A Cost Effective Alternative to CDN Services
The Need for CDN Solutions
In today's complex and media rich Internet environment, the amount of data transferred to end users to power web applications has increased dramatically. Given the highly distributed internet community, this data passes across multiple ISP networks and even international routes, and as a result, severely impacting performance and availability of the website and its applications. As the distance between the user and the web/application server they are accessing increases, there is no guarantee that the necessary bandwidth to carry data between a web/application server and the end user will be available. To overcome this challenge, many organizations turn to Content Distribution Network (CDN) providers who will accelerate the delivery of content by serving the data from servers closest to the end user.
Directional DNS Overview
The Directional DNS service is a powerful solution built on top of NeuStar's industry leading Directory Services Platform. The Directional service utilizes NeuStar's 'Geographic IP' database which contains over 500,000 IP address ranges that are tagged with the geographic region in which they are registered. The platform contains options for every country in the world, all of the United States, and the Canadian Provinces. The 'Geographic IP' database allows the resolver(s) in the Directory Services Platform to determine the location of the source IP address of a DNS query (i.e. the location of the originating recursive server) and a customer can configure Directional records to provide specific DNS responses for the different geographic regions in the database.
The UltraDNS Alternative to a CDN Solution - Directional DNS w/SiteBacker
As an alternative to using a CDN solution, the UltraDNS Directional service enables a customer to utilize their own existing geographically dispersed network of servers to optimize the delivery of content to their end users in the same manner as a CDN. The Directional service allows the customer to choose a specific DNS answer to be given for a record based on the country, US State, or Canadian province of the visitor's source IP address. By incorporating SiteBacker service, customers can monitor the health of each of their content servers and automatically failover to, by routing the traffic to an alternate location. By adding SiteBacker, the customer can utilize their existing data center footprint as a backup in the event of a failure.
Scenario:
The following is a scenario in which a customer uses our services in the same manner as a CDN. James from clothingsite.co.uk wishes to deliver content to his end users while at the same time monitoring the health of his data center and failing over if conditions warrant. Figure 1: Directional DNS Service Configuration for European CDN Alternative captures how Directional DNS Service will be used.
Setting up Directional DNS Service
Clothingsite.co.uk has three data centers across Europe to serve their end users who are predominantly located in Europe. End users' queries will be routed to the topologically closest node in the UltraDNS network (1). The UltraDNS customer configures three master A records pointing at each data center's IP address:
- dc1.mydomain.net targeting the Paris data center
- dc2.mydomain.net targeting the Warsaw data center
- dc3.mydomain.net targeting the Stockholm data center
These will be the master routing records for each data center.
Figure1: Directional DNS Service Configuration for European CDN Alternative
The UltraDNS customer will then create CNAME records for the live web service, adding the Directional DNS service to each CNAME to capture traffic from a particular European country, and then alias them to the master record for that country's preferred data center:
- CNAME www.mydomain.net, tagged with Directional record for Spain and aliased to dc1.mydomain.net will send users to the Paris data center
- CNAME www.mydomain.net, tagged with a Directional record for Ukraine and aliased to dc2.mydomain.net will send users to the Warsaw data center
- CNAME www.mydomain.net, tagged with a Directional record for Finland and aliased to dc3.mydomain.net will send users to the Stockholm data center
By adding CNAME records for each European country, this solution will route the end users to the data center that has been determined to provide them with the best performance. In the example, (2) end users in:
- The yellow shaded Western European countries will receive the IP address for the Paris data center
- The green shaded Eastern European countries will receive the IP address for the Warsaw data center
- The blue shaded Nordic countries will receive the IP address of the Stockholm data center
Note: Another record, tagged with the Directional entry for 'Others', could also be configured to route end users in all other regions to a default data center, for example Paris.
By adding the SiteBacker service to all of the master A records, each data center will be monitored. If a data center experiences a failure (3) its end users are automatically redirected to an alternate data center (4).
A Global Solution
The example solution above can be scaled to create a global distribution of traffic with as many target IP addresses as needed.
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