18 June 2016

CST311 Week 8

This was a short week due to the Final. We finished up the Link Layer, in particular ARP and switches.

The address resolution protocol (ARP) is a protocol used by IPv4 to map IP network addresses to the hardware addresses used by a data link protocol. The protocol operates below the network layer as a part of the interface between the network and link layers.

Ethernet switches are a link layer device that takes an active role in storing and forwarding Ethernet frames by examining incoming frames MAC address and selectively forwarding frame to one or more outgoing links when frame is to be forwarded on segment. Uses CSMA/CD to access segment.

14 June 2016

CST311 Week 7

This week we continued the Network Layer and introduced the Link Layer. For the network layer we covered Routing and Forwarding, Dijkstra's Algorithm, Distance Vector Algorithm and for the link layer we covered Error Detection and Correction & MAC Protocols.

Routing answers the question of what next hop IP to send a packet based on the destination prefix while forwarding functions determine which exit interface to use to send the packet to its next hop.
Parity Checking of Error Detection is the simplest technique for detecting and correcting errors. The MSB of an 8-bits word is used as the parity bit and the remaining 7 bits are used as data or message bits. The parity of an 8-bit transmitted word can be either even or odd parity.

The Medium Access Control (MAC) protocol is used to provide the data link layer of the Ethernet LAN system.

07 June 2016

CST311 Week 6

This week we covered the Network Layer, including IP datagram format, IP Addressing, ICMP and Traceroute and DHCP.
An Internet Protocol address (IP address) is a numerical label assigned to each node participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing. In the IPv4 scheme addresses are 32 bits.

Traceroute, by default, sends a sequence of User Datagram Protocol (UDP) packets addressed to a destination host; ICMP Echo Request or TCP SYN packets can also be used. The time-to-live (TTL) value, also known as hop limit, is used in determining the intermediate routers being traversed towards the destination.

Dynamic Host Configuration Protocol (DHCP) is a client/server protocol that automatically provides an Internet Protocol (IP) host with its IP address and other related configuration information such as the subnet mask and default gateway.