Computer Networks 3

internetworking

interconnecting different types of networks to build a larger, global network

IP

Internet Protocol, invented to deal with interconnection of disparate networks

switches

devices that interconnect links of the same type

bridges

switches interconnecting Ethernet segments

gateways/routers

interconnect disparate networks and links

approaches for routing

Datagram, Virtual circuit, Source routing approach

Datagram/Connectionless approach

include in very packet just enough information to enable any switch to decide how to get it to its destination

Virtual Circuit/Connection-oriented approach

setting up a virtual connection from the source host to the destination host before any data is sent

Source routing approach

all the information about network topology that is required to switch a packet across the network is provided by the source host

Forwarding/Routing table

switch consults with such table to decide how to forward a packet (what path should it choose)

Learning bridge

does not forward all frames it receives. It builds a MAC address table to intelligently forward data only to the destination port by learning which device is connected to which port

Spanning Tree Algorithm

subset of the actual network topology that has no loops and that reaches all the devices in the network, solves problem with loops

Boradcast

switch forwards a frame with a destination broadcast address out on each active port (except the one on which the frame was received)

Multicast

each host decide for itself whether or not to accept the incoming message

VLAN

Virtual LANs, allow a single extended LAN to be partitioned into several seemingly separate LANs

Network & Internetwork

Network was understanded as either a directly connected or a switched network. Internetwork is interconnected collection of such networks

Service Model

defines the framework for how network layers or providers offer functions to users

forwarding

receiving a packet, looking up its destination address in a table and sending the packet in a direction determined by that table

rotuing

process by which forwarding tables are built

periodic update

node automatically sends an update message to its neighbour nodes so that the other nodes know that this node is still running

triggered update

whenever a node notices a link failure or receives an update from one of its neighbors that causes it to change one of the routes in its routing table, it forward this update to its neighbours

distance vector

node constructs a one-dimensional array containing the ‘distances’ to all other nodes in the network and share that vector with its neighbors

Routing Information Protocol (RIP)

routers 'learn’ how to forward packets to various networks

Link State

each node knows how to reach its directly connected neighbors and if we make sure that all of this knowledge is shared to every node then every node will have complete map of network

Reliable Flooding

node send its link-state information out on all of its directly connected links

Software Defined Networks (SDN)

separates the control plane (decision-making) from the data plane (actual forwarding of packets), software-based controller decides about that