Question

Consider a 50,000 -customer video server, where each customer watches three movies per month. Two-thirds of the movies are served at 9 P.M. How many movies does the server have to transmit at once during this time period? If each movie requires 6 Mbps, how many \(\mathrm{OC}-12\) connections does the server need to the network?

Short answer

The server needs to transmit 3,333 movies at once, requiring 33 OC-12 connections.

Step-by-step solution

Calculate Total Movies Viewed per Month

Each customer watches 3 movies per month. With 50,000 customers, calculate the total monthly movies viewed: \[\text{Total Movies per Month} = 50,000 \times 3 = 150,000\]

Determine Movies Watched at 9 P.M.

Two-thirds of the movies are watched at 9 P.M. Therefore, calculate two-thirds of the total monthly movies:\[\text{Movies at 9 P.M.} = \frac{2}{3} \times 150,000 = 100,000\]

Calculate Daily Movies Watched at 9 P.M.

Since there are about 30 days in a month, determine the average number of movies watched each day at 9 P.M.: \[\text{Daily Movies at 9 P.M.} = \frac{100,000}{30} \approx 3,333.33\]Round to the nearest whole number for simplicity:\[\text{Daily Movies at 9 P.M.} \approx 3,333\]

Calculate Total Data Rate Required

Each movie requires 6 Mbps. Therefore, calculate the total bandwidth required concurrently at 9 P.M.: \[\text{Total Bandwidth} = 3,333 \times 6 \text{ Mbps} = 19,998 \text{ Mbps}\]

Determine Number of OC-12 Connections Needed

An OC-12 connection supports approximately 622 Mbps. Calculate how many such connections are needed to support the total bandwidth:\[\text{Number of OC-12s} = \frac{19,998}{622} \approx 32.15\]Round up to the nearest whole number:\[\text{Number of OC-12s} = 33\]

Key concepts

Video Server

A video server is a computer system or application that delivers video content to users over a network. In the case of our exercise, we have a video server tasked with serving movies to 50,000 customers. Each of these customers watches an average of three movies per month.

To understand how busy this server is, it's important to calculate the total number of movies it needs to deliver during peak times and overall monthly demand. This measurement allows network engineers to determine the server's capacity needs.

• The video server must handle peak usage times, like at 9 P.M., when a high percentage of customers watch simultaneously.
• In this scenario, two-thirds of movies are streamed at this peak hour, which significantly impacts bandwidth requirements.
• Understanding these peak times is crucial to ensuring seamless service without any buffering or delays.

OC-12 Connections

In the realm of networking, OC-12 connections refer to fiber-optic network connections that are capable of transmitting data at a rate of approximately 622 Megabits per second (Mbps). They are part of the Synchronous Optical Networking (SONET) standards used for transmitting digital signals.

• These connections are typically used by enterprise-level organizations, like our video server in the exercise, when they have substantial data bandwidth requirements.
• To calculate how many OC-12 connections a server like ours needs, we need to first determine the total data rate requirement during peak periods.
• In our calculation, we deduced that the video server requires a bandwidth of 19,998 Mbps at peak time.
• Since each OC-12 supports 622 Mbps, several connections are necessary to meet this total demand, ensuring all video streams are delivered smoothly at peak times.

Bandwidth Requirement

For any video streaming service, understanding the bandwidth requirement is essential to delivering a good user experience. Bandwidth refers to the maximum rate of data transfer across a network path.

In our scenario,

• The bandwidth requirement needs to be calculated based on the number of movies streamed simultaneously, particularly during the peak hour of 9 P.M.
• Each movie stream demands 6 Mbps. When combined with the number of movies being watched, this results in the total data throughput required.
• The peak demand was calculated to be approximately 3,333 simultaneous movie streams.
• Multiplying this by 6 Mbps gives a total requirement of nearly 19,998 Mbps, which is the total bandwidth required from the video server during the peak period.

Customer Movie Streaming

Customer movie streaming is a vital part of the video server's operation. The term refers to customers accessing and watching movies over the internet, managed by the server.

In the given scenario:

• Each customer, out of the 50,000 total, watches around three movies monthly. This equates to a significant monthly volume.
• Two-thirds of customers prefer to watch movies during the 9 P.M. time slot, resulting in increased pressure on the server to deliver a high-quality streaming experience.
• The streaming experience relies heavily on the server's ability to handle simultaneous requests without interruptions.
• Ensuring the server can meet this demand requires robust bandwidth management, facilitated by multiple OC-12 connections, to maintain consistent streaming quality during these popular viewing times.