255.255.0 is 192-223
What are the IP address assignment rules
Each node must have a unique IP address
If subnets on network each node connected must be assigned to a subnet
Each subnet must have a unique network id
All devices on a subnet must share the same network id
Nodes on a local subnet must have unique node ids
Nodes on different subnets can have the same node id if the network ids are different
The node address cannot be all ones or zeros
The IP address 127.0.0.1 is reserved for testing
Describe binary ANDing
To apply a subnet mask both the IP address and the subnet mask are converted to binary. The two binary numbers are ANDed together. The zeros in the subnet mask convert all bits in the node portion of the IP address to zeros leaving the network portion of the address intact
Zero AND zero or one equals zero
One AND one equals one
Define ICANN
Internet Corporation for Assigned Names and Numbers
Controls the leasing and distribution of IP addresses on the Internet
IP address Classes
Class A. Used by extremely large networks.
126 networks
Range 1.0.0.0 to 127.255.255.255
Subnet mask 255.0.0.0
Class B
16,382 networks
Range 128.0.0.0 to 191.255.255.255
Subnet mask 255.255.0.0
Class C
2,097,150 networks
Subnet mask 255.255.255.0
Class D
for multicast transmission
Range 224.0.0.0 to 239.255.255.255
Class E
For research and experimentation
Range 240.0.0.0 to 255.255.255.255
What are private IP addresses
Address they organizations use for nodes within enterprise networks for IP connectivity. Not routable and packets are not forwarded outside of the network
Private nonroutable IP address ranges
- 0.0.0 to 10.255.255.255
- 16.0.0 to 173.31.255.255
- 168.0.0 to 192.168.255.255
What is a default gateway
The IP address of a router that router remote traffic from the computers local subnet to remote subnets. The address of the Router connected to the Internet.
Describe custom TCP/IP subnets
A class of leased addresses that are divided into smaller groups to serve a networks needs. Has a custom subnet mask ANDed to the IP address. A default gateway is configured for each subnet to rout traffic between subnets
What is a custom subnet mask
Borrows node bits in a contiguous block from the left side to the node portion of the address and uses them as network bits. This divides a single network address into multiple networks each containing a few nodes.
What is variable length subnet masks
VLSM can be used for creating subnets that have different numbers of nodes. Applies the custom subnet mask which provides the number of nodes required for each subnet
What is classless inter domain routing CIDR
A classless addressing method that considers a VLSM as a 32 bit binary word. Mask bits can move in one bit increments to provide the exact number of nodes and networks required. The notation combined a network address with a number to represent the number of one bits on the mask.
Describe IPv6
The successor of IPv4. An addressing scheme that increases the available pool of IP addresses by implementing 128 bit binary address space
Replaces classful address with more flexible and logical unicast address structure.
New features include simplified address headers, hierarchical addressing, support for time sensitive network traffic and new structure for unicast addressing
What is an IPv6 address
A 128 bit binary number assigned to a computer on a TCP/IP network. Some bits represent the network and others the host. Separated by colons into eight groups of four hexadecimal digits. Leading zeros are omitted. Consecutive zeros replaced with two colons.
What is a connection
A virtual link between two nodes established for the duration of a communication session. Provide flow control, packet sequencing and error recovery functions to ensure reliable communications between nodes.
Three types of connection services
Unacknowledged connectionless
Acknowledged connectionless. Nodes do not establish a virtual connection but do acknowledge successful receipt of packets
Connection oriented nodes establish a virtual connection and negotiate communication parameters and share security information to establish a connection
Three commonly used connection modes
Simplex. One way transmission of information. No return path. Uses the full bandwidth of the medium for transmission. Ex radio & tv broadcasts
Half duplex. Permits two eat communication but in only one direction at a time. One device sends the other must receive. Then switch roles. Uses full bandwidth of the medium
Full duplex. Permits simultaneous two way communication. devices send and receive data simultaneously. Can occur over different channels or in the same channel. Not able to use the full bandwidth. Ex telephone systems
What is flow control
A technique for optimizing data exchange between systems. Buffering and data windows are two commonly used in computer networking.
What is buffering
A flow control technique in which data received is stored on a temporary memory location called a buffer until the main system components are ready to work with the data. On disk or RAM the buffer is called a cache.
What is a cache controller
A specialized processor chip that manages caching so the processor doesn’t have to
What is flooding in terms of data transmission. How can it be avoided
Data arrives too quickly to be handled. Receiving devices send a squelch signal to the sender when the buffer is 75% full
What are data windows
A flow control technique in which multiple packets are sent as a unit called a block or a window. The recipient ACKs each window resulting in higher throughput.
Describe the two types of data windows
Fixed length. Every block contains the same number of packets
Sliding windows use variable block sizes. Packets in the block sent steadily increase in size until the receiver sends the squelch. Window size is continually reevaluated to send the largest window possible
What is error detection
Determining if transmitted data has been received correctly and completely. Extra bits called Error Detection Code EDC are attached to the footer to indicate its original content. The recover generates an EDC and compares to determine if the data has been altered en route. Also include a correction component called Error Detection And Correction EDAC that helps receiver rebuild the data of an error occurs
What is a parity check
A process used to detect errors in memory or data communication. A computer checks the data word by word. The sender adds in bit to each word and transmits. The receiver compares the number of ones within a transmitted byte to those received. If matches data is valid. If not determined to be corrupt retransmission request sent
What is Cyclic Redundancy Check. CRC
An error detection method in which a predefined mathematical operation is used to calculate a CRC Code. The sender attaches the CRC to a block of data and transmits. The receiver calculate its own CRC for the data and compares to the transmitted CRC. if values match then considered unaltered
