Network Communications Ch 4

TCP Segment: Checksum

Allows the receiving node to determine whether the TCp segment became corrupted during transmission

TCP Segment: Data

Contains data originally sent by the source node.

TCP Segment: Padding

Contains filler information to ensure that the size of the TCP header is a multiple of 32 bits

IPv4 Packet: Source IP Address

IDentifies the full IP address of the source node (shorter)

IPv6 Packet: Destination address

Identifies the Full IP address of the receiving node (longer version)

TCP Segment: Sequence Number

Identifies the data segment's position in the stream of data segments already sent

IPv6 Packet: Source address

Identifies the full IP address of the transmitting node (longer version)

IPv6 Packet: Traffic class

Identifies the packet's priority. It is similar, but the same type of service field in IPv4 Packets

IPv4 Packet: Total Length

Identifies the total length of the IP packet, including the header and data, in bytes

IPv4 Packet: Protocol

Identifies the type of Transport layer protocol that will receive the datagram (ie. TCP or UDP)

IPv4 Packet: Fragment offset

Identifies where the paket fragment belongs in the incoming set of fragments

IPv4 Packet: Data

Includes the data originally sent by the source node, plus information added by TCP in the Transport Layer

TCP/Segment: Destination Port

Indicated the port number at the destination node

TCP Segment: Source Port

Indicated the port number at the source node

TCP Segment: Urgent Pointer

Indicates a location in the data field where urgent data resides

TCP Segment: Sliding-Window Size (Window)

Indicates how many bytes the sender can issue to a receiver while acknowledgement for this segment is outstanding. Flow control. Prevention of the receiver being deluged with bytes

IPv4 Packet: Destination IP address

Indicates the full IP address of the destination node (shorter)

IPv4 Packet: Time to Live (TTL)

Indicates the maximum duration that the packet can remain on the network before it is discarded.

IPv6 Packet: Hop limit

Indicates the number of times that the packet can be forwarded by routers on the network (Similar to the TTL field in IPv4 packets)

IPv6 Packet: Payload length

Indicates the size of the payload, or data carried by the packet (does not refer to the size of the whole packet like in IPv4)

IPv6 Packet: Version

Indicates what IP version the packet uses (IPv4 versus IPv6)

IPv4 Packet: Flags

Indicates whether a message is fragmented and, if it is fragmented, whether this packet is the last in the fragment

IPv6 Packet: Flow label

Indicates which flow the datagram belongs to

IPv4 Packet: Differentiated Services (Diffserv)

Inform routers the level of precedence tey should apply when processing the incoming packet.

IPv4 Packet: Options

May contain optional routing and timing informaton

IGMP (Internet Group Management Protocol)

Operates at the network layer of the OSI model. Manages multicasting on networks running IPv4

IP (Internet Protocol)

Part of Internet layer of TCP/IP protocol and Network layer of the OSI model, provides information about how and where data should be delivered, including the data's source and destination address, enables TCP/IP to internetwork

TCP Segment: Options

Specifies special options, such as the maximum segment size a network can handle

ICMP (Internet Control Message Protocol)

a Network layer core protocol that reports on the success or failure of data delivery. Used as a diagnostic tool

ARP (Address Resolution Protocol)

a Network layer protocol used with IPv4 that obtains the MAC (physical) address of a host, or node, and then creates a database that maps the MAC address to the host's IP address

TCP Segment: Flags

a collection of six 1-bit fields that signal special condition through flags

FQDN (Fully Qualified Domain Name)

a combination of a local host name and the domain name of a host

Format Prefix

a feature of IPv6 addresses, a variable-length field at the beginning of the address that indicates what type of address it is - unicast, multicast, or anycast

TCP Segment: Reserved

a field reserved for later use

DNS (Domain Name System)

a hierarchical way of associating domain names with IP addresses

TCP/IP Model

a model that roughly aligns with the OSI model but only has four layers; Application, Transport, Internet, and Network Interface

domain name

a name for a group of computers that belong to the same organization and have part of their IP addresses in common

host name

a name that describes the device connected to the Internet

link-local address

a provisional address, capable of transmitting and receiving data only on a local network segment

DHCP Scope

a range of addresses that can be leased to any network device on a particular segment, plus a list of excluded addresses, if any exist

TCP/IP (Transmission Control Protocol/Internet Protocol)

a suite of specialized protocols that contains many subprotocols. It is open, flexible, and routable.

ARP Table (ARP cache)

a table of MAC-to-IP addresses saved to a hard disk

Telnet

a terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol suite (uses port 23)

Multicast

a transmission method that allows one node to send data to a defined group of nodes

PING(Packet Internet Groper)

a utility that can verify that TCP/IP is installed, bound to the NIC, configured correctly, and communicating with the network

IPv4 Packet: Header checksum

allows the receiving node to calculate whether the IP header has been corrupted during transmission.

FTP (File Transfer Protocol)

an Application layer protocol used to send and receive files via TCP/IP using ports 20 and 21

Private Address

an IP address that allows hosts in an organization to communicate across their internal network

static IP address

an IP address that is assigned manually and doesn't change automatically

dynamic IP address

an IP address that is assigned to a device upon request and is changeable

Unicast Address

an IPv6 address that represents a single interface on a device

Anycast Address

an IPv6 address that represents any one interface from a group of interfaces, any one of which can accept a transmission

Multicast Address

an IPv6 address that represents multiple devices

host file

an antiquated system of of listing associated host names and IP addresses on a text file

DHCP (Dynamic Host Configuration Protocol)

an automated means of assigning a unique IP address to devices on a network

Static ARP table entries

an entry that someone has entered manually using the ARP utility

datagrams

another word for packets, in the IP model, they act as an envelope for data and contain information necessary for routers to transfer data between different LAN segments

UDP (User Datagram Protocol)

belongs to Transport layer of the TCP/IP and OSI models, connectionless transport service (offers no assurance that packets will be received in the correct sequence or at all)

TCP Segment: Acknowledgement Number (ACK)

confirms receipt of the data via a return message to the sender

IPv4 Packet: Padding

contains filler bits to ensure that the header is a multiple of 32 bits.

Dynamic ARP table entries

created when a client makes an ARP request that cannot be satisfied by data already in the ARP table

TFTP (Trivial File Tranfer Protocol)

enables file transfers between computers but is simpler than FTP uses ports 69

IPv4 Packet: Identification

identifies the message to which a packet belongs and enables the receiving node to reassemble fragmented messages.

IPv4 Packet: Internet Header Length (IHL)

identifies the number of 4-byte blocks in the IPv4 header. The most common header length is composed of fie groupings, as minimum length of an IPv4 head is 20 4-byte blocks. This field indicate to the receiving node where data will begin

IPv6 Packet: Next Header

identifies the type of header that immediately follows the IP packet header, usually TCP or UDP

IPv4 Packet: Version

identifies the version number of the protocol (IPv4 or IPv6)

TCP Segment: Flag: PSH

if set to 1, it indicates that data should be sent to an application without buffering

TCP Segment: :Flag: ACK

if set to 1, the Acknowledgement field contains information for the receiver (if set to 0, the receiver will ignore tha Acknowledgement Field)

TCP Segment: Flag: URG

if set to 1, the Urgent pointer field contains information for the receiver

TCP Segment: Flag: FIN

if set to 1, the segment is the last in a sequence and the connection should be closed

TCP Segment: Flag: SYN

if set to 1, the sender is requesting a synchronization of the sequence numbers between the two nodes. This code is used when TCP requests a connection to set the initial sequence number

TCP Segment: Flag: RST

if set to 1, the sender is requesting that the connection be reset

TCP Segment: TCP header length

indicates the length of the TCP header

IPv6 (IP next generation or IPng)

not as widely used as IP 6, better security, better prioritzation provisions, automatic IP address configuration, and the promise of Billions of additional IP addresses

IPv4

one of two versions of the IP protocol, unreliable, conntectionless protocols, is used by higher level protocols of the TCP/IP suite to ensure data packets are delivered to the right addresses

UDP Header

only includes Source Port, Destination Port, Length, and Checksum

TCP (Transmission Control Protocol)

operates in the Transport layer of the TCP/IP and OSI models, provides reliable data delivery services (connection oriented sub-protocol)

resolvers

part of the DNS service, any hosts on the Internet that need to look up domain name information

Name Servers (DNS Servers)

part of the DNS service, servers that contain databases of associated names and IP addresses and provide this informationn to resolvers on request

namespace

part of the DNS service, the database of Internet IP addresses and their associated names

ICMPv6

performs the functions that ICMP, IGMP, and ARP perform in the IPv4. It detects and reports data transmission errors, discovers other nodes on a network, and manages multicasting

TCP/IP core protocols

protocols in the both the Transport and Internet layers of the TCP/IP Model that provide basic services to protocols in other layers.

flow

sequence of packets issued form one source to one or multiple destination. Routers interpret this information to ensure that packets belonging to the same transmission arrive together.

NTP (Network Time Protocol)

simple but important Application layer protocol used to synchronized the clock of computer on a network. uses port 123

Port Number

the address on a host where an application makes itself available to incoming or outgoing data

Zeroconf (Zero Configuration)

the collection of protocols that assigns link-local addresses, performs DNS functions, and discovers services, such as print services, available to the node.

DHCP Leasing

the process by which a DHCP server automatically assigns IP addresses on a network

TLD (Top-level domain)

the rightmost set of characters separated by '.' s in a domain name (ie. '.com, .net, or .edu')

internetwork (verb)

to traverse more than on LAN segment and more than on type of network through a router

dual-stack approach

when a network uses both IPv4 and IPv6