IP Call Center Technology - Call Monitoring and Recording, Trunk Side. by Hoang Lihuo

    Analyzing all of the external interactions with customers, suppliers and other third parties is an important part of IP call center technology.

    Every business will seek to gain a competitive edge from better understanding their customers and acting on insights contained in interactions with them across all channels.

    In addition, agent performance, liability concerns and threat management are matters that require some form of call monitoring and recording for all contact centers.

    There are issues of how this can be technically accomplished in an IP telephony environment.

    Legacy telephone systems had a fairly easy mechanism with which to work. Calls were continuous streams of analog or digital voice, either on the trunk side or the line side of a switch.

    These streams could be recorded either by physically tapping a circuit or port or copying a TDM channel within the switch.

    However, voice over IP transmission is performed using independent voice packets representing snippets of a call interspersed with voice packets from other calls, data packets and signaling packets.

    A physical tap would result in a collection of garbage.

    A few vendors have voice over IP recording systems and they use some technical tricks to monitor and record calls.

    The components involved are call control information translation software, call content recorders, and management and administrative systems. 

    One or more recorders are placed in the contact center network depending upon the size of the network and types of calls that are to be monitored.

    The recorders are programmed to monitor or record certain calls; however, the recorders need to know information about the call packets, the Real Time Protocol packets, that would include end-point addressing and type information at a minimum.

    This signaling level data could come from a CTI server, from direct CTI output from a call control server (this will eventually be replaced by a data application-to-application interface), or it may be gleaned from the call set-up protocol packets, such as SIP packets, as they go by the recorder.

    Once the proper packets are identified for recording, copies are sniffed or snooped (sucked or plucked if you will) off the network into storage.

    Markers and labels are added to the recorded content for later identification, retrieval, or analysis by other programs which are part of the recording system.

    There are several types of monitoring and recording mechanisms, as a way of classifying the activity.

    Passive recording means that automated procedures or programmed procedures are in place to record either all of the calls, bulk recording, or certain calls, selective recording, on a link or part of a network.

    Active recording means a person must initiate the recording process, say an agent who wants to record a threatening or abusive conversation at the moment.

    In addition to these formal types or recoding there are two other variations to mention. One is the tagging, as it is called, of additional information to the recorded call for use in the analysis phase. Tagged information may include things like the application being used at the time of the call or ANI data of the call.

    Recording of calls can also be accomplished in the service provider's network as part of a hosted contact center package.

    This diagram shows one of the common configurations used to record calls.         Incoming and outgoing calls can be recorded by placing the recorder on the trunk side of the IP telephony system.

    Calls relating to the PSTN will traverse a gateway. Calls relating to an IP WAN will traverse an edge router. The recorder will have access to all external calls sitting logically between the ingress gateway or router and the rest of the telephony system – before the calls are shuttled to other parts of the network.

    Physically, this may be accomplished by having the recorder connect to the network through a dumb, three-port hub, which broadcasts all packets to all ports including the recorder. The recorder would need a "promiscuous" network interface card to receive all such packets.

    The recorder is programmed to record all or certain calls whose packets can be identified with Computer-Telephony Interface (CTI) information emanating from the call control server or from the call set-up/transfer signaling (SIP for example) going to and from the gateway or router. The recorder is receiving all traffic through the hub.

    The trunk side attached recorder option is a straight forward solution and can capture the external calls at a good aggregation point in the network. This could include self-service and information-gathering calls that go to the IVR before being passed to an agent.

    This technique is not intrusive and does not consume network bandwidth for the recording process.  If CTI information is not available to the recorder, rich information for tagging will not be available. However, internal calls, such as agent to agent, agent to supervisor, etc. will be missed.

VoIP System Components. by Hoang Lihuo

A VoIP system includes the following basic elements:

• terminals, including IP phones and software applications running on computers;
• LAN infrastructure, consisting of wiring and switches;
• a softswitch or call manager, running a SIP server that acts as a proxy to set up phone calls, manages the terminals, provides registration, authentication and permission management of the phones, plus software applications like call detail record generation, Interactive Voice Response (IVR) and Automated Call Distributor (ACD) functions;
• a router, which connects LAN broadcast domains together and to WAN circuits;
• gateways to perform format conversions between the VoIP world and the PSTN;
• and optional connections to the PSTN, the Internet and to managed IP VPN services and SIP trunking services.
• A firewall is needed when connecting to the Internet. 
• 
  

VoIP Components

• IP phone – In order to send and receive voice calls, IP phones make use of a type of network connection known as Ethernet network connection. An example of IP telephony device is Cisco IP and Cisco 7975G phone on the first picture up here.
• Gateway – A gateway is able to promote calls which take place between various networks. With the help of a gateway you can place a call between your IP phone and your office. You could also place a call to the PSTN to call your home.
• Call agent – Most of the characteristics which were formerly a part of PBX have now been replaced by Call Agents. For instance, to approximately conclude how calls are routed, a call agent can be configured with the help of rules. An example of such a call agent is Cisco UCM (Unified Communication Manager)
• Application server – Application Servers provide on the top services such as voice mail in a VoIP environment.
• Gatekeeper – Gatekeepers can be metaphorically regarded as the traffic police of the WAN. The bandwidth in WAN network is usually not widely available and so, a gatekeeper can keep an eye on the amount of bandwidth which is accessible. And so, if such a situation occurs that the amount of bandwidth is not able to sustain another voice call, then the gatekeeper can reject all trials of such calls in the future.
• Videoconference station – Videoconference stations are devices and/or software (such as Cisco Unified Video Advantage) that allow a calling or called party to view and/or transmit video as part of their telephone conversation.
• Multipoint Control Unit – MCUs have been proved to be helpful when it comes to conference calling. Several people are talking together at the same time during a conference call. And everyone can listen to them. In order to mix these audio streams, it takes processing power to do so. Such a source of processing power is the MCU. MCU can contain DSP (Digital sound processor) which are devoted to the circuitry of the computer that is able to mix these audio streams.
• Voice-enabled switch – A Cisco mechanism switch with voice feature is able to facilitate aligned power to a connected Cisco IP phone, thus there is no need for any outside power source connected to the IP Phone. And a switch with voice feature is able to distinguish between the voice frames which come from the connected IP phone and send those frames to advanced precedence then other frames.
  

Radio Spectrum and Radio Bands. by Hoang Lihuo

 Radio spectrum is the part of the electromagnetic spectrum with frequencies from 30 Hz to 300 GHz.Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU).

   

    Radio band is a small contiguous section of the radio spectrum frequencies, in which channels are usually used or set aside for the same purpose. To prevent interference and allow for efficient use of the radio spectrum, similar services are allocated in bands. For example, broadcasting, mobile radio,

or navigation devices, will be allocated in non-overlapping ranges of frequencies.

    Every country has the sovereign right to manage energy at radio frequencies in its territory.

    When the airspace through which the radio waves travel is public property (which is most of the time), and there is contention for its use (which is all of the time), regulation is required to allow the rational use of the shared resource.

    In the United States, the Federal Communications Commission (FCC) regulates spectrum for use by other than the Federal government.

    Industry Canada, which includes the former Department of Communications, regulates the airwaves in Canada.

Canada, Mexico and the USA coordinate radio frequency usage due to geographic proximity.

    The International Telecommunication Union (ITU) in Geneva facilitates coordination between countries, particularly outside of North America.

    The range of radio frequencies, called the radio spectrum, is divided into blocks of frequencies, allocated for particular different services.

    Allocations are divided into allotments, which are bands of frequencies assigned to specific users or to the public.

    A license to emit radio-frequency energy at the specified frequencies in a specified area is issued by government to record the assignment of the allotment and the conditions for its use.

    The diagram lists some of the bands that are currently in use, beginning with old-fashioned analog AM radio, CB radio and the first generations of in-home analog cordless phones.

    Analog TV channels 2-13, interrupted by a band for analog FM radio is next, followed by the Maritime VHF radio band and the UHF television channels from 14-51.

    The 700-MHz band used to be for UHF channels 52 and up, recently reallocated for new applications including cellular and WiFi-like services.

    Google's involvement in the US auction for allotments in the 700-MHz band in the US caused the inclusion of conditions in the licenses requiring openness: use of any phone and roaming on any carrier.

    The 800-MHz band was initially allocated for the first generation of mobile cellular radio in North America.

    At 900 MHz is an unlicensed band, meaning allocated to the public, and a license to emit energy at that frequency is not required. These bands are also called Industrial, Scientific and Medical (ISM) bands.

    The 900-MHz band was used for cordless phones in North America.

    In the rest of the world (called "Europe" in the telecom business), the 900-MHz and 1800-MHz bands were allocated for second generation mobile called GSM: the Global System for Mobile Communications.

    In North America, the 1900-MHz or 1.9-GHz band was initially allocated for the second generation of cellular, called Personal Communications Services.

    New bands are allocated, and older bands are re-allocated to new 4G and 5G cellular systems on an ongoing basis. These bands lie in the frequencies below 2.4 GHz.

    At 2.4 GHz is another ISM band. This band is used by numerous technologies including Bluetooth, WiFi, cordless phones, private point-to-point transmissions and … microwave ovens, to avoid the need for a license.

    This makes the 2.4 GHz band noisy.

    WiMax, like WiFi on steroids requires a license, typically at 2.5 GHz.

    The 5 GHz ISM band is used for WiFi and point-to-point systems.

    Satellite and other line-of-sight communication systems use frequencies above 5 GHz; but as with everything else, there are tradeoffs.

    It turns out that the capacity, the widths of the bands, is very good at high frequencies, but transmission characteristics like penetration through walls are not so good.

    Lower frequencies experience much better transmission characteristics but have lower capacity.

    The sweet spot appears to be in the range 500 MHz – 2500 MHz with current technologies.

Basic System Architecture by Hoang Lihuo

    System architecture is the conceptual model that defines the structure, behavior, and more views of a system. An architecture description is a formal description and representation of a system, organized in a way that supports reasoning about the structures and behaviors of the system.

System architecture can consist of system components and the sub-systems developed, that will work together to implement the overall system. There have been efforts to formalize languages to describe system architecture, collectively these are called Architecture description languages (ADLs).

    Devices, such as computers, servers, printers, etc., that connect to a local area network (LAN) are normally called stations or terminals . We use both in this course. A wireless access point (AP) is a device connected to a LAN to allow wireless stations to become part of the LAN. It is a transceiver. In a simple case, the AP may only serve one station. Normally, the AP will serve more than one station. In addition, there may be more than one AP connected to a LAN. This provides additional capacity and can serve to cover a large geographic area by placing.

    APs covering the area. APs can stand alone and serve to connect only wireless devices to each other. Normally, however, they are used in conjunction with a wired LAN. A primary use is connection to the public Internet or to a large corporate enterprise network and somewhere these networks get back to wires.

    The range of operations is measured from the AP. For example, the range of 802.11b for 11 Mb/s is about 100 feet. This distance is measured from the AP in all directions and is actually a sphere although most people only think of it as a horizontal circle around the AP. But the AP is a radio transmitter (and receiver) and the transmissions radiate in all directions from the antenna. If the AP is located on the fifth floor of a building, it will radiate around the fifth floor but also radiate up to the sixth and seventh floors as well as down to the fourth and third floors. The penetration of the radio waves through the floors may not be as great as through the walls and the sphere of radiation may be somewhat “squashed” but some radiation up and down will occur. Since most wireless applications connect to a wired LAN or to some other network like the Internet, APs also come integrated into other LAN devices such as bridges or routers.

    Multiple access points covering a geographic area such as a campus or large office complex allow roaming across the area. User stations such as laptop computers with wireless network interface cards (NIC) will communicate with the “nearest” AP. Nearest really means the AP with the greatest signal strength at the point where the user is located, which might not physically be the nearest AP. APs form a LAN segment. Wireless stations vie for use of the wireless media in the same way wired stations vie for use of the wired media. The method specified in 802.11b is called carrier sense multiple access with collision avoidance or CSMA/CA. It is a method similar to CSMA/CD first specified in IEEE 802.3, the 

bus standard for wired LANs. 

How to Use Cellular as Backup Internet Access When Your DSL, Cable or Fiber Internet Dies. by Hoang Lihuo

    The Internet connection at your office dies. Lights on your modem are flashing in a strange pattern. You call the ISP, and they quickly diagnose that the modem power supply has failed, and they will overnight you a replacement. Presumably you are not the first person to have this problem with that modem. 
    So how do you continue to operate while you are waiting for the replacement power supply? It's hard to run your business without e-mail and ordering and administration systems, which are all accessed via the Internet.
     A large business will be a station on a Metropolitan Area Network, which is a ring, meaning two connections to the Internet for that business and automatic reconfiguration in the case of one failing. But this is expensive... the second connection is not free. 
    Small and medium businesses usually have a single DSL or cable modem connection to the Internet. When that fails, connectivity to email, ordering and administration servers is impossible, and many businesses these days would be "dead in the water" until the ISP fixes the problem with their hardware. 
Unless you have an Android smartphone, a good "data" plan and a laptop with WiFi running Windows. 

    The scenario described happened at our office last week. Since many of our customers might find themselves in a similar situation - even at home - I thought I'd share the quick and painless solution I came up with. Even if you're not likely to need this solution, understanding how it works will no doubt sharpen your understanding of the devices involved and their functions. 

    In this tutorial, I will use the technology in our office: 50 Mb/s DSL, Android smartphone and Windows laptop. The solution is equally applicable to an Internet connection using a cable modem or if you are one of the lucky few, an Internet connection via fiber. 

    For the smartphone and laptop, there may be equivalent functions on Apple products, but as I am allergic to Apples, we don't have any in the office.

    The diagram above illustrates the normal network setup in our office, a typical configuration for networking at a small or medium business. On the left is the access circuit to the Internet Service Provider (ISP), terminating on a modem in our office.

    The modem is contained in a box that also includes a computer and an Ethernet switch. This box is more properly called the Customer Edge (CE). The computer in the CE runs many different computer programs performing various functions: Stateful Packet Inspection firewall, DHCP server offering private IP addresses to the computers in-building, DHCP client obtaining a public IP address from the ISP, a Network Address Translation function between the two, routing, port forwarding and more.

    In-building is a collection of desktop computers, servers and network printers. These are connected with Category 5e LAN cables to Gigabit Ethernet LAN switches, one of which is also connected to the CE.

    When a desktop computer is restarted, its DHCP client obtains a private IP address and Domain Name Server (DNS) address from the DHCP server in the CE. The private address of the CE is configured as the "default gateway" for the desktop by Windows.

    When a desktop computer wants to communicate with a server over the Internet, it looks up the server's numeric IP address via the DNS, then creates a packet from the desktop to the Internet server and transmits it to its default gateway, the CE. The NAT function in the CE changes the addresses on the packet to be from the CE to the Internet server and forwards the packet to the ISP via the modem and access circuit. The response from the Internet server is relayed to the CE, where the NAT changes the destination address on the return packet to be the desktop's private address and relays it to the desktop.

    An Android smartphone and a laptop running Windows were used to restore connectivity to the Internet without making any changes to the desktops, servers or network printers.

First, I took my Samsung smartphone running Android out of my pocket and plugged in the charger. Then on its menu under Settings > more > Tethering & portable hotspot > Set up Wi-Fi hotspot, I entered a Network SSID ("TERACOM") and a password, clicked Save, then clicked Portable Wi-Fi hotspot to turn it on.

        The smartphone is now acting as a wireless LAN Access Point, just like any other WiFi AP at Starbucks, in the airport or in your home. At this point, the smartphone is the CE device, performing all of the same functions that the DSL CE device had been before it died: firewall, DHCP client to get a public IP address from the ISP (now via cellular), DHCP server to assign private IP addresses to any clients that wanted to connect (now via WiFi), NAT to translate between the two and router to forward packets.

    Just as the DSL CE equipment "bridged" or connected the DSL modem on the ISP side to the Ethernet LAN in-building, allowing all the devices on the LAN to send and receive packets to/from the Internet via DSL, the smartphone "bridges" or connects the cellular modem on the ISP side to the WiFi wireless Ethernet LAN in-building, allowing all the devices on the wireless LAN to send and receive packets to/from the Internet via cellular radio.

    The remaining problem was that none of the desktops or servers had wireless LAN cards in them, so they could not connect to the smartphone AP and hence the smartphone's cellular Internet connection. What was needed was a device to "bridge" or connect the wired LAN to the wireless LAN in-building.

    By definition, this device would need two LAN interfaces: a physical Ethernet jack to plug into the wired LAN, plus a wireless LAN capability. Looking around the office, I spotted two devices that fit this description.

    One of them was my laptop, with both a LAN jack and wireless LAN. I fired up the laptop, plugged it into an Ethernet switch with a LAN cable, and in the Network and Sharing Center, clicked Change Adapter Settings to get to the Network Connections screen that showed the two LAN interfaces.

    I enabled both the wired and wireless LAN interfaces. Then right-clicking the Wireless Network Connection icon, selected the TERACOM wireless network and entered the password.

    Once that was successfully connected, I selected the two adapters in the Network Connections screen, right-clicked and chose "Bridge Connections". A message saying "Please wait while Windows bridges the connections" appeared, then an icon called "Network Bridge" appeared, and after a few seconds, "TERACOM" appeared as well.

    My laptop was now acting as an Ethernet switch, connecting the wired LAN to the smartphone's wireless LAN.

    Each of the desktops, servers and network printers in the office had to be rebooted so they would run their DHCP client again, obtaining a private IP address and DNS address from the smartphone AP, and be configured so the smartphone was the "default gateway" in Windows.

After rebooting my desktop computer, it had Internet access over the wired LAN, through the wired Ethernet switch to my laptop, to the smartphone via WiFi then to the ISP over cellular. After rebooting the other desktops and servers, all had Internet access again, with no changes to the configuration of the desktops or servers.

    This took about 20 minutes to get up and running, and we were back in business.

Running a bandwidth test on speedtest.net, I found we had exactly 10 Mb/s connection to the Internet via cellular. Obviously my cellular service provider limited the connection to 10 Mb/s in software - but who's complaining? 10 Mb/s is seven times as fast as a T1, which cost $20,000 per month when I first started in this business 20 years ago.

    I hope you found this tutorial useful, either as a template for your own emergency backup Internet connection, or simply as a way of better understanding the devices, their functions and relationships.