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Embedded logic analyzer module

Updated: April 15, 2026

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Describes an engineering tool that enables analysis of packet forwarding within Cisco ASICs.

ELAM (Embedded Logic Analyzer Module) is an engineering tool that

  • enables you to look inside Cisco ASICs and understand how a packet is being forwarded

  • is embedded within the forwarding pipeline and can capture a packet in real time without affecting performance or control plane resources, and

  • performs analysis functions for packet forwarding troubleshooting.

ELAM functions

ELAM can perform these functions:

  • Determine if a packet reached the forwarding engine

  • Specify the port and VLAN of the packet that was received

  • View the packet (Layer 2 to Layer 4 data)

  • Check if the packet was altered where it was sent

Generate an ELAM report in the simplified output for modular switches

Generate ELAM reports in both original and simplified formats to analyze packet forwarding information on modular switches.

The Cisco Application Policy Infrastructure Controller (APIC) 4.2(1) release introduces simplified, human-readable ELAM output. Only switch models with EX, FX, or FX2 at the end of the switch name support the simplified output. Use the following procedure for modular switches.

Procedure

  1. Run the ELAM tool to collect the packet forwarding information.

    The exact commands and parameters depend on your hardware.

  2. Run the ereport command to create ELAM reports of the packet forwarding information in the original format and the simplified format.

    Example:

    module-1(DBG-elam-el6)# ereport
Python available. Continue ELAM decode with LC Pkg
ELAM REPORT

===============================================================
                    Trigger/Basic Information
===============================================================
ELAM Report File    : /tmp/logs/elam_2019-09-04-51m-13h-30s.txt
.
.
.

module-1(DBG-elam-el6)# exit
module-1(DBG-elam)# exit
module-1# exit

apic1-leaf11# cd /tmp/logs
apic1-leaf11# ls | grep elam
elam_2019-09-04-51m-13h-30s.txt
pretty_elam_2019-09-04-51m-13h-30s.txt
apic1-leaf11#

    ELAM saves the output files in the /tmp/logs/ directory. In the example, the elam_2019-09-04-51m-13h-30s.txt file is the ELAM report in the original format. The pretty_elam_2019-09-04-51m-13h-30s.txt file is the ELAM report in the simplified format. However, the simplified format file will be empty. You must perform additional steps to get the report in the simplified format.

  3. Upload the original format ELAM report to the /bootflash directory on the supervisor.

    In the example, this report is the elam_2019-09-04-51m-13h-30s.txt file.

  4. Log in to the supervisor as admin.

  5. Change the directory to /tmp, or any directory with write privileges for the admin user.

    Example:

    # cd /tmp

  6. Run the decode_elam_parser command on the original format ELAM report.

    Example:

    # decode_elam_parser /bootflash/elam_2019-09-04-51m-13h-30s.txt

    The decode_elam_parser command saves the simplified output file in the current directory.

The system generates both original format and simplified format ELAM reports, with the simplified report available for analysis in the current directory.

Generate an ELAM report in the simplified output for fixed form-factor switches

Generate ELAM reports in both original and simplified human-readable formats to analyze packet forwarding information on compatible switch models.

The Cisco Application Policy Infrastructure Controller (APIC) 4.2(1) release introduces simplified, human-readable ELAM output. Only switch models with EX, FX, or FX2 at the end of the switch name support the simplified output. Use the following procedure for fixed form-factor leaf switches and spine switches.

Procedure

  1. Run the ELAM tool to collect the packet forwarding information. The exact commands and parameters depend on your hardware.

  2. Run the ereport command to create ELAM reports of the packet forwarding information in the original format and the simplified format.

    Example:

    module-1(DBG-elam-insel6)# ereport
Python available. Continue ELAM decode with LC Pkg
ELAM REPORT

===============================================================
                    Trigger/Basic Information
===============================================================
ELAM Report File    : /tmp/logs/elam_2019-09-04-51m-13h-30s.txt
.
.
.

module-1(DBG-elam-insel6)# exit
module-1(DBG-elam)# exit
module-1# exit

apic1-leaf11# cd /tmp/logs
apic1-leaf11# ls | grep elam
elam_2019-09-04-51m-13h-30s.txt
pretty_elam_2019-09-04-51m-13h-30s.txt
apic1-leaf11#

    ELAM saves the output files in the /tmp/logs/ directory. In the example, the elam_2019-09-04-51m-13h-30s.txt file is the ELAM report in the original format. The pretty_elam_2019-09-04-51m-13h-30s.txt file is the ELAM report in the simplified format.

You have generated ELAM reports in both the original format and the simplified human-readable format. The files are saved in the /tmp/logs/ directory with timestamps in their names.