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Upstream Spectrum Sessions
Last Updated: July 07, 2026

Upstream spectrum sessions are a desktop triage tool, providing analysis of return path issues to troubleshoot ingress noise and mitigate identified problems. You can perform a full band capture on an upstream channel by executing a quick analysis in a 5-10 minute session, or analyze longer periods, measured in hours.

Sessions track the following metrics for each frequency bucket:

  • Max power
  • Average power
  • A histogram of power in 0.1 dB increments

The metric data is refreshed at the highest rate available. The data is saved at fixed intervals.

Upstream Spectrum Sessions expand on the functionality of Upstream Spectrum Analysis. With an Upstream Spectrum Session, you have the following advantages over an on demand capture:

  • Data is collected for the specified time period, even if you navigate away from the page. This differs from the on demand capture that stops when you navigate away from the analysis page.
  • Data collected during an Upstream Spectrum Session can be shared. Multiple users can observe an on-going or completed session. This differs from on demand where only one user can analyze the data.
  • Data collected during an Upstream Spectrum Session is retained according to your data retention policy. You can capture data and return to analyze it at a later time.
NOTE:Upstream Spectrum Sessions does not support Static Pseudowire mode. It is only supported in live Upstream Spectrum Analyzer.

Upstream Spectrum Sessions appear as an additional tab in the Upstream Spectrum Analyzer application. Spectrum sessions save the data collected during spectrum analysis.

Session configuration

Configuration parameters for Upstream Spectrum Sessions are set at on a per tenant basis. You can configure the following:

  • Maximum duration of a session. The upper limit and default is 6 hours.
  • Maximum number of concurrent sessions. The upper limit and maximum is 30.

    Additional NXT engine resources and data node disk storage are required to increase this limit, please contact CommScope support for more information.

  • Data retention period. The default is 14 days, but follows your established data retention policy.

For more information on configuring Upstream Spectrum Session parameters, see ServAssure® NXT Design and Installation Guide.

For more information on concurrency limitations on active Upstream spectrum session, see Upstream Spectrum capture summary. If you try to start a new session and an active session exists on the same port, you will be given the option to view that session.

Starting a session

For details on starting a session, see Upstream Spectrum Session actions.

NOTE: For the E6000 CER, the hardware does not allow for more than one spectrum capture per slot. If a spectrum session is active on a slot, other users are prevented from starting or viewing spectrum sessions on a different port of that slot, and see an error message similar to the following:
Error dialog box. Title:Active Capture in Progress. Text: An active spectrum session is in progress. The hardware prevents creating another session on the same slot. You cannot run an analysis on <requested channel>.
This is consistent with the capture functionality described in Table 1.

Viewing a session

You can view completed and running sessions. For details on viewing sessions, see Viewing Upstream Spectrum Sessions.