Which protocol is used to reserve network bandwidth for calls?

Which protocol is used to reserve network bandwidth for calls?

• A. DNS
• B. SMTP
• C. NTP
• D. RSVP

Answer: (D)

Guaranteeing quality for real-time traffic relies on signaling that reserves resources along the path. The protocol that does this is RSVP, the Resource Reservation Protocol. RSVP works within the Integrated Services framework by letting a sender describe a data flow and the required QoS, then having routers along the route reserve the needed bandwidth for that flow. Path messages carry the flow’s characteristics, and the routers install reservation state so the required bandwidth and QoS are available for the duration of the session. This makes VoIP and other real-time calls more reliable by preventing congestion from degrading voice quality. In contrast, DNS translates domain names to IP addresses, SMTP handles email transfer, and NTP synchronizes clocks, none of which reserve bandwidth for calls.

Guaranteeing quality for real-time traffic relies on signaling that reserves resources along the path. The protocol that does this is RSVP, the Resource Reservation Protocol. RSVP works within the Integrated Services framework by letting a sender describe a data flow and the required QoS, then having routers along the route reserve the needed bandwidth for that flow. Path messages carry the flow’s characteristics, and the routers install reservation state so the required bandwidth and QoS are available for the duration of the session. This makes VoIP and other real-time calls more reliable by preventing congestion from degrading voice quality. In contrast, DNS translates domain names to IP addresses, SMTP handles email transfer, and NTP synchronizes clocks, none of which reserve bandwidth for calls.