nyoman suryadipta, st, ccna, ccnp chapter v & vi satellite & wlan
TRANSCRIPT
Nyoman Suryadipta, ST, CCNA, CCNP
Chapter V & VISatellite & WLAN
Satellite• Basics of Satellites• Types of Satellites• Capacity Allocation
Global
Suburban
Macro-Cell
Urban
Micro-Cell In- Building
Pico-Cell
Home Cell-
Terrestrial• Cooper & Cable, limited for urban areas with legacy apps
• High cost and build for backbone infrastructure
• Enhanced with xDSL technology, but limited by line distance, quality, and availability
• Enhanced with FWA, but limited by population density and technological challenges
Satellite• Alternatif solution for
terrestrial last mile bottlenecks
• For areas undeserved economically by terrestrial
• Quick infrastructure deployment ( time consideration )
• End to end based networks• Direct to user/home
interactive applications• Temporally requirements
Why Satellite
• Two Stations on Earth want to communicate through radio broadcast but are too far away to use conventional means.
• The two stations can use a satellite as a relay station for their communication
Signal Transmission
• One Earth Station sends a transmission to the satellite. This is called a Uplink.
• The satellite Transponder converts the signal and sends it down to the second earth station. This is called a Downlink.
Advantages The coverage area of a satellite greatly
exceeds that of a terrestrial system. Transmission cost of a satellite is
independent of the distance from the center of the coverage area.
Satellite to Satellite communication is very precise.
Higher Bandwidths are available for use. The distance between an earth station and a
satellite (free space).
Dis - advantages
Launching satellites into orbit is costly. There is a larger propagation delay in
satellite communication than in terrestrial communication.
Atmospheric Attenuation caused by air and water can impair the transmission. It is particularly bad during rain and fog.
Orbits GEO LEO MEO
Geostationary Earth Orbit (GEO)
• These satellites are in orbit 35,863 km above the earth’s surface along the equator.
• Objects in Geostationary orbit revolve around the earth at the same speed as the earth rotates. This means GEO satellites remain in the same position relative to the surface of earth.
Medium Earth Orbit (MEO)
• A MEO satellite is in orbit somewhere between 8,000 km and 18,000 km above the earth’s surface.
• MEO satellites are similar to LEO satellites in functionality.
• MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 to 8 hours.
• MEO satellites have a larger coverage area than LEO satellites.
Low Earth Orbit (LEO)• LEO satellites are much closer to the earth than
GEO satellites, ranging from 500 to 1,500 km above the surface.
• LEO satellites don’t stay in fixed position relative to the surface, and are only visible for 15 to 20 minutes each pass.
• A network of LEO satellites is necessary for LEO satellites to be useful
Frequency Bands• Different kinds of satellites use different
frequency bands. L–Band: 1 to 2 GHz, used by MSS S-Band: 2 to 4 GHz, used by MSS, NASA, deep space research C-Band: 4 to 8 GHz, used by FSS X-Band: 8 to 12.5 GHz, used by FSS and in terrestrial imaging,
ex: military and meteorological satellites Ku-Band: 12.5 to 18 GHz: used by FSS and BSS (DBS) K-Band: 18 to 26.5 GHz: used by FSS and BSS Ka-Band: 26.5 to 40 GHz: used by FSS
TOPOLOGY :
STAR
HX Gateway
TDM
TDMA
Outroute
InrouteHead Office
Branch
Branch
HX 50
HX 50
IP GatewayEnterprise
Router
FRAME RELAY
MPLS
INTERNET
Palapa C2
HX : Hub & Remote
HX GATEWAY (HUB) HX 50 FRONT VIEW HX 50 REAR VIEW
HX 50 : Indoor – Outdoor Connection
BUC
LNB
Outdoor UnitRF Unit
Tx (coaxial)
Rx (Coaxial)
HX 50
Indoor Unit
LAN
BUC : Block Upconverter
LNB : Low Noise Blockdownconverter
RF : Radio Frequency
Early 1990’s : Legacy protocol (X.25/SDLC) : Datao Legacy Protocolo X.25/SDLC over VSATo 2.4 Kbps – 64 Kbps
2000 : IP Connectivity - Data 2005 : IP Connectivity with QoS/CoS – Data & Voice Access Method :
o TDMA : Sharing Bandwidth – VSAT Net/VSAT IP/VSAT Multiservices
Total Remotes : + 1500o FDMA : SCPC/Teleport – VSAT Link
Total Remotes : + 300 Transponder
o Telkom 1 : PT. TELKOMo PALAPA C2 : PT. INDOSATo Apstar : SingTelo Frequency bands : C-band – Linier polarization
Study Case• Indonesia diketahui kehilangan potensi
kehilangan pajak dari biaya hak penggunaan (BHP) frekuensi sebesar Rp2,4 triliun setiap tahun karena penguasaan yang besar untuk satelit broadcasting sebesar 150 MHz di pita 2,5 GHz.
Study Case• Indonesia diketahui kehilangan potensi
kehilangan pajak dari biaya hak penggunaan (BHP) frekuensi sebesar Rp2,4 triliun setiap tahun karena penguasaan yang besar untuk satelit broadcasting sebesar 150 MHz di pita 2,5 GHz.
Study Case• Sekjen Indonesia Wireless Broadband (Idwibb)
Yohannes Sumaryo mengungkapkan di pita tersebut, terdapat PT Media Citra Indostar (Indovision) yang menguasai spektrum selebar 150 MHz dan hanya bayar BHP sebesar Rp300 juta setahun.
• Sementara operator WiMax atau LTE sanggup membayar Rp2,4 triliun per tahun untuk lebar pita yang sama
Study Case• 1 BTS seluler 5 MHz bisa untuk melayani hingga
90 stasiun pelanggan dalam satu area yang sempit 3-5 km radius,
Example• Indostar II dibuat oleh Boeing Satellite System di
Los Angeles, California, AS, dalam waktu 20 bulan, dengan total biaya sebesar US$ 300 juta — dari kas internal dan pinjaman asing. Satelit yang memiliki umur orbit 16,8 tahun lebih. Satelit Indostar II ini menempati slot orbit 107,7 derajat BT dan bekerja di pita frekuensi 2,5 GHz (2.520-2.670 GHz) selebar 150 MHz.
Source ; swa.co.id
Example• satelit high power tersebut memungkinkan
Indovision menampung kapasitas siaran hingga lebih dari 120 channel. Saat ini, jumlah kanal yang dimiliki televisi berbayar itu 62.
• Misal : 2,5 GHz / 120 channel = ± 20 MHz
1 kanal transmisi siaran video satelit membutuhkan lebar pita/bandwidth 20 MHz
WLAN
Benefits of Wireless• Mobility• Scalability
– can be added to a network easily– use of “hotspots”
• Flexibility– anytime, anywhere connectivity
• Cost– inexpensive to install– reduced installation costs
Limitations/Risks of Wireless
• Uses unlicensed regions of the RF spectrum– used by many different devices
• Interference– cordless phones– microwaves
• Security– easy access to the network– encryption/authentication helps with security issues
Wireless Technologies• WPAN
– Wireless Personal Area Network– used for:
• mice• keyboards• PDAs
Wireless Technologies• WLAN
– Wireless LAN– uses RF standards– conform to 802.11 standards– connects through Wireless AP
Wireless Technologies• WWAN
– Wireless WAN– coverage over large areas– cell phone network
Components of a WLAN
• Wireless client– any host that can participate in a wireless network
• Access point (AP)– control access between wired and wireless networks
Components of a WLAN
• Wireless Bridge– connects two wired networks through a wireless link– offers long range connectivity
• 25 miles– Uses unlicensed RF frequencies
Access Point• Antennas
– increases output signal strength (gain)– receives the wireless signal– higher gain = increased distance
• Directional antenna– concentrates signal in one direction– allows for greater distances
• Omni-directional antenna– emits signal equally in all directions– used by most Access Points
Purpose of SSID• Service Set Identifier• Allows wireless components to connect to the
WLAN– tells wireless devices which WLAN they belong to– tells devices whom then can talk to
• All wireless devices must have same SSID to communicate with each other
• Characteristics– case sensitive– alphanumeric characters– sent in the header of the frame
Infrastructure Installation
• Used by larger networks• Uses an Access Point (AP)
– makes sure all STAs have equal access
• Each device must receive permission to communicate
• BSS– Basic Services Set– area covered by a AP
Channels in a WLAN• Use of channels help to control conversations
– allows multiple Access Points close to one another to function– each AP must be on different channel
• Each channel capable of carrying a different conversation
CSMA/CA• Carrier Sense Multiple Access with Collision Avoidance• Ensures collisions do not occur on a wireless network• Reserves a channel for communication
– Device requests permission from AP (Request to Send–RTS)– If available, AP responds with all clear message
• Clear to Send Message (CTS)– CTS is broadcast to all other devices
• informs everyone the channel is being used– Upon completion of conversation
• Device that requested channel send ACK to AP• ACK indicates to AP that channel can be used again• ACK sent to other devices letting them know the channel
can be used again
IEEE 802.11 WLAN Standard Activities
• 802.11a: 5 GHz, 54 Mbps• 802.11b: 2.4 GHz, 11 Mbps• 802.11d: Multiple regulatory domains• 802.11e: Quality of Service (QoS)• 802.11f: Inter-Access Point Protocol (IAPP) • 802.11g: 2.4 GHz, 54 Mbps• 802.11h: Dynamic Frequency Selection (DFS) and Tran Power• 802.11i: Security – Ratified | WPAv2 – Draft 9• 802.11j: Japan 5 GHz Channels (4.9-5.1 GHz)• 802.11k: Measurement• 802.11m: Maintenance• 802.11n: High Throughput• 802.11p: Wireless Access for Vehicular Environment• 802.11r: Public WLAN Fast Roaming• 802.11s: Mesh Networking
LegendRatifiedDraft18 Months and Beyond
802.11 a/b/g Specifications
802.11a 802.11b 802.11g
Radio Frequency5GHz U-NII (Unlicensed National
Information Infrastructure)2.4GHz ISM (Industrial, Scientific, and Medical) 2.4GHz ISM
Bandwidth (Link Speed in Mbps)
6, 9, 12, 18, 24, 36, 48, 54 1, 2, 5.5, 11 1, 2, 5.5, 6, 9, 11, 12, 18, 22, 24, 36, 48, 54
Throughput (Actual max. payload rate)
26-27 Mbps 5-6 Mbps 20+ Mbps
Carrier Technique
OFDM (Orthogonal Frequency Division Multiplexing)
DSSS (Direct Sequence Spread Spectrum) DSSS, OFDM
Modulation Format BPSK, QPSK, 16 QAM, 64 QAM CCK, QPSK, DQPSK, DBPSK PBCC + 802.11a + 802.11b
Channel Bandwidth
16.6MHz 22MHz 22MHz
802.11 a/b/g Range vs. Bandwidth
0
20
40
60
80
100
120
1Mbps 5.5Mbps 6Mbps 11Mbps 12Mbps 24Mbps 36Mbps 54 Mbps
Bandwidth (Mbps)
Dis
tan
ce (
Mete
rs/F
eet)
Note: Bandwidth is based on RF rates. Actual throughput is lower.
802.11a 802.11b 802.11g
120/400
100/333
80/266
60/200
40/133
20/67
0
WLAN Security Standards
1997 the original 802.11 standard only offers - SSID (Service Set Identifier) - MAC Filtering (Media Access Control) - and WEP (Wired Equivalent Privacy)
1999 several industry players formes WECA (Wireless Ethernet Compatibility Alliance) for rapid adaption of 802.11 network products.
2001 Fluhrer, Mantin and Shamir had identified some weaknesses in WEP. IEEE started Task Group i.
2002 WECA was renamed in WI-FI
WLAN Security Standards
2003 Wi-Fi introduced the Wi-Fi Protected Access (WPA). - Should be an interim solution for the weakness of WEP. - Some parts of IEEE 802.11i.
2004 The WPA2 was introduced. - It based on the final IEEE 802.11i standard. - Was ratified on June 25.
WLAN Security Standards
WEP WPA WPA2
Cipher RC4 RC4 AES Key Size 40 or 104bits 104bits perPack 128bits
encry. Key Life 24bit IV 48bit IV 48bit IV Packet Key Concatenation TwoPhaseMix Not Needed Data Integrity CRC32 Michael MIC CCM Key Management None 802.1X/EAP/PSK
802.1X/EAP/PSK
Wireless Security• No physical connection needed• Attacker can “tune into” your network just like
tuning into a radio station• Easy access if all settings are set to default, so .
. .• CHANGE THE SETTINGS
– disable SSID– change default password– change default IP
• But . . – SSID transmitted in clear text– still possible to learn the SSID
MAC Address Filtering• Another security feature• Will limit access to your network• MAC address used to identify which device can
connect to the wireless network– wireless AP looks up MAC in a list (database)– only those addresses listed will gain access
Security – Authentication
• Controls who connects to the network• Permitted based on set of credentials• Helps to verify the “trustworthiness” of the
device– usernames– passwords
• Occurs before client is connected to WLAN
Open Authentication• On by default• Any and all clients can access AP• Should only be used on public wireless networks
– Schools– Internet Café
PSK (Pre-Shared Keys)
Authentication
• Both AP and client must have the same secret key or word
• Here’s how it works:– AP sends random string of bytes to client– Client accepts it, encrypts it, and sends it back to AP– AP receives encrypted string, decrypts it– if decrypted string = original string client is added
EAP (Extensible Authentication
Protocol)
• EAP software must be installed on the client device
• Client talks with RADIUS Server– Remote Authentication Dial-in User Services– server functions separately from the AP– server keeps a database of valid users– username and password checked by the server
Encryption• Process of transforming data so if intercepted,
will still be unusable• WEP (Wired Equivalency Protocol)
– advanced security feature– encrypts network traffic as it travels– 64 – 128 bits (letters and/or numbers)– AP and every device on the network must have the same WEP key
Traffic Filtering• Controls the type of traffic allowed across a
WLAN• Able to block traffic based on:
– IP Address– MAC Address– Port Numbers
