# Performance

## Problem

* As discussed in estimation, the bandwidth requirement will be

```
# If designed properly, typically CDNs could handle 95% of traffic volumes and data center only needs to handle 5% of the total requirement. 

# Bandwidth requirement for data centers:
5% * 80 Tb/s = 4 Tb/s
```

## CDN pushes

* Popular videos will be pushed to CDNs in a proactive manner.
* Most of popular videos could be returned through CDNs.
* Most of video playthrough rate is not more than 30%, the videos could be split to several chunks. And only push certain chunks into CDNs.

![](https://1010073591-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-Mk8dv8Mfudl_6ziUzDf%2Fuploads%2Fgit-blob-f62f4e98535dc0559359c09a6d377776dc576978%2Fyoutube_performance.png?alt=media)