NETWORK LAYER

NETWORK LAYER

1. Processes

   • Addressing terminals
     • Configure a unique IP address to identify yourself in the network.
   • Encapsulation
     • Encapsulates the PDU to a package.
   • Routing
     • It is done by the Router. Its function is to choose the best way to send the package.
   • Decapsulation
     • The IP header of the packet is checked at the network layer of the destination host. If the IP addresses match, the header is deleted and the PDU is sent to the appropriate service on the transport layer.

2. Protocol

   • IPV4 package
     • IPV4 limitations
       • Exhaustion of IPV4 addresses
       • Expansion of the internet routing table
       • Lack of complete connectivity
     • IPV4 Header
       • Version
         • It contains a binary value of 4 Bits set to 0100 that identifies it as an IP version 4 package.
       • Differentiated services or DiffServ (DS)
         • 8-bit field, determines the priority of a packet. The 6 bits for DSCP (differentiated services code point) and 2 bits for ECN (explicit congestion notification).
       • Time to live (TTL)
         • It contains 8 bits, is responsible for limiting the lifetime of a package.
       • Protocol
         • It is used to identify the protocol of the next level.
   • IPV6 package
     • Features
       • Larger IP address space
       • Better handling of packages
       • The need for NAT is eliminated
     • IPV6 Header
       • Traffic class
         • Equivalent to the DS field of IPV4.
       • Flow label
         • Field of 20 bits. It suggests that all the packages with the same receive the same type of handling of the routers.
       • Next heading
         • It is the equivalent to the protocol field of IPV4.
       • Limit of jumps
         • Replaces the IPV4 TTL field.
       • Version
         • It is always established in 0110.

3. Characteristics of IP

   • Connectionless
     • No connection is made to the destination before sending the data packets.
   • Minimum service
     • The delivery of the package is not guaranteed.
   • Independent of the media
     • The operation is independent of the means of transport of the data package.

4. Routing

   • Direct packages between hosts.
     • Likewise
       • It is called "loopback interface". A packet is sent to the IPV4 address 127.0.0.1.
     • To the local host
       • Host that is in the same local network as the sending host.
     • To a remote I / O module
       • Host that is in a remote network.
   • Default gateway
     • Functions
       • Route traffic to other networks
       • It has a local IP address in the same range as other hosts in the network.
       • You can carry data and forward it.
   • Routing table
   • Router
     • Anatomy of a router
       • CPU
         • Execute OS instructions, such as system initialization, routing and switching.
       • Memory
       • Router boot

Imagens e arquivos do mapa