Comcast strives to provide consumers with accessible, easy-to-understand information about the services we provide, so they can make informed decisions about which services best meet their needs. Consistent with that goal, we have designed this page to act as a single place where consumers and others can come to access and review the relevant policies, agreements, and other information about these services.

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Network management practices

Learn How Network Congestion Management Affects Your Internet Use

Managing the network helps ensure fair use of the Internet by all Comcast customers.

Comcast is committed to providing the best online experience possible for all our customers, using reasonable network management practices that are consistent with industry standards. (...). The following is intended to help clarify what we mean by network management.

• Why Comcast manages its network

Comcast manages its network with one goal: to deliver the best possible broadband Internet experience to all of our customers. High-speed bandwidth and network resources are not unlimited. Managing the network is essential to promote the use and enjoyment of the Internet by all of our customers.

All Internet service providers need to manage their networks, and Comcast is no different. If we didn't, customers would be subject to the negative effects of spam, viruses, security attacks, network congestion and other degradations of service. By engaging in reasonable and responsible network management, Comcast can deliver the best possible broadband Internet experience.

• How Comcast manages its network

Comcast uses various tools and techniques to manage the network, deliver service, and ensure compliance with the Acceptable Use Policy. Like the network, these tools are dynamic and change frequently. Network management activities may include identifying spam and preventing its delivery to customer email accounts, and detecting malicious Internet traffic and preventing the distribution of viruses or other harmful code or content.

• Changes in network management over time

As the Internet and its related technologies continue to evolve, Comcast's network management tools will also keep pace so we can deliver an excellent, reliable and safe experience to all of our customers. We will provide updates here as well as other locations if we make significant changes to our network management techniques.

• Comcast's current congestion management technique

If a certain area of the network nears a state of congestion, our congestion management technique will ensure that all customers have a fair share of network access. This technique will identify which customer accounts are using the greatest amounts of bandwidth, and their Internet traffic will be temporarily managed until the congestion period passes. Customers will still be able to do anything they want online, but they could experience longer times to download or upload files or slower web surfing.

Our technique does not manage congestion based on specific online activities, protocols or applications that a customer uses. Rather, it only focuses on the heaviest users in real time, so that congestion periods tend to be fleeting and sporadic.

It is important to note that the effect of this technique is temporary and has nothing to do with a customer's aggregate monthly data usage. Rather, it's dynamic and based on prevailing network conditions as well as a customer's data usage over a very recent period of time.

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• Targets of congestion management

Our current technique is "protocol-agnostic," which means the system does not manage congestion based on the application(s) being used. It is also content neutral, and does not depend on the type of content that is generating traffic congestion. Put simply: congestion-managed traffic is not based on specific applications or content, but on current network conditions and recent amounts of data transferred by users.

• Impacts on Xfinity Internet service [Comcast's Internet service]

Based on our experience, the large majority of our customers will notice no change in their Internet experience. In fact, we find that on average less than one percent of our high-speed Internet customers are affected by the congestion management approach. Our experience also shows that when the congestion management technique is applied to an individual user's account, it is usually only for a very brief period of time.

• Frequency of congestion management

Comcast has determined that select portions of the network tend to be congested only for small portions of the day, if at all.

We constantly monitor how user traffic is affected by this system and will make reasonably necessary adjustments to ensure that our (...) Internet customers enjoy a high-quality online experience. Comcast also routinely evaluates its overall network performance and periodically enhances its network by adding capacity to address congestion and other performance issues.

• "Real world" types of bandwidth consumption that might be considered too much

This answer depends on a number of factors, including overall usage, time of day, and the number of applications a customer might be running. First, the local network must be approaching a congested state for our technique to even look for traffic to manage. Assuming that is the case, customers' accounts must exceed a certain percentage of their upstream or downstream bandwidth (both currently set at 70%) for longer than a certain period of time, currently set at 15 minutes.

A significant amount of normal Internet usage by our customers does not last that long. For example, most downloads would have completed within that time, and the majority of streaming and downloading will not exceed the threshold to be eligible for congestion management. And the majority of longer-running applications--such as VoIP, video conferencing, and streaming video content (including HD streaming on most sites) will not exceed these thresholds either.

The point of the technique is to deliver the best online experience possible. Congestion management should help ensure that all customers get their fair share of bandwidth resources to enjoy all that the Internet has to offer, including surfing the web, reading email, downloading movies, watching streaming video, gaming, or listening to music.

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• Congestion management and high use patterns

The two are completely separate and distinct. Our new congestion management technique is based on real-time Internet activity. The goal is to avoid congestion on our network that is caused by the heaviest users. The technique is different from the current AUP policy, which permits Comcast to consider usage as an indication of a security or related issue, requiring customer outreach to help address the issue.

• XFINITY Voice services [Comcast's online voice service] affected by our congestion management technique

XFINITY Voice and Comcast Digital Voice are separate, facilities-based IP phone services that are not affected by this technique. This phone service also does not affect the last mile capacity for, or the performance of, the Xfinity Internet service.

Comcast customers who use VoIP providers that deliver calls over the public Internet who are also using a disproportionate amount of bandwidth during congestion management period may experience a degradation of call quality at times of network congestion. (It is important to note, however, that VoIP calling in and of itself does not use a significant amount of bandwidth). Furthermore, our experience with this technique does not indicate any significant change in the quality of VoIP calls, even for managed customer traffic during periods of congestion.

• Congestion management and XFINITY TV [Comcast's online TV service], streaming video, and video downloads

During periods of congestion, any customer who uses a disproportionate amount of bandwidth (no matter what type of content or online activity) may be affected by this technique. (It does not matter, for example, if the content is coming from a Comcast-owned site like XFINITY TV (...) or not).

Our technique has no ability to determine the applications or protocols being used or the content, source or destination.

• Types of content affected by congestion management

Comcast does not block P2P traffic or applications like BitTorrent, Gnutella, or others as part of its current network congestion management technique.

Comcast provides its customers with full access to all the lawful content, services, and applications that the Internet has to offer. However, we are committed to protecting customers from spam, phishing, and other harmful online activity. Comcast uses industry standard tools and generally accepted best practices to meet this customer commitment. In cases where these tools and policies identify certain online content as harmful and unwanted, this content is usually prevented from reaching customers. In other cases, these tools and policies may permit customers to identify certain content that is not clearly harmful or unwanted (such as bulk email or websites with questionable security ratings) and enable those customers to inspect the content further if they want to do so. (...).

• Other network security practices

Comcast employs a number of practices to prevent unwanted communication like spam. We limit the number of login, SMTP, DNS, and DHCP transactions per second (at levels far above 'normal' rates) that customers can send to our servers in order to protect them from Denial of Service (DoS) attacks. (We do not disclose exact rate limits in order to maintain the effectiveness of these measures.)

In order to further protect our customers, Comcast blocks a limited number of ports that are commonly used to send spam, launch malicious attacks, or steal a customer's information. Comcast conducts several security initiatives, and offers security tools for our customers at our online security page.

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Application-Specific Behavior

Comcast provides its customers with full access to all the lawful content, services, and applications that the Internet has to offer. Comcast does not block or rate-control specific protocols or protocol ports (except to prevent spam, malicious attacks, and identity theft), does not modify protocol fields in ways not prescribed by protocol standards, and does not otherwise inhibit or favor certain applications or classes of applications.

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Performance characteristics

Comcast provides a detailed summary of its Internet service performance containing information about speed and latency, as well as other related topics. (...).

Comcast provides residential and commercial customers with a variety of high-speed Internet plans from which to choose, with download speed tiers ranging from up to 3 megabits per second ("Mbps") to up to 250 Mbps (in select markets) and upload speeds ranging from up to 768 kilobits per second ("kbps") to up to 25 Mbps on our DOCSIS 3.0 cable network. In select markets we also offer a fiber-based service with download speeds up to 505 Mbps and upstream speeds up to 100 Mbps. (...).

Comcast provisions its customers' modems and engineers its network to enable customers to enjoy the speeds to which they subscribe. However, Comcast does not guarantee that a customer will achieve those speeds at all times. Unless a customer purchases a dedicated Internet connection, no Internet Service Provider ("ISP") can guarantee a particular speed at all times. Comcast advertises its speeds as "up to" a specific level based on the tier of service to which a customer subscribes. The "actual" speed that a customer will experience while using the service depends upon a variety of conditions, many of which are beyond the control of an ISP. These conditions include:

1. Performance of a customer's computer, including its age, processing capability, operating system, the number of applications running simultaneously, and the presence of any adware and viruses.
2. Type of connection between a customer's computer and modem. For example, in-home wireless connections between the computer and the router or modem may be slower than wired connections. In-home wireless connections also may be subject to greater performance fluctuations, caused by factors like interference and congestion. Comcast recommends that customers confirm that their in-home wireless connections are able to support the speeds that Comcast's services deliver. Certain older in-home wireless connections and routers cannot perform at the speeds delivered by Comcast's higher speed tiers. Customers can purchase their modem and router at a retail outlet, or they can lease the necessary equipment from Comcast, though even wireless routers leased from Comcast are subject to some of the same limitations mentioned above.
3. The distance packets travel (round trip time of packets) between a customer's computer and their final destination on the Internet, including the number and quality of the networks of various operators in the transmission path. The Internet is a "network of networks." A customer's Internet traffic may traverse the networks of multiple providers before reaching its destination, and the capabilities of those networks may affect the overall speed of that Internet connection.
4. Congestion or high usage levels at the website or destination. When you access a site or particular destination that is being visited by others at the same time, you may experience a slower connection if the site or destination does not have sufficient capacity to serve all of the visitors efficiently at the same time.
5. Gating of speeds or access by the website or destination. To control traffic or performance, many websites limit the speeds at which a visitor can download from their site. Those limitations will carry through to a customer's connection.
6. The performance of the cable modem you have installed. Modem performance may degrade over time, and certain modems are not capable of handling higher speeds. (...)

• Speed

Recently, the Federal Communications Commission ("FCC") concluded a nationwide network performance test of the largest ISPs in the U.S., including Comcast. (...) According to that test, Comcast's Xfinity Internet services deliver, on average, over 100 percent of their advertised downstream and upstream speeds during the busiest periods of the day, during sustained testing. Below are the Comcast results by tier:



While individual experiences may vary, the FCC's tests have consistently confirmed the quality of Comcast's Internet services.

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• Latency

Latency is another measurement of Internet performance. Latency is the time delay in transmitting or receiving packets on a network. Latency is primarily a function of the distance between two points of transmission, but also can be affected by the number and quality of the network or networks used in transmission. Latency is typically measured in milliseconds, and generally has no significant impact on typical everyday Internet usage. As latency varies based on any number of factors, most importantly the distance between a customer's computer and the ultimate Internet destination, it is not possible to provide customers with a single figure that will define latency as part of a user experience.

As discussed above, the FCC recently concluded a nationwide network performance test of the largest ISPs in the U.S., including Comcast. Latency tests were performed using User Datagram Protocol ("UDP") packet tests that measure the round trip time it took those packets to travel between a customer location and a target test node. According to the FCC's test results, the cable industry average latency was approximately 32 milliseconds, and DSL averaged 49 milliseconds. Below are the Comcast results by tier:



The results do not define latency as part of a particular user experience because (1) the results include time spent traversing networks not controlled by Comcast; and (2) the geographic distance between any given user and the target node may vary greatly from those employed in the FCC's broadband measurement project. (...)