CRAWDAD kaist/wibro

In order to evaluate QoS of VoIP applications over the WiBro network, we collected the CBR and VoIP traffic from the WiBro network in Seoul, Korea. We conducted experiments in both stationary and mobile scenarios, e.g., on a subway train.

last modified :

2008-06-04

release date :

2008-06-04

date/time of measurement start :

2007-10-05

date/time of measurement end :

2007-10-06

collection environment :

WiMax is a subset of the 802.16 standards whose main goal is product 
compatibility and interoperability of BWA products, just as WiFi is to 
the 802.11 standards. WiBro has been developed as a mobile BWA solution 
in Korea, and is generally considered a precursor to WiMax. It is a subset 
of consolidated version of IEEE Standard 802.16-2004 (fixed wireless 
specifications), P802.16e (enhancements to support mobility), and 
P802.16-2004/Cor1 (corrections to IEEE Standard 802.16-2004). 
The profiles and test specifications of WiBro will be harmonized 
with WiMAX Forum's mobile WiMAX profiles and test specification, 
drawing a convergence of the two standards.

Today's Internet users not only write emails and surf the web, but also make
Voice over IP (VoIP) calls, play online games, and watch streaming media. These
real-time applications have stringent Quality of Service (QoS) requirements on
delay and loss. WiMax and WiBro standards have defined multiple service types
in order to guarantee different levels of QoS. However, at the initial phase of
deployment, often only the best-effort service is made available, while users do
not limit themselves to emails and web surfing over emerging wireless technology
networks.

We conduct experiments to evaluate QoS of VoIP applications over the WiBro 
network. In order to capture the baseline performance of the WiBro network, 
we measure delay, loss, and throughput of constant bit rate streams in both 
stationary and mobile scenarios.

network configuration :

In Korea, KT (formerly, Korea Telecom) launched WiBro coverage for nine 
subway lines in Seoul on April, 2007. The Seoul subway system moves 
millions of people a day through an extensive network that reaches almost 
all corners within the city and major satellite cities outside. 

The maximum speed of Seoul subway trains is 90 km/h, and it takes 
about 1 - 2 minutes between two stations. We have considered measurement 
experiments in vehicles moving at or under 60 km/h, the upper limit of 
WiBro, but chosen the subway, as it presents a more popular scenario with users.
It has 38 stations over a total distance of 35.1 km and six RASs (Radio Access
Stations).

data collection methodology :

Commuters in subway are more likely to use mobile devices than those 
in moving vehicles, as the measurement experiment on a subway train is 
easier for us. We have conducted our measurement experiments on subway 
line number 6. 

We have placed a mobile node (a laptop with a WiBro modem) 
in the WiBro network and installed a stationary node (a desktop PC) 
connected to the Internet over a fixed line so that we could focus 
on the WiBro network performance.

Traceset

kaist/wibro/seoul

Trace set of CBR and VoIP traffic measurements from the WiBro network in Seoul, Korea.

• description: We collected the CBR and VoIP traffic from the WiBro network in Seoul, Korea in stationary and mobile scenarios, e.g., on a subway train.
• measurement purpose: Network Performance Analysis
• methodology: We have placed a mobile node (a laptop with a WiBro modem) in the WiBro network and installed a stationary node (a desktop PC) connected to the Internet over a fixed line so that we could focus on the WiBro network performance. We refer to the laptop as the Mobile Node (MN) and the PC as the Corresponding Node (CN). In order to place the CN as close to the WiBro network as possible, we use a PC directly connected to a router on Korea Research Environment Open Network (KREONET). It is a research network that interconnects super computing centers in Korea and also is used as a testbed for new networking technologies. It peers with KT's IP backbone network at one of KT's exchange points. For our measurement experiments, we generate two types of traffic: constant bit rate (CBR) and VoIP. The difference between CBR and VoIP traffic lies in the packet sending rate and follow-up analysis. For both types of traffic, we take measurements when the MN is stationary and moving in a subway. We use iperf for CBR traffic generation, and D-ITG for VoIP traffic generation. We configure D-ITG to measure round-trip time (RTT) instead of one-way delay, as we could not instrument the MN in subway and CN at an exchange point to have access to GPS-quality clock synchronization. Multiple types of handoff are possible in the WiBro network. An inter-ACR (Access Control Routers) handoff takes longer than inter-RAS (Radio Access Stations) or inter-sector handoff. An inter-sector handoff is between two sectors within an RAS. An RAS typically has three sectors. Using a custom tool developed to monitor inter-sector and inter-RAS handoffs, we collect RAS identifiers and corresponding sector identifiers. By aligning the changes in RAS and sector identifiers with the measurement data, we can pinpoint the moments of handoffs in our data.
• last modified: 2008-06-04
• dataname: kaist/wibro/seoul
• version: 20080604
• change: the initial version.
• release date: 2008-06-04
• date/time of measurement start: 2007-10-05
• date/time of measurement end: 2007-10-06

kaist/wibro/seoul Traces

• UDP: Trace of CBR traffic measurements from the WiBro network in Seoul, Korea.

• configuration: On October 5th and 12th, 2007, we took CBR measurements in Seoul. For stationary experiments, we placed the MN (the mobile node) on KAIST Seoul campus. For mobile experiments, we rode the Seoul subway line 6. We used iperf for CBR traffic generation. For traffic logging, we used windump at both the MN and CN (the corresponding node). In order to capture the baseline performance of the WiBro network, we first measure the maximum achievable throughput. We generated 5 Mbps up to 6 Mbps and 1.5 Mbps up to 2.5 Mbps traffic in quantums of 100 Kbps for download and upload, respectively, and found the bandwidth capped at about 5.3 Mbps downlink and 2 Mbps uplink. Then we set the transmission rate of our CBR traffic at 5.3 Mbps for downlink and 2 Mbps for uplink with the packet size of 1460 bytes and saturated the link. We conducted 10 sets of 300-second-long uploads and downloads.
• format: The "UDP" directory contains UDP wibro pcap files and bsid (Base Station ID) log files. It has two subdirectories "stationary" and "subway": stationary - collected with MN (the mobile node) placed at a stationary location, subway - collected with MN placed in subway. In each subdirectory, the format of file name is as follows: kw_seoul__udp_cbr__iperf____. SM: where to place the mobile node. "st" (stationary) or "mb" (mobile). SRATE: sending rate, e.g., "1500~2500kbps". UD: "up" (upload) or "dn" (download). CONF: experiment configuration. For example, "12x5x120sec" indicates that 12 different CBR throughputs are used, and the experiment repeats 5 times with the duration of 120 seconds for each experiment. "10x300sec" indicates that the experiment repeats 10 times with the duration of 300 seconds. CS: logging location. "cl" (the mobile node) or "sv" (the stationary node). DATE: YYYYMMDD. EXT: "pcap" or "bsid.log". You can find the following files: 1. pcap files (*.pcap) : pcap files captured by windump 2. bsid log files (*.bsid.log) : the log of bsid (Base Station ID) Only "subway" directory contains bsid log files. Each line contains a UNIX timestamp, a human readable time (KST), and BSID, which are seperated by a tab. This data is used to locate when handoff has occurred.
• description: We conducted CBR measurements from the WiBro network in Seoul, Korea. For stationary experiments, we placed the mobile node on KAIST Seoul campus. For mobile experiments, we rode the Seoul subway line 6.
• last modified: 2008-06-04
• dataname: kaist/wibro/seoul/UDP
• version: 20080604
• change: the initial version
• release date: 2008-06-04
• date/time of measurement start: 2007-10-05
• date/time of measurement end: 2007-10-12

• VoIP: Trace of VoIP measurements from the WiBro network in Seoul, Korea.

• configuration: On October 5th, 6th, 7th, 12th and 13th 2007, we took VoIP measurements in Seoul. For stationary experiments, we placed the MN (the mobile node) on KAIST Seoul campus. For mobile experiments, we rode the Seoul subway line 6. We use D-ITG for VoIP traffic generation. You can download D-ITG at http://www.grid.unina.it/software/ITG/ For logging, the MN and CN (the corresponding node) also dumped log files including sequence numbers, packet departure times, acknowledgement arrival times, and calculated round trip time. We have generated voice traffic that has the same characteristics of the G.711 voice codec without Packet Loss Concealment (PLC). The payload size is set to 160 bytes and the sending interval to 20 ms in G.711 codec without PLC. The resulting throughput of VoIP traffic is 64 Kbps. We collected 10 300-second-long data sets after transmitting voice packets between the MN and the CN. Because the clocks on the MN and CN were not synchronized, we could not measure the one-way delay accurately. Instead, we took round-trip measurements of VoIP traffic, and halved the delay. Due to the difference in uplink and downlink bandwidths, half the round-trip delay is likely to be larger than the one-way uplink delay. However, the WiBro link was very lightly loaded and thus we assume the difference in transmission delay to be minimal.
• format: The "VoIP" directory contains D-ITG log files for VoIP traffic, pcap trace for VoIp traffic, and bsid (Base Station ID) log files. It has two subdirectories "stationary" and "subway": stationary - collected with MN (the mobile node) placed at a stationary location. subway - collected with MN placed in subway. In each subdirectory, the format of file name is as follows: kw_voip____. CODEC: type of codec used. UD: "up" (upload) or "dn" (download). CS: logging location. "cl" (the mobile node) or "sv" (the stationary node). EXPNO: experiment number ("all" or 1-10). EXT: extension. "log", "voip", "pcap", or "bsid.log" You can find the following files: 1. D-ITG binary files (*.log) : binary log files collected with D-ITG software. 2. D-ITG text files (*.voip) : text version of D-ITG log files converted using D-ITG software. Each line contains seq #, send time, recv time, rtt, size(=168). 3. pcap files (*.pcap) : pcap files captured by windump 4. bsid log files (*.bsid.log) : the log of bsid (Base Station Identification) Only "subway" directory contains bsid log files. Each line contains a UNIX timestamp, a human readable time (KST), and BSID, which are seperated by a tab. This data is used to locate when handoff has occurred.
• description: We conducted VoIP measurements from the WiBro network in Seoul, Korea. For stationary experiments, we placed the mobile node on KAIST Seoul campus. For mobile experiments, we rode the Seoul subway line 6.
• last modified: 2008-06-04
• dataname: kaist/wibro/seoul/VoIP
• version: 20080604
• change: the initial version
• release date: 2008-06-04
• date/time of measurement start: 2007-10-05
• date/time of measurement end: 2007-10-06