Editing Proxy server (section)

===Improving performance===
A '''caching proxy''' server accelerates service requests by retrieving the content saved from a previous request made by the same client or even other clients.<ref>{{Cite web |title=Caching Proxy |url=https://www.ibm.com/docs/en/was-nd/9.0.5?topic=overview-caching-proxy |access-date=2023-07-02 |website=www.ibm.com |language=en-us}}</ref> Caching proxies keep local copies of frequently requested resources, allowing large organizations to significantly reduce their upstream bandwidth usage and costs, while significantly increasing performance. Most ISPs and large businesses have a caching proxy. Caching proxies were the first kind of proxy server. Web proxies are commonly used to [[web cache|cache]] web pages from a web server.<ref>{{cite book |quote=A proxy server helps speed up Internet access by storing frequently accessed pages |first=Keir |last=Thomas |title=Beginning Ubuntu Linux: From Novice to Professional |publisher=Apress |year=2006 |isbn=978-1-59059-627-2 |url-access=registration |url=https://archive.org/details/beginningubuntul00keir }}</ref> Poorly implemented caching proxies can cause problems, such as an inability to use user authentication.<ref name="rfc3143">{{cite IETF |title=Known HTTP Proxy/Caching Problems |rfc=3143 |author=I. Cooper |author2=J. Dilley |date=June 2001 |publisher=[[Internet Engineering Task Force|IETF]] |access-date=2019-05-17 }}</ref>

A proxy that is designed to mitigate specific link related issues or degradation is a [[Performance Enhancing Proxy]] (PEPs). These are typically used to improve [[Transmission Control Protocol|TCP]] performance in the presence of high round-trip times or high packet loss (such as wireless or mobile phone networks); or highly asymmetric links featuring very different upload and download rates. PEPs can make more efficient use of the network, for example, by merging TCP [[Acknowledgement (data networks)|ACKs]] (acknowledgements) or compressing data sent at the [[application layer]].<ref name="rfc3135.2.1">{{cite IETF |title=Performance Enhancing Proxies Intended to Mitigate Link-Related Degradations |rfc=3135 |sectionname=Layering |section=2.1 |page=4 |date=June 2001 |publisher=[[Internet Engineering Task Force|IETF]] |access-date=21 February 2014 }}</ref>