Refer to the passage below and then answer the question afterwards in the same language as the passage: Passage: One compelling example of the need for QoS on the Internet relates to congestive collapse. The Internet relies on congestion avoidance protocols, as built into Transmission Control Protocol (TCP), to reduce traffic under conditions that would otherwise lead to "meltdown". QoS applications, such as VoIP and IPTV, require largely constant bitrates and low latency, therefore they cannot use TCP and cannot otherwise reduce their traffic rate to help prevent congestion. QoS contracts limit traffic that can be offered to the Internet and thereby enforce traffic shaping that can prevent it from becoming overloaded, and are hence an indispensable part of the Internet's ability to handle a mix of real-time and non-real-time traffic applications without becoming meltdown. Mubvunzo: QoS inoda zvinhu zviviri kuti ishande nemazvo.
zvikuru nguva dzose bitrates uye yakaderera latency