Wednesday, February 17, 2021

5 Things To Know About Telecom Network

Telecom Network is the one which everyone uses these days, yet not many people know what it is exactly behind the scenes. Many of us have familiar with famous Gs like 2G, 3G, here G represents generation. 2G stands for 2nd generation, 3G for 3rd generation and so on.

1. Gs at network level
When they say 2G, 3G, 4G and 5G, these mainly represent the features of radio network. The backbone network is not called with Gs. However backbone network also changes with each generation of radio network. There is a international body ITU-T which sets the guidelines for upcoming generation. If a given technology meets the criteria then it is qualified to be G of that period.

2. G doesn't mean all network
As each generation (Gs) progress, backbone network also evolves accordingly, however it is not necessarily happen at the same time. Backbone network evolution might take different timeline.
When we say evolution, it means supporting the speed, features with each generation of network offers.

3.
Many might get wondered by the fact that, Mobile network is wireless only till the base station. From the base station, all call and data will be processed on wired/optical network. When a person calls from a cell phone, signals travels to base station via wireless radio network, then base station carries signal over copper cables or optical fiber to switching systems. Switching systems will determine the where call has to be routed to reach the destination user.

4. On the switching network side there will be mainly 2 sub networks, one will cater voice services another will cater internet services. Voice network has altogether different architecture than internet network. This gap is narrowing down now, as most of the services are provided over internet services. Within voice network  there is TDM (Time Division Multiplexing) network and IP network, voice calls could travel through both these networks when you make call.

5. You might be wondered which generation the landline phones belong to. This is a slightly different story, as landlines are not so popular now, there is no rapid changes in this sector. Yet we have a evolution in landlines, which is as follows
      a. POTS (Plain Old Telephony Services) also called PSTN (Public Switched Telephony Network), this offers only voice services.
      b. ISDN (Integrated Services Digital Network), this network offers integrated Voice, Video and Internet services on a subscriber line. Voice and Video conferencing was the major service offered on this network.
      c. VOIP (Voice Over Internet Protocol), VOIP network offers caters wide range of services. VOIP operates on internet protocol which makes it flexible to implement. Through VOIP, it becomes easier to connect. One of the major advantage of VOIP network is, you can login using multiple devices at a time and answer/make call from any device. Even soft phone (software application) can be used. VOIP opens a whole new level of service compared to earlier technologies.

OSI Model


Quick ref table on each layers of OSI Model

✔ Application Layer


Protocol

Transport Port Number

Trasport Protocol used

HTTP

80

TCP/UDP

HTTPs

443

TCP/UDP/SCTP

POP

110

TCP/UDP

SMTP

25

TCP/UDP

FTP - Data

20

TCP/UDP

FTP - Control

21

TCP/UDP/SCTP

SSH

22

TCP/UDP/SCTP

Telnet

23

TCP/UDP

DNS

53

TCP/UDP

DHCP

67,68

TCP/UDP


✔ Presentation Layer 

Protocol

Transport Port Number

Trasport Protocol used

X.25

1998

TCP/UDP

Telnet

23

TCP/UDP

ICA

 

 

LPP

 

 

 

✔ Session Layer 

Protocol

Transport Port Number

Trasport Protocol used

SMPP

2775

TCP/UDP

RTCP

548

TCP/UDP

H.245

 

TCP/UDP

PPTP

1723

TCP/UDP

ZIP

1520

TCP/UDP

SDP

 

TCP/UDP

PAP

 

TCP/UDP


✔ Transport Layer 

Protocol

Important characteristic

PDU Name

TCP

Connection Oriented

Segment

UDP

Connetionless

SCTP

Connection Oriented

RUDP

Connection Oriented

UDP - Lite

Connetionless

Multipath TCP

Connection Oriented

 

✔ Network Layer 

Protocol

Important characteristic

PDU Name

ICMP

Error Reporting

Packet

IGMP

Multicast Group Membership Management

IPSEC

Secure IP network like VPN

RIP

Dynamic IP Routing, Hop count based routing. IGP

OSPF

Link state and link cost based routing

IPv4/IPv6

32 bit address, 128 bit address


✔ Data Link Layer 

 Protocol

Services

PDU Name

HDLC


LLC - Logical Link Control

Error control - ARQ, Flow control

Frame

LLDP



MAC - Medium Access Control

CSMA/CD, LAN switching STP and SPB, MAC addressing, Store and forward, VLAN, QOS

Frame Relay

Encapsulation to frames

PPP

Frame sync

MPLS

 


✔ Physical Layer 

Technologies

PDU Name

OTN

Raw Bits

SDH

SONET