SSL/TLS session reuse is a feature that allows a client and server to resume a prior session without performing a full, computationally expensive handshake. The initial handshake involves public-key cryptography to establish a shared secret. With session reuse enabled, this shared secret is cached. Subsequent connections can use an abbreviated handshake, which significantly reduces the CPU load on the Citrix ADC. This leads directly to faster connection establishment (improved response time) and allows the appliance to process more SSL connections per second, thereby increasing overall transaction throughput.

A. SSLv3: This is an obsolete and insecure protocol. Enabling it poses a security risk and is not a recommended performance optimization technique.

B. Session timeout: This setting configures the duration for which a session is cached for reuse. It is a parameter of the session reuse feature, not the feature itself.

C. SSLv2 redirect: This is a security feature that redirects clients attempting to use the insecure SSLv2 protocol. It does not improve performance for valid SSL transactions.

1. Citrix ADC 13.1 Product Documentation

"SSL profiles": In the section describing SSL profile parameters

it states for sessionReuse: "State of SSL session reuse. Reusing an existing SSL session is faster than negotiating a new one. Reusing the session saves CPU cycles and improves the server response time." This directly confirms the benefits mentioned in the question.

2. Citrix ADC 13.1 Product Documentation

"Configure SSL session time-out": This document explains the mechanism: "To avoid the overhead of a key exchange for every transaction

the SSL protocol supports session resumption... If the session has not timed out

the ADC and the client perform an abbreviated handshake. If the session has timed out

the client must perform a full handshake..." This clarifies that session reuse is the core feature providing the performance gain.

3. Citrix Tech Zone

"Citrix ADC - SSL Profiles": This reference architecture guide explains

"Session Reuse: Enabled by default. Allows for session resumption

which improves performance by reducing the number of SSL handshakes required." This reinforces that session reuse is the key performance-enhancing feature.