CCNA Voice Passed

So I finally finished up my CCNA voice. In hind site I could of had this done months ago. I will say I was disappointed only one simulation and a lot of arbitrary questions.

CCNA Voice Study – Installing CUCME PART 1

CUCME is comprised of multiple files and file types compared to a single unified Bin file like IOS. CUCME is comprised of the following: Basic Files, GUI Files, XME Temple File, Music on Hold (MOH) Files, Script Files, and Miscellaneous Files.

To install CUCME you must first have a matching IOS version to support it such as advanced IP services or advanced enterprise services. See the Cisco download area for the proper IOS version to download to match with the CUCME version you will be installing.

Once the IOS is upgraded issue the following command:
Archive tar /xtract tftp://(ip address)/cme-full-7.0.tar flash:

Replace the details above to your actual release. This will then TFTP the tar file and extract it in real time to the flash storage. Now that all the files are on the router we need to make them accessible to the IP phones for their firmware etc. Issue the following commands:

Tftp-server flash:/phone/7940-7960/P00308000500.bin alias P00308000500.bin

What this is doing is telling the router to share out that Pxxx file via TFTP and also should a device just ask for that file and not provide a full path it will still send it. This is important as the phones will only ask for the file and not the path where that file resides. Do this for all the remaining files in that folder adjusting file names accordingly. You will also need to repeat this process for all the backgrounds, MOH files ect that the phones will need.

Now that the files are served up we need to configure some of the CUCME parameters. The majority of the commands will be issued under the telephony-service configuration mode. Four key things must be configured for the ISR to service IP Phones.

Maximum Number of Phones and DNs
Firmware load files
Source IP address information
Generated configuration files.

Commands are as follows:
Max-ephones (number of phones you’re licensed for)
Max-dn (number of lines, if you had four 2 line phones this would be 8)
Load 7960-7940 (or phone model you’re using) P00308000500
If you don’t know what firmware to use Google CME 7.x and your phone model, there will be a firmware version specified by Cisco.

More to come in part 2.

CCNA Voice Study - Integration Models

PBX- Traditional model, phones all have a unique DN perhaps DIDs. Calls come into a receptionist for direction and users must use an access digit of sorts like 9.

Keyswitch – Model in which all phones have a common lines on all of them. All users can see when a line is in use and intra-office calls are rare.

Hybrid- All phones have common lines in addition to a unique one.

CCNA Voice Study - Licensing Requirements

IOS License – Straight forward the license for the version of IOS you will be running on the ISR.

Feature License – Is the number of phones that the CUCME will be able to support. Think of it as attached to the ISR verses the phone.

Phone User License – Is the actually license for use and operating the phone. Think of it as attached to the phone verses the ISR.

Licenses can be added incrementally so you could buy a 24 phone license and later purchase a 48 phone license for a total of 72 usable phones.

CCNA Voice Study - CUCME Platform Limits

Platform	Number of Phones
1861	8
IAD2430	24
2801	24
3250	10
3270	50
2811	35
2821	50
2851	100
3725	144
3745	192
3825	175
3845	250

CCNA Voice Study - Unified Messaging Platforms

Product	Number of Users	Redundancy Support	E-mail Support	Server or Router Based
Unity Express	Up to 250	No	Relay voice-mail to outside e-mail server	Router
Unity Connection	Up to 7,500	No	Relay voice-mail to outside e-mail server	Server
Unity	Up to 7,500 per server. Expandable to 250,000 with multiple servers.	Yes	Integrates directly with MS Exchange, Lotus Notes, or Novell GroupWise	Server

CCNA Voice Study - Call Processing Platforms

Product	Number of Users	Redundancy Support	Server or Router Bassed
UC500	8 to 48	No	Router
CUCME	Up to 250 depending on router	No	Router
CUCMBE	Up to 500	No	Server
CUCM	30,000 per cluster	Yes	Server

CCNA Voice Study - Cisco VoIP Structure

Much like the OSI model Cisco has a standardized reference model to explain the various components that make up a unified communications system. From top down:

Endpoints – IP Phones, Cell Phones, Video Phone, IM Client aka what the user touches.

Applications – Voice Mail, Conference Call Apps, Call Center Apps, 911 Services aka feature rich services.

Call Processing – CUCM, CUCME, UC500 aka what handles call flow.

Infrastructure – ASA Firewall, Voice Router / Gateway, Voice switch aka what all the above layers need to communicate together.

CCNA Voice Study - PoE

Cisco pre-standard PoE verses 802.3af PoE

Cisco pre-standard PoE Process
1. Device connected to switch.

2. Switch sends a Fast Link Pulse (FLP) tone to the device. Only unpowered Cisco pre-standard PoE device will loop the FLP back to the switch.

3. Switch receives pulse back and applies a minimal amount of power (6.3W) to the line.

4. Unpowered device boots and communicates it’s actual power requirements via CDP.

802.3af PoE Process
1. Device connected to switch.

2. Constant small DC current is applied to line.

3. 802.3af device is equipped with a resistor and will return a specific level of resistance on the line.

4. Depending on level of resistance switch knows how much power to send to the device.

802.3af Power Class	Power Allocated	Actual Power Used
Class 0	15.4W	0.44W to 12.95W
Class 1	4.0W	0.44W to 3.84W
Class 2	7.0W	3.84W to 6.49W
Class 3	15.4W	6.49W to 12.95W

Class 0 devices are designed to be cheap to manufacture basically just requesting that power be sent to them. Too many Class 0 devices can exhaust your switch power supply as all Class 0 devices will be allocated the full 15.4W.

CCNA Voice Study - IP Phone Boot Process

1. Phone connected to Ethernet switch port. Receives power either via 802.3af or Cisco-Proprietary POE.
2. Cisco switch delivers voice VLAN information to the phone via CDP.
3. Phone now in voice VLAN initiates DHCP request. Switch relays this to DHCP server via ip-helper command.
4. DHCP server offers phone IP address including DHCP option 150, better known as TFTP server.
5. Phone initiates a connection with the TFTP server provided in option 150 of the DHCP response and downloads its configuration file. Included in the configuration file is a list of call processing agents such as CUCM Subscriber, CME ISRs.
6. The phone attempts to contact and register with the first call processing agent, if this fails it moves onto the next until the list is exhausted.

CCNA Voice Study

So these are more or less notes for myself, I am starting study for the CCNA Voice exam and will be posting notes here as typing and reading are just two ways to reinforce the knowledge.

Loop start signaling – Is a process in which the end point connects the tip / ring connections together to complete the circuit.

Ground start signaling – A process in which a ground signal is sent to the CO to signal that an outgoing call is going to proceed. Typically used in a PBX.

Glare – When an end user picks up the phone at the same time as an incoming call, occurs with the use of loop start signaling.

Dual-tone multifrequency (DTMF) – The keys on the phone generates two tones a high and a low frequency. AKA tone dialing verses pulse.

Pulse dialing – a process in which the phone quickly connects and disconnects the local loop circuit wires, sending a series of “pulses” to the CO to designate what number is being pressed.

Pulse-amplitude modulation (PAM) – The process of sampling an analog waveform many times to determine numeric electric amplitude values. AKA the sampling process.

Quantization – Assigning numeric values to analog signals so they can be transported over a digital network.

Pulse-code modulation – The process in which the sample (PAM) value is converted into an 8-bit, binary number.

Time-division multiplexing (TDM) – By sending data in specific time slots multiple channels of voice or data can be sent over a single connection.

Channel associated signaling (CAS) – a T1 signaling type that uses a bit from each DS0 channel to send signaling information back to the CO. Also known as Robbed Bit Signaling.

Common channel signaling (CCS) – a T1 signaling type that uses a dedicated DS0 to send signaling information back to the CO.

Robbed Bit Signaling (RBS) – See CAS steals 8th bit on every 6th frame.

Super Frame SF – Sends groups of 12 T1 frames at a time. All bits are used for synchronizing the near and far end T1 equipment.

Extended Super Frame (ESF) – Sends groups of 24 T1 frames at a time. Of the 8000 bits per second 2000 are for synchronization, 2000 for error checking and 4000 for a supervisor channel which is capable of sending control functions and error reporting.

Q.931 – ISDN CSS signaling type.

Local loop – Link between customer premises and the telco provider.

Private Branch Exchange (PBX) – customer equipment that allows them to run a private voice network.

Key system – Allows a company to run a private voice network. Usually smaller than a PBX and provides a shared line appearance. (Some new key systems may provide unique extensions like a PBX)

Signaling System 7 (SS7) – A signaling type used in the telco network to provided inter-CO connectivity and call routing.

E.164 – The ITU standard for telephone numbers and used on the PSTN.