BAI613Packet Telephony

Module 6Enterprise IP telephony

Overview

SW-based, call processing piece of Cisco’s AVVID solution Architecture for Voice, Video, and

Integrated Data CCM is the call-routing and signaling

component

AVVID Architecture

IP Soft Phone IP PhoneVideo PC

Client

Cisco UnityCisco IPCC

Applications

CCM

Call Processing

Infrastructure

Router Switch

CCM Fundamentals

Hardware Requirements Cisco has collaborated with both IBM and HP-Compaq

to manufacture the Cisco Media Convergence Servers (MCS) . Now the CCM software can be sold separately without buying the hardware from Cisco

Most are rack-mountable except for the model we use (MCS 7825)

There are currently 4 other models Windows 2000

800 MHz Intel III processor 512 MB RAM 20 GB Fast ATA Hard Drive Maximum of 500 IP phones standalone Server Maximum 2500 IP Phones in a cluster

CCM Functions

Call processing Signaling Device (phone) management Dial Plans Other features

Phone key mappings, etc. IP phones communicate with CCM via

Cisco proprietary “Skinny” protocol IP phones inter-communicate using RTP

W2K Services on Cisco AVVID Telephony Servers

CCM Provides signaling and media control

signaling for up to 2500 devices Cisco IP Voice Media Streaming

Applications Provides H.323 media termination. Music on

Hold, and G.711 media mixing capabilities Cisco MOH Audio Translator

Converts G.711 music source files to G.729a music source files for providing to G.729a capable devices

W2K Services on Cisco AVVID Telephony Servers (cont.)

Cisco RIS Data Collector Collects serviceability information from all cluster

members for improved administrability. Cisco Telephony Call Dispatcher

Allows users such as switchboard attendants to receive and quickly transfer calls to other users; provides automated routing capabilities

Cisco TFTP Provides preregistration information to devices,

including a list of CCM servers with which the devices are permitted to register, firmware loads, and device configuration files

W2K Services on Cisco AVVID Telephony Servers

Database Notification Change notification server and watchdog process that

ensures that all IP telephony applications running on a server are working properly

Publisher Database Serves as the primary read-write data repository for all

IP telephony applications in the cluster. This database replicates updates to all Subscriber databases in the cluster

Subscriber Database Serves as backup read-only database for IP telephony

applications running on the server, should the applications lose connectivity to the Publisher database

Client Devices Supported by CCM Client Devices Supported by CCM

Station Devices Generally IP telephony handsets May also be H.323 clients such as NetMeeting May also be IP softphones

Gateway Devices Provide access from one telephone system to another

CCM to another CCM CCM to a PBX CCM to the PSTN

Typically use H.323 or MGCP

Client Devices Supported by CCM (cont.)

Media Processing Devices Transcoding Resources

Perform codec conversions between devices that do not encode voice conversations using a common encoding scheme

Unicast Conferencing Devices Permit Ad Hoc and Meet-Me conferencing

Media Termination Point (MTP) Resources Allow users to invoke features such as Hold or Transfer

even though one of the endpoints does not support them Music on Hold (MOH) Resources

Provide users access to music sources when they are placed on hold

Understanding how devices use TFTP and DHCP Server

IP Phones need access to a TFTP Server that contains device loads and configuration files

The DHCP Server will automatically direct the devices to the TFTP Server (Option 150 in the DHCP Scope)

If a device has been manually added into the Cisco Call Manager database, the device accesses a configuration file corresponding to its device name.

If auto-registration is enabled in Cisco Call Manager, the phones access a default configuration file from the TFTP server.

Connecting to the Call Manager

After obtaining the configuration file from the TFTP server, a device attempts to make a TCP connection to the highest priority Cisco Call Manager in the list specified in the configuration file. If the device was manually added to the database, Cisco Call Manager identifies the device.

If auto-registration is enabled in Cisco Call Manager, phones that were not manually added to the database attempt to auto-register in the Cisco Call Manager database.

Cisco Call Manager informs devices using .cnf format configuration files of their load ID.

Devices using .xml format configuration files receive the load ID in the

configuration file. If the device load ID differs from the load ID that is currently

executing on the device, the device requests the load associated with the new load ID from the TFTP server and resets itself.

Once a telephone is ready to make a call, it will request an available ringer list from the TFTP server. If the telephone user changes the ring type, the TFTP server sends the new ring type.

Reference: Cisco Call Manager System Guide Version 3.2 from www.cisco.com

AVVID Call Establishment Step 1: Call Signaling

Using the Skinny protocol, the IP phone sends a request to the CCM to originate a call. Request contains address of destination.

CCM locates called party, sends a new call event to to the called device, and waits for called party to respond with answering event

AVVID Call Establishment (cont.) Step 2: Media Control

As called party answers, CCM determines details of media session to be established.

CCM must ensure that both devices can communicate using a common encoding scheme and CCM must provide IP address and port on which called device has chosen to receive data

AVVID Call Establishment (cont.)

Step 3: Media Exchange Once media session is successfully

negotiated, devices communicate through IP network infrastructure using RTP/UDP/IP protocols.

Configuring CCM

Initial CCM Setup DHCP Services must be running on the PC

Start – Programs – Administrative Tools – Services

Double-click DHCP Server Change Startup type: to Automatic and click Apply Click Start and wait until the service has started Click okay to close window Under Services window, DHCP Server should now

indicate Started under Status and Automatic under Startup Type

Close this window

DHCP Setup (cont.)

Start – Programs – Administrative Tools – DHCP

Under the Action menu, select Add Server Click Browse and your server will show up by

name Hi-light your server and click OK Your server will now show up in the DHCP window

An hour-glass will be apparent to the left of the server IP address. Once this disappears, it will be replace by a green arrow indicating your DHCP server is activated

DHCP Setup (cont.)

Hi-light your server, click the Action menu and select New Scope The Welcome to the New Scope Wizard

appears Click next and then enter a scope name

and description (optional) and click next Define your scope range and click next Add your exclusions (your server, default

gateway, etc.), click Add, and then next Configure a lease duration or leave at

default and click next

DHCP Setup (cont.) Leave the default settings on Configure DHCP

Options and click next Add in the address of Default Gateway if one is

present and click next If there is a DNS server, enter it on this page

and click next Same for WINS server, click next Activate scope and click next Click finish to complete the wizard The new scope now appears in your DHCP

window

DHCP Setup (cont.) Option 150 needs to be configured on your

DHCP server in order for the phones to locate the TFTP server The phones download their information via TFTP

from CCM Right-click on you server IP address in the

DHCP window and select Set Predefined Options Click Add and type in Option 150 Enter 150 for Code, IP Address for Data Type and

enter a description (IP Phones). Click OK and OK

DHCP Setup (cont.) Expand your scope and right-click on

Scope Options - select Configure Options Scroll down until you see Option 150. Select it and then enter the IP address of

your server in the box that appears and click OK

Option 150 now appears in the details pane of your DHCP window under Scope Options

Installing Your IP Phones

Pictured below is a screenshot of the initial screen when opening the CCM application Start – Programs – Cisco Call Manager

Upon initial installation of your phones in a CCM environment, it is easiest to auto-register your phones From the menu bar select System – Cisco

CallManager Click on your server name located on the left

side of the screen (server can be indicated by name or IP address)

Installing Your IP Phones (cont.) Your server will be listed either by name or IP

Address Default is Server name

Ensure all you new IP phones and the CCM are plugged into the same network segment

Tab down to or select the Staring Directory Number field Choose a 4-digit number

Tab to the next field entitled Ending Directory Number Choose a new 4-digit number ensuring enough space for all

phones The “Auto-registration disabled” tab changes from selected

to un-selected All phones will now auto-register with the CCM

Lick the Update tab

Installing Your IP Phones (cont.)

Once all the phones have auto-registered and have received all its DHCP information and a directory number, return to this filed and re-select the “Auto-registration disabled” radio button

Leaving this open is a security hole in your network

Configuring Additional Phone Features From the top menu bar select Device

– Phone A screen shot appears entitled “Find and

List Phones” with no phones shown. Click on Find

All phones that were detected by “auto-registration” will be shown

Click on the phone with the lowest DN Name of phone is its MAC address

Configuring Additional Phone Features (cont.)

You will see in screen shot below that Line 2 is not configured

Your job is to configure a DN for Line 2 Click Line 2

This screen shot will appear In the DN field, add another DN Click Insert and then click Configure Device

This will return you to “Phone Configuration” page

Configuring Additional Phone Features (cont.)

The phone will not have the new DN assigned until you click Reset Phone

Click Restart and watch your phone to see what happens and how long it takes

Configuring Additional Phone Features (cont.)

Repeat these steps with your other phones by adding a second DN to each phone but instead of clicking Restart, click Reset

You will notice that Restart is much faster than Reset – 1 second vs. 1 minute

Configuring Additional Phone Features (cont.)

Configuring Forward Busy and Forward No Answer Select Line 1 of each phone

Select Forward Busy and enter in the DN for Line 2 of same phone and click Update

Select Forward No Answer and enter DN for Line 2 of same phone and click Update

Restart the phone and test Line for both instances Note: Forward No Answer forwards the calls

without Line 1 ringing You can change this timer by clicking Configure Device

and scrolling down and enabling Forwarding Delay

Configuring Additional Phone Features (cont.)

Testing Hold / Resume View soft keys immediately below screen Place call from one phone to another and

notice the change in soft keys Place call on hold by pressing Hold soft key

and then off hold by pressing Resume key Using Transfer function

Place call from one phone to another and use Transfer soft key

Configuring Additional Phone Features (cont.)

Configuring Ring Tones Select Settings key on phone (key

indicated by square with check mark) Either use keypad to choose setting or

arrow keys to scroll down to Ring Type Select the Select soft key and test out

each ring type and choose the one you like When phone is ringing use -+ keys to

adjust volume Select Save soft key to save your choice

Configuring Additional Phone Features (cont.)

Changing Button Template From Menu select Device – Phone Button Template Select Default 7960 (this is phone model we are using)

and click Copy Change buttons 3 and 4 to Line Change the template name to BAIST Lab and click insert Return to Device – Phone – Find and choose any phone Under Phone Button Template change this to BAIST Lab Now add new DNs to each of these lines Click Update

Configuring the Voice VLAN By default, when an IP phone is first

configured on a switch, it is part of the VLAN to which the switchport belongs.

You need to configure the switchport to also belong to an auxiliary VLAN for the voice traffic

switch(config-if)#mls qos trust device cisco-phone

switch(config-if)# switchport voice vlan dot1por

switch(config-if)# switchport voice vlan 15

Setting DSCP Value for Voice In the QoS module, you learned to create

class-maps and match these classes to a certain type of traffic Typically ACLs Another way is to match IP Precedence as the IP

phone provides IP Precedence value to the switchport (IP Prec = 5) is to use Class Maps

Switch(config)# class-map match-all GOLDSwitch(config-cmap)# match ip prec 5

Switch(config)# policy-map INBOUNDSwitch(config-pmap)# class GOLDSwitch(config-pmap-c)# set ip dscp 46

Setting DSCP Value for Voice (cont.) There is another way to map the IP Precedence value to DSCP

Enable auto-qos for IP phones on the relevant interfaces

Switch(config)# interface fastethernet interface #Switch(config-if)# auto qos voip cisco-phone

The switch then enables a trust boundary between switchport and IP phone

The switch uses CDP to detect presence of phone The switch automatically generates a CoS-to-QoS

map where IP Precedence level of 5 is mapped to DSCP value of 46 (Expedited Forwarding)

CCM and Voice Gateway IP Telephony gateways enable CCM to

communicate with non-IP devices Gateway control protocols provide the

internal interface between voice gateway and CCM

Inter-cluster trunks will be used to connect remote CCMs across the WAN and will be configured as H.323 gateways

Trunk interfaces specify how gateways interfaces with PSTN or other external devices