Network-Wide Class of Service (CoS) Management with Route Analytics. Integrated Traffic and Routing Visibility for Effective CoS Delivery

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1 Network-Wide Class of Service (CoS) Management with Route Analytics Integrated Traffic and Routing Visibility for Effective CoS Delivery

2 E x e c u t i v e S u m m a r y Enterprise IT and service providers alike are under pressure to deliver on service-level expectations that have been raised for critical applications by the deployment of different Classes of Service (CoS) in their networks. Unfortunately, due to technological constraints inherent in today s network management approaches, network managers lack the networkwide CoS traffic visibility needed to engineer, operate and plan the network to deliver on those expectations. Today that lack of visibility need no longer be a given. Route analytics technology combined with a small footprint of collected NetFlow data can provide CoS traffic visibility not only to every link in the network, but to the network-wide context of each link s traffic, enabling network managers to get a handle on CoS delivery. The Scalability and Intelligence Limitations of Interface-Centric CoS Traffic Analysis Assigning CoS priorities is a way to ensure proper delivery of sensitive traffic in the essentially unpredictable world of IP networks. The issue with CoS delivery is that, IP's major advantage its distributed routing intelligence means that traffic paths can shift dynamically across various links in the network based on link conditions and network configuration changes. When shifts occur, CoS traffic can exceed thresholds, causing priority packets to be dropped or delayed, negatively impacting sensitive applications and services. As a result, network engineers need to be able to monitor every link s CoS traffic and to understand exactly how (from a routing point of view) traffic is being delivered across the network. Armed with this knowledge, engineers can catch emerging congestion issues and respond based on an understanding of the network s operational architecture. Until now, this sort of visibility has existed only in network engineers dreams. Traffic analysis has been performed either by embedding probes to collect and analyze interface data, or by enabling flow-recording techniques such as NetFlow on router and switch interfaces. While both techniques have greatly increased the knowledge of end-to-end IP traffic-flow delivery compared to simple device counters provided by SNMP polling, they suffer from a major limitation held in common with SNMP: their interface-centric approach. When probes are embedded in a network, they must be deployed against a particular interface s traffic. Likewise, NetFlow is turned on per interface. The huge networks run by enterprises and service providers can have tens of thousands of such interfaces. And while it is theoretically possible to instrument every single interface on the network with NetFlow, the traffic overhead can make this impractical, while trying to deploy such high numbers of hardware probes is so expensive that it simply is not done. The reality is that large networks tend to gather flow information only at so-called key points major WAN links, data centers, Internet peerings and major customer interfaces. Furthermore, even with NetFlow collected from many points in the network, looking at traffic from the point of view of one interface after another often reveals data at too raw a level to 1

3 help network managers deal with an emergent network condition or plan for growth. The current state of CoS traffic management is that the vast majority of network managers responsible for large, complex and redundant IP networks have little or no insight into the state and root-cause issues of CoS delivery in their large core network domains, and no idea at all how their IP network s routing affects traffic delivery. With recent technology developments, this is no longer an acceptable or necessary state of affairs. Route Analytics A Game-Changing Technology for CoS Traffic Analysis A technology called route analytics that has been adopted by hundreds of large enterprises, government agencies and service providers is changing network managers fundamental assumptions about the level of visibility they can have into network-wide CoS traffic delivery. Route analytics is built on the foundation of a different type of network visibility, afforded by tapping into the routing protocols the source of intelligence that determines how IP networks deliver traffic. Route analytics is the technique of acting like a router and peering with select routers across a network using routing protocols OSPF, IS-IS, EIGRP and BGP to record the routing control messages that routers use to calculate how traffic will be sent across the network. By taking this information and processing it just the way routers do albeit in a more comprehensive fashion route analytics creates an analyzable routing topology of the entire network that exactly reflects the way the real network is operating. As a result, route analytics understands every routed path from every host in the network to every other host. Since it records every routing protocol message, route analytics also keeps a complete, replayable history of changes in that routing topology and can be used to accurately simulate the effects of changes to that topology. Engineers find this sort of routing topology information very useful on its own for troubleshooting and network planning. But the implications of route analytics on networkwide CoS traffic analysis extend far beyond these tasks, because of the way the vast majority of traffic is disseminated across the network: From a relatively few major ingress points in major data centers, Internet and network and customer peering points, which constitute a tiny fraction of the networks total number of interfaces. By collecting NetFlow data from these points and then using knowledge of the precise route that every flow takes at any time through the network, route analytics can create a highly accurate, integrated routing and traffic map that shows the volume of CoS traffic on every link in the network. Furthermore, since route analytics understands how every flow gets to every link, it provides the network-wide context for every interface s traffic. For the first time, network engineers can see the big picture the network as a holistic, dynamic organism and immediately grasp the impact of routing changes or failures on traffic (even traffic located many hops away from where a change has occurred). Route analytics provides a number of beneficial capabilities for CoS management: 2

4 CoS monitoring visibility for all links: Route analytics allows network managers to monitor traffic by specific class of service on every network link. Alerts can be sent when service classes go out of profile. CoS traffic problem localization and root-cause analysis: Since network managers know how service traffic gets to a particular link, it's much easier to discern whether out-of-profile CoS conditions are due to routing changes that shift traffic to or from a link, or to new traffic coming into the network at the time the problem occurred. Replayable routing and CoS traffic history. One of the chief problems in troubleshooting application issues is that when the network is suspect, there is often no history to examine to prove or disprove that suspicion or localize the problem domain within the network. Route analytics continuously records routing and traffic so that network engineers can literally rewind the network to look at and even replay past event streams (see Figure 1). This high-fidelity forensic history greatly decreases mean time to repair (MTTR). Figure 1: Route analytics continuously recorded database of all routing and traffic changes can be rewound to look at a particular timeframe when a problem was occurring, providing an unprecedented forensic and troubleshooting history for network engineers. 3

5 Once an engineer has selected a timeframe, the precise routed path of the application traffic can be examined for routing instabilities such as link or prefix flapping, and for outof-profile CoS conditions, as seen in Figure 2. Figure 2: Engineers can select any two endpoint IP addresses and highlight the exact routed path taken by the application traffic in question at the time a problem was occurring in order to narrow down the part of the network that needs to be analyzed. Modeling the impact of network changes and maintenance: Network engineers planning network changes or even performing routine maintenance can simulate various changes to ensure that CoS traffic will stay in profile based on those changes. Since the modeling is done on the actual state of routing and traffic, engineers can have a high degree of confidence in their planning and maintenance operations. For example, before making changes in the network, engineers can simulate those changes in the route analytics network model, then ensure via simulated metric changes that the network will behave as intended after the change is deployed, as shown in Figure 3: 4

6 Figure 3: Route analytics can be used to simulate a variety of network changes, such as adding, downing, and moving routers, links and peerings, as well as tuning of routing metrics. Failure analysis and routing audits for service assurance: Route analytics also allows for simulation of failures on key links and components to let network managers analyze their impact on CoS traffic in the network. In addition, network engineers can run a comprehensive routing audit of the network to reveal suboptimal routing for delay-sensitive traffic such as Equal Cost Multi Paths (ECMPs), asymmetric paths, and links where failures could cause large variations in path lengths, as shown in Figure Packet Design, Inc. 5

7 Figure 4: Comprehensive path reports allow network engineers to examine the health of their routing operations for potential trouble or vulnerability, such as where there is only a single path to important destinations. The Link Between Application Delivery and the Network Infrastructure Simply assigning CoS priorities to critical traffic types such as VoIP or SAP is no guarantee that those priorities will be enforced in complex, redundant IP networks. And when priorities aren't observed, network managers in enterprises are on the line for reduced productivity, and in service provider organizations for failure to meet SLAs. Conventional link- and device-oriented management tools alone can't provide the visibility needed to detect anomalies caused by dynamic IP routing e.g., misconfigured routers, high volumes of new customer traffic that can easily disrupt traffic even when they don't cause any specific link or device to fail. Route analytics technology provides network-wide visibility into traffic flows and related routing dynamics that dramatically increase network 6

8 management visibility into CoS traffic delivery. Complementing other network management solutions, such as application performance management and SNMP device management and fault correlation systems, route analytics provides the Layer 3 network delivery link between end-to-end application performance and the underlying network infrastructure elements. For more information on route analytics technology and solutions, please: us at info@packetdesign.com Visit Packet Design s web site at Call us at Corporate Headquarters Packet Design Inc Augustine Drive Santa Clara, CA Phone: Fax: