Some tests on the 3 Network in Aalborg

1
Some tests on the 3 Network in Aalborg

• Oumer Teyeb,
• Jeroen Wigard

2
Ping measurements

• Ping was performed to trabant.kom.auc.dk with
  different packet sizes (ping uses ICMP, so 1 byte
  ping actually sends an IP packet of 20 (IP
  header) 8 (ICMP header ECHO request) 1
  (Data) 29 bytes)

3
Ping measurements , FACH DCH case
Pinging trabant.kom.auc.dk 130.225.51.16 with
256 bytes of data Reply from 130.225.51.16
bytes256 time831ms TTL238 Reply from
130.225.51.16 bytes256 time821ms TTL238 Reply
from 130.225.51.16 bytes256 time1012ms
TTL238 Reply from 130.225.51.16 bytes256
time1211ms TTL238 ---transition to DCH after
this point Reply from 130.225.51.16 bytes256
time261ms TTL238 Reply from 130.225.51.16
bytes256 time240ms TTL238 Reply from
130.225.51.16 bytes256 time231ms TTL238 Reply
from 130.225.51.16 bytes256 time230ms
TTL238 Reply from 130.225.51.16 bytes256
time230ms TTL238 Reply from 130.225.51.16
bytes256 time230ms TTL238 Ping statistics for
130.225.51.16 Packets Sent 10, Received
10, Lost 0 (0 loss), Approximate round trip
times in milli-seconds Minimum 230ms,
Maximum 1211ms, Average 529ms
4
RTT Statistics

• Ping was performed continuously for packets sizes
  ranging from 1 400, 10 byte interval. CELL_DCH
  mode entered during pinging 250 bytes, and kept
  afterwards.

CELL_FACH
CELL_DCH
5
Throughput during ping
1 32 160 240 256
320
Kbps
6
FTP Connection Establishment

• To start FTP connection, no DCH required
• To run simple commands like cd that dont
  require the download of a lot of data, DCH is not
  also required
• Commands that require download of data, even dir,
  require DCH

FTP Connection establishment
Dir (listing was app. 12KB)
Kbps
Cd dir
7
FTP Download Times

• Download 10K, pause for some seconds to go back
  to FACH mode, and download again 10k four
  times, but this time without waiting to change to
  FACH mode?Not that much difference in bit rate

Stay in CELL_DCH
Kbps
Return to CELL_FACH
8
FTP Download Times

• Download 100K, pause for some seconds to go back
  to FACH mode, and download again 100k five times,
  but this time without waiting to change to FACH
  mode?Bit rate upgrade

Return to CELL_FACH
Kbps
5 times download of 100 kB
9
FTP Download Times

• Download in this sequence, 10K, 10k, 100k ,
  100k, 100k, 10k without waiting to change to FACH
  mode?Bit rate upgrade when the 100 kB are
  downloaded.

Kbps
10
Ping FTP download

• Case 1 Start to ping with 1 byte, download 100K,
  the ping continues during and after the download
  ? FACH mode restored after the download is done
  (even though pinging is continued!)

Kbps
11
Ping FTP Download

• Case 2 Start to ping with 32 bytes, download
  100K, the ping continues during and after the
  download ? DCH mode kept after download (traces
  next slide)

Kbps
12
Ping FTP Download ,ping traces

• Reply from 130.225.51.16 bytes32 time260ms
  TTL238
• Reply from 130.225.51.16 bytes32 time260ms
  TTL238
• Reply from 130.225.51.16 bytes32 time261ms
  TTL238 -------------------------
• Request timed out.
  
• Reply from 130.225.51.16 bytes32 time260ms
  TTL238
• Request timed out.
• Request timed out.
• Request timed out. During download
• Request timed out.
• Reply from 130.225.51.16 bytes32 time290ms
  TTL238
• Reply from 130.225.51.16 bytes32 time321ms
  TTL238
• Request timed out.
• Reply from 130.225.51.16 bytes32 time361ms
  TTL238-------------------------------
• Reply from 130.225.51.16 bytes32 time161ms
  TTL238
• Reply from 130.225.51.16 bytes32 time160ms
  TTL238
• Reply from 130.225.51.16 bytes32 time181ms
  TTL238
• Reply from 130.225.51.16 bytes32 time180ms
  TTL238
• Reply from 130.225.51.16 bytes32 time180ms
  TTL238

13
FACH performance during handover

• Continuous ping of 32 bytes started, operating in
  FACH mode. Then user was moving around to reach
  areas till there was a handover. Ping continued
  during and after the handover.
• Traces from ping show that either there is a
  timeout due to cell reselection or the RTT
  increase by an amount ranging from 700-900ms,
  which is the cell reselection time (trace shown
  in the next slide)

14
FACH performance, ping measurements

• Reply from 130.225.51.16 bytes32 time290ms
  TTL239
• Reply from 130.225.51.16 bytes32 time270ms
  TTL239
• Request timed out.
• Reply from 130.225.51.16 bytes32 time350ms
  TTL239
• Reply from 130.225.51.16 bytes32 time301ms
  TTL239
• Reply from 130.225.51.16 bytes32 time270ms
  TTL239
• Reply from 130.225.51.16 bytes32 time1192ms
  TTL239
• Reply from 130.225.51.16 bytes32 time371ms
  TTL239
• Reply from 130.225.51.16 bytes32 time270ms
  TTL239
• Reply from 130.225.51.16 bytes32 time281ms
  TTL239
• Reply from 130.225.51.16 bytes32 time310ms
  TTL239
• Reply from 130.225.51.16 bytes32 time1042ms
  TTL239
• Reply from 130.225.51.16 bytes32 time400ms
  TTL239
• Reply from 130.225.51.16 bytes32 time230ms
  TTL239

Timeout/increase in RTT due to handover
15
Conclusions measurements 3 network (/// is the
vendor)

• After a certain level of inactivity of 5-15sec,
  CELL_DCH to CELL_FACH transition is observed.
• While in CELL_DCH mode, minimum bit rate (DL)
  seems to be 64kbps.
• Continious transmission within CELL_DCH leads to
  bit rate upgrade up to 384kbps, when enough data
  is available.
• Even when there is a small amount of activity,
  CELL_DCH is left and the connection turns to
  CELL_FACH.
• When handover occurs during CELL_FACH, ping times
  out or an increase in the RTT occurs. The
  increase in RTT is due to cell reselection time
  and ranges from 700-900ms.