AppResponse functions by capturing and analyzing network packets to derive performance metrics. It calculates metrics such as Round Trip Time (RTT), TCP Retransmissions, and Server Delay directly from this packet-level analysis. This rich performance data is then exported as Application Flow (AppFlow) records to NetProfiler.

Conversely, Network Device Interface Utilization is a metric typically obtained by polling network infrastructure like routers and switches directly via the Simple Network Management Protocol (SNMP). While NetProfiler can be configured to perform this SNMP polling to gather utilization data, this metric is not generated by AppResponse's packet analysis nor is it forwarded by AppResponse to NetProfiler.

B. Round Trip Time: This is a core network delay metric that AppResponse calculates by measuring the time between TCP SYN and SYN/ACK packets and is a key component of the data it forwards.

C. Retransmissions: AppResponse identifies TCP retransmissions by analyzing packet sequence numbers, providing crucial insight into packet loss and network health, which it reports to NetProfiler.

D. Server Delay: This is a critical application performance metric representing the time a server takes to process a request. AppResponse measures this from packet timings and includes it in the flow data sent to NetProfiler.

1. Riverbed SteelCentral NetProfiler User's Guide: In the section describing data sources, the guide distinguishes between flow data from AppResponse and SNMP data. It states, "AppResponse appliances provide the richest flow data, called Application Flow... Application Flow includes... performance metrics, such as... Network time [RTT], Server time... Retransmission counts." (Reference: SteelCentral NetProfiler 10.9 User's Guide, Chapter 2: "Getting Started," section on "Data Sources").

2. Riverbed SteelCentral AppResponse User's Guide: The documentation details the metrics available through packet analysis. It explains that "AppResponse breaks down end-user response time into contributing sources of delay, including server delay and network delay (round-trip time)." It also describes the monitoring of TCP health metrics like retransmissions. (Reference: SteelCentral AppResponse 11.8 User's Guide, Chapter 1: "Introduction," section on "Key Features").

3. Riverbed Command-Line Interface Reference Manual: The manual's sections on configuring flow export from AppResponse (flow-export) list the specific metrics derived from packets that are included in the AppFlow records. These lists consistently include RTT, server delay, and retransmission-related metrics, but do not include device-specific SNMP metrics like interface utilization. (Reference: Riverbed SteelCentral AppResponse Command-Line Interface Reference Manual, section on flow-export commands).