RTTOmeter

Método de RTTometer
Alunos: Gisele Akemi Igami
Vitor Alexandre de Almeida
Método de RTTometer
• Desenvolvido por Amgad Zeitoun e
Zhiheng Wang.
• É uma ferramenta de medida para estimar
o RTT mínimo do caminho.
• Utiliza o handshake do TCP para estimar
o RTT. Assim não sofre com a filtragem
de pacotes ICMP e taxas limitadoras
setadas pela maioria dos firewalls e
roteadores.
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MÉTODO DE RTTometer
• Utiliza variável chamada epsilon para
calcular a medida de confiança do canal.
• Esta variável representa a variação
tolerada do RTT que é considerada
próxima o bastante do RTT mínimo.
• Ela representa a variação randômica
devido a processamento nos roteadores,
busca de rotas, resolução do ARP, etc.
Modo de usar:
As opções do RTTometer podem ser visualizadas
digitando ./rttometer, ./rttometer -h, ou ./rttometer --help.
Usage: rttometer [-hvnzNFSAE]
[-i <interface>] [-l <packet length>] [-c <number of probes>]
[-C <confidence>] [-e <Epsilon>] [-z to estimate epsilon]
[-t <timeout>] [-T <inter-probe interval (msec)>] [-m <ttl>]
[-p <destination port>][-P <source port>] [-s <source
address>]
[-o <tos>] <host>
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Exemplo 1:
$ ./rttometer -c 3 www.ebay.com
Selected device fxp0, port 4686 for outgoing packets
RTTometer to www.ebay.com (66.135.208.88) on TCP port 80, 255 hops max
pages.ebay.com (66.135.208.88) seq=0 ttl=47 time=124.086 ms [open]
[0.0000][0.0000][0.0000] send_time=1064861470.988110
pages.ebay.com (66.135.208.88) seq=1 ttl=47 time=139.488 ms [open]
[0.0000][0.0000][0.0000] send_time=1064861471.501908
pages.ebay.com (66.135.208.88) seq=2 ttl=47 time=123.316 ms [open]
[0.0000][0.0000][0.0000] send_time=1064861472.11938
--------------- Statistics ---------------------Min/10-tile/Q1/Median/Mode/Q3/90-tile/Max:
123.316/123.316/123.316/124.086/
1.000/139.488/139.488/139.488
Min RTT: 123.316 msec, confidence 0.000 (CI), epsilon 2.000 msec
Number of probes sent: 3
Number of replies received: 3
Probes lost: 0
Exemplo 2:
• O valor de epsilon (flag z) é estimado
como o dobro da diferença entre o RTT da
modalidade.
• O número mínimo de probes (flag c) é
100.
• O valor default para epsilon é 6ms.
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$ ./rttometer -n -c 120 -z 12.13.176.164
Selected device fxp0, port 4699 for outgoing packets
RTTometer to 12.13.176.164 on TCP port 80, 255 hops max
12.13.176.164 seq=0 ttl=45 time=57.765 ms [open] send_time=1048260177.80813
12.13.176.164 seq=1 ttl=45 time=54.708 ms [open] send_time=1048260177.593458
12.13.176.164 seq=2 ttl=45 time=54.415 ms [open] send_time=1048260178.103402
12.13.176.164 seq=3 ttl=45 time=57.192 ms [open] send_time=1048260178.613447
12.13.176.164 seq=96 ttl=45 time=55.664 ms [open] send_time=1048260226.67562
12.13.176.164 seq=97 ttl=45 time=60.884 ms [open] send_time=1048260226.577579
12.13.176.164 seq=98 ttl=45 time=55.672 ms [open] send_time=1048260227.87653
12.13.176.164 seq=99 ttl=45 time=68.079 ms [open] send_time=1048260227.598067
--------------- Statistics ---------------------Estimation of Epsilon: 4.210 msec
CI = 0.657
CII = 0.313
CIII = 0.030
Min/10-tile/Q1/Median/Mode/Q3/90-tile/Max:
53.595/54.108/54.514/55.238/55.700/56.823/62.207/78.327
Min RTT: 53.595 msec, confidence 0.657 (CI), epsilon 4.210 msec
Number of probes sent: 100
Number of replies received: 100
Probes lost: 0
Exemplo 3:
•
•
•
•
Número máximo de probes (flag c)de 40.
O nível de confiança (flag C) é 0.8.
Epsilon é 5.5ms.
RTTometer começa a calcular o nível de
confiança após o quinto probe
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$ ./rttometer -n -c 40 -C 0.8 -e 5.0 12.23.55.212
selected device fxp0, port 4951 for outgoing packets
RTTometer to 12.23.55.212 on TCP port 80, 255 hops max
12.23.55.212 seq=0 ttl=44 time=154.302 ms [open] [0.0000][0.0000][0.0000]
send=1048215707.810432
12.23.55.212 seq=1 ttl=44 time=155.290 ms [open] [0.0000][0.0000][0.0000]
send=1048215708.318987
12.23.55.212 seq=2 ttl=44 time=172.467 ms [open] [0.0000][0.0000][0.0000]
send=1048215708.829037
12.23.55.212 seq=3 ttl=44 time=191.184 ms [open] [0.0000][0.0000][0.0000]
send=1048215709.339457
12.23.55.212 seq=4 ttl=44 time=168.046 ms [open] [0.5000][0.5000][0.0000]
send=1048215709.849129
12.23.55.212 seq=5 ttl=44 time=166.660 ms [open] [0.6000][0.4000][0.0000]
send=1048215710.359189
12.23.55.212 seq=6 ttl=44 time=155.653 ms [open] [0.6667][0.3333][0.0000]
send=1048215710.869209
12.23.55.212 seq=7 ttl=44 time=153.396 ms [open] [0.7143][0.2857][0.0000]
send=1048215711.379259
12.23.55.212 seq=8 ttl=44 time=160.005 ms [open] [0.7500][0.2500][0.0000]
send=1048215711.889296
12.23.55.212 seq=9 ttl=44 time=169.485 ms [open] [0.7778][0.2222][0.0000]
send=1048215712.399340
12.23.55.212 seq=10 ttl=44 time=182.804 ms [open] [0.8000][0.2000][0.0000]
send=1048215712.909383
--------------- Statistics ---------------------Min/10-tile/Q1/Median/Mode/Q3/90-tile/Max:
153.396/154.302/155.290/166.660/153.400/172.467/182.804/191.184
Min RTT: 153.396 msec, confidence 0.800 (CI), epsilon 5.500 msec
Number of probes sent: 11
Number of replies received: 11
Probes lost: 0
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