TCP/IP
American Registry for Internet Numbers (ARIN)
ARIN assigns IP address space to ISPs & end users, but only to those who qualify. This requires that the ISP or end user be large enough to merit a block of addresses. When blocks of addresses are allocated by ARIN to ISPs, the ISPs issue addresses to their customers. A local ISP could also be assigned a block of IP addresses from ARIN, but the local ISP must have a large number of users. end user must qualify to receive a block of addresses from ARIN (end user must be large) For example, many universities and large businesses can receive a block of IP addresses from ARIN Most end users will get their IP addresses from an ISP or have IP addresses assigned dynamically when they connect to the ISP.
Private IP Addresses (non-internet routable IP addresses)
Address ranges in class A, B, & C have been set aside for private use these private addresses are not used for Internet data traffic but are intended to be used specifically on internal networks called intranets. private addresses work the same as public addresses except they are not routed on the Internet non-internet routable IP addresses and are blocked by Internet service providers (ISPs) Class A: 10.0.0.0-10.255.255.255 Class B: 172.16.0.0-172.31.255.255 Class C: 192.168.0.0-192.168.255.255
Five RIRs accounting for different regions of the world
AfriNIC: Africa Region APNIC: Asia/Pacific Region ARIN: North America Region LACNIC: Latin America & some Caribbean Islands RIPE NCC: Europe, the Middle East. & Central Asia
Full IPv6 address
All 32 hexadecimal positions contain a value other than 0. 6789:ABCD:1234:EF98:7654:321F:EDCB:AF21
TCP/IP model
Application layer: Defines the applications used to process requests & which ports & sockets are used Transport layer: defines the type of connection established btn hosts & how acknowledgements are sent Internet layer: Defines protocols used for addressing & routing the data packets Network Interface layer: Defines how the host connnects to the network
0.0.0.0 & 127.x.x.x addresses
Are special purpose addresses 0.0.0.0 IP address refers to the source host on this network 127.x.x.x IP addresses are used as the internet loop back address A datagram sent by a higher-level protocol to an address anywhere within this block should loop back inside the host most common loopback address used is 127.0.0.1 127.x.x.x addresses should never appear on the network
Breakdown of address classes for network & host bits
Class A Network=8 bits Host=24 bits #ofHosts =16,777,214 Class B Network=16 bits Host=16 bits #ofHosts=65,534 Class C Network=24 bits Host= 8 bits #ofHosts=254
Internet layer
Defines the protocols used for addressing and routing data packets IP ARP ICMP IGMP
6to4 prefix for hosts
FP: is format prefix, which is made up of higher order bits. 001 indicates that this is a global unicast address. TLA ID (0x2002): is the top-level identifiers issued to local internet registries. administered by IANA. TLA is used to identify highest level in routing hierarchy. TLA ID is 13 bits long. V4ADDR: is the IPv4 address of the 6to4 endpoint & is 32 bits long SLA ID: is the site-level aggregation identifier that is used by individual organizations to identify subnets within their sites. SLA ID is 16 bits long. Interface ID: is the link-level host identifier, used to indicate an interface on a specific subnet. The interface ID is equivalent to the host IP address in IPv4.
Well-known port examples
HTTP (TCP port 80) HTTPS (TCP port 443) SSH (TCP port 22)
IP Address Assignment
IP address allocation is governed by IANA. To coordinate the global effort of IP allocation more effectively, IANA delegates the allocation to the regional internet registries (RIRs), each of which is responsible for a different area.
ICMP
Internet Control Message Protocol (ICMP) is used to control the flow of data in the network, to report errors, & to perform diagnostics. A networking device, such as a router, sends an ICMP source-quench packet to a host that requests a slowdown in the data transfer.
Class A IPv4 Address Range
0.0.0.0-127.255.255.255
Two transport protocols within TCP/IP transport Layer
TCP (Tansmission Control Protocol: connection oriented protocol, establishes the network connection, manages the data transfer, & terminates the connection. establishes a set of rules or guidelines for establishing connection. Verifies delivery of the data packets through the network support for error checking & recovering lost data specifies a procedure for terminating the network connection virtual connection that is made over the network
transport layer protocols
TCP/IP protocols are important in establishing a network connection, managing the delivery of data between a source & destination host, & terminating the data connection.
OUI (Organizationally Unique Identifier)
The first three bytes of a MAC address that uniquely identify a network device manufacturer.
Three types of IPv6 Addresses
Unicast: used to identify a single network interface address & data packages are sent directly to the computer w/ the specified IPv6 address. Types of unicast addresses: - link-local addresses: are designed to be used for & are limited to communication on the local link. Every IPv6 interface will have one link-local address. - global unicast addresses - unique local addresses Multicast: are defined for a group of networking devices. Data packets sent to a multicast address are sent to the entire group of networking devices, (ex. group of routers running the same routing protocol). Multicast addresses all start w/ the prefix FF00::/8 next octet is called the scope scope bits are used to identify which ISP should carry the data traffic Anycast: is obtained from a list of addresses but is only delivered to the nearest node.
UDP
User Datagram Protocol. connectionless protocol, this means UDP packets are transported over the network w/o a connection being establish & w/o any acknowledgement that that data packets arrive at the destination. videoconferencing & audio feeds (acknowledgements aren't necessary)
Supernets
When you group two or more classful networks together (CIDR block) example: group of four IP addresses from 192.168.76.0 to 192.168.79.0 with a CIDR of /22 is a supernet
CIDR blocks
are used to break down the class barriers in IP addressing. problem with randomly applying CIDR blocks to Class A, B, and C addresses is that there are boundaries in each class, and these boundaries can't be crossed. If a boundary is crossed, the IP address maps to another subnet
Classful Networks
classful means that the IP addresses & subnets are within the same network. problem w/ classful addressing that there is a lot of unused IP address space and only a limited number of class A & B address space has been allocated for Internet use
How computers use the subnet mask
computers use the subnet mask to control data flow within networks. computers in a LAN use a subnet mask to determine whether the destination IP address is intended for a host in the same LAN or if the data packet should be sent to the gateway IP address of the LAN Gateway IP address is typically the physical network interface on a layer 3 switch or a router
IP (Internet Protocol)
defines addressing used to identify source & destination addresses of data packets being delivered over an IP network. IP address is a logical address that consists of a network & a host address portion network portion is used to direct data to the proper network. Similar to area code for a telephone number. host address identifies the address locally assigned to the host. Similar to the local exchange number. Network & host portions of IP address are then used to route the data packets to the destination.
Network Interface layer
defines how the host connects to the network. host can be a computer or networking device type of network to which the host connects is not dictated by the TCP/IP protocol. host could be a computer connected to an Ethernet or token-ring network or a router connected to a frame relay wide area network. TCP/IP is not dependent on a specific networking technology, therefore, TCP/IP can be adopted to run on newer networking technologies such as asynchronous transfer mode (ATM) every TCP/IP data packet must have a desination & a source MAC address in the TCP/IP header.
Network Control Protocol (NCP)
developed by the Defense Advanced Research Projects Agency (DARPA) to provide a way to network the computers of government researchers DARPA-funded initiative forced the use of a standard networking protocol by all defense contractors.
Supernetting
eliminates the class boundaries & to make available the unused IP address space. Supernetting allows multiple networks to be specified by one subnet mask (class boundary could be overcome)
Stateless address autoconfiguration SLAAC
feature of IPv6. allows for a serverless basic network configuration of the IPv6 computers. With IPv6, a computer can automatically configure its network settings without a DHCP server by sending a solicitation message to its IPv6 router router then sends back its advertisement message, which contains the prefix information that the computer can use to create its own IPv6 address This feature significantly helps simplify the deployment of the IPv6 devices, especially in transient environments such as airports, train stations, stadiums, hotspots, and so on.
Classless Interdomain Routing (CIDR)
specifies the # of bits set to a 1 that make up the subnet mask.
6to4 Prefix
technique that enables IPv6 sites to communicate over the IPv4 Internet. Requires use of a 6to4 enabled router, which means that 6to4 tunneling has been enabled. Requires 6to4 Relay router that forwards 6to4 data traffic to other 6to4 routers on the Internet
Address Resolution Protocol (ARP)
used to resolve an IP address to a hardware address for final delivery of data packets to the destination. ARP issues a query in a network called an ARP request, asking which network interface has this IP address. Host assigned the IP address replies with an ARP reply, the protocol that contains the hardware address for the destination host. A query (Q) is asking who has the IP address 10.10.10.1 (PA=). PA is an abbreviation for protocol address. HA is an abbreviation for hardware address. In this case, the owner of the IP address replied to the message, but this is not always the case. Sometimes another networking device, such as a router, can provide the MAC address information. In that case, the MAC address being returned is for the next networking device in the route to the destination.
Unique sequence of three data packets is exchanged at the beginning of a TCP connection
1. The SYN (Synchronizing) packet 2. The SYN ACK (Synchronizing Acknowledgment) packet 3. The ACK (Acknowledgement) packet
Class A Private Address Range
10.0.0.0 - 10.255.255.255
IP version 6 (IPv6) / IPng
128-bit address 2^128 possible IP addresses written in hexadecimal 32 hex digits X 4 bits/hex digit = 128 bits example: 6789:ABCD:1234:EF98:7654:321F:EDCB:AF21
Class B IPv4 Address Range
128.0.0.0-191.255.255.255
Class B Private Address Range
172.16.0.0 - 172.31.255.255
Class C IPv4 Address Range
192.0.0.0-223.255.255.255
Class C Private Address Range
192.168.0.0 - 192.168.255.255
Class D IPv4 Address Range
224.0.0.0-239.255.255.255
Class E IPv4 Address Range
240.0.0.0-254.255.255.255
# of hosts/subnet
2^(y-x) x = # of bits borrowed from host bits y = # of bits for the class
# of usable hosts/subnet
2^(y-x) - 2 x = # of bits borrowed from host bits y = # of bits for the class
# of subnets created
2^x x = # of bits borrowed from host bits
TCP/UDP ports
65,536 possible ports 1 - 1023 are well-known ports (reserved ports) by ICANN Ports 1024-49151 are registered ports with ICANN Ports 49152 - 65535 are dynamic or private ports
IGMP
internet Group Management Protocol used when one host needs to send data to many destination hosts. (multicasting) multicast addresses: addresses used to send a multicast data packet. are reserved addresses not assigned to hosts in a network. example of an application that uses IGMP packets is when a router uses multicasting to share routing tables when a host wants to stream data to multiple hosts Streaming means the data is sent w/o waiting for any acknowledgements that the data packets were delivered. Source doesn't care whether the destination receives a packet. Streaming is an important application in the transfer of audio and video files over the internet. data is handed off to the application layer as it arrives. enables the appropriate application to begin processing data for playback.
Subnetting
is a technique used to break down (or partition) networks into subnets. subnets are created through use of subnet masks. Subnet mask identifies which bits in the IP address are to be used to represent the network/subnet portion of an IP address Subnet are created by borrowing bits from the host portion of the IP address. The network portion of the IP address & the new subnet bits are used to define the new subnet. Routers use this information to properly forward data packets to the proper subnet.
Application layer
layer is used to process requests from hosts & to ensure connection is made to an appropriate port port is basically an address used to direct data to the proper destination application
Ping
packet internet groper troubleshooting tool within ICMP protocol. used to verify connectivity w/ another host in the network. destination host could be in a LAN, in a campus LAN, or on the Internet. uses a series of echo requests, & the networking device receiving the echo requests responds w/ a series of echo replies to test a network connection.
TCP/IP Transmission Control Protocol/Internet Protocol
protocol suite used for communications btn hosts in most local networks & on the internet. TCP/IP can be used to enable network communications in LANs, campus networks, & wide area networks (WANs) as long as the hosts support the protocol. included in most operating systems TCP/IP replaced NCP as the standard networking protocol used by the Advanced Research Projects Agency network (ARPAnet)
