Optimizing encrypted wide area network traffic

A method for distributing WAN optimization between a server and an endpoint, the server and endpoint being located in a subnet of a hub and branch network, the method comprising the steps of:

• storing, in a traffic database on the server, data indicative of traffic observed flowing in to and out of the subnet;
• storing, in a central dictionary store on the server, dictionaries usable by the endpoint to respectively compress and decompress traffic flowing out of and in to the subnet;
• and
• sending data from one of the traffic database or central dictionary store to the endpoint, the endpoint being arranged to compress outbound traffic before being encrypted and further arranged to decompress inbound traffic after being decrypted.

A method performed by devices, including an endpoint and a central server in a subnet of a hub and branch network, to optimize performance of a WAN link between the hub and branch, the method comprising the steps of:

• storing in a database on the central server traffic data representative of traffic flowing in to and out of the subnet;
• caching traffic data in a cache at the endpoint, the cached traffic data being a subset of the traffic data stored in the database;
• periodically refreshing the traffic data in the cache with traffic data from the database;
• and
• optimizing compression and decompression, respectively, of outbound and inbound traffic at the endpoint using the cached traffic data.