Hi friend!
Differentiated Service (DiffServ) is another service model proposed by the IETF working group in 1998 to overcome the poor scalability of Inter-Serv. The purpose is to develop a method with relatively high scalability to ensure IP QoS.
Differentiated Services (DiffServ) is a class-based QoS technology that does not require signaling. At the ingress of the network, the network device examines the contents of the packets, classifies and marks the packets, and all subsequent QoS policies are made based on the tags in the packets.
DiffServ does not need to store flow state and signaling information and has good scalability. However, due to the lack of end-to-end bandwidth reservation, service guarantees may be weakened on congested links.
Since both integrated services and differentiated services have no obvious advantages, the QoS mechanism still uses the combination of integrated services and differentiated services to provide the required service bandwidth on the network.
In the Int-Serv model, the Resource Reservation Protocol (RSVP) is used as signaling for the transmission of QoS requests. When a user needs QoS guarantee, the user sends a QoS request to the network devices through the RSVP signaling. The request may be a requirement for delay, bandwidth, or packet loss ratio. After receiving the RSVP request, the nodes along the transfer path perform admission control to check the validity of the user and the availability of resources. Then the nodes decide whether to reserve resources for the application program. The nodes along the transfer path meet the request of the user by allocating resources to the user. This ensures the QoS of the user services.
Hope this helps!
