IT Network Services

A traditional hierarchical network design is based on the idea of three basic network layers. Each layer handles a separate portion of the dataflows on a network. Those layers are:

Core layer. This is the layer that routes traffic between different geographical sites. In other words, it’s the network backbone. The core layer is where high-throughput, expensive core routers shine.

Distribution layer. The distribution layer sits between the core and access layers. It acts as a boundary and implements network policies to restrict or allow data flows between different subnets within the network. Less expensive routers and L3 switches are the common workhorses of the distribution layer.

Access layer. The access layer is the layer for endpoint devices like user PCs, printers, and VoIP phones. Smaller “access switches” are responsible for switching packets and routing traffic at this layer.

Top-down and bottom-up are two approaches to network design based on the OSI model. With a top-down approach, you start designing your network at the application layer and work your way down the model finishing with the physical layer. The bottom-up design is exactly the opposite. Top-down is generally considered a better approach when you start with business requirements and work your way down. However, top-down is also often more time-consuming. Bottom-up network design starts with the physical aspect of the network and works upwards.

A network topology in which nodes are directly connected to a common half-duplex link called a bus. A host on a bus network is called a station. In a bus network, every station will receive all network traffic, and the traffic generated by each station has equal transmission priority. A bus network forms a single network segment and collision domain. In order for nodes to share the bus, they use a medium access control technology such as carrier-sense multiple access (CSMA) or a bus master.

A computer networking technology used to build local area networks. It was introduced by IBM in 1984, and standardized in 1989 as IEEE 802.5. It uses a special three-byte frame called a token that is passed around a logical ring of workstations or servers. This token passing is a channel access method providing fair access for all stations, and eliminating the collisions of contention-based access methods. Token Ring was a successful technology, particularly in corporate environments, but was gradually eclipsed by the later versions of Ethernet.

A implementation of a spoke–hub distribution paradigm in computer networks. In a star network, every host is connected to a central hub. In its simplest form, one central hub acts as a conduit to transmit messages. The star network is one of the most common computer network topologies. The star topology reduces the impact of a transmission line failure by independently connecting each host to the hub. Each host may thus communicate with all others by transmitting to, and receiving from, the hub. The failure of a transmission line linking any host to the hub will result in the isolation of that host from all others, but the rest of the network will be unaffected.

A tree network, or star-bus network, is a hybrid network topology in which star networks are interconnected via bus networks.[1][2] Tree networks are hierarchical, and each node can have an arbitrary number of child nodes.

A mesh network (or simply meshnet) is a local network topology in which the infrastructure nodes (i.e. bridges, switches, and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data from/to clients. This lack of dependency on one node allows for every node to participate in the relay of information. Mesh networks dynamically self-organize and self-configure, which can reduce installation overhead. The ability to self-configure enables dynamic distribution of workloads, particularly in the event a few nodes should fail. This in turn contributes to fault-tolerance and reduced maintenance costs.