Scenario:
Make: Cisco
Device: Cisco Voice Gateway / CUBE (ISR G2, ISR 4000 Series and other IOS / IOS-XE routers)
Telecom: SIP Trunk
Mode: Command Line Interface [CLI]
Description: In this article, we will discuss the step-by-step method to check and confirm the SIP registration status on a Cisco Voice Gateway, and what to do if SIP is not registered. If you use an ISDN line instead, refer to the article on what it means when TEI_ASSIGNED Status shows on a Voice Gateway.
Understanding SIP
SIP stands for Session Initiation Protocol. It is the signalling protocol that sets up, manages and ends voice and video calls over IP networks (VoIP). SIP only controls the call, while the actual voice travels separately using RTP. With a SIP trunk, your voice gateway connects to the telecom provider over the internet or a private link instead of traditional phone lines.
SIP signalling commonly uses port 5060 (UDP or TCP), or port 5061 when it is encrypted with TLS. Before the provider accepts calls, many SIP trunks require the voice gateway to register with the provider’s server. If the registration fails, inbound and outbound calls stop working.
How to Check SIP Status on a Cisco Voice Gateway
Follow the steps below to check and confirm the SIP registration status on the Cisco Voice Gateway.
Step 1: SSH to the Voice Gateway
Open an SSH session to the Voice Gateway using PuTTY or any other SSH client.
Step 2: Login
Log in to the Voice Gateway with your username and password.
login as: admin
Using keyboard-interactive authentication.
Password: ********
edledge-vg#
Step 3: Check the SIP Registration Status
Check the SIP registration status using the command below.
edledge-vg#show sip-ua register status
Line peer expires(sec) reg survival P-Associ-URI
========== ======= ============= ===== ========= =============
EDLEDGE$!P -1 41 yes normal
edledge-vg#
The reg column shows yes, which means SIP is registered with the provider. If SIP is not registered, the output looks like this:
edledge-vg#show sip-ua register status
Line peer expires(sec) reg survival P-Associ-URI
========== ======= ============= ===== ========= =============
EDLEDGE$!P -1 41 no normal
edledge-vg#
Understanding the Output
| Column | Meaning |
| Line | The number or username registered with the provider |
| peer | The dial-peer linked to the registration (-1 means it is not tied to a specific dial-peer) |
| expires(sec) | Seconds left before the gateway renews the registration |
| reg | yes = registered, no = not registered |
| survival | Survivability state; normal means the gateway is operating normally |
Important Note: Not every SIP trunk uses registration. Some providers authenticate the gateway by its public IP address instead. In that case, show sip-ua register status shows no lines at all, which is normal. Use the additional commands below to check the trunk instead.
Other Useful SIP Commands
| Command | Purpose |
show sip-ua status | Shows whether the SIP user agent is enabled and listening on UDP/TCP/TLS |
show sip-ua connections udp brief | Lists active SIP connections to the provider (use tcp instead of udp if your trunk uses TCP) |
show dial-peer voice summary | Shows the dial-peers and whether they are up |
show voip rtp connections | Shows active voice (RTP) streams during a call |
debug ccsip messages | Shows the SIP messages exchanged with the provider. Use with care in production, and stop it with undebug all |
What to Do If SIP Is Not Registered
Knowing the SIP status is the first step when calls fail, because it tells you quickly whether the problem is the trunk or something else. If SIP is not registered, check the following:
- Internet or WAN link: make sure the gateway can reach the provider’s server, for example with ping to the registrar address.
- DNS: if the registrar is configured as a hostname, make sure the gateway can resolve it.
- Credentials: confirm the SIP username and password under sip-ua match the details from the provider.
- Firewall and NAT: allow SIP (port 5060/5061) and RTP traffic between the gateway and the provider. Disable SIP ALG on the firewall if it modifies SIP packets.
- Provider side: contact the service provider to confirm there is no outage on their side and that your account is active.
- Reload: as a last resort, reload the Voice Gateway during a maintenance window and check the status again.
Other Important Topics
- TEI_ASSIGNED Status On Voice Gateway
- Commonly Used TCP and UDP Port Numbers
- Check & Change SSH Version Of Cisco Switches
- Couldn’t Agree a Key Exchange Algorithm SSH Error with PuTTY
Disclaimer: This article is for educational purposes only and is not professional financial, medical, or legal advice. It may contain affiliate links, which earn us a small commission at no extra cost to you. See our Disclaimer and Affiliate Disclosure.
Article ID: EA00101