By David Le Goff – 6WIND Product Marketing Manager
“Be Always On”
While High Availability (HA) and Carrier Grade class of services were expected as the main requirement for business continuity, service providers are now facing consumer requirements to provide HA and Carrier Grade class of services both for business communications and consumer entertainment.
As consumers strive to be “always connected” or “always on” by rich media and social network applications, their respective service providers have to consider the best reliability over their networks regardless of the applicative context. Service downtime may translate into major risks like the loss of business and revenues, branding degradations, Service Level Agreement (SLA) penalties, and sometimes reaching tens of millions euros (easy to calculate with tens thousands of churn multiplied by 40€ ARPU per month).
Full Data Availability
Given the specifications of any networking equipment, network flow and packet information are extremely important to manage efficient workloads with minimum latency and maximum bandwidth. In the database environment, network information has to be duplicated (at least) twice to secure their availability by synchronizing in near real-time to enable failover systems or disaster recovery solutions in order to provide service continuity.
Besides the hardware reliability expressed in “Mean Time Between Failure” (MTBF) and “Mean Time To Repair” (MTTR), software reliability is handled by rapid convergence of services, data redundancy and non-stop networking services.
In Active/Standby mode in the control planes and Active/Standby or Active/Active modes in fast paths (data plane), the 6WINDGate software maintains coherent protocol information in several instances like ARP/NDP tables, routing tables, IPsec SA/SP tables, connection states of NAT and firewall, as well as, flow information such as ARP hit flags, and IPsec SA sequence numbers.
Figure 1: High Availability Systems
By using the following specific extensions, networking equipment providers can benefit from the ideal environment to build complete HA systems:
- Synchronization daemons for keeping the information consistent between the control plane and the fast paths;
- Daemon Monitoring System, both static and dynamic based on service health checks;
- Graceful Restart, to enable a zero packet loss system, allows for the forwarding of data packets to continue along known routes while the networking information is being restored;
- Export Visibility of the Interfaces with distributed system designed with one control plane and multiple fast paths (data plane) where the control plane accesses all the fast path Ethernet ports in a logical way to enable traffic engineering based on protocols such as Link Aggregation Group (LAG), Equal Cost Multipath Protocol (ECMP) and Virtual Router Redundancy Protocol (VRRP).
Distributed Architecture to design 5×9’s (and beyond) High Availability Systems
Currently, many systems have to be designed in a 3-way configuration to ensure the best availability of information to achieve service continuity. Coupled with the expectation of designing high performance systems, 6WINDGate enables the design of N+ K architectures by mixing active and standby networking nodes, where multiple fast paths (data plane) are managed through a single (redundant) control plane.
6WINDGate has the ability to overcome the challenges of whole system synchronization based on its system daemons and traffic engineering capabilities along with the ability to physically separate control plane from data plane as demonstrated in the diagram below.