Types of Network Topology
The arrangement of a network that comprises nodes and connecting lines via sender and receiver is referred to as network topology. The various network topologies are:
Types of Topology
There are five types of topology in computer networks:
1. Mesh Topology
2. Star Topology
3. Bus Topology
4. Ring Topology
5. Hybrid Topology
Defining a VPN
In Firewall Policies and VPN Configurations, 2006
Meshed Topology
Like their traditional WAN counterparts, meshed VPN topologies can be implemented in a fully or partially meshed configuration. Fully meshed configurations have a large number of alternate paths to any given destination. In addition, fully meshed configurations have exceptional redundancy because every VPN device provides connections to every other VPN device. This topology was illustrated in Figure5.1. A simpler compromise is the partial-mesh topology, in which all the links are connected in a more limited fashion to other links. A partial-mesh topology is shown in Figure5.5.
Figure5.5. Partial-Mesh VPN Topology
Mesh topology provides an inherent advantage that there is no single point of failure. Overall performance of the setup is independent of a single node or a single system. Sites that are geographically close can communicate with each other. Its main drawback is maintenance and key maintenance. For a fully meshed network, whenever a new node is added, all the other nodes will have to be updated. Even with the replacement of traditional WAN services such as frame relay or leased lines, fully meshed topologies can be expensive to implement due to the requirement to purchase a VPN device for every link in the mesh.
Note
Another issue you should be aware of with full versus partial-mesh topology is the number of tunnels you need to configure and manage. If you have 100 sites and add one router, think of all the connections you must make to rebuild a full mesh! In essence, the partial mesh is the way you want to go, but you might see an extra hop in the route from place to place because you will no longer have a single hop to any single destination. There is always give and take. Think about what method suits your design needs, and implement that method accordingly.
View chapterPurchase book
Read full chapter
URL://www.sciencedirect.com/science/article/pii/B9781597490887500074
1.Mesh Topology:
In a mesh topology, every device has a dedicated point-to-point link to every other device. The dedicated link carries traffic only between the two devices it connects. The number of physical links needed in a fully connected mesh network with n nodes are, n[n - 1]. However, if each physical link allows communication in both directions [duplex mode], we can divide the number of links by 2. In other words, we can say that in a mesh topology, we need n[n -1] /2 duplex-mode links. To accommodate that many links, every device on the network must have n – 1 input/output [I/O] ports to be connected to the other n - 1 stations which are shown in the following figure:
You May Also Like:
Data Communications and Its Characteristics
Characteristics of Networks
Protocols and Standards
Components of Data Communication
Advantages of Mesh Topology:
1. The dedicated links guarantees that each connection can carry its own data load, thus eliminating the traffic problems that can occur when links must be shared by multiple devices.
2. A mesh topology is robust. If one link becomes unusable, it does not incapacitate the entire system.
3. Another advantage of Mesh topology is advantage of privacy or security. When every message travels along a dedicated line, only the intended recipient sees it. Physical boundaries prevent other users from gaining access to messages.
4. point-to-point links make fault identification and fault isolation easy. Traffic can be routed to avoid links with suspected problems. This helps to discover the precise location of the fault and aids in finding its cause and solution.
Disadvantages of Mesh Topology:
1. Every device must be connected to every other device. So large amount of cabling and the number of I/O ports are required. So, the installation and reconnection are difficult.
2. The sheer bulk of the wiring can be greater than the available space [in walls, ceilings, or floors] can accommodate.
3. The hardware required to connect each link [I/O ports and cable] can be prohibitively expensive.