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

...

Practical Power Guidelines for VoIP and Internet Telephony Applications

www.tripplite.com

WHITE

PAPER

95-2914

by David Slotten

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 in the U.S. and certain other countries.

SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

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 circuit-

switched 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

SPECIFICATIONS ARE SUBJECT TO CHANGE WITHOUT NOTICE.

ALL TRADEMARKS ARE THE PROPERTY OF THEIR RESPECTIVE OWNERS.

Consider the Diverse Needs of VoIP Network Equipment

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.

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

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.

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

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

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 — — 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

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.

Line-Interactive UPS Systems

On-Line UPS Systems

STEP 1: Determine Configuration

STEP 2: Consider Failure Scenarios

STEP 3: Consider System Status

STEP 2: Consider Failure Scenarios

STEP 3: Consider System Status

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

Configuration 1 2 3 Power Supply PS1 PS2 PS1 PS2 PS1 PS2 Power Source Wall Wall UPS1 UPS1 UPS2

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 — 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

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.

STEP 1: Determine Configuration

Line-Interactive UPS Systems

On-Line UPS Systems

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