Network final

• Full Duplex

  • Point to point only
  • Attached to dedicated switched port
  • Requires full duplex support on both ends
  • Collision-free
  • Collision detect circuit disabled
• Half Duplex

  • Unidirectional data flow
  • Higher potential for collision
  • Hub connectivity
• A cut-through switch forwards the frame before it is entirely received.
• Fast-forward switching – lowest level of latency immediately forwards a packet after reading the destination address.
• Fragment-free switching – switch store the first 64 bytes of the frame before forwarding, most network errors and collisions occur during the first 64 bytes.
• port-based memory buffering, frames are stored in queues that are linked to specific incoming and outgoing ports
• Shared memory buffering deposits all frames into a common memory

  buffer, which all the ports on the switch share.
• MAC address

  • this address does not change
  • similar to the name of a person
  • known as physical address because physically assigned to the host NIC
• IP address

  • similar to the address of a person
  • based on where the host is actually located
  • known as a logical address because assigned logically
  • assigned to each host by a network administrator
• IP Header- identifies the packet characteristics.
• Payload – contains the layer 4 segment information and the actual data.
• Version – contains a 4-bit binary value identifying the IP packet version. For IPv4 packets, this field is always set to 0100.
• Differentiated Services (DS) – Formerly called the Type of service field, the DS field is an 8-bit field used to determine the priority of each packet.
• Time-to-live (TTL) – contains an 8-bit binary value that is used to limit the lifetime of a packet.
• Protocol – this 8-bit binary value indicates the data payload type that the packet is carrying, which enables the network to pass the data to the appropriate upper layer protocol. Common values include ICMP (1), TCP (6), and UDP (17).