List of measurements in rural area

Transcription

1 List of measurements in rural area Network Distance / Delay / HOP! Tool " ICMP Ping and UDP Ping (traceroute)! Targets / Tests " VSAT Gateways / Earth Station # Testing distance to VSAT FTP server at the gateway to approximate the distance to the VSAT gateway # using traceroute to determine the gateway # using traceroute and ping to find distance from the gateway to our landmarks The purposes of this test are! to understand the last mile delay from the MP to its gateway! to discover a number and locations of VSAT gateways! to understand the last mile delay and its distribution to VSAT gateways for clients from different regions! to understand how reliable the connection from MP to its the gateway! to understand the effect of time of the day! we probably see a small number (or even single) gateway for all the VSAT clients we have from all regions! last mile delay deviation might stem from poorly install VSAT dish and corresponding equipments! time of the day shouldn t effect the distance to VSAT gateways " Cellular Gateway (GGSN for UMTS) # using single or two HOPs traceroute to find the GGSN and to determine last-mile delay # using traceroute and ping to find distance from GGSN to our landmarks The purposes of this test are! to understand the last mile delay from the MP to its gateway! to discover a number and locations of GGSNs! to understand the last mile delay and its distribution to GGSNs for clients from different regions! to understand the effect of time of the day

2 ! the deviation of last mile delay to GGSN should be larger than the delay distribution to client-side / dest-side VAT gateways! Interesting to compare between distance to GGSN and distance to VSAT gateway because they both are the access points to the Internet for these two systems of our interest! time of the day might effect the distance to GGSN because cellular network has limited available channels for each base transceiver station (BTS) or cell site. So, during busy period, possible queuing delay or congestion at BTS could happen.! Distances to set of Landmarks (Static and Dynamic Landmarks) " Static URLs # Academic Institution Networks (e.g. IIT Delhi) # News paper sites / Television network sites in India # interesting other static landmark sites " List of CDN Cache servers # Akamai Edge server # Limelight Cache server / data center # Google App Engine node # Amazon S3 cache server # Any local CDNs in India or in the region? " Social media / service # Social Network! Facebook / Twitter / etc. # Search engines! Google and Bing! Although they both probably utilize some kinds of content distribution services, this test is only for direct user experience toward these services. The purposes of this test are! To understand the distances from rural area to certain landmarks! To understand the deviation of distance to certain landmarks from different rural areas! To understand how reliable of the Internet connection from different rural areas! To directly compare the cellular-distance and VSAT-distance from each MP to each landmarks! To directly compare the distances to search engines from rural areas

3 ! Akamai CDN might on average have smaller distances to clients in rural areas due to their approach to push the edge servers (cache server) toward edge of the network while others seem to engineer their platforms around large data centers! I m not sure about Bing but Microsoft uses Akamai for some of their services. So, if the above speculation about Akamai is true, Bing might be closer to clients in rural areas Content Retrieval Performance " Tool # Curl " Targets / Tests # VSAT Gateway (ftp server)! VSAT usually place a FTP server at the location of their gateway for testing purposes from VSAT clients. So, we can use this FTP server to test download throughput from VSAT gateway. The purposes of this tests! To understand the download throughput from VSAT gateway. " VSAT usually try to improve this performance using the performance enhancement proxy.! To understand the consistency of throughput for VSAT clients! To see if VSAT offers the right bandwidth as promise to the customers " This is to satisfy the request by Pradan NGO " In this case, we have to pick the target object large enough to capture the actual available bandwidth.! throughput should be quite consistent and similar to all VSAT clients! improper installation of VSAT might contribute to the deviation of VSAT performance! It would be interesting if we can compare throughput / available bandwidth from VSAT and Cellular gateways directly in addition to directly comparison of download throughput from certain landmarks to VSAT and Cellular clients in rural areas. # Landmarks! The same set of static and dynamic landmarks as used in network distance measurement above

4 The purposes of this tests! To understand the consistency of throughput from clients in rural areas to certain landmarks! To directly compare throughput and its consistency from clients in rural areas to certain landmarks through VSAT and Cellular link! To understand the average throughput and response time for each regions! To see the effect of time of the day! I don t expect that CDNs could bring much benefit to the clients in rural area. However, it s interesting to see how much benefit / performance improvement that CDNs can bring to the rural clients by compare the download performance of the same object size from CDNs and static landmarks.! Cache miss penalty for CDNs in rural areas could be relatively high and Akamai migth have higher penalty than others because their edge servers have to utilize available Internet access (could be relatively slow) to the edge / isp in rural areas to retrieve the content from origin / immediate parent server Accessibility " Tool # Curl / Ping / Traceroute " Targets / Tests # detect if the both VSAT and Cellular clients have public IP or not The purposes of this tests! To understand how VSAT and mobile network in india allocate IP addresses to their clients! Most of the clients in VSAT might have private IP addresses # detect if the MP is accessible from outside?! through TCP! through UDP! through ICMP we can have the echo demon on MP listening on certains TCP/UDP port The purposes of this tests! Should the client has public IP " Can it be access from outside? (ICMP test)

5 ! If so, through which transport protocols? (TCP/UDP test) " detect if there is an transparent proxy/cache exist # download the same unique object twice and then we can check the the server side to see how many requests for this unique object # don t expect to see so many of the transparent proxies DNS! Tool " Dig! Targets / Tests " Discover Local DNS for both VSAT and cellular network clients " A record for CDN s CNAMEs # To see how many nodes / prefix each CDN allocates for rural area # Target all the CDNs from our above Network Distance Test # To understand the geographical locations of CDN cache servers allocated to the rural area clients (using Geo IP database such as MaxMind) # To understand how many networks or data centers (by AS number or IP prefix) each CDN has footprint on " TTL record for DNS response # To understand the Hit / Miss rate of local DNS in rural area # use all the targets in our above Network Distance Test " DNS resolution time # we will also collect this DNS resolution time during the object download throughput above so that we can see how much the DNS resolution contributes to the overall download performance. Available and Bottleneck Bandwidth / Loss The iperf test consume all available network resources on the MP, therefore we need to be careful not to run the test in concurrent with any other tests we have. Otherwise, it will skew result of other tests.! Tool " pathchirp # check the paper pathchirp: Efficient Available Bandwidth Estimation for Network Paths or talk to Vinay as he s the 1st author of this paper " iperf! Targets / Tests " a few landmarks that we have access (e.g. IIT Delhi) Characteristic / Profile! Locations of MPs

6 ! Learn topology of rural network with collective traceroutes from different MPs in the region References! pathchirp: Efficient Available Bandwidth Estimation for Network Paths, PAM 2003! On the Use and Performance of Content Distribution Networks, IMW 2001! Strategies for Sound Internet Measurement, IMC 2004! On Dominant Characteristics of Residential Broadband Internet Traffic, IMC 2009