The aim of this paper is to provide measurement results of data transmission over symmetrical DSL out of all DSL technologies. The paper looks at the symmetrical services with virtual private network (VPN) connections, security and end-to-end quality of service (QoS), thus offering a guideline to service providers and end-users to select the services that best suite their needs. CPEs based on the symmetrical DSL technology are widely deployed, however there are no published results of their performance measurements. Our aim is to fill these gaps, as the work of benchmarking DSL modems with different protocol stacks is of interest to network operators. This article reports upon benchmarking results, i.e., presents a series of measurement results of five CPEs using symmetrical DSL lines for connection to the central office. Throughput, IP packet latency and IP packet-loss statistics of these transceivers are analyzed and compared. Bridged, routed, and PPP configurations are investigated in details. The overhead due to L2TP tunneling, IP security and encryption is measured in case of one modem. FTP file transfer performance is shown for all different protocol stacks. Finally, the maximum distance (loop reach rate) vs. line transmission rate is also indicated for each tested equipments.
['Sandor Szekely', 'Szabolcs Mate Kis']
Benchmarking symmetrical DSL modems with different protocol stacks