Citrix HDX Adaptive Transport and EDT: ICA’s New Default Transport Protocol – Part II
In Part 1, we talked about why EDT was needed, as well as its main features. In Part II, which I am co-authoring with our HDX Product Manager Fernando Klurfan, we would like to switch gears and explain the configuration aspects of the protocol.
Even though we are turning HDX Adaptive Transport to Preferred by default in our next XenApp/XenDesktop Q4 release, there are a few details you need to be aware of.
Common Gateway Protocol (CGP)
In the figure below you will notice that the TCP and UDP stacks share one common component: Common Gateway Protocol (CGP).
Our old friend CGP has been with us since the days of Citrix Secure Gateway and Citrix Presentation Server. CGP is a general-purpose tunneling protocol with its own handshake and commands. CGP is the protocol upon which Session Reliability — “session recoverability” in case of broken transport — is built, but is more than just that.
CGP is also used as an authorization protocol via NetScaler: it carries the Secure Ticket Authority (STA) ticket. CGP is also critical for supporting High Availability failover from one Gateway instance to another.
Therefore, CGP is required for EDT connections via NetScaler Gateway. But CGP is optional on direct EDT connections between Receiver and VDA, e.g. corporate MPLS. So, if you have a NetScaler Gateway, EDT requires Session Reliability Policy to be enabled, which, in turn, enables CGP (since currently CGP and Session Reliability are coupled).
Read the entire article here, HDX Adaptive Transport and EDT: ICA’s New Default Transport Protocol (Part II)
Via the fine folks at Citrix Systems, Inc.