Transcript CCNA 1 Module 7 Ethernet Topologies

CCNA 1 Chapter 6, Part 1
Ethernet Technologies
By
Your Name
Copyright 2003
www.ciscopress.com
Objectives
• 10 Mbps and 100 Mbps
• 1000 Mbps and Gigabit Ethernet
Copyright 2003
www.ciscopress.com
Ethernet Family Tree
Copyright 2003
www.ciscopress.com
10 Mbps Ethernet
• 10BASE-5, 10BASE-2, and 10BASE-T Ethernet
are considered Legacy Ethernet.
• The four common features of Legacy Ethernet
are timing parameters, frame format,
transmission process, and a basic design rule.
Copyright 2003
www.ciscopress.com
10BASE-5
• 10BASE-5 systems also
represent a single point of
failure.
• 10BASE-5 uses
Manchester encoding.
• Each of the maximum 5
segments of thick coax
may be up to 500 meters
in length.
• The cable is large, heavy,
and difficult to install.
Copyright 2003
www.ciscopress.com
10BASE-2
• 10BASE-2 also uses Manchester encoding.
• Only 1 station can transmit at a time; otherwise a
collision will occur.
• It uses half duplex.
• The maximum transmission rate is 10 Mbps.
• There may be up to 30 stations on any individual
10BASE-2 segment.
Copyright 2003
www.ciscopress.com
10BASE-T
• 10BASE-T also uses Manchester encoding.
• 10BASE-T uses cheaper and easier-to-install
Category 3 unshielded twisted-pair (UTP)
copper cable rather than coax cable.
• Half duplex or full duplex is a configuration
choice.
• 10BASE-T carries 10 Mbps of traffic in halfduplex mode and 20 Mbps in full-duplex mode.
Copyright 2003
www.ciscopress.com
10BASE-T Wiring and Architecture
• 10BASE-T links generally consist of a
connection between the station and a hub or
switch.
Copyright 2003
www.ciscopress.com
100 Mbps
• 100 Mbps Ethernet is also known as Fast
Ethernet.
• The two technologies that became important are
100BASE-TX, which is copper UTP based, and
100BASE-FX, which is multimode optical fiber
based.
Copyright 2003
www.ciscopress.com
1000BASE-TX
• 100BASE-TX uses 4B/5B encoding, which is
then scrambled and converted to multilevel
transmit-3 levels or MLT-3.
Copyright 2003
www.ciscopress.com
1000BASE-FX
• A fiber version desired for backbone applications
as well as connections between floors and
buildings where copper is less desirable, and
also in high noise environments
Copyright 2003
www.ciscopress.com
Fast Ethernet Architecture
Copyright 2003
www.ciscopress.com
1000 Mbps and 10 Gigabit Ethernet
Copyright 2003
www.ciscopress.com
1000 Mbps Ethernet
• The 1000 Mbps Ethernet or Gigabit Ethernet
standards represent transmission using both
fiber and copper media.
• The 1000BASE-X standard (IEEE 802.3z)
specifies a 1-Gbps full duplex over optical fiber.
• The 1000BASE-T standard (IEEE 802.3ab) uses
a media of Category 5 or higher UTP.
• 1000BASE-TX, 1000BASE-SX, and 1000BASELX use the same timing parameters.
Copyright 2003
www.ciscopress.com
1000BASE-T
• 1000BASE-T standard is interoperable with
10BASE-T and 100BASE-TX.
• 1000BASE-T uses all 4 pairs of wires instead of
the traditional 2 pairs of wires used by 10BASET and 100BASE-TX.
– This provides 250 Mbps per pair. With all 4 wire pairs,
this provides the desired 1000 Mbps.
Copyright 2003
www.ciscopress.com
1000BASE-SX and LX
Copyright 2003
www.ciscopress.com
Gigabit Ethernet Architecture
• Daisy-chaining, star, and extended star
topologies are all allowed.
• It is recommended that all links between a
station and a hub or switch be configured for
autonegotiation to permit the highest common
performance.
Copyright 2003
www.ciscopress.com
10 Gigabit Ethernet
• IEEE 802.3ae was adapted to include 10-Gbps
full-duplex transmission over fiber-optic cable.
• When using single-mode fiber as the
transmission medium, the maximum
transmission distance is 40 kilometers (25
miles).
• Some discussions between IEEE members have
begun that suggest the possibility of standards
for 40-, 80-, and even 100-Gbps Ethernet.
Copyright 2003
www.ciscopress.com
10 Gigabit Ethernet Architectures
• 10 Gigabit Ethernet uses two separate encoding
steps.
• The encoded data provides synchronization,
efficient usage of bandwidth, and improved
signal-to-noise ratio characteristics.
• All 10GbE varieties use optical fiber media.
Copyright 2003
www.ciscopress.com
Future of Ethernet
• Ethernet has gone
through an evolution from
Legacy → Fast → Gigabit
→ MultiGigabit
technologies.
• The future of networking
media is threefold:
– Copper (up to 1000
Mbps, perhaps more)
– Wireless (approaching
100 Mbps, perhaps
more)
– Optical fiber (currently at
10,000 Mbps and soon
to be more)
Copyright 2003
www.ciscopress.com