User ID Configured User ID
Registration Status Current registration status of the line. Values are Registration Disabled, Registering, Registration Failed, Registered.
Call State Current call state of the line. Values are On-hook, Off-hook.
Caller ID Caller ID value received from the calling party
Remote IP Only available if remote party is using a SIP phone
Packets Sent The number of packets sent for this call.
Packets Received The number of packets received for this call
Bytes Sent The number of bytes sent for this call
Packets Lost The number of packets that were not received during this call
Receive Packet Loss Rate The ratio of packets that were not received during this call expressed as a percentage
Far-End Packet Loss Rate If available, the ratio of packets that were not received by the remote party expressed as a percentage
Receive Interarrival Jitter The jitter experienced during the call expressed in milliseconds.
Far-End Receive Interarrival Jitter The jitter experienced during the call by the remote party expressed in milliseconds.
Round Trip Delay The round trip delay of packets during the call
Codec In User The codec in use for this call.
RTCP
The RTCP tab displays the last two RTCP receive and transmit packets of the last attempted call. This information is usefully in debugging a VoIP issue after the phone call has already completed.
VoIP Log
The VoIP Log tab displays all events related to VoIP activity on the available zNID voice lines.
Figure 152: VoIP Log
Clear Log Empties the log of all entries
Save Log Saves the log to a local computer as a text file
Network-based applications and traffic are growing at a high rate, producing an ever-increasing demand for bandwidth and network capacity. For obvious reasons, bandwidth and capacity cannot be expanded infinitely, requiring that bandwidth-demanding services be delivered over existing infrastructure, without incurring additional, expansive investments. The next logical means of ensuring optimal use of existing resources are Quality of Service (QoS) mechanisms for congestion management and avoidance.
Quality of Service refers to the capability of a network device to provide better service to selected network traffic. This is achieved by shaping the traffic and processing higher priority traffic before lower priority traffic. As Quality of Service is dependent on the “weakest link in the chain”, failure of but a single component along the data path to assure priority packet transmission can easily cause a VoIP call or a Video on Demand
(VoD) broadcast to fail miserably. QoS must therefore obviously be addressed end-to-end.
Figure 153: End-to-end QoS Challenge Areas
The following are the potential bottleneck areas that need be taken into consideration when implementing an end-to-end QoS-enabled service.
The Local Area Network
LANs have finite bandwidth, and are typically limited to 100 Mbps. When given the chance, some applications will consume all available network bandwidth. In business networks, a large number of network-attached devices can lead to congestion. The need for QoS mechanisms is more apparent in wireless LANs (802.11a/b/g), where bandwidth is even more limited (typically no more than 20
Mbps on 802.11g networks).
The Broadband Router
All network traffic passes through and is processed by the broadband router. It is therefore a natural focal point for QoS implementation. Lack of sufficient buffer space, memory or processing power, and poor integration among system components can result in highly undesirable real-time service performance. The only way to assure high quality of service is the use of proper and tightly-integrated router operating system software and
applications, which can most effectively handle multiple real- time services simultaneously.
The Broadband Connection
Typically the most significant bottleneck of the network, this is where the high speed LAN meets limited broadband bandwidth. Special QoS mechanisms must be built into routers to ensure that this sudden drop in connectivity speed is taken into account when prioritizing and transmitting real-time service-related data packets.
The Internet
Internet routers typically have a limited amount of memory and bandwidth available to them, so that congestions may easily occur when links are over-utilized, and routers attempt to queue packets and schedule them for retransmission. One must also consider the fact that while Internet backbone routers take some prioritization into account when making routing decisions, all data packets are treated equally under congested conditions.
The following figure depicts the zNID’s QoS role and architecture in a network. Many of the terms it contains will become familiar as you read on.
Figure 154: The zNID’s QoS Architecture
General
The ‘General’ tab provides a Quality of Service “wizard”, with which you can configure your QoS parameters according to predefined profiles, with just a few clicks. A chosen QoS profile will automatically define QoS rules, which you can view and edit in the rest of the QoS tab screens, described later in this chapter.
Note: Selecting a QoS profile will cause all previous QoS configuration settings to be permanently lost.
Press the QoS button on the sidebar. The ‘Quality of Service’ screen will appear, displaying the ‘General’ Tab.
WAN Devices Bandwidth (Rx/Tx) Before selecting the QoS profile that mostly suits your needs, select your bandwidth from this combo-box. If you do not see an appropriate entry, select ‘User Defined’, and enter your Tx and Rx bandwidths manually.
Tx Bandwidth Enter your Tx bandwidth in Kbits per second.
Rx Bandwidth Enter your Rx bandwidth in Kbits per second.
QoS Profiles Select the profile that mostly suits your bandwidth usage. Each profile entry displays a quote describing what the profile is best used for, and the QoS priority levels granted to each bandwidth consumer in this profile. • Default – No QoS preferences
• P2P User – Peer-to-peer and file sharing applications will receive priority • Triple Play User – VoIP and video streaming will receive priority
• Home Worker – VPN and browsing will receive priority • Gamer – Game-related traffic will receive priority
• Priority By Host – This entry provides the option to configure which computer in your LAN will receive the highest priority and which the lowest. If you have additional computers, they will receive medium priority.
High Priority Host Enter the host name or IP address of the computer to which you would like to grant the highest bandwidth priority.
Low Priority Host Enter the host name or IP address of the computer to which you would like to grant the lowest bandwidth priority.