On speed tiers not covered by the Measuring Broadband America study, in tests conducted by Comcast, the test nodes are located in the Comcast network. Customers can test the latency characteristics of their service using the xFi app or web-based Xfinity speed test noted below. Other latency tests may also be available on the Internet. Of course, other than for the test to the cable modem gateway, these tests will reflect limitations in a customer's home network especially Wi-Fi and computers, and therefore will not necessarily reflect the performance of the Comcast network alone.
When reading these results, each row represents a specific service tier with its respective advertised downstream and upstream speed. The tiers listed in the table below are limited to those currently available for purchase as of March 15, , and tiers that have been retired as an offering but that a substantial number of customers have retained for the time being.
This table may include service tiers that are not available in all markets. As the results demonstrate, Comcast's Xfinity Internet broadband Internet access services deliver over percent of their advertised downstream and upstream speeds during both peak and off-peak times. While individual experiences may vary, the FCC's and Comcast's tests consistently confirm the delivery quality of Comcast's Xfinity Internet broadband Internet access services.
However, multiple devices simultaneously connected to the cable modem gateway can push aggregate usage up to the advertised 1. Consumers can also test their speeds themselves. The test from a customer device can be run in three ways:. There are other speed tests available that measure Internet performance as well. We have provided links to a few of these sites below for your reference.
Please note, however, that speed tests that originate from a consumer device on the customer's home local area network not a gateway or modem have limitations and flaws and some of them have difficulty measuring multi-hundred megabit per second or gigabit per second service tiers, among other potential issues.
Each of these tests measure limited aspects of an ISP's performance and therefore must be seen as a guide rather than a definitive measurement of the performance of the Comcast network.
In addition to the residential or commercial broadband Internet access service that you enjoy at your home or office, Comcast provides eligible subscribers and other consumers with access to Xfinity WiFi hotspots, which allows those users to access the Internet when they are at one of the many Xfinity WiFi or Cable WiFi hotspots.
Comcast engineers the network underlying Xfinity WiFi hotspots to deliver high-performance access to the Internet. These hotspots use spectrum that the FCC has allocated for "unlicensed" use, which means that Comcast's use of this spectrum is not protected from interference from other devices using the same spectrum in the same geographical area.
Cox, for one, is still using it. See Cox Gives Wideband a 'Powerboost'. CBS Corp. CBS claimed it was a streaming record for a single game sporting event in the U. To put it all in context, though, the big game drew a total U. And, why not? He's got hundreds of millions of reasons to be pleased. Microsoft Corp. He says Xbox will serve as the exclusive gaming console launch partner for the Verizon Communications Inc. The catch for Xbox users is that they'll need to pony up for the Xbox Live Gold subscription.
The upgrade involves MetroCast's connections between Rochester, N. As our network technologies and usage of the network continue to evolve, we reserve the right to implement a new congestion management system if necessary in the performance of reasonable network management and in order to maintain a good broadband Internet access service experience for our customers, and will provide updates here as well as other locations if a new system is implemented.
Comcast provides residential customers with a variety of high-speed Internet plans from which to choose, with download speed tiers ranging from up to 5 megabits per second "Mbps" to up to 1 gigabit per second in select markets and upload speeds ranging from up to kilobits per second "Kbps" to up to 35 Mbps on our DOCSIS 3.
Comcast provisions its customers' modems and engineers its network with the goal of enabling customers to enjoy the speeds to which they subscribe.
Comcast advertises its speeds as "up to" a specific level based on the tier of service to which a customer subscribes. The FCC determined that Comcast's Xfinity Internet services deliver, on average, over percent of their advertised downstream and upstream speeds during the busiest periods of the day, known as "peak" times, during sustained testing. We are including the FCC's measurement of the Mbps speed tier, which we no longer offer, on an interim basis until internal measurements of our Mbps speed tier are completed, but we do not expect the results to differ significantly.
Service tiers noted below were not included in the FCC's study either because they are newer products with limited availability or they do not meet the study's reporting requirements. Comcast's Xfinity Internet services also deliver over percent of their advertised downstream and upstream speeds during periods of time when Internet usage is generally lighter, known as "off peak" times, during sustained testing. While individual experiences may vary, the FCC's tests have consistently confirmed the quality of Comcast's Xfinity Internet services.
Packet loss is a third measurement of Internet performance. Packet loss is the percentage of packets that are sent by the source but not received by the destination. This is sometimes due to congestion along the route but may also reflect an impairment in a customer's home network, including their Wi-Fi and coaxial cable network as well as the connection from the customer's home to the Comcast network.
Customers should diagnose their home network for possible repair if packet loss is high. Packet loss is also a normal part of the Transmission Control Protocol TCP , and signals to a sender to slow their sending rate to adjust to available bandwidth along a network path.
As a result, a small amount of packet loss is expected and normal, but it is unlikely to directly affect the perceived quality of applications that request retransmission of lost packets, such as web browsing and email. In addition, measures to further reduce packet loss would require unacceptable increases in latency.
However, packet loss may affect the perceived quality of applications that do not request retransmission of lost packets, such as VoIP phone calls and video chat. Nevertheless, packet losses of a few tenths of a percent are sufficiently small so that they are unlikely to significantly affect the perceived quality of these applications.
The Internet's technical community continues to debate the merit and meaning of packet loss measurement. Comcast has no basis for saying what level of packet loss should be expected by any particular user at any particular time but notes that the measured results from the FCC study as to past performance are perhaps the closest one can come to identifying expectations of future performance as well. The FCC study includes packet loss tests performed using packet tests that measure the time it takes those packets to travel from a customer location to a target test node and back.
Packets not received back within three seconds of sending were treated as lost. Below are the Comcast average packet loss results by tier during peak times as defined above , during sustained testing. Comcast currently does not have packet loss data for our 5, 10, , , Mbps and 1 Gbps services tiers.
However, based on data from the latest FCC study, we expect packet loss to be in the range of 0. Below are the Comcast average packet loss results by tier during off peak times, during sustained testing. However, based data from the FCC study, we expect packet loss to be in the range of 0. Customers can test their packet loss by performing ping tests or other tests. 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 Wi-Fi 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. At Comcast, we periodically review and revise our website to ensure that customers have the latest information about our services. We have revised our Internet service performance webpage to give customers the latest information to help them make informed choices.
Comcast provides residential customers with a variety of high-speed Internet plans from which to choose, with download speed tiers ranging from up to 5 megabits per second " Mbps" to up to Mbps in select markets and upload speeds ranging from up to kilobits per second "Kbps" to up to 25 Mbps on our DOCSIS 3. In select markets, we also offer a fiber-based service with symmetrical download and upload speeds up to 2 gigabits per second "Gbps".
Service tiers noted with an asterisk were not included in the FCC's study either because they are newer products with limited availability or they do not meet the study's reporting requirements. For these noted tiers, the information below is based on data compiled independently by Comcast using a largely similar testing methodology.
Below are the Comcast median speeds by tier during off peak times:. Comcast has no basis for saying what level of latency should be expected by any particular user at any particular time but notes that the measured results from Measuring Broadband America as to past performance are perhaps the closest one can come to identifying expectations of future performance as well. Measuring Broadband America measures latency using packet tests that calculate the time it takes for packets to travel from a customer location to a target test node and back.
Comcast has no basis for saying what level of packet loss should be expected by any particular user at any particular time but notes that the measured results from Measuring Broadband America as to past performance are perhaps the closest one can come to identifying expectations of future performance as well. Measuring Broadband America includes packet loss tests performed using packet tests that measure the time it takes those packets to travel from a customer location to a target test node and back.
Comcast currently does not have packet loss data for our 5, 10, , , and Mbps services tiers. However, based on the MBA data, we expect packet loss to be in the range of 0. NetForecast completed a comprehensive study of Comcast's usage meter platform covering a month period between January and April The report provides an overview of how our usage management platform works, methodology used to measure and validate accuracy, along with the overall performance rating.
The results of the study have been published on NetForecast's website. Primarily, adoption of the Mutually Agreed Norms for Routing Security requires that Internet Service Providers ISPs explicitly filter routing announcements received from their customer networks at the "prefix" level. Comcast has been employing this method for at least the past several years and expects neighboring networks to do the same.
These attacks take advantage of the fact that some networks have not taken steps to prevent network address spoofing. Comcast takes several steps to prevent network spoofing, and a list of FAQs on subject can be found here.
Finally, the Mutually Agreed Norms for Routing Security asks that ISPs maintain usable contact information and coordination capability for real-time troubleshooting between network operators, to which Comcast is also committed. We hope that other ISPs will adopt the guidance in the Mutually Agreed Norms for Routing Security in order that we may improve the stability and reliability of the Internet upon which we all depend.
In response to malicious network activity, we have implemented a block of TCP port 0 traffic. Based on testing, we believe this block prevents network abuse and should not impact legitimate traffic. A full list of blocked ports can be found here. You can read more about the performance of our Internet service here.
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 Mbps in select markets and upload speeds ranging from up to kilobits per second "kbps" to up to 25 Mbps on our DOCSIS 3.
In select markets we also offer a fiber-based service with download speeds up to Mbps and upstream speeds up to Mbps. Comcast provisions its customers' modems and engineers its network to enable customers to enjoy the speeds to which they subscribe. Unless a customer purchases a dedicated Internet connection, no Internet Service Provider "ISP" can guarantee a particular speed at all times.
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:.
According to that test, Comcast's XFINITY Internet services deliver, on average, over 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:. 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. 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.
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. 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.
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. We have provided links to a few of these sites, above in the Speed Test Section, for your reference. 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.
Therefore, this service is provided on a "best efforts" basis. Comcast joins ISOC and other network operators in calling for community action on this subject, and joining us to support this Manifesto. Primarily, adoption of the Routing Resilience Manifesto requires that Internet Service Providers ISPs filter routing announcements received from their customer networks explicitly at the prefix level. Finally, the Manifesto asks that ISPs maintain usable contact information and coordination capability for real-time troubleshooting between network operators, to which Comcast is also committed.
We hope that other ISPs will adopt the guidance in the Routing Resilience Manifesto in order that we may improve the stability and reliability of the Internet upon which we all depend. The report provides an overview of how our usage management platform works, NetForecast's validation methodology, and the overall performance rating.
We recently contracted with them to conduct the comprehensive study, and the results have been published on their website. On May 20, , we first posted about these rules. These rules pertain to the attachment of devices to our High-Speed Internet network by customers. You can find information concerning the devices approved for use on the network, and the tiers of our service that they are appropriate for at My Device Info.
Please also note that customers may purchase their own cable modem for use on the Comcast network. However, Comcast does not support all possible modems on its network because there may be compatibility issues with some devices. The Comcast Agreement for Residential Services Sections 6 b 1 - 3 makes clear that a device must meet Comcast's minimum technical specifications in order to successfully install, access, operate or use a particular service.
In addition to our full list of approved devices , a list of recommended retail devices can be found at My New Modem. Since we have been asked what steps Comcast takes to prevent network spoofing, we have put together an FAQ on the subject. Using these techniques our customers are prevented from sending traffic with spoofed IP addresses through their cable modems.
Computers and other devices connected to the Internet use IP Internet Protocol addresses to establish end-to-end communications. Most devices use a single IP address, though some have several. Successful communication relies on both the source and destination addresses being encoded in packets sent between the systems to enable two-way interactions.
Thus, your packet has the destination address, as well as the return source address, much like a letter. Many network attacks make use of the ability to "spoof" or "forge" the source IP address in a packet.
By using this forged source address, it can make it difficult or impossible to trace the source of an attack. In addition, this can be used to take down networks in large-scale Distributed Denial of Service DDoS attacks where many computers are told to send a response to the forged source address.
Unfortunately, the Internet's architecture does not prohibit source address spoofing by default; network operators are relied upon to do so. Since each device on the Internet should be assigned a given IP address, rules and configuration settings on the source network must be used to ensure that that device cannot send packets with a source address that was not assigned to it.
Proper configuration and policy that effectively block IP spoofing go a long way to cutting down on the avenues available for abuse and attack on the network. Comcast implements "source address filtering" or "source address validation" as a basic technique to prevent IP address filtering. Using these methods, customers are prevented from sending traffic with spoofed IP addresses through their cable modems. Although Comcast does its best to prevent IP address spoofing, there are situations where applying uRPF checking is not feasible or practical.
This includes services for some commercial customers that have multiple Internet service providers, known as multi-homing. In cases such as these, Comcast can and does provide guidance to such customers so that they can effectively implement uRPF or similar checking within their own networks.
Implementation of techniques to prevent IP address spoofing can be thought of as an "environmental benefit" for the Internet.
When implemented by Comcast or another network operator, these measures don't only or even primarily benefit that operator's customers. Rather, they benefit the broader community by plugging security holes in the Internet, and preventing more widespread DDoS attacks that leverage spoofing. The broader the uptake of these techniques, the greater the improvement overall and the safer we all become on the Internet. Our techniques help limit malicious traffic that could otherwise come from Xfinity Internet customers, destined to or targeted at other Internet networks or servers.
As a result, any attack launched from a Comcast subscriber will have the true IP address of the subscriber's cable modem and as such can be rapidly traced back and mitigated. As such it is not possible to use a Comcast residential Internet customer as an originating source for distributed denial of service DDoS attacks that use IP address spoofing to conceal the addresses of computers used in those attacks, such as a recent DNS amplification attack against an anti-spam organization or a recent NTP amplification attack against a content delivery network CDN.
You can find more information in two blog posts. One is a general post about both issues, and the other is specific to SMTP. While the policy change was announced today, implementation will occur gradually. We've announced some important changes - there's more information on our blog and our FAQs for more information. We will be revising our Acceptable Use Policies in the near future. As noted here on our blog , we have signed all of our domain names and all customers are now using DNSSEC-validating resolvers.
In addition, Comcast Domain Helper has been turned off, as we noted here. We have revised our Internet service performance and Internet 2go service performance webpages to give customers the latest information on these services and help them make informed choices. Comcast provides residential and commercial customers with a variety of high-speed Internet plans from which to choose, ranging from our Economy tier with download speeds up to 1.
Comcast provisions its customers' modems and engineers its network to enable its customers can enjoy the speeds to which they subscribe. However, Comcast does not guarantee that a customer will actually achieve those speeds at all times. Unless a customer purchases an expensive, dedicated Internet connection, no Internet Service Provider "ISP" can guarantee a particular speed at all times.
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 such as Comcast. Again, while individual experiences may vary, the FCC's test validates the superior quality of Comcast's Xfinity Internet services. Data gathered from our own speed tests show that the average speed customers experience should fall at or near the advertised downstream and upstream speeds.
The results of our testing are as follows:. But 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. 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.
Please note, however, that all speed tests have biases and flaws. As a result, in many circumstances, Comcast customers experience speeds in excess of that provisioned as part of their chosen speed tier.
According to the FCC's test results, the cable industry average latency was approximately 28 milliseconds, and DSL averaged 44 milliseconds. Data gathered from our own latency tests are as follows:. The results do not define latency as part of a particular user experience because i 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.
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. As previously explained, however, all tests have biases 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 to enjoy at your home or office, Comcast provides its Internet subscribers with XFINITY WiFi, which allows Internet subscribers to access, at no additional cost, the Internet through up to three devices when you are in one of our many, public WiFi hotspots.
Specifically, Comcast provisions to each hotspot a connection that provides a maximum of 5 Mbps.
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