Transcript xDSL Digital Subscriber Line Technology

Cisco Systems CCNA Version 3 Semester 1
Module 5
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 1
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 2
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 3
•Digital
•Intel
•Xerox
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 4
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 5
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All physical specs are LAYER 1 specs.
Main factors to consider…
•
cost
•
cable length
•
ease of installation
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Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 7
This is the
Jack
This is the
Connector
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 8
This is the
Jack
568A
This is the
Connector
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 9
This is the
Jack
568B
This is the
Connector
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 10
Good Jacket
Length
Properly
Crimped
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Transmit Data
Tip +ve
568B
Receive Data
Ring -ve
Transmit Data
Ring -ve
Receive Data
Tip +ve
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 12
Signal leaves the cable and enters the NIC on the SPLIT
Green pair. White-Green is +ve, solid Green is negative.
568B
Signal leaves the NIC and enters the cable on the Orange
pair. White-Orange is +ve, solid Orange is negative.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 13
568B
568A
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Use straight-through cables for…
•Switch to router
•Switch to PC or server
•Hub to PC or server
Use roll-over cables to…
•Connect a terminal to a
console port
Use crossover cables for…
•Switch to switch
•Switch to hub
•Hub to hub
•Router to router
•PC to PC
•Router to PC
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 16
No more than four repeaters can be used between
hosts on a LAN. This rule is used to limit latency
added to frame travel by each repeater thus
reducing Late Collisions.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 17
•Passive – A passive hub serves as a physical connection point only.
It does not boost or clean the signal and does not need electrical
power.
•Active – An active hub needs power to repeat the signal before
passing it out the other ports.
•Intelligent – Intelligent or smart hubs are active hubs with a
microprocessor chip and diagnostic capabilities
•Also called a Concentrator or Multiport Repeater.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 18
•Devices attached to a hub receive all traffic traveling through
the hub.
•The more devices there are attached to the hub, the more
likely there will be collisions.
•A collision occurs when two or more workstations send data
over the network wire at the same time.
•All data is corrupted when that occurs.
•Every device connected to the same network segment is said
to be a member of a collision domain.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 19
Two approaches currently being used to implement spread spectrum for
WLAN transmissions are Frequency Hopping Spread Spectrum (FHSS) and
Direct Sequence Spread Spectrum (DSSS).
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 20
•There are times when it is necessary to break up a large LAN into
smaller, more easily managed segments.
•This decreases the amount of traffic on a single LAN and can
extend the geographical area past what a single LAN can support.
•The devices that are used to connect network segments together
include bridges, switches, routers, and gateways.
•Switches and bridges operate at the Data Link layer of the OSI
model.
•The function of the bridge or switch is to make intelligent
decisions about whether or not to pass signals on to the next
segment of a network.
•They makes these decisions based upon the layer 2 physical
address (MAC).
•A switch therefore has two main functions:
•switch data frames
•build and maintain tables
If placed strategically, a bridge can greatly improve network performance.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 21
•If the destination device is on the same segment as the frame, the bridge blocks the
frame from going on to other segments. This process is known as filtering.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 22
•If the destination device is on a different segment, the bridge forwards the frame to
the appropriate segment.
•If the destination address is unknown to the bridge, the bridge forwards the frame to
all segments except the one on which it was received. This process is known as flooding.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 23
A bridge or switch determines whether the frame should be forwarded to
the other network segment based on the destination MAC address.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 24
A switch has many ports with many network segments connected to them. A switch
chooses the port to which the destination device or workstation is connected.
Ethernet switches are becoming popular connectivity solutions replacing hubs...
•reduces network congestion
•maximizes bandwidth
•reduces collision domain size
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A switch is sometimes described as a multiport bridge.
Switches build forwarding tables to determine the destination of data being sent by one
computer to another computer on the network.
A switch is a more sophisticated device than a bridge.
Switching is a technology that alleviates congestion in Ethernet LANs by reducing the
traffic and increasing the bandwidth.
Switches can easily replace hubs because switches work with existing cable infrastructures.
This improves performance with a minimum of intrusion into an existing network.
Switches equipment performs two basic operations. The first operation is called switching
data frames. Switching data frames is the process by which a frame is received on an input
medium and then transmitted to an output medium. The second is the maintenance of
switching operations where switches build and maintain switching tables and search for
loops.
Switches operate at much higher speeds than bridges and can support new functionality,
such as virtual LANs (VLANs).
An Ethernet switch allows many users to communicate in parallel through the use of virtual
circuits and dedicated network segments in a virtually collision-free environment.
This maximizes the bandwidth available on the shared medium. Another benefit is that
moving to a switched LAN environment is very cost effective because existing hardware and
cabling can be reused.
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The function of a NIC is to connect a host
device to the network medium.
NICs are considered Layer 2 devices because each
NIC carries a unique code called a MAC address.
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Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 28
1. Two computers typically communicate
with each other by using
request/response protocols.
2. The requestor takes on the role of a
client, and the responder takes on the
role of a server.
3. In a peer-to-peer network, networked
computers act as equal partners, or peers.
4. As peers, each computer can take on the
client function or the server function.
5. Recommended maximum number of peerto-peer hosts is 10.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 29
In a peer-to-peer network,
individual users control their
own resources.
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•Peer-to-peer networks are relatively easy to install and
operate.
•No additional equipment is necessary beyond a suitable
operating system installed on each computer.
•Since users control their own resources, no dedicated
administrators are needed.
•As networks grow, peer-to-peer relationships become
increasingly difficult to coordinate.
•A peer-to-peer network works well with 10 or fewer
computers.
•Their efficiency decreases rapidly as the number of computers
on the network increases.
•Also, individual users control access to the resources on their
computers, which means security may be difficult to maintain.
•The client/server model of networking can be used to
overcome the limitations of the peer-to-peer network.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 31
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In a client/server arrangement, network services are located on a dedicated
server.
The server is a central computer that is continuously available to respond to
requests from clients for file, print, application, and other services.
Most network operating systems adopt the form of a client/server relationship.
Typically, desktop computers are the clients and one or more computers with
additional processing power, memory, and specialized software function as
servers.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 32
•easy to create
•no centralized equipment required
•centralized administrator not required
•centralized security
•centralized backups
•enhanced network services
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The B channels use PPP (Point –to-Point Protocol).
5.2.1 WAN physical layer
ISDN BRI is 2 Bearer channels
plus a Data channel (2B+D).
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The Service Provider usually provides the clock at the DCE connector end.
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Use roll-over cables
to connect a terminal
to a console port.
The console port is
for initial router
configuration.
The auxiliary port is a
console port but you
connect with a modem.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 40
Use roll-over cables
to connect a terminal
to a console port.
The console port is
for initial router
configuration.
The auxiliary port is a
console port but you
connect with a modem.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 41
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Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 43
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 44
xDSL - Digital Subscriber Line Technology
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The key in xDSL technology is modulation, a
process in which one signal modifies a properties of
another.
Hardware: DSL requires modems and splitters for
end-users; carriers use DSLAMs (digital subscriber
line access multiplexers)
Differences between xDSL technologies: speed,
operating distance, applications, ratio between up
and downstream
Different approaches: ATM-based ADSL, ISDN
DSL.
The important thing is what is running over xDSL...
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 45
xDSL - Digital Subscriber Line Technology
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 46
xDSL Digital Subscriber Line Technology
ADSL - Asymmetric Digital Subscriber Line
•expected in general use in 1999
•twisted pair copper (single loop)
•asymmetric: most commonly: 6Mbps (down), 640 Kbps
(up)
•downlink: 1.5 Mbps-8 Mbps
•uplink : 176 Kbps - 1 Mbps
•limited distance (18000 feet over 26-gauge copper)
RADSL - Rate-Adaptive Digital Subscriber Line
•varying speeds depending upon line quality; asymmetric
•downlink: 1.5 Mbps-8 Mbps
•uplink : 176 Kbps - 1 Mbps
•limited distance (18000 feet over 26-gauge copper)
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 47
xDSL Digital Subscriber Line Technology (cont.)
HDSL - High-speed Digital Subscriber Line
•full-duplex, symmetric
•1.544 Mbps or 2.048 Mbps in each direction
•two twisted pairs (for T1) and 3 pairs (for E1)
•max distance 12,000 feet
VDSL - Very-high-bit-rate Digital Subscriber Line (known
as BDSL)
•asymmetric
•downlink: 12.96-51.84 Mbps
•uplink : 1.6 - 2.3 Mbps
•max 4,500 - 1,000 feet
•applications: High definition TV, multimedia
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1.
A network interface card (NIC) provides network communication
capabilities to and from a PC.
2. Use a crossover cable to connect between two similar devices, such as
switches, routers, PCs, and hubs.
3. Use a straight-through cable to connect between different devices, such
as connections between a switch and a router, a switch and a PC, or a hub
and a router.
4. There are two major types of LANs, peer-to-peer and client/server.
5. WANs use serial data transmission. WAN connection types include ISDN,
DSL, and cable modems.
6. A router is usually the DTE and needs a serial cable to connect to a DCE
device like a CSU/DSU.
7. The ISDN BRI has two types of interfaces, S/T and U interfaces. To
interconnect the ISDN BRI port to the service-provider device, a UTP
Category 5 straight-through cable with RJ-45 connectors, is used.
8. A phone cable and an RJ-11 connector are used to connect a router for
DSL service.
9. Coaxial cable and a BNC connector are used to connect a router for cable
service.
10. Rollover cable is used to connect a terminal and the console port of an
internetworking device.
Oct-03 ©Cisco Systems CCNA Semester 1 Version 3 Comp11 Mod5 – St. Lawrence College – Cornwall Campus, ON, Canada – Clark slide 52
FIN
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