Google Global Cache


Google Global Cache is an edge caching infrastructure operated by Google LLC, consisting of Google-supplied servers deployed inside the networks of partner Internet service providers. It is used to deliver popular static content for Google services from locations closer to end users, reducing latency and keeping more traffic within an ISP's network.

Overview

Google describes its network infrastructure as including data centers, edge points of presence, and edge nodes, also referred to as Google Global Cache. GGC nodes are intended to be the tier of Google's infrastructure closest to users, with caching servers hosted within participating ISP networks.

Operation

GGC nodes temporarily cache static content that is popular with an ISP's user base, including YouTube and Google Play content. Google traffic management systems direct user requests to the node expected to provide the best experience for a given user.

Hardware and requirements

Under the GGC program, Google provides the hardware server nodes at no cost to the ISP. In exchange, the ISP provides rack space, power, and high-speed network ports to connect the nodes directly to their internal network backbone. The hardware typically consists of rack-mounted servers designed by Google. The company requires a minimum amount of traffic from the ISP's user base to Google services to justify the deployment of a cache node.

Deployment

In 2021, Google said its edge nodes operate from over 1,300 cities in more than 200 countries and territories. Earlier reporting on Google's traffic growth described GGC as a network of caching servers placed with large numbers of ISPs; in July 2013, The Register reported that GGC servers were placed with over half of ISPs in the United States, as well as in European and South American networks.

Regional availability and restrictions

Russia

Following the 2022 Russian invasion of Ukraine, reports indicated that Google suspended the delivery of new GGC hardware to Russian internet service providers. By 2024, the degradation of existing, unmaintained GGC servers became a focal point in the restriction of YouTube access within the country.
In July 2024, the major state-backed provider Rostelecom announced that "technical problems" with Google's equipment were causing significant slowdowns in YouTube playback speeds, attributing the issue to the obsolescence of the GGC servers which had not been updated for over two years. However, independent media outlets and IT experts reported that the degradation was inconsistent with simple hardware failure and was likely the result of intentional throttling by the Russian censor Roskomnadzor, using the status of the GGC infrastructure as a pretext.

Impact on traffic costs

By caching high-bandwidth content within the ISP's own network, GGC reduces the amount of data the ISP must retrieve from the public internet. This offloading reduces the ISP's operating costs, as they generally pay for external bandwidth capacity, whereas traffic inside their own network is significantly cheaper. Google promotes this "offload" capability as a primary incentive for ISPs to host the nodes.

Routing and autonomous system numbers

Some GGC deployments present themselves using a separate autonomous system number from Google's primary network presence. For example, in November 2019 a Google employee wrote to participants at the PTT São Paulo internet exchange that a GGC deployment there was "presenting itself as AS36040", in addition to existing Google AS15169 presence. ARIN's WHOIS record lists AS36040 with the name "YOUTUBE" and the organization as Google LLC, with a registration date of August 3, 2005.

Regulatory disputes

The deployment of Google Global Cache has occasionally led to disputes between Google and ISPs regarding peering agreements and infrastructure costs. In 2013, French ISP Free temporarily blocked advertisements on Google services, a move widely interpreted as an attempt to force Google to pay for the traffic load its services placed on Free's network. The dispute drew the attention of the French government and the telecommunications regulator ARCEP. Following an investigation into the technical and financial relationships between ISPs and content providers, ARCEP noted that while traffic imbalances existed, the installation of offloading equipment like GGC nodes was a standard industry practice to mitigate costs.

Role in YouTube delivery

In the context of YouTube's adoption of HTTPS, Google described "the Google Global Cache" as YouTube's CDN and noted that migrating YouTube's video serving to HTTPS required encrypting a very large amount of traffic.