Welcome back in this section I'd like to show you the Cisco IP phone start up process and by doing that
explained the infrastructure requirements for Cisco IP phones to function we need to talk about power
the lands IP addressing configurations firmware and so forth which are all required for Cisco IP phones
to function before getting Dolton on a Cisco IP phone.
A sequence of events has to take place and infrastructure needs to be provided for the phone to function.
In this section I'd like to explain phone startup in more detail.
I'd also like to give you more detail on skinny client control protocol or a CCP commonly known as skinny
and session Initiation Protocol or SAP.
So this section assumes that you've been through the introductory sections and you understand what a
codec is.
You have an understanding of the history of voice technologies and a basic foundation to voice.
Now this is an important overview of the phone start up process and I would remember the steps before
troubleshooting in the real world and for study purposes.
I'm going to mention the process in brief now and then in the following slides we're going to dive into
each of these topics in a lot of detail.
The first thing the phone requires is power.
So the phone will obtain power from the switch or from world power or by using misspend power.
So the phone will obtain power from a switch.
For example the phone once it has obtained power will load it's a locally stored image.
This can cause a lot of confusion.
The phone will boot up with the image files stored locally and the configuration that it had previously.
So if a phone has a configuration already it will use that configuration when it boots up.
The switch will then provide the information to the phone using either CD or L-L DP.
Once again I'll discuss those in more detail in upcoming slides.
Once the phone has its Villon it will require an IP address and Wolf for instance get an IP address
from a DHP server.
DHP uses a very special option.
Option one fifty two point the phone to a TFT B server.
The phone will then download its firmware and configuration from a TFT server.
If the locally stored image file or firmware is a different version to the version that it's meant to
use when connecting to a C UCM for example the phone will upgrade its firmware.
It will also download its configuration from the TFT the server will then register using either skinny
or set to the C UCM and then in Skinny's case it will download its soft template.
This EUCOM essentially sends a soft template to the phone using skinny messages.
So that's an overview of the phone start a process.
Let's dive into the details.
I once again what does a phone require to function and the first thing is power.
There are multiple ways to provide power to an IP phone.
The first method is to use a power Q We a local power adapter is used to provide power to the phone.
This would typically be used where power of the ethernet or Peary's not available.
I've just put the pod code for one of the adapters here.
Please check the specifications of the individual handset so that the right power cube is ordered for
a specific handset.
Typically a phone is connected directly to a switch and a PC is connected to the back of the phone.
The phone requires power to operate and this is the first method to provide power to the phone and one
of the most simple methods.
However it does have multiple disadvantages.
If power is lost to the Boulding phones will no longer be able to make and receive calls.
So U.P.S. would be required on each individual power key and that doesn't scale well so these days this
is one of the least used methods.
A second option would be to use a power injector where misspend powers provided to the fine this would
be typically used where a switch does not support power of the Senate.
So the switch is physically connected to a power injector and the power injectors physically connected
to the phone with the power injector providing power to the handset.
So notice here on the back of the power injector there are two ports one to connect back to the switch
and one to connect to the phone.
The power injector would be physically powered from a wall socket.
The advantage of this method is that you do not have to upgrade switches and the power injector would
typically reside in a wiring closet where there may be U.P.S. power in the real world.
This is typically used where you have a single or a small number of phones connected to a switch and
it's less costly to purchase power injectors than it is to replace the entire switch.
The preferred and recommended way to provide power to IP phones and other devices is to use power over
Ethernet.
Historically power of Isa that was used for two main applications IP telephony and $8.2 Lebon wireless
networking IP phones like stented PBX phones require 48 volts of power switches and other devices providing
power unknown as power source equipment or PC devices and the phones are known as powered devices.
Harvey Ethan is provided on 10s of 1 2 3 and 6.
So the same pins used to transmit data that is different to the mid spent power that we discussed previously
which uses pins 4 5 7 and 8.
There are three main types of power of Ethernet.
The first one is the original power over ethernet or P E developed by Cisco many years ago.
This provided 6.3 watts of power to the phones.
Older models of phones that you may encounter like the 79 60 and 70 940 you Ciscos P.O.D. and requies
6.3 watts of power.
The Industry Standard editor two or three A.F. was ratified to provide interoperability between multiple
vendors phones and network equipment.
So you can connect a Nortel phone to a Cisco switch or Cisco phone to an HP switch.
They are different classes of devices and attitude or 3am IP phones fall into what is called Class 3
which provides power at fifteen point four watts.
Since the completion and ratification of the Triple E Ada 2.3 AAF stented the required power consumption
for these devices has begun to extend beyond the level specified in the standard.
Specifically with the introduction of triple E Ada 2.0 11 in wireless technology.
There is now a requirement to provide power above the maximum of fifteen point for what's available
in a row 2.3 standard.
Cisco also has an extension to 8 or 2 or 3 A.F. providing up to 20 watts of power known as power of
it isn't it.
Plus here E-plus was developed because Cisco did not want to wait for the ratification of a two or three
eighty here plus allowed for the immediate implementation of technologies requiring power greater than
fifteen point four watts.
The introduction of networked devices that require more than fifteen point four watts has forced the
Tripoli to develop a new pillowy standard that can deliver even more power than what was defined in
the I triple E attitude or three standard.
The new standard edited at 380.
Also known as P.O.D. Pless is designed to deliver up to 30 watts of power per port.
The two that we can concentrate on in the course of power over the net or P.O.D. and edited or three
A.F. which also goes by the name P.O.D..
Just note the names P.O.D. is often used to refer to Ada 2.3 AEF that an older documentation it refers
to Cisco's proprietary implementation of power of Ethernet.
So just read carefully between the lines to know which power is actually being referenced.
Another advantage of power of the Internet is that the switch can dynamically and automatically discover
whether an IP phone is plugged into a port or whether a PC or other device is plugged into that port
in Cisco's original implementation.
A fast link pulse or if LP was sent down the wire to detect whether a phone was connected or not.
So the switch would send an if all peed on the wire and in its unpowered state the phone would the loop
back.
They fell to the switch if LPs are normally used for speed and duplex negotiation.
So the switch wouldn't normally expect to see it's own.
If OLP return to it.
But in this case the phone does and the switch therefore knows that an IP phone is connected to it and
can provide power down to the handset.
The Industry Standard editor for three A-F uses a different method to detect the presence of an IP phone
in edited or if the power sourcing equipment or switch in this case applies a small current limited
voltage to the cable so a DC voltage is applied to the cable.
We obviously want to make sure that no damage is possible to the equipment that might be present in
an Ethernet system.
So the switches are going to look for a device that complies with the ADA 2.3 specification and thus
applies a DC voltage between the transmit and receive Pais on the Senate cable and then measures the
received current in amps or voltage received the switchy expects to receive a 25 K resistance between
the pays for the device attached to be considered a valid powered device.
In other words the switch is looking for this resistance from the phone or other type of device to ensure
that it's a valid powered device.
If the switch or PC does not detect a valid resistance power is not applied to the port.
But if a power device is discovered power is applied and optionally a powered device specification can
be done.
The PC can then detect what a cold a two or three clauses by default Siska switches the sign phones
or other power devices to close to zero.
None edited or created.
We have clauses 0 1 2 and 3 clause 0 has a maximum power of fifteen point four watts which is the default
clause allocated to a powered device.
The switch in the phone can negotiate the amount of power required.
So for example a 79 41 with 79 61 phone is deemed to be a class 2 device.
And through CTP can negotiate down to 6.3 watts of power 79 65 for example is deemed to be a Class 3
device that's using 15 point four watts of maximum power.
But through CTP can negotiate down to only use 12 watts of power a 79 71 also a close three device who'll
negotiate down to fourteen point nine watts of power.
Now the amount of power required by different phone varies firstly on the phone model as you can see
in this example.
And also the state of the phone as an example is seventy nine seventy one phone in the idle state only
requires nine point one seven watts of power and a maximum power consumption of twelve point to eight
what's phone model and features and use of preferences can increase the power consumption on a fine
point since if it's a color screen versus Gray scale the gigabit ethernet line speed the ring and speakerphone
volume and the illuminated keys such as message waiting light and line buttons for this course you don't
need to know the amount of detail but I just want you to be away in the real world.
Different phones require different amounts of power and that's you need to be careful when specifying
your switches in a real world environment.
Now certain phones in the 80 900 series and 90 900 series are deemed to be close for a day or two or
three devices.
In other words they are eight to 380 devices in certain cases that require more power especially with
the use of external add on devices like a video camera.
Now the power requirements for individual hence a very we're not going to go through a comprehensive
list.
I've mentioned some examples already.
Please refer to the data sheets and other information for details of the power requirements for individual
phones and individual power over the net devices such as access points.
However Glassford devices may require more than fifteen point four watts of power.
For example a Cecka error it quoll 50 series access point requires eighteen point five watts of power
thus exceeding the fifteen point four watts in attitude or three.
If this is required to support Ada 10:58 and we are not going to go through it in this course but there's
a calculator on Cisco's website called The Power calculator which allows you to work out how much power
is required in a specific switch or PC to power a certain number of phones or wireless access points.