Configure Cisco Router as DHCP relay Agent

A DHCP relay agent is any host or IP router that forwards DHCP packets between clients 
and servers.



Note :  Follow below given Picture 
====

note  :   click on image to view  


Here we have  a  DHCP Server   IP  address  (192.168.2.254)

Router   :-

Fastethernet  0/1 --   192.168.2.1            (connected  to  DHcp Server Using Switch  )

Fastethernet  0/0 --   192.168.1.1            


Note :   we need to  setup  two dhcp pooL  in  DHCP server   :


PooL1 :--   FOr  192.168.2.0/24

PooL 2:   For  192.168.1.0/24  

For doing  This check below :


Setting  PooL 1 :  Go to  DHCP server  and click on  COnfig  services dhcp 

Setting  PooL 2:     Go to  DHCP server  and click on  COnfig  services dhcp 

Now   Go to  Router  and SET as DHCP relay  agent  so  that  from  PC 0  from  First  switch  DHCP  broadcast  can reach to dhcp server 


Important :    Go to  Router  fastether 0/0  Interface  

Now  you can go to Client  and click for dhcp IP  request  like given below :

Enjoy  DHcp  Relay  power

Intro About PBX phone system

PBX stands for Private Branch Exchange, which is a private telephone network used within a company or organization. The users of the PBX phone system can communicate within their company or organization and the outside world, using different communication channels like Voice over IP, ISDN or analog. A PBX also allows you to have more phones than physical phone lines (PTSN) and allows free calls between users. It also provides features like transfers, voicemail, call recording, interactive voice menus (IVRs) and ACD call queues.

PBX phone systems are available as Hosted or Virtual solutions (sometimes also called Centrix), and as inhouse solutions to be used on your own hardware.


Some More Terminology :

SIP :  (Session Initiation Protocol)

SIP  is the most widely used protocol in IP telephony. SIP controls how a call is established, how voice data is transferred during the call, as well as the termination of the connection. It can be used for other communication services as well.


How does SIP work :- 

The Session Initiation Protocol is text based and only used for establishing a communication session. The actual data transmission is done by the Transmission Control Protocol (TCP) or the User Datagramm Protocol (UDP) on layer 5 of the OSI model.

The Session Description Protocol SDP controls which of the protocols is used.
SIP is very similar to the Hypertext Transfer Protocol (HTTP), which makes it easy to integrate it into web browsers, applications, services and electronic devices. Since most electronic devices have access to the internet nowadays, it is easy to have them all use the SIP protocol for instant messaging, presence information, file transfer and voice calls.