Tripp Lite H2562, H2561, H2550FL16, H2550, H2550EFL16 User Manual

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www.tripplite.com

Practical Power Guidelines for VoIP and Internet Telephony Applications

by David Slotten

WHITE

PAPER

Cisco, Cisco Systems, the Cisco Systems logo, and the Cisco Square Bridge logo

are registered trademarks or trademarks of Cisco Systems, Inc. and/or its affiliates 95-2914 in the U.S. and certain other countries.

Integrate Backup Power into VoIP Networks

Voice over IP (VoIP) is exploding in popularity as an application for business data networks. VoIP promises to consolidate a company's data and telecommunications infrastructure as well as its support resources. As a result, a company can lower its hardware and service costs while raising productivity through the use of more elaborate and customizable telephony applications.

Unfortunately, there are serious limitations inherent to the data networks that are increasingly called upon to support VoIP. The primary limitation is power availability. Before moving voice traffic from traditional circuitswitched public phone systems to private data network connections, one must consider a public phone system's unique attribute—battery support. In order to deliver extremely high availability for such vital services as emergency 911 support in the event of extended power outages, public phone systems are connected to massive battery arrays.

While most data networks have some type of backup support during power outages (provided by UPS Systems and/or generators), the backup runtime is generally much less than the 4 to 8 hours of backup that is typically provided for public phone systems. Because of this shortcoming, VoIP applications generally require an increase in the UPS System-supported power capacity (e.g. more or larger UPS Systems). Increased UPS System capacity provides power for network-dependent phones and increases overall backup runtime to ensure that normal telephone operation (including 911 service) remains available in the event of an extended power outage.

Reflecting on important lessons learned during its own transition to IP telephony, Cisco provides several best-practice recommendations. One of the most important recommendations is installing a UPS System to guarantee availability:

“Plan Your Power: When an IP network carries voice, reliability is essential. In case of an emergency, people need to summon assistance by dialing 911. When using inline power to switches and routers, make sure they are connected to an uninterruptible power supply [UPS System] to guarantee dial tone if the power should go out.”

Source: Cisco Systems white paper “The Transition to IP Telephony at Cisco Systems”.

http://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a00800cb7fd.shtml

© 2008 TRIPP LITE. ALL RIGHTS RESERVED. THE POLICY OF TRIPP LITE IS ONE OF CONTINUOUS IMPROVEMENT.

2

SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

Tripp Lite H2562, H2561, H2550FL16, H2550, H2550EFL16 User Manual

Consider the Diverse Needs of VoIP Network Equipment

Typical VoIP

Network Design

Source: Cisco Systems white paper “Power and Cooling for VoIP and IP Telephony Applications”.

http://www.cisco.com/application/pdf/en/ us/guest/netsol/ns412/c654/cdccont_ 0900aecd801a2c5f.pdf

Before selecting a UPS System to ensure 100% availability of IP telephony systems, it's important to consider the unique requirements of VoIP network equipment. Network designs hosting VoIP applications will vary widely from business to business due to a number of variables, including the scale of the network and the variety of legacy equipment involved. However, three devices are common to all networks:

Client Devices (phones, PC-based soft phones, etc.)

During the transition to IP telephony, these devices will either (a) derive their power from the network cable via a Power over Ethernet (PoE) connection scheme, or (b) plug into a local AC source.

If they plug into a local AC source, they must be protected by a UPS System. Often a desktop UPS not only safeguards phone service, but also guarantees file integrity for associated PC users.

Networking Devices (switches, routers, etc.)

During the transition to IP telephony, port capacity on the network and in wiring closets will increase to accommodate additional devices (phones) connected to the network. Increased port capacity will increase the power requirements placed on your UPS System, either reducing runtime or overloading the UPS. Note that if a networking device also supplies Power over Ethernet, the aggregate load of all client devices will also be borne by the networking device's UPS System.

Generally, an existing UPS will be inadequate to (a) power the increased load [watts] and (b) power the load for an acceptable length of time. Five to fifteen minutes of runtime provided to gracefully shut down the typical data network is inadequate for IP telephony users who expect phone service to continue for HOURS, not minutes.

Call Processing Devices (servers and related storage systems)

During the transition to IP telephony, dedicated servers are typically added to drive voice and messaging applications, while storage systems are required for voicemail and other messaging applications. Similar to the increased burden placed on networking devices, call processing devices will experience increased loads and will require increased runtime.

© 2008 TRIPP LITE. ALL RIGHTS RESERVED. THE POLICY OF TRIPP LITE IS ONE OF CONTINUOUS IMPROVEMENT.

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SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

Select a UPS System which Provides the Highest Availability, Resiliency and Manageability

When selecting a UPS System, the most obvious criterion to consider is whether a UPS System has enough capacity (VA/watts) to power equipment while having enough battery capacity to operate during a power outage for your required duration. Specific Tripp Lite UPS System recommendations are listed at the end of this document. Often overlooked during the selection process, however, are more subtle, yet critical, criteria that should be considered, including availability, resiliency to power anomalies and manageability.

1. Availability

Availability hinges on three considerations: the VoIP equipment's power supply configuration, the UPS System's battery configuration and the UPS System's power electronics topology.

A. VoIP Equipment Power Supply Configuration

Many switches and routers are equipped with redundant power supply capability. If one power supply fails, a second power supply steps in and powers the device. Redundant power supply configurations are strongly recommended to ensure continuous system availability.

Whether one or two power supplies are deployed, the equipment can draw power from one of three sources: directly from facility power alone (for simplicity's sake we will use the term “wall” to describe this source), from a single UPS System or from multiple UPS Systems.

The following tables detail a switch's operational status, from a power perspective, in both redundant and combined (non-redundant) modes. The tables detail switch status under a variety of operational scenarios, including power supply failure, utility failure and UPS System failure.

Note: Larger switches often have the capability to be alternatively configured to operate in a combined (non-redundant) configuration. In combined mode, two power supplies' capacities will be summed. A true doubling is not generally achieved. A factor of 1.67x is typical. In combined mode, there is no redundancy. Should a power supply fail, the available power is generally reduced to the capacity of a single power supply.

© 2008 TRIPP LITE. ALL RIGHTS RESERVED. THE POLICY OF TRIPP LITE IS ONE OF CONTINUOUS IMPROVEMENT.

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SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

Single Power Supply, or Multiple Power Supplies Operating in Redundant Mode

STEP 1: Determine Configuration

 

 

 

 

 

 

 

 

 

 

Configuration

 

1

 

2

 

3

4

 

5

 

 

Power Supply

 

PS1

PS1

PS2

PS1

PS2

PS1 & PS2

PS1

PS2

 

 

Power Source

 

Wall

Wall

Wall

UPS1

Wall

UPS1

UPS1

UPS2

 

 

 

 

 

 

 

 

 

 

 

 

STEP 2: Consider Failure Scenarios

 

STEP 3: Consider System Status

 

 

 

 

PS1 Status

Utility Status

UPS Status

 

System Status

System Status

System Status

System Status

System Status

OK

OK

OK

 

OK

 

OK

 

OK

OK

 

OK

Failure

OK

OK

 

Crash

 

OK

 

OK

Crash

 

OK

OK

Blackout

OK

 

Crash

Crash

 

OK

OK

 

OK

OK

Blackout

UPS1 Battery

 

Crash

Crash

 

Crash

Crash

 

OK

 

 

Fails

 

 

 

 

 

 

 

 

 

OK

Blackout

UPS1 Internal

 

Crash

Crash

 

Crash

Crash

 

OK

 

 

Fault

 

 

 

 

 

 

 

 

 

OK

OK

UPS1 Battery

 

 

 

OK

OK

 

OK

 

 

Fails

 

 

 

 

Hot swap battery

Hot swap battery

Hot swap battery

OK

OK

UPS1 Internal

 

 

Line-Interactive UPS Systems

 

 

 

 

 

OK

Crash

 

OK

 

 

Fault

 

 

 

 

Replace UPS.

Replace UPS.

Replace UPS.

 

 

 

 

 

 

 

System on PS2/Wall.

 

System on PS2/UPS2.

 

 

 

 

 

 

 

Vulnerable to outage

 

Services OK during

 

 

 

 

 

 

 

during UPS

 

UPS replacement

 

 

 

 

 

 

 

replacement

 

 

 

 

 

 

 

 

 

 

On-Line UPS Systems

 

 

 

 

 

 

 

 

 

 

OK

OK

 

OK

 

 

 

 

 

 

 

UPS on bypass,

UPS on bypass.

UPS on bypass,

 

 

 

 

 

 

 

System on PS2/Wall.

System on Wall.

System on PS2/UPS2.

 

 

 

 

 

 

 

Replace UPS1.

Services down*

Replace UPS1.

 

 

 

 

 

 

 

Vulnerable to

while replacing

Services OK during

 

 

 

 

 

 

 

outage during UPS

UPS1

UPS replacement

 

 

 

 

 

 

 

replacement

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

*SmartOnline Hot-Swappable Modular 5-16KVA UPS system hardware can be hot swapped without service outage.

Multiple Power Supplies Operating in Dual (Combined, Non-Redundant) Mode

STEP 1: Determine Configuration

 

 

 

 

 

 

 

 

Configuration

 

1

2

 

 

3

 

 

Power Supply

PS1

PS2

PS1

PS2

PS1

PS2

 

 

Power Source

Wall

Wall

UPS1

 

UPS1

UPS2

 

 

 

 

 

 

 

 

 

STEP 2: Consider Failure Scenarios

STEP 3: Consider System Status

 

 

 

PS1 Status

Utility Status

UPS Status

System Status

System Status

 

 

System Status

OK

OK

OK

 

OK

OK

 

 

OK

Failure

OK

OK

Reduced Output

OK

 

 

OK

OK

Blackout

OK

 

Crash

OK

 

 

OK

OK

Blackout

UPS1 Battery

 

Crash

Crash

 

 

Reduced Output

 

 

Fails

 

 

Replace UPS1.

 

 

Replace UPS1.

 

 

 

 

 

Output reduced during UPS

Output reduced during UPS

 

 

 

 

 

replacement

 

 

replacement

OK

Blackout

UPS1 Internal

 

Crash

 

 

Reduced Output

 

 

Fault

 

 

Replace UPS1

 

Replace UPS1. Output reduced

 

 

 

 

 

 

 

until UPS1 replacement

OK

OK

UPS1 Battery

 

OK

 

 

OK

 

 

Fails

 

 

Hot swap battery

 

 

Hot swap battery

OK

OK

UPS1 Internal

 

Line-Interactive UPS Systems

 

 

 

Crash

 

 

Reduced Output

 

 

Fault

 

 

Replace UPS. Plug into wall until

Replace UPS1. Plug PS1 into wall

 

 

 

 

 

UPS replacement

 

to restore full power until UPS1

 

 

 

 

 

 

 

replacement. Output reduced

 

 

 

 

 

 

 

until UPS1 replacement

 

 

 

 

 

On-Line UPS Systems

 

 

 

 

 

 

 

 

OK

 

 

OK

 

 

 

 

 

Replace UPS1.

 

 

Replace UPS1.

 

 

 

 

 

Both PS on UPS Bypass.

PS1 on UPS1 Bypass circuit,

 

 

 

 

 

Services down* while replacing

vulnerable to outage. Reduced

 

 

 

 

 

UPS1

 

power during UPS1 replacement

 

 

 

 

 

 

 

 

 

*SmartOnline Hot-Swappable Modular 5-16KVA UPS system hardware can be hot swapped without service outage.

© 2008 TRIPP LITE. ALL RIGHTS RESERVED. THE POLICY OF TRIPP LITE IS ONE OF CONTINUOUS IMPROVEMENT.

5

SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

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