DiffServ vs IntServ | IntServ vs DiffServ Models
DiffServ (Differentiated Services) is a model for providing QoS (Quality of Service) in the internet. This improves the best effort services provided by internet differentiating the traffic. For differentiation, it uses facts like the user, service requirements, etc. Depending on this differentiation, different levels of services are provided to different packets. IntServ (Integrated Services) is also a model for providing QoS in networks. IntServ is based on building a virtual circuit in the internet using the bandwidth reservation technique. Requests for reserving the bandwidth come from the applications that require some kind of level of service.
What is DiffServ?
DiffServ is a model for providing QoS in the Internet by differentiating the traffic. The best effort method used in the internet tries to provide the best possible service depending on the varying traffic flow, rather than trying to differentiate the flow and provide higher level of service to some of the traffic. DiffServ tries to provide a improved level of service in the existing best effort environment by differentiating the traffic flow. For example, DiffServ will reduce the latency in traffic containing voice or streaming video, while providing best effort service to traffic containing file transfers. Packets are marked by the DiffServ devices at the boarders of the network with information about the level of service required by them. Other nodes in the network read this information and respond accordingly to provide the requested level of service.
What is IntServ?
IntServ is another model for providing QoS in networks. IntServ is based on building a virtual circuit in the internet using the bandwidth reservation technique. Requests for reserving the bandwidth come from the applications that require some kind of level of service. According to this model, each router in the network has to implement IntServ and each application that requires a service guarantee has to make a reservation. When bandwidth is reserved for a certain application, it cannot be reassigned for another application. Routers between the sender and the receiver determine whether they can support the reservation made by the application. If they cannot support it, they notify the receiver. Else they have to route the traffic to the receiver. Therefore, in this method, routers remember the properties of the traffic flow and also supervise it. The task of reserving paths would be very tedious in a busy network such as the Internet.
What is the difference between DiffServ and IntServ?
DiffServ is a model for providing QoS in the Internet by differentiating the traffic whereas IntServ is a model for providing QoS in networks by building a virtual circuit in the Internet using the bandwidth reservation technique. DiffServ does not require the nodes in the network to remember any state information about the flow as oppose to IntServ, which remembers state information in the routers. Furthermore, reserving paths and remembering state information in a busy network such as the Internet would be a tedious task. Therefore, implementing IntServ would be practically difficult in the Internet. Because of that, IntServ would be suitable for smaller private networks whereas DiffServ is much suitable for the Internet.