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Introduction
UC300 support standard SIP according to IETF RFC3261, plus some extensions, so it may work properly with many different Service Providers, allowing for VoIP connectivity. This page includes information and configuration details provided as means to ensure a smooth integration and the proper operations of the features.
SIP trunk basics
A SIP trunk is a service offered by an ITSP to use SIP protocol to set up communications between an enterprise PBX and the ITSP. SIP trunks are similar to a phone lines, except that SIP trunks use the IP network, not the PSTN. In addition, SIP trunks permit the convergence of voice and data onto common all-IP connections. For example, besides the voice services, SIP trunks can also provide services like Instant Messaging and presence applications, etc.
In order to access the IP network using an SIP trunk, it is necessary that configurations be made on the ITSP, as well as on the customer side.
UC 320 SIP Trunk Configuration
SIP Trunk configuration is achieved via the UC320 Configuration Utility. You can enter the main parameters for your Service Provider account on a "Generic SIP Provider". We provide below the configuration for a list of Certified Service Providers. The SMART Designs and the UC320W Administration Guide (English) provide guidance about SIP Trunks deployments and associated parameters. Figure below shows an example of the UC320 Configuration Utility SIP Trunk Configuration Screen.
Configuration Guides
Validated SIP Trunk Service Providers*
Note: The information on this section is provided as is and currently represents the testing results performed by Cisco or Cisco Partners on a specific UC320W firmware release and date. This is not an official certification of the tests or the Service Provider Service. This information is provided as reference only and may change at any point of time without notice.
The following table contains the list of SIP Trunk Service Providers that have been validated on UC320W, either by Cisco or by a Cisco Partner (Service Provider and/or reseller partner).
If you are a Service Provider who would like to test and validate the UC320W, please check the UC320 SIP Trunk Validation Process.
SIP Trunk FAQ
Is there a list of SIP trunk Service Providers in the UC320 Configuration Utility drop-down menu?
No, the UC320 configuration utility allows for easy configuration of generic SIP trunk accounts, please check the table above for the tested SIP trunks Service Providers and their associated configuration.
I represent a Service Provider, how do we get listed on the UC320 Validated SIP Trunk list?
Please check the UC320 SIP Trunk Certification Process for instructions about how to get listed on the UC320 Validated SIP Trunk list.
Does the UC320 supports multiple SIP Trunks?
Yes. UC300 supports SIP trunks to up to 4 different simultaneous Service Providers. In current release, the Service Providers must be within same dial plan (country). Connectivity with Mediatrix ISDN Digital gateways for BRI connectivity uses one SIP trunk.
What are the maximum number of concurrent calls supported over UC320 SIP trunks?
On current release, the maximum number of concurrent calls per each SIP trunk is eight (8). The maximum total number of external calls, included all SIP trunks and PSTN (FXO) lines is 12. Note that maximum number of concurrent calls over SIP trunks depends also on the available broadband connection bandwidth and the codec used.
Does UC320 supports Direct Inward Dialing (DID) numbers over SIP trunks?
Yes. UC320 provides the possibility for using multiple DID numbers over SIP trunks, with the following characteristics and limitations:
- DID mapping is performed on the inbound (incoming) direction only, i.e. customers calling to the DID number can be mapped automatically to the mapped extension. In the outbound direction, all calls use the main trunk number.
- Individual DIDs cannot be registered (SIP REGISTER) from the UC320. UC320 register the main (account) number only.
Does UC320 supports registration over SIP trunks?
Yes. UC320 supports both Peer-to-peer (no registration) and client-server (registration) SIP Trunks. This is defined on the SIP trunk configuration.
What codecs are supported via SIP trunks?
UC320 supports G.711a, G.711u and G.729 over SIP trunks
Does UC320 supports multisite connectivity via SIP trunks?
No. Current release does not support multisite connectivity. SIP trunks are designed for connectivity to an Internet Telephony Service Provider (ITSP).
Does UC320 SIP trunks supports NAT mapping?
UC320 supports multiple NAT configuration scenarios, which depending on the network connectivity and the Service Providers capability allows for handling the commonly known "NAT issue". This configuration scenarios are:
- Service Provider provides an Outbound Proxy: UC320 can communicate to an SBC/Outbound Proxy
- Service Provider provides/support a STUN server: UC320 SIP trunk configuration can use a STUN server to determine WAN public address. In this case, UC320 can be configured to send NAT keepalive messages to keep UDP ports open.
- Service Provider does not offer any NAT handling issue. UC320 SIP trunk can be configured for providing a static mapping to an external IP address. In this case, UC320 can be configured to send NAT keepalive messages to keep UDP ports open.
Does UC320 supports SIP proxy redundancy?
Yes. UC320 supports DNS SRV records for having SIP proxy redundancy
Troubleshooting SIP Trunks on UC320W
Troubleshooting SIP trunks includes on UC320 is no different from troubleshooting SIP trunks on any other SIP-able device. Following are the main issues related to SIP trunk troubleshooting and the associated resolution and/or tool to use. Please note this is a living document that will be expanded and enhanced over time
| Area | Issue | Problem/resolution | Tools |
|---|---|---|---|
| Registration | No register - SIP proxy not reachable (DNS not resolved) | Wrong SIP Trunk configuration, make sure SIP trunk domain can be resolved or configure Outbound proxy | Registration status can be seen on Configuration Utility, Status -> External Trunks UC320 System Logs |
| Registration | No register - No reply (200 OK) received | Wrong SIP Trunk configuration, make sure proper SIP Proxy and Outbound proxy are configured | UC320 System Logs |
| Registration | No register - No reply (200 OK) received | Firewall (on external router/IAD) configuration, incoming 200 OK blocked at incoming | UC320 System Logs + Wireshark (at WAN of external router) |
| Registration | No register - Authentication Failure (403 Forbidden) | Wrong SIP Trunk configuration, make sure Authentication ID and password matches what provided by the ITSP. If so, check with SP that account is enabled | UC320 System Logs |
| Outgoing Calls | Call Failed to establish- 404 not found | Ensure you dial according to the applied dial plan. Check the outbound number signaled on the "To" header of SIP INVITE matches to what SP expects. It is typically related to a Wrong dial plan or SIP Trunk configuration (e.g. add "+1" to "To") | UC320 System Logs |
| Outgoing Calls | Call Failed to establish- Media Not Acceptable | Check SIP Trunk Codec Configuration, check codec offered on the SDP offer and session establishment | UC320 System Logs |
| Outgoing Calls | Call drop after a few seconds (1-45 sec) | Typically related to Firewall issues, check traces at UC320 and also at Ext. router/firewall WAN port to see if RTP packets are on transit (both ways) | UC320 System Logs + Wireshark (at WAN of external router) |
| Incoming Calls | No incoming calls received | Typically related to Firewall issues (close UDP port after X seconds), then incoming messages do not reach UC320. Use NAT Keepalive on SIP Trunk to keep UDP port open | UC320 System Logs + Wireshark (at WAN of external router) |
| Incoming Calls | No incoming calls - 404 not found on UC320 | Related to Inbound Call Routing. Check Inbound Call Routing and make sure there is a router for SIP trunks and their associated DIDs | UC320 System Logs |
| Incoming Calls | No incoming calls - Media Not Acceptable | Check SIP Trunk Codec Configuration, check codec offered on the SDP offer and session establishment | UC320 System Logs |
| One Way Audio | One way audio - local party no audio | This is typically related to a NAT Issue. Check SIP Trunk configuration to match SP NAT requirements (e.g. STUN server or static NAT mapping in case SP do not offer an Outbound proxy or SBC functionality) | UC320 system logs |
| One Way Audio | One way audio - local party no audio after X seconds | This is typically related to an ext. firewall issue that blocks RTP flow. check traces at UC320 and also at Ext. router/firewall WAN port to see if RTP packets are on transit (both ways) | UC320 System Logs + Wireshark (at WAN of external router) |
| One Way Audio | One way audio - other party no audio | This is typically related to an ext. router SIP ALG issue, which affects the SDP of the SIP message sent by the ITSP. Solution is to disable SIP ALG on the external router or replace router | UC320 System Logs + Wireshark (at WAN of external router) |
Tools for troubleshooting SIP Trunks
UC320W Configuration Utility Status page
The UC320 Configuration Utility offers SIP Trunk registration status, enabling partners to check the registration status of each SIP trunk. This is useful for setup of client-server SIP trunks (i.e. SIP trunks that requires registration). It can be found on Status -> External trunks section. Possible states are: Registered (registration successful), Not-Registered (Registration unsuccessful) and blank (this happen on peer-to-peer or no registration required SIP trunks).
UC320W System Logs
Wireshark Tool
Wireshark tool is useful to debug RTP and Fax related issues as well as generic SIP issues when there is an external router/firewall/ALG (e.g. a security appliance) connected to the WAN port of the UC300. Steps to gather traces with Wireshark tool includes:
- Setup a PC with wireshark caputure from http://wireshark.org
- Connect a HUB or SWICTH on the WAN interface of the UC320W or the WAN interface of the firewall device, depending the issue to troubleshoot.
- Enable Wireshark capture on the PC with a filter set up for SIP & RTP traffic to/from the UC300 - example is below
- Make the failed call or event
- Stop the capture and save the trace file. Be sure to note the IP address of the UC320 and firewall WAN ports and the SIP trunk service provider's SIP proxy IP address
