Your Internet Service Performance
- Published on Thursday, July 03, 2014
Your Internet Service Performance
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. To see the plans currently available to you, please go to http://www.comcast.com/internet-service.html
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:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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. Please visit MyDeviceInfo for information regarding cable modems approved for use on Comcast's network.
Recently, the Federal Communications Commission ("FCC") concluded a nationwide network performance test of the largest ISPs in the U.S., including Comcast. The results of that test can be found at http://www.fcc.gov/reports/measuring-broadband-america-2014. 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:
|Down (Mpbs)||Up (Mbps)|
While individual experiences may vary, the FCC's tests have consistently confirmed the quality of Comcast's XFINITY Internet services.
You also can test your speeds yourself. Comcast offers its customers the ability to test the speeds that they are receiving on Comcast's network - from the customer's computer to test sites located throughout Comcast's network. Simply go to http://speedtest.comcast.net to test your connection. These tests are heavily dependent on many of the factors outlined above, however, and therefore do not necessarily reflect the performance of the Comcast network alone.
There are other speed tests that measure Internet performance. We have provided links to a few of these sites below for your reference. Please note, however, that all speed tests have limitations and flaws. Each of these tests measures limited aspects of an ISP's speed and therefore must be seen as a guide rather than definitive measurements of performance.
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:
|Speed Tier (Mbps)||Latency|
|Down 3, Up 0.768||38.99 ms|
|Down 20, Up 4||30.97 ms|
|Down 25, Up 5||38.99 ms|
|Down 50, Up 10||37.74 ms|
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. But customers can test the latency characteristics of their service at http://speedtest.comcast.net. Of course, this test also may incorporate limitations in a customer's home network and computers, and therefore will not necessarily reflect the performance of the Comcast network alone.
There are other latency tests available on the Internet. We have provided links to a few of these sites, above in the Speed Test Section, for your reference. As previously explained, however, all tests have limitations and flaws, and therefore must be seen as a guide rather than definitive measurements of performance.
In addition to the residential or commercial Internet service that you enjoy at your home or office, Comcast provides its Internet subscribers with XFINITY WiFi, which allows XFINITY Internet subscribers to access the Internet when they are at one of the many XFINITY or Cable WiFi hotspots. Comcast engineers the underlying network to deliver high-performance access to the Internet. However, the performance you experience, once you connect to the hotspot, may vary based on any number of factors, such as the number of other subscribers trying to use the same hotspot at the same time, your computer or wireless device, your Wi-Fi receiving antenna, your distance from the hotspot router, attenuation from walls and foliage, and interference from other devices using the same spectrum, in addition to many of the factors already mentioned above. These WiFi hotspots use spectrum that the FCC has allocated for "unlicensed" use, which means that our use of this spectrum is not protected from interference from other devices using the same spectrum in the same geographical area. This makes it inherently difficult to predict the kind of performance you can expect. Therefore, this service is provided on a "best efforts" basis.