Enterprises have been successfully running WAN optimization appliances at their many distributed sites for years. The devices have done a good job of helping businesses squeeze as much capacity as possible out of their WAN links and to improve performance across low-bandwidth, long-distance network circuits.
WAN optimizers were a boon to telecom budgets when network bandwidth was particularly pricey. Businesses also have used the devices to prioritize applications that are sensitive to delay and packet loss--particularly when traffic is shuttled among corporate-controlled sites.
However, changes in network traffic patterns and application protocols, the tendency to encrypt data in transit, the emergence of software-defined WAN (SD-WAN) and other factors are all challenging the need for WAN optimization in the edge appliance form factor that IT shops have traditionally deployed.
Shifting Network Landscape
While historically most application requests were directed inward, toward corporate data centers, most are now outbound, toward cloud and Internet locations. As the software as a service (SaaS) computing model continues to gain steam, these trends will only get stronger.
With much of corporate traffic headed toward the cloud, enterprises have little or no control over the far-end site. As a result, it becomes difficult to support a network topology requiring optimization appliances at both ends of the WAN link. Ever try asking Salesforce.com if you could install your own, specially configured WAN optimization appliance in their network? Good luck.
In addition, today’s security schemes can throw a wrench into traditional WAN optimization setups. Nearly all cloud-bound traffic is SSL/TLS-encrypted from the workstation to the cloud using keys that aren’t readily accessible. WAN optimizers can’t see that traffic to shape or treat it, unless the device is brought into the certification path for decryption and re-encryption before delivery. Adding that step introduces a processing burden to the optimization appliance that can impede scalability.
Another change factor is that Internet bandwidth is more plentiful than it was when WAN optimizers came to market, and it’s far more affordable than MPLS capacity. So the requirement to compress data and deduplicate packets to conserve expensive bandwidth, which traditional WAN optimizers are good at, has become less stringent.