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VoIP Service Level Monitoring and the iMarc Solution
By
Glenn Jenkins, Director of Product Line Management - Access Products
Verso Technologies
glenn.jenkins@verso.com
The challenge
VoIP deployments are now outpacing traditional voice deployments. The result is a dramatic increase in the number of customers and their networks which are required to support VoIP. Many (if not all) of these networks were architected for data applications which can be tolerant of delay, packet loss, and jitter. VoIP has rigid network requirements for those parameters and any one of them can significantly impact the user’s perceived quality of experience. Voice services have traditionally been very high quality and robust. As a result, users do not expect their voice service to show any degradation or unavailability. The slightest voice degradation will make the user’s quality of experience unsatisfactory. In order to provide service in line with the customer’s expectations, a tool is needed for both pre and post VoIP deployment. This tool, VoIP Service Level Monitoring (VoIP SLM) must have the ability to assess the network’s capability to support VoIP, provide real-time monitoring of jitter, delay, and packet-loss on a per call and site-to-site basis, assist in forecasting potential network problems and help isolate and resolve network problems.
Introducing iMarc
iMarc is ideal for delivering VoIP SLM. First and foremost, the iMarc resides at the demarcation point between the customer and the network. By focusing on automatic provisioning and sophisticated service level management, iMarc is able to cohesively manage an enterprise network beyond the demarcation point, allowing end-to-end network monitoring and the greatest degree of application and service monitoring in the industry. By putting intelligence at the edge of the network, where it is needed most, iMarc solutions enable new services to be deployed faster, existing services to remain reliable, and inactive services to be restored more quickly.
The iMarc VoIP SLM solution consist of 4 levels, which address both pre-deployment and post-deployment issues.
- Pre-deployment - One of the often overlooked and under-funded aspects of any VoIP deployment is the pre-deployment planning of the network. The customer needs to account for many factors to determine the network’s capability to meet the requirements for VoIP along with their particular needs.
- Passive VoIP Readiness Assessment
- Based on Service Level Parameters
- Uses Historical SLV and IP SLM statistics
- Requires some user supplied parameters
- Codecs
- Number of active calls
- Number of fax machines
- Value for network jitter
- Jitter buffer size.
- Calculates # of VoIP calls that can be supported from site-to-site, taking data traffic into account
- Assesses the network’s capability to support VoIP
- Active VoIP Readiness Verification
- Based on Passive VoIP Readiness Assessment & historical SLV statistics
- iMarc can inject simulated RTP streams from site-to-site (iMarc to iMarc)
- Verifies jitter, packet loss, and network delay
- Verifies # of active calls (media streams) that can be supported
- Calculates a theoretical MOS score based on codec, jitter, packet loss, and delay (R-factor)
- Verifies the network’s ability to support VoIP
- Post-deployment - After deployment of VoIP services it is important to continually monitor the network and the customer’s usage of the network to verify SLAs promised by the service provider, to assist in troubleshooting customer complaints, and forecast potential issues.
- Passive VoIP Service Level Monitoring
- Monitors defined VoIP Signaling Protocols
- Correlates phone # and calls to IP addresses and RTP streams
- Parse SDP for codecs, packet size
- Captures call completion, call failures
- Monitors RTP for media statistics
- Gathers codec, jitter, packet loss, and delay information for each call
- Precedence information (TOS bits, DiffServ)
- Transmit statistics indicate customer’s network performance
- Receive statistics compared to remote transmit statistics indicate network performance
- Calculate MOS score (R-Factor)
- Real-time monitoring on a per call and site-to-site basis
- Active VoIP Service Level Monitoring
- iMarc can inject a lightweight RTP stream from site to site to verify network performance
- Removes the customer’s network from the analysis
- iMarc can ping VoIP Servers to verify connectivity
- Forecasts potential network issues
- Helps determine where problems are occurring
Verso's iMarc solutions help reduce customers' operational costs through automation, reliability, security and technological sophistication providing the versatility needed to adapt to changes in network technology as new services and applications are introduced.
Verso’s iMarc solutions consist of a wide range of intelligent access products with advanced diagnostics and Service Level Management features. iMarc is available with DDS, T1/FT1, SDSL, IDSL and G.SHDSL WAN interfaces.
Key benefits include:
- Cost effective intelligent demarcation device with end-to-end QoS for SLA enforcement.
- Reduced Service Turn-Up Time
- Higher Availability and rapid fault isolation
- Easy Integration into Carrier OSS Process and Systems and Enterprise Management Systems
- Ubiquitous Access & Application Support
The iMarc intelligent access devices are available in two feature sets:
- Basic diagnostic feature set provides basic diagnostic capability.
- Service Level Management (SLM) provides basic features, plus reporting and monitoring.
Full Service Level Management (SLM) capability can be activated in units that have the basic diagnostic feature set at any time. This is an optional feature that adds real-time and historical network performance monitoring and SLA (Service Level Agreement) reporting capabilities to your iMarc unit and network.
