Estimating network bandwidth to launch YouTube TV live streaming in San Francisco
Company: Google
Role: Product Manager
Category: Product / Decision Making
Difficulty: medium
Interview Round: Other
YouTube TV is Google's paid subscription service for streaming live TV channels over the internet. Suppose you are planning to launch it in SFO. Estimate how much bandwidth the launch would require.
Set up an equation, label every assumption, do the arithmetic and sanity-check the result.
```hint Rate or volume
"Bandwidth" can mean the capacity needed at the busiest moment or the total data moved over a period. Decide which one a launch team has to plan for before you build the equation.
```
### Clarifying Questions
- Does "SFO" mean the San Francisco Bay Area market, or San Francisco International Airport with live TV offered to travelers?
- Should the estimate be the peak rate the network must handle, or the total data moved per day, month or year?
- Which leg of the network counts: bringing the channels into Google's network, or delivering streams to viewers' devices?
- What time horizon should the capacity cover: launch week, or the subscriber base expected after the first year or two?
### What a Strong Answer Covers
- Resolving the ambiguous scope (market or airport, peak or volume, which network leg) before estimating.
- A clear equation from audience size to concurrent streams to bits per second, with every input labeled as an assumption.
- Defensible inputs for adoption, peak concurrency, streams per household and the bitrate mix, including 4K.
- Correct arithmetic and units (bits versus bytes, rate versus volume), plus headroom for spikes such as major live sports.
- A sanity check and a sensitivity view showing which assumption moves the answer most.
### Follow-up Questions
- How does the answer change on the night of a championship game that a large share of subscribers watch live?
- Internet live TV is usually delivered as one stream per viewer rather than broadcast. Where would you place caching or edge servers to keep that traffic off long-haul links?
- If 4K became the default on TVs, what would happen to your estimate, and what would you do about it?
Overview: An estimation question asking how much network bandwidth a launch of YouTube TV, Google's live-TV streaming service, would need in SFO. It tests clarifying an ambiguous scope, separating peak rate from total data volume, building a concurrency-based equation with labeled assumptions, and sanity-checking the result.