Combining Global Load Balancing and Geo-location with Emissary TM

Transcription

1 Combining Global Load Balancing and Geo-location with Emissary TM A New Kind of Global Internet Traffic Management Appliance from Coyote Point Systems and Digital Envoy

2 Establishing a Geo-Sensitive, Highly Available Internet Presence with Coyote Point and Digital Envoy s Emissary For companies transacting business on the Web, two imperatives are in constant tension: on the one hand, enabling ever-more complex interactions and personalized content, and on the other, meeting of everhigher quality-of-service standards. Any product that simultaneously aids personalization and improves site performance has the potential to maximize ROI for the entire site. Tothat end, Coyote Point Systems and Digital Envoyhave partnered todevelop Emissary, the first global load balancing product incorporating state-of-the-art geo-location capability. The new appliance will enable global companies to manage geographically dispersed server farms by routing Internet users according to location with precision and reliability never before possible, speeding access to Web content. In addition, this new appliance will be able to personalize web content based on the geographic location of a user in real-time, without the need for additional equipment. With Emissary, global enterprises with geographically dispersed server farms will be able to: 1. Instantly route Internet traffic to the server farm best able to handle the user request based on best available geo-location/global load balancing technology, providing users quicker access to web content (up to 300% faster downloads) 1 ; 2. Target web content based on the geographic location of the user down to a city-level worldwide, enabling any global enterprise with a web site to: Provide a local look and feel to the user, instantly presenting a user with web content in local language, currency, etc. as well as geo-targeted product offerings Save as much as 20% 2 of the enterprise s bandwidth costs by eliminating downloads of web pages that ask users to choose your location ; and Allow geo-restriction of downloads and content to enable compliance with local laws or contractual obligations 3. On the Web as surely as in the brick-and-mortar world, geography is crucial. The language you speak, the currency you use, the laws under which you live, and the products you are likely to need all depend on your location. Geography is important when opening up a retail store, targeting an ad campaign, or attending a business meeting. Companies establishing a web presence ignore these global realities at their peril one site does not fit all. Emissary Components Emissary will incorporate technology from Coyote Point s Equalizer, an intelligent load balancing appliance; Coyote Point s Envoy, a software plug-in that adds geographic load balancing capability to Equalizer; and Digital Envoy s NetAcuity, software that targets a user s country of origin with 99% accuracy and city of origin with more than 90% accuracy. 4 Coyote Point's Equalizer is a premier high-volume load balancing appliance that can handle route traffic among an unlimited number of clusters, handling millions of connections per hour. As user requests come in, Equalizer makes real-time intelligent decisions about the physical server best able to satisfy each incoming request. Routing decisions are based on multiple factors: capacity, availability, response time, current load, historical performance, and administrative weights. Designed to meet the extreme demands imposed by heavily loaded, mission-critical web sites, the Equalizer can handle over 130,000 HTTP GET operations per minute. The Equalizer can also balance , news, and FTP traffic, supporting "sticky connections" required to efficiently handle Active Server Pages and SSL. UDP enabled, Equalizer works with DNS servers, network-attached storage devices, and WAP devices. Active Content Verification

3 ensures that target applications are fully operational, circumventing failures that might go undetected by other load balancers. For maximum reliability, Equalizers can be deployed in a hot-backup configuration. Coyote Point s Envoy software adds geographic proximity to the load balancing mix. An Envoy-enabled Equalizer routes incoming traffic among the widely-distributed servers, using criteria such as network topology and site availability and performance to determine which server is best equipped to handle the next request. Digital Envoy s NetAcuity incorporates patent-pending technology that enables a website to instantly determine each user s precise global geographic location (country, region and metro area), as well as the user s connection speed all without use of cookies or inaccurate third party databases. Because NetAcuity does not collect any personal information, users can feel secure knowing that their privacy is not being violated when they log on to a NetAcuity-enabled site NetAcuity is run in several of the largest networks on the Internet including AOL Time Warner, Google, Digital Island/Cable & Wireless and 24/7 Media. NetAcuity is the fastest geo-targeting technology available; with latency well under 1 ms How Geo-sensitive Load Balancing Works An Emissary-equipped web site is a geographic server cluster, composed of regional clusters. Each regional cluster is composed of servers that provide a common service, supervised by an Emissary appliance. For example, the web site might be supported by three regional clusters, located in California, New York City, and London. An Emissary load balancer and web servers with similar but geographically differentiated content is deployed at each of these locations. Here's how Emissary routes each client request to the "best" server, avoiding regional clusters and servers that are unavailable or overloaded. When a client browser addresses an HTTP request to this fully-qualified domain name is resolved using Internet standard Domain Name Server (DNS) protocol. A "lookup" query is sent by the client to its local ISP or enterprise DNS [figure 1, step 1]. The local DNS forwards the query to the "authoritative" DNS: in this case, the one responsible for coyotepoint.com [step 2]. The authoritative DNS returns IP addresses for the three Emissary load balancers. The client s DNS repeats the query to one of the Emissary systems, trying other addresses if no response is received [step 3]. In this manner, the first reachable Emissary site receives the client s name resolution request: in our example, New York. Figure 1: DNS Resolution for Geographic Cluster When Emissary receives a client DNS request [figure 2, step 1], it uses configuration data to identify all regional sites for the geographic cluster Geographic probes containing information about the client and the requested URL are sent to Emissary agents at each regional site: the New York Emissary probes itself, California, and London [step 2]. Each agent checks local resource availability and responds with an error if the requested URL is unavailable. If the URL is available, Digital Envoy s RealPath technology determines which server is topologically closest to the requestor based on all available servers. Realpath uses over 20 different methods to determine the physical location of an IP address by

4 creating a dynamic map of Internet connectivity. This dynamic map enables the determination of the location of the end points on the Internet (ie, Visitor location), down to a city level [step 4]. Figure 2: Emissary Probes for Geographic Cluster In our example, the California cluster is selected to handle this request. This site may be selected because it is topographically closest to the client (i.e., has the shortest round-trip time). However, if the requested resource at the California were down or heavily loaded, the request would be handled by New York or London, without any client intervention or awareness. Administrator-defined policies can influence Emissary's decision: for example, a cluster with regional ads might favor proximity over load factors. It is easy to see how Emissary works transparently and adaptively to optimize response time, distribute load across geographically distributed sites, maximize bandwidth utilization, and bypass failures. Deploying Distributed High-Availability Clusters with Emissary Each geographically distributed, high-availability cluster is configured in three easy steps. 1. DNS Configuration: For each geographic cluster to be balanced, the authoritative name server must be configured to delegate (return name server and addresses) to Emissary appliances at every regional site. In our example, the authoritative DNS for coyotepoint.com delegates authority for to east, west, and europe.coyotepoint.com. When any client looks up the authoritative DNS identifies all three Emissaries in its DNS response. 2. Add A Geographic Cluster: Emissary is administered through a graphical user interface. Create a new geographic cluster with the name defined in DNS, then specify geography, load balancing method and responsiveness factor [see figure 3]. The Geography parameters associate a site with specific countries or even cities. Associating a city with a geographic site will direct clients coming from thar city to the associated site. Many cities and/or countries may be associated with a single site. There are four load balancing methods supported by Emissary. Adaptive lets Emissary take all factors into consideration when selecting a regional site. Round Trip emphasizes client proximity, while Site Load gives greater weight to server load measured by Equalizer. Site Weight specifies a static factor that skews request redirection. Weights might be used to implement primary and backup sites, while load optimizes overall server utilization at the expense of client response. Round trip may be appropriate when delivering regionalized content. Emissary also supports five load balancing responsiveness levels, controlling how quickly balancing decisions will be impacted by dynamic changes. Slowest causes probe results to be averaged over a longer period of time, while Fastest causes Emissary to recalculate balancing criteria more frequently. Medium provides rapid response to changing conditions, while smoothing out transient network glitches. Slow and Fast levels are also supported.

5 3. Add Sites To The Geographic Cluster: Finally, use the Emissary GUI to add each regional site to the geographic cluster created in step 2 [see figure 4]. Each site identifies the virtual cluster used to balance requests locally and the resource accessed through this virtual server. A static weight can be used to bias results towards individual resources with greater capacity. One site can be designated as the default for this geographic cluster. In our example, one geographic cluster would be created for [figure 3], and three regional sites would be configured for east, west, and europe.coyotepoint.com [figure 4]. Figure 3: Geographic Cluster Figure 4: Site west.coyotepoint.com Keeping Tabs On Your Internet Presence Of course, any enterprise that is balancing requests for a mission critical resource must have quick, easy, reliable access to status and performance data. Emissary continuously monitors operational statistics for geographic clusters and regional sites within them. Using the Emissary GUI, an administrator can view configured parameters and instantaneous statistics for each regional site, including: Missed: Triangulation Timeouts: Retries: Resource Errors: Returned: Default: Average Time: Resource Load: Emissary probes with no response, indicating network or site failure Emissary agent to client pings with no response Emissary probes that were resent Emissary probes that returned resource unavailable error Client requests directed to this site Client requests directed to the default site for this cluster Average successful client ping response time Calculated instantaneous load supported by this resource Site statistics can help identify network configuration errors -- for example, a large number of triangulation timeouts may indicate an incorrectly configured firewall. Site weights can be tuned to establish desired load distribution, based on the number of requests directed to each site. And key performance metrics like average client response time can be gathered without requiring any further network instrumentation. Both graphical and text views for are available for site statistics. For a quick view of overall performance, plot geographic cluster statistics with a single click [figure 5]. Four overall values are available: Site Summary: Request Rate: Active Requests: Network Latency: Client requests directed to all sites in this cluster Client requests received per minute by this cluster Client requests being routed by Emissary Average triangulation time when at least one site responded

6 Values can be plotted over the past hour, five hours, twelve hours, or day, and the administrator can zoom in on any area of interest for a closer look. With a single glance, administrators can spot performance degradation signaling network or site failure, or see improvements caused by tuning changes or addition of sites or resources. While many other products charge extra for monitoring and performance tools, Coyote Point includes this essential "dashboard" capability at no extra charge.. Figure 5: Keeping Tabs on Your Geographic Cluster Conclusion With Emissary, balancing load across geographically distributed server clusters isn't rocket science, and geographically targeting content on your web site is a snap. Emissary's adaptive load balancing algorithms are easy to understand and configure. Results are easily quantified. Tuning parameters are available for administrators who need them, without the added complexity and cost that can discourage deployment with some other load balancing products. NetAcuity geo-targeting features can be activated directly from Emissary with no additional hardware deployment, customizing content to visitor s geography--increasing sales while decreasing bandwidth usage. Emissary is not only the only true turn-key web site globalization product it s the only load-balancing product that automatically delivers location-specific content. 1 Based on a Digital Envoy customer s actual results running NetAcuity in its content distribution network. 2 Based on typical user patterns and web design. 3 Examples include obeying Federal Encryption Law requirements, on-line gaming restrictions, streaming syndication rights, etc. 4 Based on the results of actual customer testing. Accuracy rates may vary based on the composition of a given site s traffic.