Fixing Algo 8186 Intermittent Disconnections

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Fixing Algo 8186 Intermittent Disconnections

The Algo 8186 SIP paging adapter intermittently loses SIP registration and becomes unreachable for incoming calls, reconnecting after variable time periods ranging from seconds to minutes. Polycom phones at the same site typically continue working, which indicates the network itself is functional.

Root Causes

The Algo 8186 is particularly sensitive to:

1. NAT binding timeouts — the device uses longer keepalive intervals than most IP phones
2. DNS resolution failures — the 8186 does not recover gracefully from DNS errors
3. Aggressive firewall session pruning — some routers close idle SIP sessions before the Algo re-registers
4. TCP vs. UDP registration — default settings may not suit the network’s NAT behavior
5. Registration timer mismatches — between the device and the PBX

Solution Steps

Apply these in order. Test for at least 30 minutes after each step before moving to the next.

Step 1: Configure Aggressive Keep-Alive Settings

This is the most critical fix. It prevents NAT bindings from expiring between registrations.

Access the Algo 8186 web interface at http://[device-ip], then navigate to Basic Settings > SIP Settings:

Setting	Recommended Value	Default	Reason
Registration Period	120 seconds	3600	Forces frequent re-registration
Keep Alive Period	20 seconds	60	Maintains NAT binding
SIP Options Keep-Alive	Enabled	Disabled	Sends OPTIONS ping to server
NAT Keep Alive	Enabled	Enabled	Sends UDP keepalive packets

Step 2: Switch to TCP Registration

If UDP registration continues to drop, switch to TCP transport which is more resilient through NAT.

Navigate to Advanced Settings > SIP > Transport:

Setting	Value	Notes
SIP Transport	TCP	More reliable through NAT
Local SIP Port	5060	Standard port
RTP Port Range	10000–10100	Narrow range appropriate for Algo

Note

After changing to TCP, the device will reboot. Test for 24 hours before proceeding to additional steps.

Step 3: Configure DNS and Proxy Failover

Navigate to Basic Settings > Network:

Setting	Recommended Value
Primary DNS	8.8.8.8
Secondary DNS	1.1.1.1
DNS Cache Time	300 seconds

Navigate to Advanced Settings > SIP:

Setting	Value
Outbound Proxy	Primary SIPSTACK SIP server IP
Backup Proxy	Secondary SIPSTACK SIP server IP
Proxy Failover	Enabled

Step 4: Optimize Network Recovery Settings

Navigate to Advanced Settings > Network:

Setting	Recommended Value	Default
Link Monitor	Enabled	Disabled
Link Monitor Interval	30 seconds	60
Network Recovery	Auto-Reboot	None
Max Registration Attempts	10	5
Registration Retry Interval	30 seconds	120

Step 5: Router and Firewall Adjustments

Even when Polycom phones work without issue, the Algo 8186 requires special handling due to its longer keepalive requirements.

Caution

Configure the following on the customer’s router/firewall.

1. Create a dedicated firewall rule for the Algo:

   Source: [Algo device IP]
   Destination: SIPSTACK SIP server IPs
   Protocol: UDP 5060, 10000–10100 (or TCP 5060 if using TCP transport)
   Session Timeout: 600 seconds

2. Assign a static IP to the Algo’s MAC address via DHCP reservation to prevent IP changes during network events.

3. Disable SIP ALG for the Algo’s IP address. Some routers allow per-device ALG settings.

4. Set QoS priority for the Algo device to highest. It is more sensitive to packet loss than standard IP phones.

Advanced Troubleshooting

Enable Detailed Logging

1. Navigate to Advanced Settings > Debug.
2. Enable SIP Debug, Network Debug, and System Log.
3. Download the logs after a disconnection occurs.
4. Look for: Registration timeout, DNS resolution failed, or Network unreachable.

Firmware-Specific Issues

Firmware	Known Issue	Solution
5.4	Memory leak after 30 days	Schedule weekly reboot
5.3	TCP registration broken	Use UDP only
5.2	DNS cache corruption	Upgrade to 5.4+

The current recommended stable firmware is 5.4.2 or newer. Download from algo.com/support.

Quick Fix Checklist

If you need a fast resolution, apply these in order:

1. Set Registration Period = 120 seconds
2. Set Keep Alive Period = 20 seconds
3. Enable SIP Options Keep-Alive
4. Set DNS to 8.8.8.8 / 1.1.1.1
5. If still failing, switch to TCP transport
6. If still failing, schedule a daily reboot at 3 AM

Last Resort: Scheduled Auto-Reboot

For firmware memory leak issues that cannot be resolved by other means, configure an automatic reboot schedule.

Navigate to Advanced Settings > Maintenance:

Setting	Value
Auto Reboot	Enabled
Reboot Schedule	Daily
Reboot Time	03:00 (3 AM local time)
Pre-Reboot Warning	Disabled

Note

Scheduled reboots are a workaround for known firmware memory leaks and should not be treated as a permanent solution. Check for updated firmware regularly.

Related Resources

• General Firewall Configuration for VoIP
• Disabling SIP ALG on FortiGate Firewalls