END TO END SERVICE LEVEL MANAGEMENT IN THE CONVERGED WORLD A WHITEPAPER DETAILING WIDE AREA NETWORK CHALLENGES AND OPPORTUNITIES

Transcription

1 END TO END SERVICE LEVEL MANAGEMENT IN THE CONVERGED WORLD A WHITEPAPER DETAILING WIDE AREA NETWORK CHALLENGES AND OPPORTUNITIES TM 995 Old Eagle School Road Suite 315 Wayne, PA USA

2 Table of Contents Executive Summary. The Current State of the WAN Costs of Managing the WAN.. Causes of WAN Downtime... Disaster Recovery... Competition in the Converged Network.. Class and Quality of Service. WAN Architecture An MPLS Overview. MPLS Versus Traditional WAN Technologies.. WAN Management.... Managed End to End Wide Area Networking.... Conclusion and Next Step Considerations.. Glossary of Terms and Acronyms Acknowledgements Scott Kinka Senior Vice President, Network Services Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 2 of 18

3 Executive Summary The Challenges and Realities That Network Managers Face The Wide Area Network (WAN) is an essential component of any multi location businesses strategy, enabling seamless data communications between locations that support the distributed nature of employees and resources. Quite simply, employees require the WAN to do their jobs, and they expect it to be available when called upon without much thought as to what goes into delivering always on connectivity between sites. Built on traditional best effort, circuit or packet switched IP networks, the WAN has historically served a singular purpose reliable bandwidth between locations. However, with the proliferation of VoIP, interoffice voice and video traffic, and integration of delay sensitive and chatty applications like SAP and Citrix, the Quality of IP communication on the WAN has become nearly as important as the amount of available bandwidth and speed of the connection. Increased sensitivity towards disaster recovery has also added additional considerations that traditional WAN technologies such as Frame Relay and Private Line cannot answer without considerable additional expense. As the requirements on the WAN evolve, the job of managing it becomes more complicated. Beyond the physical carrier connections, there are many additional components necessary to deliver these critical applications including: routers, software, VPNs, remote access, PBX s and their various integrators and distributors. Ensuring optimal, interoperable and secure performance among them is no easy task. Couple this with geographically disperse locations to manage, often times limited technical staff, and ever present budget constraints, and IT directors are left with the age old technology requirement of getting more with less. In order to answer the real world challenge of delivering a utility like experience to end users, while upgrading networks to provide for the burgeoning list of applications that are competing for bandwidth, Network managers must address two distinct, but equally important, questions. First, is the network infrastructure (network and equipment) capable of supporting the demands of the enterprise? And second, does the in house staff have the capability to manage and maintain this new infrastructure? The purpose of this paper is to explain the performance and convergence challenges that today s network managers face, and to detail options for answering these challenges through upgraded WAN infrastructure (network and equipment) and through a holistic and proactive approach to WAN management, whether in house or outsourced. Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 3 of 18

4 The Current State of the Wide Area Network (WAN) While convergence may be an emerging challenge for network managers, the challenge of controlling the cost and availability the network has been around as long as the network itself. The following section explains these challenges in more detail. Cost of Managing the WAN Before we address these ways it be helpful to detail the actual cost of WAN Management and any associated downtime. For example, a typical 25 location WAN with legacy technologies could cost $360,000 per year for service and maintenance. Approximately 35 40% of these costs go towards network personnel and administration. Implementation costs could run another $75,000 $100,000 on average (Source: Netsolve). Smaller businesses generally spend an even higher percentage on network maintenance, as they still require personnel to run their network, regardless of how small the WAN may be. Keep in mind that this is just for legacy technologies and not inclusive of VoIP, Video, VPNs, Disaster Recovery, etc. WAN personnel must be knowledgeable and experienced in the configuration, moves/adds/changes (MACs) and management of hardware such as modems, CSUs, routers, and switches, and this requires a reasonable amount of ongoing training. This type of personnel can often be difficult for a smaller organization to retain in house. Causes of WAN Downtime There are 2 types of service interruption: degradation and outage. Degradation occurs when a service is slower than usual, possibly to the point of being useless to end users and outages occur when a service is outright unavailable. The following recent statistics are average and typical among North American firms although your specific situation will vary depending on actual size and industry vertical: WAN Downtime Metrics Service Outage Statistics: Average number of outages per month Average outage duration Total hard downtime per year Average employees affected Service Degradation Statics: Average service degradations per month Average duration per service degradation Average total service degradation time per year Average percent of employees affected 1.7 outages 67 minutes 23 hours 28% of employees 4.4 degradations 47 minutes 41 hours 27% of employees Source: Infonetics Research Leading Causes: Hardware Failures Service Provider Faults Physical Layer Faults Leading Causes: Hardware Failures Traffic Congestion and Competition Service Provider Faults Additional causes of downtime can occur due to: Power outages Configuration errors or changes Hardware or software upgrades Component failure Internal or external scheduled maintenance Acts of nature A study cited by Cisco Press reports that these incidences contribute to downtime at the following rates: 23 percent for router failure caused by software/hardware faults, denial of service attack) 32 percent for link failures (fiber cuts, network congestion) 36 percent for router maintenance (upgrades, configuration errors) The remaining 9 percent for other miscellaneous reasons Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 4 of 18

5 Disaster Recovery In addition to the above standard network management challenges and costs, there has also been an increase in sensitivity towards business continuity and disaster recovery. Increasing regulatory requirements, 9.11 and the various recent natural disasters have led many Network Managers to look for ways to make their WAN infrastructure more resilient. Unfortunately, most traditional WANs are built in a format where a host location houses the central computing power of the organization and/or is the critical WAN connecting point. In the event that the host experiences some form of disaster, the entire organization could be rendered out of business. In order to answer the host site concern, IT managers have begun to replicate the back office of the company at a second location or a disaster recovery center. While this plan ensures the company from the loss of its data asset, it does not account for exactly HOW the remaining active sites on the WAN will communicate with the new host. Re architecting existing WAN structures to account for disaster recovery is expensive with traditional site to site technologies that do not scale well. IT managers are left with completely replicating existing networks around a second host to accomplish the goal, or upgrading to leverage the connectivity benefits of newer technologies. With the goal of secondary connectivity achieved, IT Managers must turn to data virtualization and/or replication tools to keep the secondary site up to date in order to prepare for continuity. These applications add yet another application for the converged network to contend with. Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 5 of 18

6 Competition in the Converged Network In a traditional WAN, data transmission meant simply having enough bandwidth to support the usage on the WAN, whether that usage be file sharing, or enterprise client server applications. As more applications are becoming IP enabled and moved over the WAN (Voice/Video over IP, hosted/network based applications (SaaS), thin and fat client applications), the convergence of competing applications over the network is inevitable and sometimes disruptive. This same point applies to Local Area Networks (LANs). On one hand, this convergence creates many advantages. Businesses have to manage only one network to handle most of their business applications. The costs of equipment and management have been and can be further reduced. Convergence to a single network allows for greater efficiency as the gaps in one application are filled by the bursts in the next. The promise of getting more done with fewer networks can be realized. On the other hand, these applications require different amounts of bandwidth, ebb and flow in wildly different patterns and require that different standards be maintained in order to operate optimally. Careful planning is required to ascertain that the network will and continue to support this traffic. For the promise of convergence to come to fruition, LANs and WANs must be able to classify, prioritize and treat with varying levels of care, the traffic which moves over them. This planning and deployment encompasses all components of the WAN, inclusive of customer premise devices such as routers and switches, in addition to carrier networks. Class and Quality of Service It s Not Just a Bandwidth Issue Because of these new applications, speed and uptime as the measurement of a WAN s effectiveness are quickly being augmented by Class and Quality of Service to more accurately indicate the WAN s ability to meet the needs of the business. As a result, IT managers who are looking to improve the performance of applications on the network are looking at deploying QoS/CoS first and then adding additional bandwidth to the WAN only as a secondary option:... corporations with generally poor application performance over the WAN will find that prioritizing applications by need will significantly improve their performance. Thus, grouping all applications into different classes with different performance levels suitable to each application is often a more costeffective method of increasing overall application performance than simply increasing bandwidth. Gartner Dataquest Getting the Most Out of MPLS Services, 2005 At a more specific level, Class of Service refers to a network s ability to classify and treat traffic differently based on the type of data being transmitted, while Quality of Service applies to the standards that can be placed on the classified traffic. Once data can be classified into groups, it can be prioritized into varying service levels based on the availability of bandwidth. Example: Class of Service Voice and Video over IP, Streaming applications Mission critical applications, E commerce Internet browsing, file transfers Priority Expedited Forwarding Assured Forwarding Default Forwarding (best effort) Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 6 of 18

7 More importantly, once that data is classified and prioritized it can be treated differently based on its need and the end user s expectation of availability. Internet browsing requires a very low Quality of service because it is, at its very nature delay oriented. A user makes a request, that request is transmitted, the server sends back the data and the page is delivered to the user s browser. If there is a slight delay in delivery, it is hardly noticed and even expected by the end user. VoIP, in comparison, requires a significantly higher Quality of service. First, the end user expects a utility like experience with zero delay oriented transmissions. Second, the data itself is transmitted more evenly over greater periods of time (a data stream). As a result, packet loss, latency or jitter (see glossary for definitions) can all greatly affect the quality of the call. By applying different types of Quality of Service (QoS) to the different classes (CoS), greater efficiency and increased quality can be delivered simultaneously over the WAN: Class of Service Priority Quality of Service Voice and Video over IP, Streaming Expedited Forwarding Very low loss, jitter and latency apps Mission critical apps, E commerce Assured Forwarding Low loss, controlled jitter and latency Internet browsing, file transfers Default Forwarding (best effort) Unmanaged Quality Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 7 of 18

8 WAN Architecture In the preceding section of this paper, we discussed the increased application load that traditional WANs face and the importance of establishing Class and Quality of Service in the WAN to support them. The first step towards preparing for the convergence of applications on the network is to select the appropriate underlying architecture. MPLS (short for Multiprotocol Label Switching) is the first carrier class WAN technology to support end to end COS/QOS in the carrier network. The following section provides some high level background on MPLS and compares it to traditional WAN technologies such as Private Line and Frame Relay. An MPLS Overview MPLS (short for Multiprotocol Label Switching): simplifies and improves IP packet exchange. It s a sophisticated tunneling technology that quickly and easily routes traffic to its intended destination. It is traditionally delivered through standard last mile technologies such as T1 or DS3 but Ethernet is quickly becoming more and more available. With MPLS, a short label is added to each IP packet as a shorthand representation of the packet s destination address (header). Subsequent routing decisions (made by Label Switched routers) are made based on the label and not the original IP address, allowing core network routers to operate at higher speeds without having to examine each packet in detail. The label also contains information about how the data should be prioritized (QoS). MPLS combines the intelligence of routing (Layer 3) with the performance of switching (Layer 2). This allows Service Providers to deliver private networks for customers over their core network. In an MPLS network: - Incoming packets are assigned a "label" by an edge router. - Packets are forwarded along a "label switch path (LSP)" where forwarding decisions are based solely on the contents of each label. MPLS enabled platforms understand prioritization bits on the incoming packet and assign the appropriate label for transport through the network - At each hop, the LSR (Label Switch Router) strips off the existing label and applies new label, which tells the next hop how to forward and handle the packet - Label switch paths can be created by platform engineers to: Honor certain performance parameters in network based VPN s Route around network congestion or outages - LSR s use the intelligence of routing and routing protocols for route discovery, route distribution, and bandwidth reservation across the network for meshing and end to end to Quality of Service. This efficiency, however, comes with similar security as traditional WAN services: Most IPsec based VPNs use the public Internet, or one operator's portion of it; most MPLS networks use a dedicated network, where the underlying addressing is not accessible from the Internet or by other enterprises sharing the network. In these circumstances, MPLS can provide security comparable to that achieved using frame relay, without needing encryption. This simplifies the equipment and the management burden. In a dedicated MPLS network, service levels can be higher, multiple service classes can be delivered and denial of service attacks should not be an issue. Internet backbones, even when managed by one operator, are vulnerable to traffic and routing disruption as well as hacking and denial of service attacks. MPLS VPN Services: A Better Frame Relay Gartner, 2005 Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 8 of 18

9 There are a number of ways that service providers can build MPLS into their networks and product offerings. When discussing MPLS strategic advantages, this paper is focusing on network based Layer 3 IP VPNs (over MPLS). This is largely considered an outsourced or managed MPLS offering in that the routing and management happens in the provider network. The result of this engineering is that the provider builds a private network for the customer over its IP infrastructure that this logically separate from other customers networks and the Internet. Benefits of MPLS The ability to use a provider s common network infrastructure combined with the advanced abilities to identify not only destination, but priorities and handling instructions, for every packet, creates distinct advantages for MPLS over other traditional WAN methodologies. Traffic isolation for privacy MPLS separates traffic to ensure privacy between the service provider s customers. MPLS isolates the traffic by containing routes within a separate VRF (virtual route forwarding table) and forwarding the traffic between customer sites based on the VPN label. Enables Class and Quality of Service MPLS allows the Service Provider to assign class of service based on prioritization of traffic and bandwidth reservation in the network. This allows the customer to implement diverse applications in the network without worrying about performance degradation. MPLS is the recommended option for deployment of Voice and Video over IP and delay sensitive applications such as Citrix and SAP. Reduces Network Complexity MPLS reduces network complexity and cost because of its inherently meshed topology. This frees the customer from maintaining complex configurations as the network grows. With MPLS, the hardware can be more basic and less expensive because the service provider delivers the network intelligence. Customers are also able to maintain their existing IP address scheme when migrating from Frame Relay or ATM networks. Disaster Recovery Readiness Because sites on an MPLS VPN are intrinsically fully meshed, the network is natively ready for use in a disaster recovery plan. Any additional site on the WAN can easily operate as a failover site without the time and expense of replicating the network. Data virtualization and replication can easily be protected to ensure instantaneous recovery across the network without interfering with mission critical applications such as VoIP, through the use of Class of Service. Scalability MPLS provides the ability to integrate sites connected via different technologies. For example, a company can integrate a frame relay site into the MPLS network and exchange data. In addition, since the intelligence is being supplied by the network, new sites require a very basic hardware setup and configuration to become part of the meshed network. Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 9 of 18

10 MPLS Versus Traditional WAN Technologies In order to fully understand the strategic advantages of MPLS as the basis for next generation corporate WANs, it is important to distinguish it from traditional WAN methodologies. MPLS vs. IPSec VPN The major difference between MPLS and IPSec VPNs is the underlying network. Most IPSec VPNs use the public Internet as the infrastructure for connectivity while MPLS uses a private dedicated network infrastructure. By using the Internet as the underlying network IPSec VPNs are susceptible to traffic and routing disruptions as well as security issues such as denial of service attacks and hacking. MPLS networks ensure higher service levels, deployment of multiple classes, and reduced security constraints. In addition, MPLS does not require the additional overhead relative to encryption and authentication. IPSEC Advantages Connectionless uses IP routing Secures data through the use of tunneling and encryption protocols Widely available utilizes the public internet for transport Can be network based or premise based IPSEC Disadvantages Often times difficult manage; administrator intensive Additional workload on routers to encrypt/decrypt secure data Does not offer end to end network QoS or CoS Performance routing decisions are made locally Premise based neighbor routes need to be maintained by customer edge equipment Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 10 of 18

11 MPLS vs. Frame Relay A widely deployed WAN technology used to connect LANs at two or more locations, Frame relay uses dedicated local access facilities and private, virtual, long haul circuits to allow both guaranteed bandwidth and the ability to "burst" at higher speeds as network transmission requires. Frame relay is based on the older X.25 packetswitching technology which was designed for transmitting analog data such as voice conversations. Like MPLS, it efficiently uses the provider s network infrastructure and eliminates the need for point to point circuits between locations. Unlike MPLS, it does not control data transmission, as the quality of the data is the responsibility of the edge IP routers. This approach is very complex because it requires mapping between two architectures designed for different functions and requires manual mappings between the edge locations be built and managed on a per connection (as opposed to location) basis. This connection is called a Private Virtual Connection, or PVC. Frame Relay Advantages Widely available Accepted Secure Single interface to network Scales well in hub and spoke environments Relay Disadvantages Connection oriented Fault correction needs to be pre built in the network Link failure on a PVC map will cause outages Does not honor priorities and QoS on packets when they enter the network In mesh and full mesh environments, PVC s can be difficult to manage Additional PVC s can be costly depending on the provider Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 11 of 18

12 Since the MPLS network is IP aware, any to any connectivity is inherent and there is no need for the enterprise to deploy concentration routers to aggregate traffic from branch sites, as is often the case with large frame relay or ATM networks. In fact, for many providers, Frame Relay s days may be numbered: Most providers already are in the process of establishing their strategy for migrating established WAN services onto MPLS and phasing out their legacy WAN network. Most carriers will likely discontinue frame relay and ATM from 2006 through Gartner: It s Time to Migrate to MPLS or Pay the Price for Not Doing So MPLS vs. Private Line Private line is a physical point to point WAN connection between two or more locations that uses private, dedicated, "leased lines" for transmission of data and/or voice traffic at a constant and guaranteed level of bandwidth. Private Line Advantages Widely available Accepted Secure Guaranteed bandwidth; private Private Line Disadvantages Expensive Does not scale well As nodes increase so does the cost of CPE interfaces to support them Need to manage and maintain separate networks for different services Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 12 of 18

13 WAN Management Thusfar, we have established the importance of QoS in the network, and defined MPLS as the preferred carrier technology of choice on which to implement QOS, but this does not complete the picture. While MPLS networks can support COS and QOS, their ability to support the converging needs of the business still depend on the quality and prioritization of the data that is being presented to them for transport, which creates additional requirements on the CPE, or Customer Premise Equipment, namely routers and switches. This brings us full circle to our original discussion about WAN downtime. With only 32% of downtime attributed to physical network issues (as detailed previously in this paper), the majority of WAN downtime falls into process based and human centered "soft" causes. Fortunately, these are often easily prevented by experienced and knowledgeable personnel with systems and software for proactive WAN monitoring and management. Therein lies the biggest challenge, particularly for small and mid sized businesses carrying specialized personnel and software for the singular task of managing the WAN. A quick summary of current requirements and challenges on WAN managers: Increased need for tangible end to end performance Network Availability and QoS Mitigation and elimination of downtime and service degradation Keeping IT staff focused on core and future strategic initiatives to keep business competitive Ability to implement and support next generation products such as Voice/ Video over IP and SaaS Proactive CPE maintenance, troubleshooting and fault resolution Ubiquitous delivery of mission critical, always on applications to end users Increased need for specialized skill sets and tools and subsequent costs Carrier / Access Vendor Management (Uptime, Quality and Service Level Agreement Monitoring) Given these challenges, today s businesses leaders must consider whether or not their organization has the skills to not only manage the WAN, but to do it right and at the right cost while still keeping focused on longer term strategic initiatives. To determine if your organization has the necessary in house expertise to effectively manage your WAN, it can be helpful to ask the following questions: 1. Do we have the time to effectively research, implement and maintain the proper solution? 2. If we have already implemented a solution, how do we know if it is effective? 3. Do we have the in house expertise to analyze our current and future traffic patterns? 4. Do we have the necessary software to manage our WAN equipment and service providers? 5. Do we effectively maintain and proactively report our network health? If the answer to any of these questions is no, then you may want to consider augmenting your IT Staff with a Managed Solution to ensure optimal performance and reduce total cost of ownership. Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 13 of 18

14 Managed End To End Wide Area Networking Selective staff augmentation via a Managed WAN Service allows companies to concentrate on their core competencies while taking advantage of the latest technology and the highest level of service. A managed WAN service should offer your business the following: Expertise and support in emerging technologies such as VoIP Assistance in network design and security Tangible Service Level Agreements (SLAs) for network availability and quality Improved IS performance with lower staffing expenses Monthly reports on key performance and network health Single point of contact one contact for all WAN issues Ongoing maintenance, monitoring, event notification and fault resolution in the event of a disruption Equipment support and replacement Benefits of Deploying Managed WAN Services Generally speaking, a Managed WAN Service Provider will ensure crucial support across four functional areas: Network Monitoring and Critical Event Notification Objective: Continuously monitor all network elements for optimal performance and provide network status and event notification Key Deliverables: Critical Element Monitoring: Network Availability Quality (latency, QoS, Health) CPE statistics (CPU, memory, errors) Critical Event Notification: Network down Element failure Threshold violation (quality/service degradation) Change and Lifecycle Management Objective: Provide proactive network maintenance for optimal performance and continuously support ongoing moves adds and changes for end users and network components Key Deliverables: Network Maintenance: Configuration management Software updates, patches and fixes Security alerts, vulnerabilities and patches Network Support: Moves, adds, changes and deletions (MACD) Inventory management Correct problems before they happen Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 14 of 18

15 Fault Resolution Objective: Provide immediate resolution and restoration in the event of a network outage or service degradation Key Deliverables: Immediate notification of outage Remote troubleshooting and diagnostics Vendor coordination if applicable Repair and restoration Root cause analysis and reporting Disaster recovery and business continuity planning Performance Management Objective: Collect critical network and device data and report network health and performance against key targets Key Deliverables: Data Collection: Device, interface and protocol statistics Network statistics (uptime, QoS, performance) Network traffic Performance Reporting: Performance against SLAs Web view and monthly report Correct problems before they happen Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 15 of 18

16 Conclusion and Next Step Considerations Businesses with multiple locations need to deploy a network that provides the performance and stability needed to support current users while being flexible and performance oriented enough to adapt to next gen applications. Quality sensitive applications are converging over IP networks currently not engineered to maintain acceptable service levels. Businesses are looking for ways to leverage existing WAN infrastructure to build more resiliency into their network. Simply stated: traditional WAN technologies are not suited for next generation, application centric networks. You are most likely deploying, have deployed or thinking of deploying Voice over IP in your organization either in a premise based or hosted PBX environment. Your organization s employees dependence on anytime, anywhere applications is increasing by the day. You may be thinking of deploying a hosted business application or other critical Internet based service. Your current WAN/LAN infrastructure may or may not be scalable and flexible enough to handle these requests. MPLS will enable you to implement the right core WAN infrastructure and can address the business needs of convergence, Class and Quality of Service and Disaster Recovery with price points that are similar to traditional WAN technologies. Once you have the appropriate underlying network in place, businesses must consider exactly how they are managing the network and the premise equipment that connects the network to the business. With additional requirements on the network, come additional skills that are required by in house staff. Outsourced WAN management should be heavily considered by any business without full time staff and software systems dedicated to managing the Network. Businesses with full time staff should consider outsourcing these specialized requirements in order to keep staff focused on strategic initiatives and maintain service levels. Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 16 of 18

17 Glossary of Terms and Acronyms COS Classification of Service. Method of managing traffic by grouping similar types (e.g. voice, video, ). [Source: cnpwireless.com] CPE Customer Premise Equipment: Any equipment located on the customer's side of a demarcation point (the point that distinguishes where the service provider's equipment ends and where the customer's begins.) [Source: voip news.com] CSU/DSU Channel service unit/data service unit. 1. A device used for interfacing data terminal equipment (DTE) to the public telephone network. 2. A type of short haul, synchronous data line driver, usually installed at a user location, that connects user synchronous equipment over a 4 wire circuit at a preset transmission rate to a servicing central office. Note This service can be for a point to point or multipoint operation in a digital data network. [Source: TelecomTerms.com] FEC Forwarding Equivalence Class. An identity for packets that all get routed via MPLS in the same way. [Source: cnpwireless.com] FRAME RELAY An interface protocol for statistically multiplexed packet switched data communications in which (a) variable sized packets (frames) are used that completely enclose the user packets they transport, and (b) transmission rates are usually between 56 kb/s and Mb/s (the T 1 rate). Note 1 In frame relay, (a) there is neither flow control nor an error correction capability, (b) there is information content independence, (c) there is a correspondence only to the ISO Open systems Interconnection Reference Model Layers 1 and 2, (d) variable sized user packets are enclosed in larger packets (frames) that add addressing and verification information, (e) frames may vary in length up to a design limit, usually 1 kilobyte or more, (f) one frame relay packet transports one user packet, (g) implementation of fast packet technology is used for connection oriented frame relay services, and (h) there is a capability to handle time delay insensitive traffic, such as LAN interworking and image transfer. Note 2 Frame relay is referred to as the local management interface (LMI) standard and is specified in ANSI T [Source: TelecomTerms.com] Jitter Abrupt and unwanted variations of one or more signal characteristics, such as the interval between successive pulses, the amplitude of successive cycles, or the frequency or phase of successive cycles. Note 1 Jitter must be specified in qualitative terms (e.g., amplitude, phase, pulse width or pulse position) and in quantitative terms (e.g., average, RMS, or peak to peak). Note 2 The low frequency cutoff for jitter is usually specified at 1 Hz. Contrast with drift, wander. [Source: TelecomTerms.com] LAN LAN is a premises high speed (typically in the range of 10 Mbps to 100 Mbps) data communications system wherein all segments of the transmission medium (typically coaxial cable, twisted pair or optical fiber) are contained within a single location such as a home, campus, or office. [Source: outsideplantsoftware.com] Latency The delay associated with the time it takes a packet to travel from entry point to exit point. [Source: telecombooksblog.com] MPLS Multi Protocol Label Switching. An IP protocol (RFC 3031) designed to provide preferred treatment to priority traffic to achieve a higher QoS. Every packet labeled with the same FEC gets the same treatment. [Source: cnpwireless.com] Packet Loss A problem that occurs when there is congestion at the packet switches or routers. It can considerably degrade real time applications. [Source: telecombooksblog.com] Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 17 of 18

18 Private Line The channel equipment furnished to a customer as a unit for exclusive use, generally with no access to or from the public switched telephone network. Also called leased line. [Source: telecombooksblog.com] PVC Permanent virtual circuit. A defined path that provides essentially a dedicated private line between users in a packet switching network. The network is aware of a fixed association between two stations, permanent logical channel numbers are assigned exclusively to the permanent circuit, and devices do not require permission to transmit to each other. [Source: telecombooksblog.com] QOS Quality of Service. A list of measurable attributes such as bandwidth, delay and jitter that should be met for a specific communications service. [Source: cnpwireless.com] Router Interface between two networks that finds the best route between the two; provides network management capabilities. [Source: telesoft solutions.com] SLA Service Level Agreement. A carrier agrees to provide a certain level of service (e.g. availability, bit rate, voice quality) and provide significant discounts if the levels are not met. [Source: cnpwireless.com] Switch A mechanical or electronic device that opens or closes circuits, completes or breaks an electrical path or selects paths or circuits. Switches with more than two ports are able to route traffic. [Source: telesoft solutions.com] VPN Virtual Private Network: A private communications network usually used within a company or group of companies to communicate over a public network. VPNs are typically encrypted with various grades of cryptography. [Source: voip news.com] WAN Wide Area Network data communications network that extends a LAN outside its geographic area, over common carrier lines, to link other LANs (see LAN). [Source: telesoft solutions.com] Evolve IP 995 Old Eagle School Road Suite 315 Wayne, PA info@evolveip.net Page 18 of 18