Guides
Guides for voice engineers
Troubleshooting methods, migration plans and design checklists, written from field work. Each one stands alone, whatever tools you use.
Troubleshooting
Reading traces, finding the failing leg, and fixing the configuration behind it.
Troubleshooting guide
How a Cisco CUBE chooses a dial-peer
The order a CUBE uses to match inbound and outbound dial-peers on SIP calls, what dial-peer 0 does, and how to see the match.
Troubleshooting guide
Read a SIP trace: where to look first
A short method for reading a SIP trace from a gateway or SBC: find the call, find who ended it, and read the SDP.
Troubleshooting guide
One-way audio on a SIP call: causes and checks
Why a SIP call connects but only one side hears the other, and how to find the cause from the SDP, the packet counters and a capture.
Troubleshooting guide
SIP 488 Not Acceptable Here: what it means and how to fix it
A SIP 488 response means the media offer was rejected. The common causes on gateways and SBCs, and how to read the SDP to find which one.
Troubleshooting guide
SIP 503 Service Unavailable on a trunk: finding who sent it
A SIP 503 can come from the carrier, the SBC or your own gateway. How to tell which device generated it and what each source usually means.
Troubleshooting guide
DTMF not working on a SIP trunk: methods and mismatches
Why keypad digits fail to reach an IVR or voicemail system over SIP, the DTMF methods in use, and how to see which one a call negotiated.
Reference
Q.850 cause codes and the SIP responses they map to
A reference table of Q.850 disconnect cause codes, what each means, and the SIP response a gateway sends for it under RFC 3398.
Troubleshooting guide
Cisco voice translation rules: syntax, examples and testing
How to write Cisco IOS voice translation rules that match: the pattern syntax, capture groups, worked examples and the test command.
Troubleshooting guide
SIP profiles on Cisco CUBE: modify, add and remove headers
How SIP profiles on Cisco CUBE change SIP headers and SDP, where to apply them, and how to check that a rule did what you intended.
Troubleshooting guide
Build an evidence-first UC investigation
Scope a failed call, choose a meaningful comparison, and test one explanation at a time.
Migration
Planning a move from Cisco Unified CM to cloud calling.
Migration guide
Plan a Cisco Unified CM to Webex Calling migration
What to inventory, decide and test when moving users, numbers and devices from Cisco Unified CM to Webex Calling.
Migration guide
Plan a Cisco Unified CM to Zoom Phone migration
What to inventory, decide and test when moving users, numbers and devices from Cisco Unified CM to Zoom Phone.
Migration guide
Cisco Unified CM migration inventory: what to export and check
A checklist of what to inventory in Cisco Unified CM before moving to a cloud calling platform, and what each item tells you about the migration.
Migration guide
Plan a Cisco Unified CM to Webex Calling Dedicated Instance migration
What changes and what stays the same when moving an on-premises Cisco Unified CM cluster to Webex Calling Dedicated Instance, and the order to plan it in.
Design
Designing call flows and the configuration that carries them.
Design guide
Microsoft Teams Direct Routing: what the SBC has to do
The requirements a session border controller must meet for Microsoft Teams Direct Routing: name, certificate, signaling, media and routing.
Design guide
How to document a call flow before you build it
What a call flow document needs before anyone configures an auto attendant, queue or routing rule, and the questions that expose missing paths.
Design guide
What a generated configuration proves
Separate design intent, simulation, and observed behavior before calling a workflow validated.
Start with one environment and one outcome.
Tell us what you run and what you need to fix, move or build. Or write it down first as a pilot brief you can review with your team.