5. Original PSTN
UTP
• Manual switching directly connected two local loops
• Due to microphone technology, audio BW was 4 kHz (4000 oscillations per second)
• PSTN is the network
• POTS is the service
UTP
Diaphragm
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
6. Analog switched PSTN
• Invention of tube amplifier enabled long distance
• Between central offices used FDM spaced at 4 kHz (each cable carrying 1
group = 12 channels)
CO CO
Local loop
(analog)
Local loop
(analog)
Telephone
network
(analog)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
7. Data support via voice-grade modems
• To send data, it is converted into 4 kHz audio (modem)
• Data rate is determined by Shannon's capacity theorem (there is a
maximum data rate (bps) called the "capacity”, that can be reliably sent
through the communications channel. The capacity depends on the BW
and SNR)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
9. Digital PSTN, Cont.,
“last mile”CO SWITCH
“last mile”
Subscriber Line
PSTN
CO SWITCH
TDM
TDM
digital
analog
LP filter to 4 kHz at input to CO switch (before A/D)
• Sample 4 kHz audio at 8 kHz (Nyquist)
• Need 8 bits per sample = 64 kbps
• Multiplexing 64 kbps channels leads to higher and higher rates
• Only the subscriber line (local loop) remains analog (too expensive to replace)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
10. Digital Local Loop Technologies
• ISDN
– Voice and Data
– Longer distance
• DSL
– Higher speed
– Several variants
• Different encoding technologies ->
different data transmission rates
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
11. ISDN
• set of communication
standards for
simultaneous digital
transmission of voice,
video, data, and other
network services over
the traditional
circuits of the PSTN
Source: http://www.cisco.com/en/US/docs/ios/dial/configuration/guide/dia_isdn_pri_slt_ps6350_TSD_Products_Configuration_Guide_Chapter.html
Different access interfaces
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
12. DSL technologies
ADSL ANSI T1.413 Issue 2
ITU G.992.1 (G.DMT)
ITU G.992.2 (G.Lite)
ADSL2 ITU G.992.3
ITU G.992.4
ITU G.992.3 Annex J
ITU G.992.3 Annex L
ADSL2+ ITU G.992.5
ITU G.992.5 Annex M
HDSL ITU G.991.1
HDSL2
IDSL
MSDSL
PDSL
RADSL
SDSL
SHDSL ITU G.991.2
UDSL
VDSL ITU G.993.1
VDSL2 ITU G.993.2
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
14. Last (1st) mile connectivity media
Electrical Signal
(Current)
Optical
Signal
(Light)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
26. Legacy NGN
Multiple Control Layers Single Control Layer
Multiple Transport Networks Single Transport Network
Multiple Access Network Multiple Access Network
Multiple Access Connection Single Access Connection
Migration to an IP converged network
Multiple Applications Multiple Applications
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
28. King of England
Scriber
Translator
Negotiator
Manager
Mail room
Envelop
Delivery
King of France
Scriber
Translator
Negotiator
Manager
Mail room
Envelop
Delivery
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
29. Please Do Not Throw Sausage Pizza
Away
User A
Application
Presentation
Session
Transport
Network
Data Link
Physical
User B
Application
Presentation
Session
Transport
Network
Data Link
Physical
Layer 7
Layer 1
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
30. TCP/IP vs. OSI
Source: http://webpage.pace.edu/ms16182p/networking/protocols.html
layer
serves
the layer
above it
and is
served
by the
layer
below it
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
36. Data Link Layer
• provides the functional and procedural
means to transfer data between network
entities and might provide the means to
detect and possibly correct errors that may
occur in the physical layer
• Ex: - ATM, L2TP, IEEE 802.3, Frame
Relay, PPP, X.25
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
37. X.25
• an ITU-T standard protocol suite for
packet switched WAN communication
• X.25 WAN consists of packet-switching
exchange (PSE) nodes as the networking
hardware, and leased lines, plain old
telephone service connections or ISDN
connections as physical links
• replaced by less complex protocols,
especially the IP
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
39. Frame Relay (FR)
• Standardized WAN technology that specifies the
physical and logical link layers of digital
telecommunications channels using a packet switching
methodology
• Network providers commonly implement Frame Relay
for voice (VoFR) and data as an encapsulation
technique, used between LANs over a WAN
• Each end-user gets a private line (or leased line) to a
FR node
• Reason for its popularity:
– Less expensive than leased lines
– Simplicity of configuring user equipment
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
41. ATM
• Defined by ANSI and ITU
standards for carriage of a
complete range of user traffic,
including voice, data, and video
signals
• Uses asynchronous TDM &
encodes data into small, fixed-
sized cells (Differs from
approaches such as the IP or
Ethernet that use variable sized
packets or frames)
• Provides data link layer services
that run over a wide range of OSI
physical Layer links
• Has functional similarity with both
circuit switched networking and
small packet switched networking
Source: http://support.novell.com/techcenter/articles/nc1997_02c.html
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
43. Network Layer
• Responsible for packet forwarding including routing
through intermediate routers
• Provides the functional and procedural means of
transferring variable length data sequences from a
source to a destination host via one or more networks
while maintaining the QoS functions
• Since many networks are partitioned into subnetworks
and connect to other networks for wide-area
communications, networks use specialized hosts,
called gateways or routers to forward packets between
networks
• Ex: -IPv4, IPv6, ARP, ICMP, IPSec, IGMP, IPX,
AppleTalk
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
44. IP
• IP is the primary protocol in the Internet Layer of the
Internet Protocol Suite and has the task of delivering
packets from the source host to the destination host
solely based on the addresses.
• For this purpose, IP defines datagram structures that
encapsulate the data to be delivered
• also defines addressing methods that are used to label
the datagram source and destination
• connectionless
• The first major version of IP, Internet Protocol Version
4 (IPv4), is the dominant protocol of the internet
• successor is Internet Protocol Version 6 (IPv6), which
is increasing in use.
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
49. Transport Layer
• provides E2E communication services for
applications within a layered architecture
of network components and protocols
• provides convenient services such as
connection-oriented data stream support,
reliability, flow control, and multiplexing
• Ex:-TCP UDP
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
50. TCP
• one of the two original components of the suite,
complementing the IP, and therefore the entire suite is
commonly referred to as TCP/IP
• provides reliable, ordered delivery of a stream of
octets from a program on one computer to another
program on another computer
• used by major Internet applications such as the WWW,
email, remote administration and file transfer
• applications, which do not require reliable data stream
service, may use the User Datagram Protocol (UDP),
which provides a datagram service that emphasizes
reduced latency over reliability
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
51. Application Layer
• abstraction layer reserved for
communications protocols and methods
designed for process-to-process
communications across a IP computer
network
• application layer protocols use the underlying
transport layer protocols to establish host-to-
host connections.
• Ex:- DHCP, DHCPv6, DNS, FTP, HTTP, IRC,
MGCP, BGP ,NTP ,POP, RTP, RTSP, RIP,
SIP, SMTP, SNMP, SSH, Telnet, SSL
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
53. 1.Local Area Network (LAN)
2.Wide Area Network (WAN)
3.Metropolitan Area Network (MAN)
Types of Networks
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
54. • Group of computers and network communication
devices interconnected within a geographically
limited area, such as a building
• Characterized by,
• Transfer data at high speeds
• Exist in a limited geographical area
• Resources are managed by the company
running the LAN
LAN
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
56. • Interconnects LANs
• Characterized by,
• Transfer data at low speeds
• Exist in an unlimited geographical area
• Interconnects multiple LANs
• Connectivity and Resources are managed by a
Telephone Company
WAN
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
61. L2 switching vs. L3 routing
• Until the
destination is found
the network is
flooded
• VLAN reduces
unnecessary
flooding
• Does not flood the
network
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
62. • MAC learning table
(forwarding table)
– MAC/VLAN <-> port
• VLAN table
identification/
separation (used for
tagging/un tagging)
– VLAN <-> port
– VLAN is assigned to a
port by the switch. This
is not dynamic. Need
to provision.
L2 switch
Source : http://www.networkmagazineindia.com/200205/primer.shtml
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
63. Functions of a L2 Switch
• MAC learning (populating the MAC/VLAN
table)
• Forwarding (uses MAC/VALN table)
• If a computer does not send traffic (silent),
then all the traffic coming to that computer
come as flooding (the switch learns the
computers MAC by the source MAC)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
64. Broadcasting
• Ex:- server advertises its presence to the
clients
L2 Switch
(flood)
Server (broadcast)
ClientClient
Single
broadcast
domain
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
65. intranets
• A computer network that uses IP
technology to share information,
operational systems, or computing
services within an organization
• Sometimes, refers only to the
organization's internal website, but may be
a more extensive part of the organization's
information technology infrastructure
• May be composed of multiple LANs
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
66. internet
• A network between organizations
• Internet vs. internet
Source: herweightlossdiary.blogspot.com
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
67. extranet
• A computer network that allows controlled access
from the outside, for specific business or
educational purposes
• In a business-to-business context, an extranet can
be viewed as an extension of an organization's
intranet that is extended to users outside the
organization, usually partners, vendors, and
suppliers, in isolation from all other Internet users
• An extranet is similar to a DMZ in that it provides
access to needed services for channel partners,
without granting access to an organization's entire
network
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
70. What Do We Mean By “Ethernet?”
• Ethernet as an interface
• Ethernet as a point-to-point link
IEEE 802.3 view
• Ethernet as a Packet Switched Network (PSN) infrastructure
(transport)
IEEE 802.1 (bridging) view
ITU-T SG15 / SG13 managed Ethernet network view
• Ethernet as a protocol
• Ethernet as a service
MEF view – user-to-user transfer of 802.3 frames over any
transport layer
E-Line, E-LAN, E-Tree, E-Access
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
71. The Basic Ethernet Bus
Thinet coaxial cable
Disconnecting a single connection will bring the whole network down!
Source : http://www.datacottage.com/nch/eoperation.htm
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
72. Using a Hub
• Bus - >Star
• Collisions still possible
• Centralized wiring
• Can automatically bypass any ports that are disconnected or have a cabling fault
• -> network much more fault tolerant than a coax based system
Source : http://www.datacottage.com/nch/eoperation.htm
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
73. Using a Switch
• To overcome the problem of collisions and other effects on network speed
• Machines can transmit simultaneously
Source : http://www.datacottage.com/nch/eoperation.htm
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
76. MPLS
• Traffic is switched
• Control signal is routed (IP/MPLS)
• Mechanism in high-performance telecommunications
networks that directs data from one network node to
the next based on short path labels rather than long
network addresses, avoiding complex lookups in a
routing table
• Labels identify virtual links (paths) between distant
nodes rather than endpoints (LSP)
• Can encapsulate packets of various network protocols
• Supports a range of access technologies, including
T1/E1, ATM, Frame Relay & DSL
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
77. Outer label 1
Ethernet
Inner label
Ethernet
Inner label
Outer label 2
Ethernet
Inner label
Outer label 3
Ethernet
Inner label
Outer label 4
EthernetEthernet
A E
D
C
B
Ethernet Ethernet
MPLS
LDP signaling session (TCP port 646)
RSVP-TE signaling
MPLS operation (carrier Ethernet)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
78. Traffic
Service
Ethernet Service Switch
Physical Network
Ethernet over MPLS over
Ethernet
MPLS
Ethernet
Physical
IP
Ethernet
MPLS or GRE
.1q
GE,10GE etc.
Outer label
Service label=VC label=inner label
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
81. The world of headers
1
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
82. Usage of IP in SP networks (ex:-)
• Networks
– IP/Ethernet
• L3 (IP)
– Core (Private IP + routing +
MPLS)
– Edge (Private IP + routing +
MPLS)
– Aggregation (Private IP +
routing + MPLS)
• L2 (Ethernet)
– Access (Private IP (only for
management ))
– TDM
• No IP
– Management (Private IP)
• Core
• Edge
• Aggregation
• Access
• Services
– IP based
• Private IP (VPN,
IPTV, NGN voice)
• Public IP (Internet)
– Ethernet based
• E-LINE, E-LAN
(customer may use
private IPs)
– TDM based
• PP, IPLC (customer
may use private IPs)
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
83. Service flow scenarios
IP network
TDM Network
IP network
TDM Network
IP Service
IP Service
TDM Service
TDM Service
• Service is routed/switched
• Service end points have IP addresses
• Service is tunneled
• Service end points do NOT have IP addresses
• Service takes a dedicated circuit path
• Service end points have IP addresses
• Service takes a dedicated circuit path
• Service end points do NOT have IP addresses
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU
84. Aggregation of IP traffic over a
packet-optical infrastructure
Aggregation network can be made less complex and given
better performance if the IP functionality is restricted to the
end nodes, i.e. the access nodes and the routers of the core
network.
Source: Transmode
Anuradha Udunuwara | udunuwara@ieee.org | www.linkedin.com/in/anuradhau | @AnuradhU