Tugas Akhir Makalah Kuliah ET6285 – Keandalan & Kualitas Jaringan Telekomunikasi
Ukuran dan Konsep Evaluatif untuk FTP (File Transfer Protocol) M Reza Kahar Aziz (23210044) Dosen: Sigit Haryadi Progam Studi Magister Teknik Elektro, Opsi Teknik Telekomunikasi Sekolah Teknik Elektro dan Informatika – ITB Email :
[email protected]
I.
PENDAHULUAN
Tujuan makalah ini adalah untuk mendefinisikan ukuran terpercaya yang intuitif dari percieved quality layanan tersebut. Makalah ini dibagi menjadi dua bagian: •
Konsep evaluasi (Evaluative concepts), Menggambarkan concern pengguna terhadap layanan FTP dan mendefiniskan generic measure dari kinerja/keefektifan yang sesuai dengan concern tersebut.
•
Quantifiers, yang mendifinisikan quantifier untuk generic measure..
FTP (File Time Protocol) adalah arti yang populer dari mentransfer file antar komputer. Komunikasi FTP mengikuti model client/server yaitu client menginisiasi sebuah conversation dengan mengirimkan command dan server menanggapi dengan message dan kode status dan juga mengirimkan atau menerima files. Konten FTP pada hal ini adalah File. Last data packet: paket yang diperlukan untuk menyelesaikan transmisi konten pada sisi penerima. Untuk FTP download, paket data terakhir terdiri dari sebuah bit flag TCP FIN. FTP berjalan di atas layer transport TCP. Proses terjadinya koneksi TCP disebut juga TCP Three-way Handshake. Tujuan metode ini adalah agar dapat melakukan sinkronisasi terhadap nomor urut dan nomor acknowledgement yang dikirimkan oleh kedua pihak dan saling bertukar ukuran TCP Window. Prosesnya dapat digambarkan sebagai berikut: -
Host pertama (yang ingin membuat koneksi) akan mengirimkan sebuah segmen TCP dengan flag SYN diaktifkan kepada host kedua (yang hendak diajak untuk berkomunikasi).
-
Host kedua akan meresponsnya dengan mengirimkan segmen dengan acknowledgment dan juga SYN kepada host pertama.
-
Host pertama selanjutnya akan mulai saling bertukar data dengan host kedua.
TCP menggunakan proses jabat tangan yang sama untuk mengakhiri koneksi yang dibuat. Hal ini menjamin dua host yang sedang terkoneksi tersebut telah menyelesaikan proses transmisi data dan semua data yang ditransmisikan telah diterima dengan baik. Itulah sebabnya, mengapa TCP disebut dengan koneksi yang reliable.
II.
KONSEP ELVAUATIF
Concern dari QoS FTP adalah -
Berapa lama waktu yang dibutuhkan untuk mendownload dan upload suatu file dengan menggunakan layanan FTP.
-
Berapa banyak kegagalan yang terjadi ketika melakukan download dan upload sebuah file dengan menggunakan layanan FTP.
-
Berapakah kecepatan rata-rata ketika mendownload dan upload sebuah file dengan menggunakan layanan FTP.
Seseorang memilih filosofi payload throughput dan yang lain memilih filosofi transaction throughput: -
Metoda A mendefinisikan titik trigger yang sebebas mungkin dari layanan yang digunakan, karena itu merepresentasikan pandangan yang lebih umum (payload throughput).
-
Metoda B mendefinisikan titik trigger pada layer aplikasi, oleh karena itu merepresentasikan pandangan yang lebih terorientasi pada (transaction throughput). Metode ini juga dibagi menjadi dua jenis yaitu o
Active FTP
o
Passive FTP
Measure yang didefinisikan oleh ETSI TS 102.250 untuk FTP adalah 2.1. Service Non-Accessibility Service Non-Accessibility ratio menunjukkan peluang bahwa seorang pengguna tidak dapat membangun sebuah konteks Packet Data Protocol (PDP) dan mengakses layanan dengan sukses.. 2.2. Setup Time Setup Time menggambarkan perioda waktu yang diperlukan untuk mengakses layanan dengan sukses, dari mulai dial-up koneksi ke titik waktu ketika konten dikirimkan atau diterima. 2.3. IP-Service Access Failure Ratio IP-Service Access Ratio menunjukkan peluang bahwa seorang pengguna tidak dapat membangun sebuah koneksi TCP/IP ke server layanan dengan sukses. 2.4. IP-Service Setup Time IP-Service Setup Time adalah perode waktu yang dibutuhkan untuk membangun sebuah koneksi TCP/IP ke server layanan, dari mengirimkan initial query ke sebuah server pada titik waktu ketika konten dikirimkan atau diterima. 2.5. Session Failure Ratio Session Failure Ratio adalah proporsi sesi yang tidak lengkap dan sesi yang dimulai dengan sukses. 2.6. Session Time Session Time adalah perioda waktu yang dibutuhkan untuk menyelesaikan sesi data PS dengan sukses. 2.7. Mean Data Rate
Setelah sebuah data link telah dibangung dengan sukses, kriteria ini menjabarkan rata-rata kecepatan transfer data yang diukur pada seluruh waktu connect ke layanan. 2.8. Data Transfer Cut-off Ratio Data Transfer Cut-off Ratio adalah proporsi transfer data yang tidak lengkap dan transfer data yang dimulai dengan sukses.
III.
QUANTIFIERS
3.1. FTP {Download|Upload} Service Non-Accessibility [%] ݊ܰ ݁ܿ݅ݒݎ݁ܵ}݈ܷ݀ܽ | ݈݀ܽ݊ݓܦ{ܲܶܨ− [ ݕݐ݈ܾ݅݅݅ݏݏ݁ܿܿܣ%] =
ܿܽ݁ݎ ݐ ݏݐ݉݁ݐݐܽ ݈ݑ݂ݏݏ݁ܿܿݑݏ݊ݑℎ ݐℎ݁ ݓ ݐ݊݅ℎ݁݊ ܿ݀݁ݒ݅݁ܿ݁ݎ ݎ ݐ݊݁ݏ ݏ݅ ݐ݊݁ݐ݊ × 100 ݈݈ܽ ܽܿܽ݁ݎ ݐ ݏݐ݉݁ݐݐℎ ݐℎ݁ ݓ ݐ݊݅ℎ݁݊ ܿ݀݁ݒ݅݁ܿ݁ݎ ݎ ݐ݊݁ݏ ݏ݅ ݐ݊݁ݐ݊
Trigger Points: Event from abstract equation
Trigger point from user's point of view
Service access attempt
Start: User initiates the service
Technical description/protocol part
Download Start: (Attention Dial) ATD command.
access. Successful attempt
Stop: File download starts.
Stop Method A: Reception of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. Unsuccessful attempt
Stop trigger point not reached. Upload
Service access attempt
Start: User initiates the service
Start: ATD command.
access. Successful attempt
Stop: File upload starts.
Stop Method A: Sending of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. Unsuccessful attempt
Stop trigger point not reached.
3.2. FTP {Download|Upload} Setup Time [s]
= ]ݏ[ ݁݉݅ܶ ݑݐ݁ܵ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨ൫ ݐ௦௩ ௦௦ ௦௨௦௦௨ − ݐ௦௩ ௦௦ ௦௧௧ ൯ []ݏ Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
Download tservice access start: Time of service access
Start: User initiates the service access..
Start: ATD command.
Stop: File download starts.
Stop Method A: Reception of the first data packet
attempt tservice access successful: Time of successful service access
containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket.
Upload tservice access start: Time of service access
Start: User initiates the service
attempt
access.
tservice access successful: Time of successful
Stop: File upload starts.
service access
Start: ATD command.
Stop Method A: Sending of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket.
3.3. FTP {Download|Upload} IP-Service Access Failure Ratio [%] ܲܫ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨ− ܵ݁[݅ݐܴܽ݁ݎݑ݈݅ܽܨ ݏݏ݁ܿܿܣ݁ܿ݅ݒݎ%] =
ݏ݈ܾ݅ܽݐݏ݁ ݐ ݏݐ݉݁ݐݐܽ ݈ݑ݂ݏݏ݁ܿܿݑݏ݊ݑℎ ܽ݊ ݐ ݐ ݊݅ݐܿ݁݊݊ܿ ܲܫℎ݁ ݎ݁ݒݎ݁ݏ × 100 ݈݈ܽ ܽݏ݈ܾ݅ܽݐݏ݁ ݐ ݏݐ݉݁ݐݐℎ ܽ݊ ݐ ݐ ݊݅ݐܿ݁݊݊ܿ ܲܫℎ݁ ݎ݁ݒݎ݁ݏ
Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
IP-Service access attempt
Start: User initiates file download.
Start: First [SYN] sent on the data socket.
Successful attempt
Stop: File download starts.
Stop Method A: Reception of the first data packet
Download
containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket.
Unsuccessful attempt
Stop trigger point not reached. Upload
IP-Service access attempt
Start: User initiates file upload.
Start: First [SYN] sent on the data socket.
Successful attempt
Stop: File upload starts.
Stop Method A: Sending of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. Unsuccessful attempt
Stop trigger point not reached.
3.4. FTP {Download|Upload} IP-Service Setup Time [s] ܲܫ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨ− ܵ݁]ݏ[݁݉݅ܶ ݑݐ݁ܵ݁ܿ݅ݒݎ = ൫ݐூିௌ௩ ௦௦ ௦௨௦௦௨ − ݐூିௌ௩ ௦௦ ௦௧௧ ൯ []ݏ Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
Download tIP-Service access start: Time of IP-Service
Start: User initiates file download.
Start: First [SYN] sent.
Stop: File download starts.
Stop Method A: Reception of the first data packet
access attempt tIP-Service access successful: Time of successful IP-Service access
containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket.
Upload tIP-Service access start: Time of IP-Service
Start: User initiates file upload.
Start: First [SYN] sent.
Stop: File upload starts.
Stop Method A: Sending of the first data packet
access attempt tIP-Service access successful: Time of successful IP-Service access
containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket.
3.5. FTP {Download|Upload} Session Failure Ratio [%] [ ݅ݐܴܽ ݁ݎݑ݈݅ܽܨ ݊݅ݏݏ݁ܵ}݈ܷ݀ܽ | ݈݀ܽ݊ݓܦ{ ܲܶܨ%] =
ݏ݊݅ݏݏ݁ݏ ݀݁ݐ݈݁݉ܿ݊ݑ × 100 ݏ݊݅ݏݏ݁ݏ ݀݁ݐݎܽݐݏ ݕ݈݈ݑ݂ݏݏ݁ܿܿݑݏ
Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
Successfully started session
Start: User initiates file download.
Start: First [SYN] sent on the control socket.
Completed session
Stop: File download successfully
Stop: Reception of the last data packet
completed.
containing content.
Download
Uncompleted session
Stop trigger point not reached. Upload
Successfully started session
Start: User initiates file upload.
Start: First [SYN] sent on the data socket.
Completed session
Stop: File upload successfully
Stop: Reception of the [FIN, ACK] for the last
completed.
data packet containing content.
Uncompleted session
Stop trigger point not reached.
3.6. FTP {Download|Upload} Session Time [s] = ]ݏ[݁݉݅ܶ ݊݅ݏݏ݁ܵ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨሺݐ௦௦௦ ௗ − ݐ௦௦௦ ௦௧௧ ሻ []ݏ Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
Download tsession start: Time of successfully
Start: User initiates file download.
Start: First [SYN] sent on the control socket.
tsession end: Time when session
Stop: File download successfully
Stop: Reception of the last data packet
completed
completed.
containing content.
tsession start: Time of successfully
Start: User initiates file upload.
Start: First [SYN] sent on the data socket.
tsession end: Time when session
Stop: File upload successfully
Stop: Reception of the [FIN, ACK] for the last
completed
completed.
data packet containing content.
started session
Upload
started session
3.7. FTP {Download|Upload} Mean Data Rate [kbit/s] Setelah sebuah data link telah dibangung dengan sukses, parameter ini menjabarkan rata-rata kecepatan transfer data yang diukur pada seluruh waktu connect ke layanan. Transfer data akan diterminasi dengan sukses. Prasyarat untuk parameteri ini adalah akses jaringan dan layanan. ݐܾ݅݇[݁ݐܴܽ ܽݐܽܦ ݊ܽ݁ܯ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨ/= ]ݏ
]ݐܾ݅݇[݀݁ݎݎ݂݁ݏ݊ܽݎݐ ܽݐܽ݀ ݎ݁ݏݑ ൫ݐௗ௧ ௧௦ ௧ − ݐௗ௧ ௧௦ ௦௧௧ ൯ []ݏ
Rata-rata throughput diukur dari membuka koneksi data kepada akhir transfer konten (file) yang. Event from abstract equation
Trigger point from user's point of view
Technical description/protocol part
Download tdata transfer start : Time of
Start: File download starts.
successfully started data transfer
Stop Method A: Sending of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. tdata transfer complete: Time when
Stop: File download successfully
Stop: Reception of the last data packet
data transfer complete
completed.
containing content.
Upload tdata transfer start : Time of
Start: File upload starts.
Stop Method A: Sending of the first data packet
successfully started data transfer
containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. tdata transfer complete: Time when
Stop: File upload successfully
Stop: Reception of the [FIN, ACK] for the last
data transfer complete
completed.
data packet containing content.
3.8. FTP {Download|Upload} Data Transfer Cut-off Ratio [%] ݐݑܥ ݎ݂݁ݏ݊ܽݎܶ ܽݐܽܦ}݈ܷ݀ܽ |݈݀ܽ݊ݓܦ{ܲܶܨ− [݅ݐܴܽ ݂݂%] =
݅݊ܿݏݎ݂݁ݏ݊ܽݎݐ ܽݐܽ݀݁ݐ݈݁݉ × 100 ݏݎ݂݁ݏ݊ܽݎݐ ܽݐܽ݀ ݀݁ݐݎܽݐݏ ݕ݈݈ݑ݂ݏݏ݁ܿܿݑݏ
Event from abstract equation
Trigger point from user's point of view
Successfully started data transfer
Stop: File download starts.
Technical description/protocol part
Download Stop Method A: Reception of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. Complete data transfer
Incomplete data transfer
Stop: File download successfully
Stop: Reception of the last data packet
completed.
containing content. Stop trigger point not reached.
Upload Successfully started data transfer
Stop: File upload starts.
Stop Method A: Sending of the first data packet containing content.
Stop Method B: Reception of the [ACK] from the [SYN, ACK] for active mode connections, sending of the [ACK] for the [SYN, ACK] for passive mode connections on the data socket. Complete data transfer
Stop: File upload successfully
Stop: Reception of the [FIN, ACK] for the last
completed.
data packet containing content.
Incomplete data transfer
Stop trigger point not reached.
Timeout values for an FTP (ULandDL) service are: •
Service Accessibility Timeout: 150 seconds + IP-Service Access Timeout;
•
Setup Time Timeout: 150 seconds + IP-Service Access Timeout;
•
IP-Service Access Timeout (and IP-Service Setup Time Timeout): 30 seconds;
•
Data Transfer Cut-off Timeout: -
-
Over GPRS: o
UL: File size[kByte] × 8/5;
o
DL: File size[kByte] × 8/10.
Over UMTS: o
-
ULandDL: File size[kByte] × 8/50.
Dual mode: The average between the timeout over GPRS and UMTS shall be considered.
KESIMPULAN FTP QoS menggunakan delapan buah measure yaitu service non accessibilty, setup time, IP-service access failure, IP-service setup time, session failure ratio, session time, mean data rate, data transfer cut-off ratio.
APPENDIX A: EXAMPLE FTP SEQUENCE DIAGRAM Detail contoh FTP sequence diagram yang lengkap bisa dilihat di http://www.eventhelix.com/realtimemantra/networking/FTP_Port_21.pdf
BIBLIOGRAFI [1] William C. Hardy, QoS Measurement and Evaluation of Telecommunication Quality of Service, John Wiley and Sons, Ltd: 2001. [2] Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in GSM and 3G networks; Part 2: Definition of Quality of Service parameters and their computation, Technical Specisification, ETSI TS 102 250-2 V1.7.1 (2009-10). [3] Speech Processing, Transmission and Quality Aspects (STQ); QoS aspects for popular services in GSM and 3G networks; Part 1: Identification of Quality of Service criteria, Technical Specisification, ETSI TS 102 250-1 V1.2.1 (2007-03). [4] http://www.eventhelix.com/realtimemantra/networking/FTP_Port_21.pdf [5] N. Patwardhan, E. Siever, S. Spainhour, Perl in a nutshell, O’Reilly Media, Inc: 2002 [6] http://www.linuxhomenetworking.com/wiki/images/a/a7/Ftp.gif [7] http://id.wikipedia.org/wiki/Transmission_Control_Protocol [8] Speech and multimedia Transmission Quality (STQ); QoS aspects for popular services in GSM and 3G networks; Part 5: Definition of typical measurement profiles, Technical Specification, ETSI TS 102 250-5 V1.6.1 (2009-06).
