fostering interoperability with voip solutions via hp ...€¦ · fostering interoperability with...

FosteringInteroperability withVoIP Solutions via HP ProCurveNetworking

Performance evaluation of the HP ProCurve Networking AdaptiveEDGE Architecture and its ability to'interoperate' with leading VoIP solutions suppliers

A white papercommissioned by

Hewlett-Packard Co.

Document #204113

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©2004 The Tolly Group

January 2004January 2004

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This document was authored by:

WHITE PAPER:Fostering Interoperability with VoIP Solutions via

HP ProCurve Networking

©2004 The Tolly Group

T H E

TO L LYG R O U P

January 2004

Charles Bruno,Executive EditorThe Tolly Group

Kevin Tolly,President/CEOThe Tolly Group

http://www.tolly.com/TV/TV_Home.Aspx

http://www.tolly.com

http://www.tolly.com/UTS/UTS_Home.Aspx

http://www.tolly.com/UTS/UTS_Home.Aspx

1 A Blueprint for VoIP Infrastructure 2 Gaining a Competitive EDGE 3 Bandwidth control services 4 Open approach to standards 6 Fostering Interoperability for VoIP 6 Cisco AVVID traffic across HP ProCurve 7 AVVID/HP ProCurve Switch 2650-PWR edge scenario 7 AVVID/HP ProCurve Switch 4104gl edge scenario 8 AVVID/HP ProCurve Switch 5304xl edge scenario 8 VoIP call quality using Mitel 3300-ICP traffic across HP ProCurve9 Mitel/HP ProCurve Switch 2650-PWR edge scenario 9 Mitel/ProCurve 4104gl edge scenario 10 Mitel/HP ProCurve Switch 5304xl edge scenario 10 VoIP call quality using 3Com NBX-100 traffic across HP ProCurve11 NBX-100/HP ProCurve Switch 2650-PWR edge scenario 11 NBX-100/HP ProCurve Switch 4104gl edge scenario 11 NBX-100/HP ProCurve Switch 5304xl edge scenario 12 VoIP call quality using Avaya IP403 Office 12 VoIP call quality using NEC NeaxIPS 13 VoIP call quality using Nortel BCM200 14 Making Smart Purchase Decisions

©2004 The Tolly Group January 2004



7 Figure 1. AVVID over HP ProCurve PSQM summary8 Figure 2. AVVID over HP ProCurve PESQ summary9 Figure 3. PSQM summary results for Mitel VoIP over HP ProCurve10 Figure 4. PESQ results for Mitel VoIP over HP ProCurve11 Figure 5. PSQM summary results for 3Com NBX VoIP over HP ProCurve12 Figure 7. PSQM summary results for Avaya, NEC and Nortel12 Figure 6. PESQ summary results for 3Com NBX VoIP over HP ProCurve13 Figure 8. PESQ summary results for Avaya, NEC and Nortel13 Figure 9. Latency results for Avaya, NEC and Nortel

Table of Contents

List of Figures

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1

A Blueprint for VoIP Infrastructure

Organizations intent on transitioning their physically separate voice and

data networks onto a single, shared transport infrastructure are seeking

an economical means to unite multiple platforms yet do so without

compromising the quality of either voice or data traffic.

Call it ironic, then, that the road to network convergence sometimes is

paved with architectural complexity that either intentionally walls off the

network to third-party equipment, or makes it extremely difficult to build

a heterogeneous converged network. The irony, of course, is that the

foundation of converged enterprise networks these days is IP – only the

most ubiquitous and open protocol in network use.

Yet, as enterprise network designers begin to shape their converged

networks, they sometimes are guided toward a homogeneous network

infrastructure that will "guarantee" acceptable call quality once latency-

sensitive voice is mixed with data applications. The oddity here is that IP

is IP; once voice data is converted into an IP packet, it travels across the

IP network just like any other data. There should be no issue with where

a VoIP packet originates since all IP should be equal.

Certainly, provisions must be made to recognize the latency-sensitive

voice over IP (VoIP) packets and treat them with special provisions for a

class of service above and beyond what some data types are afforded.

That's where quality of service (QoS) comes into play as a means to

supplement adequate bandwidth provisioning at the front end.

Unfortunately, some network infrastructure vendors blow QoS out of propor-

tion and make it overly complex. They reject the notion that adequate

bandwidth planning at the front-end design can help alleviate concerns

about VoIP call quality. Instead, they push the idea through resellers that

QoS is the sole means to guarantee VoIP call quality in enterprise networks.

HP ProCurve Networking, however, stands behind the belief that a

combination of careful upfront bandwidth provisioning, plus QoS as an

insurance policy for periods of link oversubscription, is an effective way

to ensure VoIP call quality.

That's why QoS is an important part of the HP ProCurve Networking

Adaptive EDGE Architecture™, the company's blueprint for deploying an




Fostering Interoperability with VoIPSolutions via HP ProCurve Networking




effective switching infrastructure that is capable of supporting VoIP traffic

in a secure manner.

HP commissioned The Tolly Group, in March 2003, and again in October

2003, to conduct a comprehensive, "hands-on" evaluation of the HP

ProCurve networking solution as implemented by the HP ProCurve

Networking Adaptive EDGE Architecture. The aim was two-fold:

First, testing sought to better understand the Adaptive EDGE Architecture

and the range of functionality it delivers to users.

Second, testing sought to demonstrate that HP ProCurve switches can

deliver VoIP traffic on an end-to-end basis without degrading call quality

– regardless of two variables: the level of congestion and the brand of IP

PBX products that attach to the VoIP switching infrastructure. The Tolly

Group constructed a microcosm of an enterprise IT converged network

using HP ProCurve products, and then measured and compared the call

quality of VoIP traffic from three IP telephony solutions (e.g. representa-

tive VoIP products from Mitel Corp., 3Com Corp. and Cisco Systems, Inc.)

to learn what impact, if any, the underlying ProCurve network has on

voice traffic. In the recent October tests, The Tolly Group evaluated three

additional VoIP solutions – from Avaya Networks, NEC and Nortel

Networks – as VoIP traffic originating from those brands of equipment

traverses an underlying HP switching infrastructure.

In the chapters that follow, readers will learn about the effectiveness of

HP ProCurve switch offerings at delivering VoIP traffic. Readers will see

that ProCurve is an efficient host infrastructure for VoIP traffic generated

by a variety of third-party products. And readers will learn that the

Adaptive EDGE Architecture provides an open, fertile infrastructure upon

which any VoIP traffic can flow across – regardless of what brand device

generates it.

Gaining a Competitive EDGE

HP ProCurve Networking designed its Adaptive EDGE Architecture to

provide intelligent services (such as security and QoS) at the edge of

the network thus providing greater control and functionality at the

edge. This means services like QoS, traffic conditioning and rate limiting

occur before traffic makes it onto the enterprise network core.

HP ProCurve took into account three factors in designing its Adaptive

EDGE Architecture that are influencing the design and evolution of

enterprise nets: the Internet, convergence and mobility.

Since the Internet has become such a force, it has provided enormous

access for outsiders to gain entry to enterprise-class data and services.

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HP evaluated ProCurve interoperabilitywith VoIP solutions from:

3ComAvayaCisco SystemsMitelNECNortel Networks

HP ProCurve's Adaptive EDGEArchitecture addresses three key market factors:

SecurityConvergenceMobility




That means the network architecture must be able to grant that access,

at the network's edge, taking into account the proper level of access

and privileges afforded different "visitors."

Network convergence, or the unification of physically separate voice

and data networks into a single IP-based transport infrastructure,

means that any underlying switching infrastructure must support a broad

range of applications.

Finally, the emergence of mobility means that the network infrastructure

must stretch to accommodate wireless users, and still maintain the

security policies enforced on wired networks.

In essence, HP contends that these factors combine to create a need

for a flexible multi-service transport architecture where control and

functionality are deployed to the edges of the network. Control of

security and of bandwidth at the edge ensures that latency-sensitive

applications get the bandwidth they need, when they need it and

that other applications can yield to higher priority traffic.

One of the tenets of the Adaptive EDGE Architecture is that each of

the traffic types residing on converged networks – voice, video, storage,

interprocess communications and trusted (authenticated and encrypted)

traffic – requires different responses and behaviors that the network

adjust to and respond to accordingly. Delivering that right response

hinges largely on pushing authentication of the traffic type out to the

network edge where users can be identified and applications connect –

despite changes to the user's physical location.

The network edge, HP contends, is where traffic, applications and users

must be identified and decisions must be made on how traffic should be

handled. The edge is where security policies are enforced. Control to

the edge means that sufficient capabilities must be deployed in

ProCurve Layer 2/Layer 3 and Layer 4 switches.

Bandwidth control services

The HP ProCurve Networking Adaptive EDGE Architecture focuses

on a handful of strategic infrastructure services:

Traffic monitoring is employed to control bandwidth optimization

throughout the network grid.

Industry-standard virtual LAN (VLAN) security provides access

management on EDGE-enabled ports.

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HP ProCurve switches offer a weightedrandom fair queueing mechanism to limit delay and improve QoS byscheduling packets for bandwidthavailability.




Standards-based traffic routing and Layer 2 mesh networking provides

multipath failover and load balancing for enhanced reliability. HP

ProCurve Layer 2 and Layer 3 switches can recognize priority tags and

tag non-prioritized traffic for end-to-end delivery across the network.

An extensive set of traffic prioritization features and Quality of Service

(QoS) functions enable various traffic types to co-reside peacefully

to ensure the delivery of voice and video traffic.

HP ProCurve switches offer a weighted fair queuing mechanism to

limit delay and improve QoS by scheduling packets for bandwidth

availability. This approach ensures that higher-priority traffic types,

like VoIP, video and network management data, get the bandwidth

they need when they need it and still permit other traffic types to

share the same physical link.

Port prioritization is another technique offered in the HP ProCurve

switch line that enables priority levels to be set for untagged packets

received on any port. Such a capability enables administrators to

assign a higher priority to certain ports – such as those that service

large amounts of VoIP traffic – to guarantee faster access to and

availability of bandwidth.

Beyond these traffic management services, ProCurve switches support

a variety of protocols used in traffic classification including: UDP/TCP

port, source port, VLAN, Ethernet, IP address, IP Type of Service bit, and

the IETF's Differentiated Services (DiffServ) policies for IP prioritization.

In addition to distributed control at the edge, central command of the

network edge devices facilitates user security and application policies.

In the Adaptive EDGE Architecture, these services combine to ensure

that latency is kept to a minimum and to guard against packet loss –

two factors that otherwise could adversely impact the toll quality

of VoIP traffic.

In addition to the prioritization and QoS services, the Adaptive EDGE

Architecture also provides a foundation for security at the network's

edge – be it wired or wireless. Network designer's can make use of

port-based access control, media access control facilities and a

variety of other functions.

Open approach to standards

One of the basic themes of this white paper is to demonstrate how the

HP ProCurve switching line provides a fertile infrastructure for converged

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Traffic Classification Types Supportedby HP ProCurve:

UDP/TCPVLANEthernetIP addressType of Service bitDiffServe




networks supporting voice, video and data. Paramount to HP's

approach with ProCurve is its support for a plethora of standards to

promote openness and interoperability. It is this very strategy that makes

ProCurve a viable platform for any number of VoIP solutions to utilize.

HP understands that an open standards-based approach to IP

networking is a key underpinning to providing an open switching

infrastructure for VoIP convergence. HP ProCurve's broad support for

standards begins with IP support, extends to support for the H.323

telephony standard and ranges into a number of other areas.

HP ProCurve also supports the IETF's Session Initiation Protocol, which

is emerging as a major factor in enterprise-class VoIP services.

Likewise, the IEEE 802.3af standard for Power over Ethernet is supported

on the HP ProCurve line – an important factor that ultimately plays

into system reliability.

By embracing standards such as these, and more, HP positions

ProCurve as an effective open platform for third-party VoIP solutions –

IP PBXs, gateways, etc – to use as a transport for voice traffic. HP's

pervasive standards support ensures third parties that ProCurve can

"interoperate" with other VoIP gear to carry IP traffic and ensure that

voice calls placed across the network deliver a level of call quality

excellence unsurpassed by other infrastructure providers. HP refers

to this as a "universal" infrastructure that can accommodate virtually

any industry-standard vendors' VoIP solution.

In Chapter 3, The Tolly Group examines HP ProCurve's capability to

support VoIP traffic generated by six different VoIP platforms: Cisco

AVVID traffic generated by a Cisco Call Manager, VoIP traffic gener-

ated by an older generation 3Com Corp. NBX-100 IP PBX and VoIP

calls handed off from a Mitel Corp. 3300-Integrated Communications

Platform (ICP). The 3Com NBX-100, Cisco AVVID and Mitel 3300-ICP

VoIP solutions originally were tested in May 2003. More recently, in

October 2003, The Tolly Group tested three more VoIP platforms for

their 'interoperability' with the HP ProCurve switching infrastructure:

Avaya IP403 Office, NEC NeaxIPS and a Nortel Networks BCM200.

Note as you examine Chapter 3, HP was not intent to demonstrate

that ProCurve can deliver VoIP traffic with just a single configuration

of access switch, aggregation switch and core switch. HP under-

stands that users often have different requirements at the access

level, and, consequently it tested three different access switches to

demonstrate the uniformity of call quality that HP ProCurve

Networking solutions deliver.

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By embracing standards, HP positionsProCurve as an open, viable platformfor third-party VoIP solutions.




Fostering Interoperability for VoIP

HP ProCurve's switch line is based upon a QoS strategy that delivers band-

width provisioning, traffic control services and prioritization policies to man-

age traffic effectively and ensure that high-priority data types receive the

bandwidth they need, when they need it.

HP ProCurve's commitment to QoS in its switch product line, and in the

Adaptive EDGE Architecture, is the keystone to enabling third-party voice

solutions, such as IP PBX and VoIP gateways, to utilize HP ProCurve switch

fabrics effectively as an IP transport. HP's broad support for QoS mecha-

nisms assures third-party VoIP solution providers that they can overlay their

IP-based voice traffic on top of a switching fabric that will treat latency-

sensitive voice in the manner it deserves and needs.

In the sections that follow, The Tolly Group will chronicle six VoIP solutions:

Avaya IP403 Office, Cisco's AVVID/Call Manager, Mitel Corp.'s 3300-

Integrated Communications Platform, NEC NeaxIPS, Nortel Networks Business

Communication Manager 200 (BCM200) and 3Com Corp.'s NBX-100. All of

these offerings have been tested to determine the quality of VoIP when tra-

versing an HP switching infrastructure and the amount of latency produced.

Cisco's AVVID also was tested as it ran across a Cisco switching fabric and

3Com's NBX-100 was tested across a 3Com switching fabric.

Engineers tested the call quality of each of these systems supporting

calls placed across the HP ProCurve network between a pair of IP phones.

The goal here is to demonstrate that HP ProCurve and its QoS facilities

transport VoIP traffic with no adverse impact on call quality – regardless of

the VoIP solution employed.

Lastly, in the May 2003 version of this white paper, The Tolly Group reported

PSQM and PESQ call quality results. However, upon deeper analysis, we

have come to the conclusion that call quality is largely a factor of the

IP PBX or VoIP gateway that generates the traffic. What we seek to prove

in this white paper is the delta between the baseline call quality and

the toll quality when congestion is present and QoS kicks in. That percentage

delta is the true arbiter of the underlying switch fabric and its impact, or

lack thereof, on VoIP traffic.

Cisco AVVID traffic across HP ProCurve

If there ever was any question about whether Cisco AVVID VoIP traffic

can ride over an HP ProCurve switch fabric and still deliver the same

call quality as a Catalyst network, then Tolly Group testing will put

that to rest.

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Tests focused on passing AVVID VoIP traffic across a ProCurve switching

fabric. By contrast, Cisco's AVVID master plan for VoIP consists of a

Cisco Call Manager for the voice portion of the AVVID solution. Some

Cisco resellers contend that users must employ a Cisco Catalyst

switching infrastructure to obtain the QoS attributes and call quality

necessary for enterprise networks.

Tests measured call quality on an "ear-to-ear" basis from the access

(edge) switch level, through the aggregation point and into the

core where the call terminated at a locally attached IP phone.

AVVID/HP ProCurve Switch 2650-PWR edge scenario

In one scenario, engineers measured the call

quality of AVVID traffic traversing a network with

an HP ProCurve Switch 2650-PWR (a stackable

50-port edge device), an HP ProCurve Switch

5308xl and an HP ProCurve Routing Switch

9308m at the core.

On the PSQM side, there was virtually no differ-

ence between the baseline score and the

with QoS tests, highlighting that the HP ProCurve

infrastructure had no impact on VoIP call quality.

(See Figure 1.)

PESQ test scores bear out same result. Test results

show that there was less than a 1% reduction in toll

quality of baseline tests versus tests conducted with

congestion and QoS active. Again, this demon-

strates that HP ProCurve has no adverse affect on

toll quality (See Figure 2). Likewise, one-way delay

was a low 76 ms. for the baseline and 71 ms. during

the congestion scenario.

AVVID/HP ProCurve Switch 4104gl edge scenario

Next, we re-ran the voice quality tests, this time swapping out the

HP ProCurve Switch 2650-PWR and replacing it with an HP

ProCurve Switch 4104gl, a four-slot modular chassis switch. It oper-

ated alongside the HP ProCurve Switch 5308xl and an HP ProCurve

Routing Switch 9308m at the core to support AVVID VoIP traffic.

On the PSQM side, here again the HP ProCurve delivered voice traffic,

actually improving toll-quality by less than 1% during the test of con-

gestion with active QoS. (See Figure 1.) This establishes a pattern of

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Performance Delta of PSQM ScoresAVVID over ProCurve Scenario

Baseline vs. Congestion QoS Test(Higher bars are better)

0%

+1%

+2%

0

0.5

1

1.5

2

2.5

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HP2650-PWR HP4104gl HP5304xl

Figure 1. AVVID over HP ProCurve PSQM summary




voice quality consistency, regardless of which access

switch is used in the underlying HP ProCurve fabric.

PESQ scores again backed up the PSQM results. In

tests, the HP ProCurve Switch 4104gl scenario

yielded an improvement of about 1% over base-

line results when the congestion with QoS test was

run. (See Figure 2.)

One-way delay was just 75 ms. for the baseline

and 72 ms. during the congestion scenario.

AVVID/HP ProCurve Switch 5304xledge scenario

Engineers inserted the HP ProCurve Switch 5304xl as

the edge switch; this device is a four-slot Layer 2/3/4

chassis switch that can be used either at the edge

or as an aggregation point. It operated alongside

the HP ProCurve Switch 5308xl aggregation switch

and an HP ProCurve Routing Switch 9308m as a

core switch to support AVVID VoIP traffic.

Here there was a 2% performance improvement between the base-

line and the PSQM congestion with QoS test – however, such a small

delta indicates there a subtle improvement, if at all perceptible, that

the HP ProCurve switch fabric has on the voice traffic.

Likewise, there was less than a 1% decline in voice quality between the

baseline and congestion with QoS tests when the HP ProCurve Switch

5304xl was measured with PESQ. The baseline yielded a PESQ score of

4.03 and the congestion with QoS test resulted in a score of 4.00 – both

well above the PESQ threshold of 3.8 for excellent toll quality and both

providing a delta that shows consistency of toll quality provided by the

underlying HP ProCurve infrastructure.

One-way delay was fine, at 67 ms. for the baseline and 65 ms.

for the congestion test with QoS.

VoIP call quality using Mitel 3300-ICP traffic across HP ProCurve

HP ProCurve Networking partners its own data networking expertise

with Mitel, a premiere VoIP supplier. Certainly that message rang in

loud and clear during call quality testing.

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Performance Delta of PESQ ScoresAVVID over ProCurve Scenario


-1%

+1%

-1%-1.5

-1

-0.5

0

0.5

1

1.5

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Figure 2. AVVID over HP ProCurve PESQ summary




Here we measured call quality and demonstrated the close connec-

tivity between the Mitel 3300-ICP and the ProCurve switching infra-

structure. Engineers subjected the Mitel 3300-ICP to the same switch

scenarios as tested with the Cisco AVVID traffic.

Mitel/HP ProCurve Switch 2650-PWR edge scenario

In this scenario, we measured the call quality of Mitel 3300-ICP

traffic traversing a network with an HP ProCurve Switch 2650-PWR

at the edge (a stackable 50-port device), an HP

ProCurve Switch 5308xl aggregation switch and

an HP ProCurve Routing Switch 9308m core

switch.

In PSQM tests, the Mitel call quality over the HP

ProCurve fabric yielded a delta of almost -3.5%

between the baseline and the congestion with

QoS tests. (See Figure 3.) Such a small dip does

not result in noticeable impact on toll quality to

the human ear. This scenario yielded phenome-

nally high call quality that equates to a perform-

ance improvement of almost 100% versus the

Cisco AVVID traffic operating in the same switch

fabric.

The PESQ scores were fine also, indicating less

than a 1% delta in voice quality for the baseline

versus the congestion with QoS test for each of

the switches tested. (See Figure 4.)

One-way delay was satisfactory, with 80 ms. for

the baseline and 94.5 ms for the congestion with

QoS test – well within standard limits.

Mitel/ProCurve 4104gl edge scenario

We re-ran the voice quality tests, this time swapping out the HP

ProCurve 2650-PWR and replacing it with an HP ProCurve 4104gl, a

four-slot modular chassis switch. It operated alongside the HP

ProCurve 5308xl aggregation switch and a HP ProCurve 9308m core

switch to support Mitel 3300-ICP VoIP traffic.

Again, PSQM scores indicated excellent voice quality with a base-

line score of 0.56 and congestion with QoS score of 0.58 - less than

a 4% delta in performance but one that would be imperceptible

since the toll quality is still excellent.

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Performance Delta of PSQM ScoresMitel VoIP over ProCurve Scenario

Baseline vs. Congestion QoS Test(Smaller % decrease is better)

-4% -4%

-12%1

-14

-12

-10

-8

-6

-4

-2

0

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Figure 3. PSQM summary results for Mitel VoIP over HP ProCurve

1 Note: The call quality measured during the baseline test and the QoS test representextremely high PSQM call quality score of 0.62 in the ProCurve 5304 scenario. Toll quality is considered any score less 1.29.




(Any score less than 1.29 is considered excellent

toll quality.) Here again, this shows consistency of

call quality, regardless of the access switch type

in the infrastructure.

PESQ scores also indicated excellent voice quality,

with a delta of less than 1% between the baseline

and QoS test, further indicating that the ProCurve

switching infrastructure has no adverse impact on

call quality.

One-way delay was extremely low, with 58 ms. for

the baseline and 83 ms for the congestion with

QoS test.

Mitel/HP ProCurve Switch 5304xl edgescenario

Engineers inserted the HP ProCurve Switch 5304xl

as the edge switch; this device is a four-slot Layer

2/3/4 chassis switch that can be used either at the

edge or as an aggregation point. It operated

alongside the HP ProCurve 5308xl aggregation switch and an HP

ProCurve 9308m core switch to support Mitel 3300-ICP VoIP traffic.

In the PSQM baseline tests, the VoIP solution/switch fabric yielded a

score of 0.55 and a score of 0.62 in the congestion with QoS test – a

12% performance difference but still well within the 'excellent toll

quality' range. Once more, this demonstrates call quality consistency,

regardless of changes to the underlying switch infrastructure. For PESQ

tests, the performance delta was less than 1%, meaning there is no

perceptible impact on call quality by the HP ProCurve switching fabric.

One-way delay was 67 ms. for the baseline and 65 ms. for the con-

gestion with QoS test.

VoIP call quality using 3Com NBX-100 traffic across HP ProCurve

In addition to demonstrating the effectiveness of using an HP

ProCurve switching fabric to handle VoIP traffic on AVVID and Mitel

VoIP solutions, The Tolly Group also measured the 3Com NBX-100. The

NBX-100 IP PBX is an older generation IP PBX.

Engineers subjected the NBX-100 to the same switch scenarios as

with the Cisco AVVID and the Mitel-generated VoIP traffic.

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Performance Delta of PESQ ScoresMitel VoIP over ProCurve Scenario

Baseline vs. Congestion QoS Test(lower bars are better)

-0.2%

-0.7%

-0.2%

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0

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Figure 4. PESQ results for Mitel VoIP over HP ProCurve




NBX-100/HP ProCurve Switch 2650-PWR edge scenario

In one scenario, engineers measured the quality of the 3Com NBX-100

traffic traversing a network with an HP ProCurve 2650-PWR edge switch

(a stackable 50-port device), an HP ProCurve 5308xl aggregation

switch and an HP ProCurve 9308m core switch.

In PSQM tests, the baseline yielded a score of 1.05

and the congestion with QoS test yielded a score of

1.02. Those call quality scores, again, are consistent

with the AVVID scores and represent toll quality

voice. The performance delta shows a 3% improve-

ment from the baseline to the congestion with QoS

test. (See Figure 5.) Again, the HP ProCurve switch

fabric does not adversely impact voice quality.

On the PESQ side, there was virtually no percepti-

ble difference between the baseline and conges-

tion with QoS tests. (See Figure 6.)

One-way delay was 79 ms. for the baseline and 78

ms. for the congestion with QoS test.

NBX-100/HP ProCurve Switch 4104gledge scenario

We re-ran the voice quality tests, this time swap-

ping out the HP ProCurve Switch 2650-PWR and

replacing it with an HP ProCurve Switch 4104gl, a

four-slot modular chassis switch. It operated

alongside the HP ProCurve 5308xl aggregation

switch and an HP ProCurve 9308m core switch to support NBX-100

VoIP traffic.

In PSQM tests, there was barely a 1% performance gain from the

baseline to the congestion with QoS test, indicating the HP ProCurve

network does not negatively impact VoIP. (See Figure 5.)

The PESQ scores showed virtually no change between the scores

for the baseline and the congestion with QoS tests. (See Figure 6.)

One-way delay was 83 ms. for the baseline and 80 ms. for the

congestion with QoS test.

NBX-100/HP ProCurve Switch 5304xl edge scenario

Engineers inserted the HP ProCurve 5304xl as the edge switch; this

device is a four-slot Layer 2/3/4 chassis switch that can be used

T H E

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Performance Delta of PSQM Scores3Com NBX VoIP over ProCurve Scenario


+3%

-1%

+1%

-1.5

-1

-0.50

0.5

1

1.5

22.5

3

3.5

Perc

enta

gein

crea

se/d

ecre

ase


Figure 5. PSQM summary results for 3Com NBX VoIP over HP ProCurve




either at the edge or as an aggregation point. It

operated alongside the HP ProCurve 5308xl aggre-

gation switch and an HP ProCurve 9308m core

switch to support NBX-100 VoIP traffic.

PSQM test results mirrored the Cisco AVVID call

quality with a score of 1.01 for the baseline and

1.02 for the congestion with QoS test – basically

less than a 1% performance change. (See Figure

5.) PESQ scores, likewise, showed barely a 1%

change in call quality. (See Figure 6.) Again, the

message is that HP ProCurve does not adversely

impact the call quality of VoIP traffic riding over

the switching infrastructure.

One-way delay was 79 ms for the baseline and 82

ms for the congestion with QoS test.

VoIP call quality using Avaya

IP403 Office

In this scenario, Tolly Group engineers measured

Avaya IP403 Office VoIP traffic traversing a net-

work with an HP ProCurve 2650-PWR edge switch

(a stackable 50-port device), an HP ProCurve

5308xl aggregation switch and a ProCurve 9308

core switch.

In PSQM tests, the difference between the PSQM

baseline score and the congestion with QoS

score represents a 1% drop in toll quality, which

likely would be imperceptible to users. (See Figure

7.) This is the same performance delta as

observed in the PESQ tests. Again, there is no evi-

dence that the ProCurve switching fabric has any

deleterious effect on VoIP call quality.

One-way delay was 117 ms. for the baseline and

131 ms. for the congestion with QoS test.

VoIP call quality using NEC NeaxIPS

Tolly Group engineers measured the quality of

NEC NeaxIPS VoIP traffic traversing a network with

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Performance Delta of PESQ Scores3Com NBX VoIP over ProCurve Scenario


+1%

0%

-1%-1.5

-1

-0.5

0

0.5

1

1.5

Perc

enta

gein

crea

se/d

ecre

ase


Figure 6. PESQ summary results for 3Com NBX VoIP over HP ProCurve

Performance Delta of PSQM ScoresAvaya/NEC/Nortel VoIP over ProCurve Scenario

Baseline vs. Congestion QoS Test(Positive bars are better)

-1%

0%

-1%

-2.5

-2

-1.5

-1

-0.5

0

Perc

enta

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crea

se/d

ecre

ase

Avaya IP 403 NEC NeaxIPS Nortel BCM200

Figure 7. PSQM summary results for Avaya, NEC and Nortel




an HP ProCurve Switch 2650-PWR (a stackable

50-port edge device), an HP ProCurve 5308xl

aggregation switch and an HP ProCurve 9308m

core switch.

In PSQM tests, there was no difference in quality

between the baseline and QoS test scores.

(See Figure 7.)

In PESQ tests, the NEC NeaxIPS yielded a 1%

performance hike when comparing the toll

quality of the baseline and QoS tests. Again, such

a delta would be imperceptible to business users

and indicates there is no adverse effect of the

HP ProCurve switch fabric on the VoIP traffic.

(See Figure 8.)

One-way delay was 73 ms. for the baseline and

75 ms. for the congestion with QoS test.

VoIP call quality using Nortel BCM200

In this scenario, we measured the quality of Nortel BCM200 VoIP traffic

traversing a network with an HP ProCurve Switch 2650-PWR (a stack-

able 50-port edge device), an HP ProCurve 5308xl aggregation

switch and an HP ProCurve 9308m core switch.

In PSQM tests, the BCM200 call

quality over the HP ProCurve fabric

dropped by 1% between the

baseline and QoS tests; again this

delta is too small to have a per-

ceptible impact on calling parties.

(See Figure 7.)

By contrast, the PESQ scores show

that call quality increases from the

baseline to the QoS test by 3%.

(See Figure 8.)

One-way delay was satisfactory,

with 59 ms. for the baseline and

69 ms for the congestion with QoS

test – well within standard limits.

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Performance Delta of PESQ ScoresAvaya/NEC/Nortel VoIP over ProCurve Scenario


+1% +1%

+3%

0

0.5

1

1.5

2

2.5

3

3.5

Perc

enta

gein

crea

se/d

ecre

ase

Avaya IP 403 NEC NeaxIPS Nortel BCM200

Figure 8. PESQ summary results for Avaya, NEC and Nortel

One-Way Delayas reported by Agilent VQT

(Lower bars are better)

117

7359

131

75 69

0

20

40

60

80

100

120

140

Avaya IP403 Office NEC NeaxIPS Nortel BCM200

VoIP gatekeeper utilized

One

-way

del

ay in

m

illis

econ

ds

Baseline Congestion with QoS

Figure 9. Latency results for Avaya, NEC and Nortel




Making Smart Purchase Decisions

Users embarking upon a VoIP deployment have the option of installing a

solution from a one-stop shopping supplier, or adopting a best-of-breed

approach to VoIP. The Tolly Group advocates the latter approach.

Clearly, testing demonstrates that the HP ProCurve product line delivers a

stable IP switching infrastructure over which a variety of VoIP gateway

traffic can run unencumbered. Moreover, tests of congestion with QoS

show that ProCurve has the type of facilities necessary to ensure that

VoIP traffic receives preferential treatment – with little to no impact on

voice quality.

In test after test, with six different brand VoIP solutions, HP ProCurve

delivered consistent call quality and, equally important, low delay that

otherwise could imperil the quality of voice traffic. Certainly, HP ProCurve

has delivered a level of call quality equal to or better than other IP

switching fabrics tested by The Tolly Group.

But best-of-breed extends well beyond performance and call quality. It

factors in cost of ownership. In many instances, purchase decisions come

down to a price/performance issue. Here, HP historically has had a

compelling story to tell.

An August 2002 Tolly Group Test Summary commissioned by HP compared

the HP ProCurve Switch 5308xl versus a Cisco Catalyst 4006 on a

performance and cost-of-ownership basis (Test Summary document

202153 at www.tolly.com). From a performance standpoint, the HP

ProCurve switch delivered 100% of wire-speed Layer 2 throughput with

Gigabit Ethernet uplinks compared to just 25% from the Catalyst device

in the same scenario. Moreover, the HP ProCurve offered 20% less laten-

cy, which is important to latency-sensitive

applications like VoIP.

On the cost-of-ownership front, The Tolly Group found that the HP

ProCurve switch offered four times better the price/performance at less

than half the cost of the Catalyst device in a Fast Ethernet configuration

and about a fourth of the cost of the Cisco product in a 32-port Gigabit

Ethernet configuration. Moreover, HP ProCurve does not require an

extra-cost support contract, whereas the Catalyst required a $1,520

annual service/support contract.

Further, a November 2001 Test Summary on the HP ProCurve Switch

4108gl versus the Cisco Catalyst 4006 showed that the HP device posted

a cost-per-gigabit of throughput of $1,417 versus $9,261 in the Catalyst's

most expensive Gigabit Ethernet scenario tested (Test Summary

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document 201138 at www.tolly.com). Still, the HP ProCurve proved that its

cost-per-gigabit comes in anywhere between two to 12 times less than

the Cisco switch.

That's a compelling argument in favor of HP ProCurve as the underlying

network transport for a converged voice/data network.

Factor in HP's commitment to standards such as the ITU's 802.1p/Q, H.323

and others and users have an open communications platform capable

of accommodating VoIP traffic from literally any IP telephony vendor.

Tests prove that HP ProCurve Networking delivers able voice quality for

several representative VoIP IP PBX suppliers.

The fact that ProCurve provides an effective industry-standard solution

at an affordable price means that users can build their networks

affordably over time with a choice of solutions and can adapt to future

applications. In effect, clients get more out of technology to reduce

the initial cost of ownership and provide a better return on IT infrastructure.

It all boils down to one simple fact: HP ProCurve Networking delivers

excellent call quality for enterprise network users, and it does so while

providing an extremely competitive cost-of-ownership. Users will be

hard-pressed to find a better combination.

###

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The Tolly Group, Inc.3701 FAU Blvd. Suite 100

Boca Raton, FL 33431Phone: 561.391.5610

Fax: 561.391.5810http://www.tolly.com

[email protected]



16

Information technology is an area of rapid growth and constant change. The Tolly Group conductsengineering-caliber testing in an effort to provide the internetworking industry with valuable infor-mation on current products and technology. While great care is taken to assure utmost accuracy,mistakes can occur. In no event shall The Tolly Group be liable for damages of any kind includingdirect, indirect, special, incidental, and consequential damages which may result from the use ofinformation contained in this document. All trademarks are the property of their respective owners.

The Tolly Group doc. 204113 rev. clk 12 Jan 2004

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