Product Specification: Active-Standby and Active-Active redundancy

Introduction

Redundancy on the Escaux UC solution can be achieved in two ways: Through an active-standby or an active-active setup. Both topologies offer high availability, the aim of this data sheet is to explain the benefits and limitations of both solutions.

The active-standby topology is build with pairs of SOPs. Each master has its own clone with identical hardware (server and cards). Both appliances are generally located at the same place but can be located in geographically different locations as long as they are connected on the same network. The active server processes the services requested by the users while the standby is ready to start working but doesn't participate in the processing. In case of a problem with the active server, a switchover from the master to the clone can be performed through a simple manual procedure.

The active-active topology is comprised of at least two SOPs. Each appliance (server and cards) can be different. Both appliances can be located in geographically different locations as long as they are able to communicate with each other (see technical details). All servers are simultaneously active and can process a part of the services requested by the users. In case of a problem with one of the servers, another continues offering most services to all users. Note that some services require a manual operation to restart.

Benefits

Communication is business critical for most organizations these days. By deploying a redundant topology, the impact of a hardware or network failure can be reduced to the minimum so that day-to-day operations are not impacted.

Features

This tables gives an overview of which devices, applications and services support the active-standby or active-active topology:

	Active - Standby	Active - Active
SIP phones
Soft phones
Voicemail
PUM
Corporate Directory
Reporting
Recording
net.Desktop
net.Console
net.Supervisor
Fax Server
Queue

Legend:

• : Supported
• : Not supported

Limitations

Active-Standby and Active-Active

• Voicemails are recorded on the Active SOP and are available when it comes back Active. During breakdown, they are recorded on the Secondary/Clone SOP and require manual intervention to be available when the Primary/haMaster SOP comes back Active.
• Recordings triggered in a callflow are stored on the Active SOP and are available when it comes back Active. During breakdown, they are stored on the Secondary/Clone SOP and require manual intervention to be available when the Primary/haMaster SOP comes back active.
• When using the SOP's DHCP server module, the DHCP leases are not synchronized. This might result in a small service interruption of the endpoint when the lease expires and if another IP address is assigned.
• Queued e-mails or faxes are no synchronized.

Active-Standby specifically

• When a switchover from the master to the clone is performed, the endpoints will need a bit of time to detect the change. For Polycom phones, this is about 2 minutes. For SNOM phones, this is about 1 minute. This delay is dependent on the network infrastructure and conditions.
• PUM status, profile parameters, audio prompts, voicemails are not synchronized real-time, but on regular intervals. If a switchover is done shortly after a modification and before the synchronization has been performed, this change will not be present on the standby SOP.
• CDR's are not synchronized between active and standby sop (but can be synchronized from both SOPs to SMP)
• When a SOP is disconnected from the SMP (red ball), the HA status cannot be known.

Active-Active specifically

• When a switchover from the master to the clone is performed, the endpoints will need a bit of time to detect the change. For Polycom phones, this is about 2 minutes. For SNOM phones, this is about 1 minute. This delay is dependent on the network infrastructure and conditions.
• PUM status, profile parameters, audio prompts, voicemails are not synchronized real-time, but on regular intervals. If a switchover is done shortly after a modification and before the synchronization has been performed, this change will not be present on the standby SOP.
• CDR's are not synchronized between active and standby sop (but can be synchronized from both SOPs to SMP)
• When a SOP is disconnected from the SMP (red ball), the HA status cannot be known.

Requirements

Hardware and connectivity

	Active - Standby	Active - Active
Server	(Same server & cards)	(Various servers & cards)
ISDN (BA / PRA)	(1)	(2)
SIP trunk		(3)

Legend:

• : Supported
• : Not supported
• (1): Same interface cards in both servers. Generally, the ISDN lines are connected only in the active server and in case of failure, they need to be moved manually to the corresponding interface in the standby server.
• (2): Each ISDN line is connected in an interface card in a server. In case of failure of this server, the line is no longer available, except if it can be manually moved in a free interface on another server. Requires additional lines to keep full capacity during breakdown.
• (3): At least one (virtual) SIP Trunk is required on each SOP. While all SIP trunks can be defined on every SOP, every incoming call will end on the extensions' primary SOP. No dynamic load balancing between active sops can be achieved. Contact us for complex design.

Licenses

	Active - Standby	Active - Active
Software Edition	Enterprise (1) or Corporate (2)	Corporate only (2)
ISDN (BA / PRA)
SIP trunk	(3)	(3)
SIP phones	(4)	(4)
Soft phones	(4)	(4)
Voicemail
PUM	(5)	(5)
Reporting
Recording
net.Desktop	(6)
net.Console	(7)	(8)
Escaux Connect
Fax Server	(9)	(9)

Legend:

• : No license required
• : Not supported
• (1): One Enterprise Edition Project Module and one Enterprise Edition Appliance Module per SOP
• (2): One Corporate Edition Project Module and one Corporate Edition Appliance Module per SOP
• (3): One External Channel per trunk
• (4): One net.Phone per phone
• (5): One net.Phone per user (SIP phones not included), one PUM Project Module and one PUM Appliance Module per SOP
• (6): One net.Desktop Xxx0 per user and one net.Desktop Xxx0 Project Module
• (7): One net.Console Xx00 per user and one net.Console Xx00 Project Module
• (8): One net.Console X900 per user and one net.Console X900 Project Module
• (9): One Virtual Fax Channel Module per channel and one Virtual Fax Appliance Module per SOP

Other resources

• Administrator Guide: Active-standby redundancy
• Administrator Guide: Active-active redundancy
• Service Assurance: Active-Active redundancy
• Multi-site, high availability SOP configuration

About Escaux UCS

Escaux has developed the Unified Communication Solution as a modular solution based on open standards. Escaux UCS offers companies an easy-to-use platform with high operational efficiency. This guarantees increased efficiency, both for the users as well as for the administrators. Because of the modularity, an Escaux UCS solution is typically cheaper than solutions based on an IP PBX, while retaining configuration-to-measure advantages over a Centrex solution. As a result, Escaux UCS offers very high value for money in a future-proof solution, while offering market beating performance. Its high configurability, even for international multi-site setups, means cost saving opportunities on any level in your company.

About Escaux

Escaux was founded in 2002 and has a wide range of unique Unified Communication (UC) and Fixed Mobile Unification (FMU) building blocks in portfolio allowing Service Providers, Integrators and Mobile Operators to build Industrialized On-Premise, Hybrid-Cloud and Cloud based solutions suited to the needs of SOHO, SME and Corporate customers. The company has gained the trust of many corporate, stock quoted and public companies.