diff --git a/draft-iab-mnqeu-report.md b/draft-iab-mnqeu-report.md index caadc92..088dcd9 100644 --- a/draft-iab-mnqeu-report.md +++ b/draft-iab-mnqeu-report.md @@ -469,25 +469,35 @@ TBD: ### Capacity metrics -To achieve the desireable network quality, the line capacity must be sufficient -to meet the user demands. If the line capacity isn't sufficient, adding -capacity may improve the quality of the connection. Once sufficient, further -capacity increases will not lead to improvements in quality, as the line will -become underutilized. - -The actual line capacity varies throughput the day and across multiple days. -The variance is not uniform across the different technologies and across the -different service levels. For example, data indicates that the variance have -increased for the DSL lines that were upgraded to 100Mbps and above. - -Similarly, the user demands vary through the course of the day, depending on the -number of users, as well as on the way in which they use the network. - -To measure both accurately, multiple measurements must be run through the -course of each day. - -Other types of traffic, such as browsing the web, can benefit from increases in -throughput, up to a certain point. +If the network capacity does not meet the user demands, the network quality +will be impacted. Once the capacity meets the demands, increasing capacity +won't lead to further quality improvements. + +The actual network connection capacity is determined by the equipment and the +lines along the network path, and it varies throughout the day and across +mutliple days. Studies involving DSL lines in North America indicate that over +30% of the DSL lines have capacity metrics that vary by more than 10% +throughout the day and accross multiple days. + +Some factors that affect the actual capacity are: +1. Presence of a competing traffic, either in the LAN or in the WAN + environments. In the LAN setting, the competing traffic reflects the + multiple devices that share the Internet connection. In the WAN setting the + competing traffic often originates from the unrelated network flows that + happen to share the same network path. +2. Capabilities of the equipment along the path of the network connection, + including the data transfer rate and the amount of memory used for + buffering. +3. Active traffic management measures, such as traffic shapers and policers + that are often used by the network providers. + +There are other factors that can negatively affect the actual line capacities. + +The user demands of the traffic follow the usage patterns and preferences of +the particular users. For example, large data transfers can use any available +capacity, while the media streaming applicaitons require limited capacity to +function correclty. Video-conferencing applications typically need less +capacity than high-definition video streaming. ### Latency metrics