bcmsh — the Broadcom diag shell

The Broadcom diag shell is the command interpreter built into the Broadcom switch SDK. On SONiC switches it is reached with bcmsh or bcmcmd and shows the prompt drivshell>. It gives direct access to the switch ASIC: port status, forwarding tables, registers, counters and the SDK API.

This guide describes the shell as shipped with SONiC for Trident 3 (BCM56870) switches. It covers how to reach the shell, the concepts its commands share, task-oriented how-tos, and a reference entry for every command, including those not listed by help.

New here? Start with Accessing the shell and Reading this guide, then look up commands in the Command reference or the Index.

Getting started

• Introduction
• Accessing the shell
  • How the pieces fit together
  • How syncd starts the shell server
  • Host commands
  • Other network operating systems
  • The drivshell> front-end
  • Shell modes and prompts
  • Command-line syntax
  • Control commands
  • rc scripts
  • Line editing, history and output
  • Files inside the syncd container
  • Interrupting commands
• Reading this guide
  • Command entries
  • Examples
• Example validation
  • Hardware-validated
  • VMM-validated
  • Unvalidated

Concepts

• Units
• Ports and port bitmaps
  • Port names
  • Port bitmap grammar
  • Port status
• Memories and registers
  • Finding names
  • Table views
  • Table suffixes
  • Register references
  • Fields and values
  • Display options
  • Safety
• Configuration variables
  • Port mapping and SerDes
  • Forwarding table sizes
  • Buffers and queues
  • Variable reference
  • Where the configuration comes from
  • File format
  • Names, scopes and precedence
  • When changes take effect
  • Changing variables from the shell
  • Inspecting the configuration
• Cint: the C interpreter
  • When to use Cint
  • Starting and leaving the interpreter
  • Running a file
  • The interpreter keeps its state
  • What the interpreter knows
  • Running diag commands from Cint
  • BCMSAI Cint
  • Troubleshooting
• The Cint language
  • Program structure
  • Types and declarations
  • What is not supported
  • Functions
  • Control flow
  • Enums and constants
  • Printing
  • Return codes
• Scripting
  • Variables
  • Expressions and conditions
  • Loops
  • rc scripts
  • Shell options
  • Diagnostic tests

How-to

• KNET and the CPU port
  • Router MACs and the CPU
  • Inspecting KNET from the diag shell
• Capture port traffic with tcpdump
• Debugging a link
  • Is the port up?
  • Signal and lock: phy diag dsc
  • Eye diagram
  • Bit error rate with PRBS
  • Transmit FIR taps
  • FEC
  • Speed
  • Putting it back
• PHYs and RJ-45 SFPs
  • Which PHY does a port have?
  • PHY settings
  • RJ-45 SFPs
• An L2 switch with two VLANs and SVIs
  • 1. Check that the ports are free
  • 2. VLANs
  • 3. Port settings
  • 4. Check L2 forwarding
  • 5. SVIs in the switch chip
  • 6. SVI addresses on the CPU
  • Removing it again
• Inspecting L3 forwarding
• Changing the chip configuration live
• Cint recipes
  • Chip identity
  • Port status
  • Port counters
  • L3 table usage
  • Routes
  • Egress objects
  • L2 table
  • VLANs
  • KNET interfaces
  • Field-processor groups
  • Enum values and switch controls
  • Arguments
  • Diag commands from Cint

Command reference

• Command reference
  • Shell commands
  • Commands for other chip families
• Cint API on this build
  • Registered names
  • Compared with OpenBCM 6.5.27

Appendix

• Glossary
• Further reading

• Index

• Search Page