Delivering the Data

Nội dung Addressing, Routing, and Multiplexing IP Address Internet Routing Architecture Routing Table Protocols, Ports, and Sockets

Addressing, Routing,Multiplexing TCP/IP uses 3 schemes to accomplish these tasks Addressing IP addresses, which uniquely identify every host on the network, deliver data to the correct host. Routing Gateways deliver data to the correct network. Multiplexing Protocol and port numbers deliver data to the correct software module within the host.

IP Address 32-bit value that uniquely identifies every device attached to TCP/IP Internet 4 decimal numbers separated by dots assigned to network interfaces, not to computer systems Systems can be addressed in 3 way unicast address individual host multicast address Groups of systems, broadcast address All systems on a network , IP address with all host bits set to 1

IP Address An IP address with all host bits set to 0 identifies network itself 172.16.0.0 refers to network 172.16 Network addresses with a first byte value greater than 223 cannot be assigned to physical network default route Network 0.0.0.0 loopback address network 127.0.0.0 allowing the local host to be addressed in the same manner as a remote host

Address Structure IP address contains network part (prefix) host part (suffix)

Address Structure address bit mask notation if a bit in mask is 1 -> equivalent bit in address:network bit if a bit in mask 0, bit belongs : host part 172.22.12.4, network mask 255.255.255.0, 24 bits ON and 8 bits OFF notation network 172.31.26.32 with mask 255.255.255.224  write 172.31.26.32/27

Subnets allows decentralized management of host addressing use host address bits as additional network address bits defined by changing the bit mask of the IP address difference is that a subnet mask is only used locally

Subnets - Example Network 192.168.32.0/24 subdivide into 16 subnets bit mask: 255.255.255.0, contains 256 addresses subdivide into 16 subnets use the mask 255.255.255.240, 192.168.32.0/28 first 3 bytes contain original network address block 4th byte is divided between subnet address and address of the host on subnet 4 high-order bits of the 4th byte as the subnet part of the address (1111) last 4 bits of the 4th byte—as the host portion of the address (xxxx) 240 <-> 1111xxxx

Subnets - Example

Natural Mask IP address space divided into 5 fixed-length structures (address classes) 3 main address classes class A, class B, class C

Natural Mask

Private Network Numbers host is connected to a private network, its IP address only needs to be unique within that private network network numbers that are reserved for private use Network 10.0.0.0 (10/8 prefix) 24-bit block of addresses. Networks 172.16.0.0 to 172.31.0.0 (172.16/12 prefix) 20-bit block of addresses. Networks 192.168.0.0 to 192.168.255.0 (192.168/16 prefix) 16-bit block of addresses

Private Network Numbers Advantages It's easy. not have to apply for an official address or get anyone's approval. It's friendly. save address space for those who need to connect to the Internet. It's free. RFC 1918 addresses cost nothing—public addresses cost money. Disadvantage have to change your address in the future if you directly connect your full network to the Internet and wish to make all of the systems on the network accessible from the Internet

IPv6 provides an enormous 128-bit address to solve the address depletion problem can uniquely identify 3.4 x 1038 devices

IPv6 first three bits of the address indicate address type

IPv6 currently defined special-use addresses include Unspecified address all 128 bits are 0. used to explicitly indicate that an address has not been assigned. For example, a client might use an unassigned address as source address before being assigned an address by a configuration server. Loopback address first 127 bits are set to zeros followed by one bit set to 1. serves same purpose as the IPv4 loopback address. IPv4-compatible IPv6 address format 96 bits of zeros followed by a 32-bit IPv4 address. used to tunnel IPv6 packets over IPv4 networks. IPv4-mapped IPv6 address format 80 bits of zeros, 16 bits of ones, and then a 32-bit IPv4 address. represent an IPv4 address as an IPv6 address.

IPv6 Global Routing Prefix Subnet ID is a 16-bit field synonymous with the network portion of an IPv4 address assigned to the enterprise by the address registry Subnet ID is a 16-bit field to create subnets within the larger network like subnets in IPv4 does not require taking bits away from the host-specific portion of the address 64-bit Interface Identifier analogous to the host portion of an IPv4 address

IPv6 IPv6 addresses are written using a colon-hexadecimal syntax 16-bit values separated by colons.

IPv6

Internet Routing Architecture original Internet structure, there was a hierarchy of gateways core gateways processed the information and then exchanged it among themselves using the Gateway to Gateway Protocol (GGP )

Routing Table all network devices, hosts as well as gateways, must make routing decisions If the destination host is on the local network, the data is delivered to the destination host. If the destination host is on a remote network, the data is forwarded to a local gateway. Using simply table look-ups

Routing Table

Routing Table all processes that use the Transport Layer protocols to deliver data Telnet The Network Terminal Protocol provides remote login over the network. FTP The File Transfer Protocol is used for interactive file transfer. SMTP The Simple Mail Transfer Protocol delivers electronic mail. HTTP The Hypertext Transfer Protocol delivers web pages over the network.

Routing Table

Protocols, Ports, and Sockets Protocol Numbers identifies protocol in the layer above IP to which the data should be passed a single byte in the third word of the datagram header Windows system, protocol numbers are documented in protocol file

Protocols, Ports, and Sockets Protocol Numbers

Protocols, Ports, and Sockets Port Numbers Application processes (network services) identified by port numbers, 16-bit values Port Port numbers below 1024 are reserved for well-known services Ports numbered from 1024 to 49151 are "registered ports.“ Windows Server 2003 systems port numbers are listed in services file in the %SystemRoot%\system32\drivers\etc directory

Protocols, Ports, and Sockets Port Numbers

Protocols, Ports, and Sockets Port Numbers

Protocols, Ports, and Sockets dynamically allocated ports are not preassigned assigned to processes when needed to support multiple users Ex telnet first user is given a random source port number and a destination port number of 23 (Telnet). second user is given a different random source port number and the same destination port  combination of an IP address and a port number is called a socket

Protocols, Ports, and Sockets

Protocols, Ports, and Sockets Use the netstat command to see active sockets onr Windows Server 2003