Diff-Serv (Differentiated Services)

DiffServ es un protocolo QoS (Calidad de servicio) para administrar el ancho de banda (bandwidth) en conexiones de medios a Internet, tal como una conexión de voz VoIP.

Cuando se utilizan conexiones con bajo ancho de banda (bandwidth), tal como ADSL, los usuario pueden experimentar Jitter. Una forma para tratar de emularlo es permitiendo que todo el ancho de banda upload sea utilizado para una aplicación P2P en Internet o usando una aplicación para streaming HD y, al mismo tiempo, realizando una llamada telefónica en G.711, en una conexión con bajo ancho de banda.

Regarding many documents, the correct DiffServ value is EF (Expedited Forwarding).
The EF DiffServ also contains the ToS Low Delay bit, which is treated by many routers without any configuration.
This is called PFIFO (Priority Fist In First Out, or FIFO with Priority).

Traffic Classes (Service levels)

• Expedited Forwarding (EF): Has a single codepoint (DiffServ value). EF minimizes delay and jitter and provides the highest level of aggregate quality of service. Any traffic that exceeds the traffic profile (which is defined by local policy) is discarded [DiffServ EF].


• Assured Forwarding (AF): Has four classes and three drop-precedences within each class (so a total of twelve codepoints). Excess AF traffic is not delivered with as high probability as the traffic "within profile," which means it may be demoted but not necessarily dropped [DiffServ AF].