CCNA Voice Tutorial - DHCP and the IP Phone Boot Process

Just as our switches and routers have selected checks and processes they run once they boot, so do Cisco IP Telephones - but naturally, there's a major change or two involving the Cellphone and router boot procedures!

Here is the basic boot technique for your Cisco IP Cell phone:

As you would count on, the main stage is always to bodily hook up the Cellular phone into a swap port. The Mobile phone can obtain its electricity via Electricity about Ethernet (PoE) in case the Mobile phone and Switch concur around the PoE approach to become employed. At first called "inline power"; Poe let the power of being sent by way of the copper cable from the related machine.

Our previous friend Cisco Discovery Protocol enters the picture now, as its CDP that tells the Phone what Voice VLAN to utilize. Make certain CDP is operating over the swap port which is connected to the IP Cellphone, as its commonplace to disable CDP.

The Telephone now requires an IP address - in fact, an IP Cellular phone will not be considerably excellent without having 1! That handle and other similar information are acquired in a great deal a similar way a "regular" host product does so - via DHCP. The IP Phone sends a DHCP Request, that's forwarded from the router to your DHCP Server.

That forwarding required the router to become configured along with the IP helper-address command; routers tend not to forward broadcasts by default.

From there, the method is much similar to a Computer system receiving an IP handle - the DHCP server responds using the regular Present, as well as Cell phone accepts the primary Provide it gets.

This method isn't really specifically similar to a PC requesting a tackle via DHCP, although. With IP Phones, there's a tiny added solution in DHCP - Possibility one hundred fifty, to become exact. This option tells the IP Cell phone exactly where to uncover the TFTP Server that holds the Phone's configuration file and is particularly a vital element of IP Mobile phone operation.

The Cell phone then contacts that TFTP server and afterwards downloads its configuration file. Through the contents of that config file, the Telephone learns the location of the connect with processing agents it must use, after which you can make an attempt to speak to them during the get through which they are stated in the file.
For anyone who is configuring a Cisco router for a DHCP Server, be sure you permit Option a hundred and fifty - and I will display you just the way to do this during the following CCNA Voice tutorial with this collection in addition as through a video clip accessible via your favorite movie sharing websites!