CH 2 Unified Communications REVIEW

Question 1

Four types of Cisco Unified Communications

Answer 1

1. Cisco Unified Communications Manager Express (CME)
2. Cisco Unity Express (CUE)
3. Cisco Unified Communications Manager
4. Cisco unity Connection

Question 2

Cisco Unified Communications Manager Express (CME)

Answer 2

• Embeds in router (2800)
• Terminates T1 ports and other ports for VoIP phones (FXO, FXS)
  
  • FXO - foreign exchange office - analog interface type that connects to a CO or PBX system; FXO ports receive dial tine from the attached device.
  • FXS - foreign exchange station - analog interface type that connects to a legacy analog device; FXS ports provide dial tone to the attached device.
• Supports up to 450 phones
• Need product authorization key (PAK) to unlock.

Question 3

CME Features

Answer 3

• Call processing, Device control - handles signaling to endpoints, call routing and termination.
• Configd via CLI or GUI (CCP)
• Local Directory - can house a local database of users you can use for authentication in the IP Telephony Network.
• Computer Telephony Integration support - Integrated with MS Office contacts with Cisco Unified CallConnector. Use Cisco Unified CallConnector to make calls directly from your MS Outlook contact list.
• Trunks to other VoIP systems, such as CUCM cluster of servers. Use CUM for a small 40-user office and have it connect directly over your data network to the corporate HQ supported by a full CUCM cluster of service.
• Direct Integration with CUE - can work with CUE to get voice mail.

Question 4

CME Interaction with Cisco IP Phones

Answer 4

• CME controls virtually every action performed at the Cisco IP phones.
• As the user begins to dial digits, each digit is sent to the CME router via SSCP or SIP.
• Once the user completely dials the phone number of the other Cisco IP phone, CME connects the IP phones directly and steps out of the communication stream.
• The two IP phones now communicate directly using the RTP, which handles the actual audio stream between the devices.

Question 5

The Cisco IP phone to the CME router using either the SSCP or the SIP protocols.

Answer 5

• SSCP –Skinny Client Control Protocol – signaling protocols that allow the CME to communicate with and control an IP phone.
• SIP –Session Initiation Protocol – signaling protocols that allow the CME to communicate with and control an IP phone.

Question 6

CME Benefits

Answer 6

The fact that CME steps out of the middle of the RTP stream and allows the IP phones to communicate directly is fantastic because of two primary reasons:

• It eliminates the CME router as a point of failure. After CME establishes the RTP stream between the IP phones, CME can crash, reboot and the conversation between the two endpoints continues unhindered.
• The CME router does not become a bottleneck for the RTP stream. If the links to the CME router became saturated or the router ran out of resources, RTP packets can drop, causing the call quality to degrade.

Question 7

CME Call Flow for calls to the PSTN

Answer 7

• User of the Cisco IP phone picks up the phone to place a call, all the communication is handled by SSCP or SIP.
• After the user finishes dialing the phone number of the PSTN phone, the CME router realizes (due to its dial-plan) that the all needs to exit out a PSTN-connected interface.
• CME now assumes the role of voice gateway and signals to the PSTN to establish the call on behalf of the Cisco IP phone. (the CME router is attached to the PSTN using a digital T1/E1 or analog FXO trunk.)
  
  • Many VoIP now connect to the PSTN using Internet Telephony Service Provider (ITSP) rather than a traditional TSP using a SIP trunk rather than an analog or digital circuit.
• Once the audio for the call connects, the CME router assumes the role of converting between VoIP audio and PSTN audio.
  
  • Use of DSP at this point.
• The CME router has now established two different legs of the call:
  
  • one to the PSTN
  • the other to the Cisco IP Phone
  • the CME stands in the middle, independently handling signaling from both sides in two different formats.

Note: Unlike the first example, the CME router is now a critical piece of the ongoing RTP audio flow. If it were to fail in the middle of the call, the audio for the call would also fail.

Question 8

Cisco Unity Express (CUE)

Answer 8

• CUE is a voicemail system – Gives us voicemail.
• CME does not have CU by itself.
• You can install into your CME router in one of two form factors:
  
  • CUE AIM
  • CUE NM

Note: ISM and SM are upgrades from the previous AIM and NM.

• Internal Service Module (ISM) – installs internal to the CME router and uses solely flash memory for storage.
• Service Module (SM) – installs externally to the router and uses a hard disk for storage. Because of this, it can hold ten times as much voicemail as the ISM form factor.

Question 9

CUE Modules Chart

Answer 9

• CUE AIM
  
  • 6 ports included
  • 6 ports max
  • 65 max mailboxes
  • 14 hours of storage.
• CUE NM
  
  • 8 ports included
  • 24 ports max
  • 275 mailboxes
  • 300 hours of storage
• ISM
  
  • 2 ports included
  • 10 ports max
  • 100 max mailboxes
  • 60 hours of storage
• SM
  
  • 4 ports included
  • 32 ports max
  • 300 max mailboxes
  • 600 hours of storage

Question 10

CUE Features

Answer 10

• Voicemail
• Auto attendant – dial by name, extension, etc.
• Interactive voice response (IVR) – more features than auto attendant with menu driven options.
• Fax - Native T.37 fax processing, to receive and process faxes as TEFF email attachments.
• Backup voice mail with Unity connection - Survivable Remote Site Voicemail (SRSV)
• Standards-based: All signaling between the CME router and CUE module use the SIP protoco.

Question 11

Cisco Unified Communications Manager (CUCM)

Answer 11

• Current version 8.X
• Runs as a Linux appliance on certified hardware platforms and acts as the powerful call-processing component of the Cisco Unified Communications solution. Think of CUCM as the “director” behind any large org’s Cisco IPT solution.
• It provides the core device control, call routing, permissions, features, and connectivity to outside applications.

Question 12

CUCM Features

Answer 12

• Appliance based – which means the OS is harden (secure) and inaccessible.
• Supports audio and video
• Redundant server cluster – supports redundant servers configured in a cluster relationship.
  
  • Replicates static (directory numbers and route plans) and real-time (dynamic data such as active calls) database
  • Up to 30,000 phones (unsecure mode) and 27,000 (secured mode)
• VMWare – this brings all the high availability and scalability benefits of virtualization to your CUCM deployment.
• Disaster Recovery with SFTP – built-in feature, this service allows you to backup the CUCM database to a network device or over Secure FTP (SFTP)
• Can integrate into a directory structure (Microsoft Active Directory) – CUCM has the capability to be its own directory server to hold user accounts or it can integrate into an existing corporate directory structure like MS AD and pull user account info from there.

Question 13

CUCM Database Replication & Interacting with Cisco IP Phones

Answer 13

• CUCM works in a cluster relationship.
• CUCM server clusters function as multiple, individual servers with their own, unique config working for the common good of the IP phones.
• In CUCM server cluster, there are 8 servers.
• The CUCM cluster relationship includes two types of communication.
  
  • CUCM Database Relationship
  • CUCM Runtime Data

Question 14

CUCM Database Relationship

Answer 14

The CUCM IBM Informix database includes all the “static” data of the cluster (directory numbers, route plan, calling permissions) This data replicates to ALL the servers in the cluster.

Question 15

CUCM Runtime Data

Answer 15

The runtime data encompasses anything that happens in “real-time” in the CUCM cluster. Example, when a device registers with a CUCM server, it communicates to all the other servers that it now “owns” that IP phone.

Question 16

Intracluster Communication Signaling (ICCS)

Answer 16

CUCM uses a method designed specifically by Cisco for this type of communication: Intracluster Communication Signaling (ICCS)

Question 17

CUCM Runtime Data Functionality

Answer 17

• All the servers in the cluster form TCP sessions to each other for ICCS communication via ports 8002 to 8004 when something interesting happens such as phone registering, a call initiation, a call disconnect to inform each other of the event.
• All this ICCS communication takes virtually no additional configuration other than adding CUCM server to the cluster.

Question 18

CUCM Database Relationship Functionality

Answer 18

• The CUCM IBM Informix database uses a one-way replication method where a server known as the Publisher holds the master copy of the database.
• All changes to the database (with some minor exceptions) occur on the Publisher server and replicate to the Subscribers.
• Each CUCM cluster supports a single Publisher and up to eight Subscribers

Question 19

Publisher and Subscriber Servers

Answer 19

Publisher server performs two primary functions:

• maintains the database
• serves TFTP requests. (The TFTP requests come from the Cisco IP phones during their boot process)

Subscriber servers provide: dial tone, receiving digits, routing calls, and streaming music.

Question 20

If the CUCM Publisher has the only writable copy of the database, what happens if it fails?”

Answer 20

If the Publisher fails, the CUCM cluster goes into a type of “locked configuration” mode.

• You can no longer make changes to the database (such as adding a new IP phone, changing the route plan, modifying a music on hold selection, and so on).
• The only exception to this is the user-facing features. These include functions such as forwarding your phone, enabling the message waiting light, pressing the Do Not Disturb button, and many others.
• The CUCM Subscribers are able to write these changes to their local database, replicate them to the other Subscribers in the cluster, and eventually back to the Publisher when you have restored connectivity.
• By allowing the user-facing features to write to the Subscriber database, the users will never know when a Publisher failure has occurred! This capability emerged in CUCM version 5 and beyond. Before this version, a Publisher failure absolutely impacted the user experience.

Question 21

Compare CME and CUCM

Answer 21

• Once you understand the database replication piece of CUCM, the call flow is nearly identical to CME.
• As with CME, the primary CUCM server used by the Cisco IP Phone receives the SCCP or SIP off-hook message and responds appropriately in a stimulus/response fashion until the call is placed.

Question 22

Contrast CME and CUCM

Answer 22

• One difference is that the IP phones can now use redundant servers (as opposed to the single CME router).
  
  • Based on your configuration, a phone can use a list of up to three redundant CUCM servers for failover purposes.
  • If the primary server is down, it uses the secondary. If the secondary is down, it uses the tertiary
• One difference is that the IP phones can now use redundant servers (as opposed to the single CME router).

Question 23

Cisco Unity Connection

Answer 23

• The term “unity” related to messages: voice msgs, email msgs, fax msgs, IM.
• Goal of unity was to make any message retrievable from any voice-enabled device or application.

Question 24

Cisco Voice Messaging Systems Comparsion Chart

Answer 24

• Cisco Unity Express
  
  • 300 Max mailboxes
  • Router platform
  • Rundundancy Not Supported
• CUCM Business Edition
  
  • 500 Max mailboxes
  • Applicance platform
  • Rundundancy Not Supported
• Cisco Unity
  
  • 15,000 Max mailboxes per server
  • Window Server platform
  • Rundundancy Active/Passive (which meant a backup server would sit idle until the primary server failed)
• Cisco Unity Connection
  
  • 20,000 Max mailboxes per server
  • Appliance platform
  • Rundundancy Active/Active (allowing the redundant servers to load balance the mailboxes)

Question 25

Cisco Unity Connections Features

Answer 25

• Microsoft Windows and Exchange Server – can integrate with an existing MS Exchange deployment to enable features such as different call treatment based on your Exchange calendar, email text-to-speech, manage Exchange calendar from a phone.
• Gives voicemail, fax, IM - allows voicemail retrieval from phone, e-mail, web browser, mobile devices, and instant-messenger platforms.
• Up to 20,000 mailboxes.
• Voice Profile for Internet Mial (VPIM) - A feature that allows one voicemail system to exchange messages with another voicemail system.
• Appliance
• Redundancy: Active/Active – uses a Publisher/Subscriber IBM Informix database scheme.
• Works with non-cisco VoIP phones or PBX systems.

Note: CUE and CUCM Enterprise do not provide failover

Question 26

Cisco Unity Connection and CUCM Interaction

Answer 26

• Excludes CUCM Business Edition – Where CUCM and Cisco Unity Connection reside on a single server; Cisco Unity Connection operates independently from CUCM.
  
  • Because it runs independently, you can run Cisco Unity Connections as a voicemail server for other non-Cisco VoIP deployments or PBX systems.
• You have to set up Cisco Unity Connection as an outside system that CUCM can communicate with using the SCCP and SIP.

Question 27

Cisco Unity Connection and CUCM call flow

Answer 27

1. An incoming call from the PSTN arrives at the voice router. The dial-plan on the voice router causes it to route the incoming call to the CUCM server.
2. CUCM receives the call and directs it to the appropriate IP phone (using SCCP or SIP). If someone does not answer the IP phone the call to voicemail, CUCM forwards the call to the preconfigured extension that reaches the Unity Connection Server.
3. CUCM transfer the call (again using SCCP or SIP) to the Unity Connection server. The extension of the originally called phone is contained in the signaling messages, which allows Unity Connection to send the call to the correct voicemail box.
4. After the caller leaves a message on the voicemail server, Cisco Unity Connections then “makes a call” (via SCCP or SIP) back to a Message Waiting Indicator (MWI) extension on the CUCM server.
5. CUCM then lights the voicemail indicator light on the Cisco IP phone, alerting the user that they have a voice mail message.

Question 28

Cisco Unified Presence

Answer 28

• Promotes an awareness of the VoIP and data networks.
  
  • Example, allows IM clients to see the status of a user – available, busy or offline.
• Cisco Unified Presence stretches this capability to the voice network allowing you to see the status of a user: on the phone, off the phone, not available.

Question 29

Cisco Unified Personal Communicator

Answer 29

This single-software application brings together frequently used services in a single location: soft phone, presence, instant messaging, visual voicemail, employee directory, communication history, video, and web conferencing.

• you can start both voice and video calls with video resolutions able to reach High Definition (HD) quality.
• Acts as a full softphone, allowing audio only calls from other audio devices (IP phones, softphones, and so on) in the network.