Best Practices Guide for Over-the-Top (OTT) Deployment

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UNIVERGE Cloud Services

19 July 2015

Best Practices Guide for Over-the-Top

(OTT) Deployment

Table of Contents

Introduction page 4

NEC’s Unified Communication as a Service (UCaaS) or (nUCaaS) page 5

Understanding the infrastructure page 7

Network considerations page 7

Types of SMB networks page 9

Option 1

Option 2

Equipment page 12

Routers page 14

Switches page 15

VOIP Analyzer page 16

Troubleshooting Suggestions page 18

Conclusion page 21

Introduction

Unified Communications (UC) refers to the collaboration of voice, data, and different software

based applications in a business environment. When these intertwining communications are

hosted and managed by a service provider other than the end user (i.e., the PBX no longer

resides on the customer premise) it now becomes considered a “cloud” service. Cloud services

allow companies different ways to mitigate the capital and operating expenditures of owning,

implementing, and maintaining on premise hardware. These functions or services include

Storage as a Service (“SaaS”), Infrastructure as a Service (“IaaS”) and Platform as a Service

(“PaaS”). Unified Communication as a Service, or “UCaaS” for short, refers to the delivery of

collaborative voice, data and business applications to the end user as a cloud based service.

“nUCaaS” is NEC’s UCaaS service offering. Some of the many different types of services

delivered by NEC under the nUCaaS umbrella include voice telephony, web services, audio and

video conferencing, call center as a service, and unified messaging.

NEC enables the customer to connect from the customer’s premise to the nUCaaS cloud in a

couple of fundamental ways. The preferred method is via a dedicated, NEC provided, MPLS

circuit from the customer’s premise to the nUCaaS cloud. This is preferred because it provides

visibility to NEC for monitoring and managing the WAN (or circuit side) of the customer’s

connection to the nUCaaS cloud. It will also provide Quality of Service (QoS), eliminate the

need for NAT in the network and will enable NEC to be proactive in detecting and addressing

any performance degradation of the customer’s service that may occur on the managed circuit.

An alternative method of connecting from the customer’s premise to the nUCaaS cloud is by

the use of customer-provided bandwidth, i.e. an unmanaged Internet Service Provider (ISP)

WAN connection to an Internet. This method of connectivity is often referred to as “Over-The-

Top” (or “OTT”) connectivity and it’s suitability for any particular customer deployment is

subject to certain networking guidelines. For deployments that wish to use OTT connectivity,

NEC requires that the customer provided bandwidth be in accordance with the quote provided

for the service. It would be the customer’s responsibility to increase the bandwidth accordingly

to support service expansions as they occur. Furthermore, the customer must use an NEC

approved CPE demarcation device, have adequate voice and data segmenting on their network

and receive a “Pass” result on both a network (circuit/WAN) side and local area (LAN) side VoIP

ready check as performed by the NEC Associate. All OTT deployments over 25 users require a

design review between NEC and the NEC Associate.

For customer deployments where an NEC-provided MPLS circuit is used (due to the ability for

NEC to monitor the managed circuit), NEC can provide the customer with a Service Level

Agreement (“SLA”) that provides significant availability assurances backed with service level

credits. A Service Level Agreement for OTT deployment with a “Pass” result is available;

however the availability assurances provided for the OTT deployment reflect that of a non-

managed circuit environment (i.e. without service level credits) and is delivered as a best effort

deployment.

Some of the biggest concerns when contemplating the migration from a typical premise based

VOIP solution to a hosted Cloud based solution are first and foremost voice call quality; with

network security, startup and conversion costs, pre and post-sales technical support, and

network scalability or growth finishing off the list. As the technology to support Cloud services

grows, the possibilities for smaller sized customers to offer greater business services and

applications to their customers become more financially feasible. Because the Cloud can offer

both flexibility and agility in key areas of UC deployment, a well thought out network design

and implementation is important. This document is intended to provide insight into best

practices for configuring nUCaaS SMB OTT deployments.

NEC’s Unified Communication as a Service (nUCaaS)

Bringing to the table over 100 years experience in both TDM and IP telephony, NEC is offering

end to end hosted telephony solutions through its Cloud Services division. With its completely

hosted behind the scenes telephony solution, NEC’s UNIVERGE Cloud Services for UCaaS,

nUCaaS is able to deliver on-premise voice quality services from the cloud. By following

established industry standards and guidelines for VOIP network deployments nUCaaS is able to

completely monitor, troubleshoot, and provide quality technical expertise to its customers for

all of its currently hosted services. With this in mind, nUCaaS strives to implement next

generation Cloud telephony technology on the customer’s solid functioning switched IP

network. NEC Cloud Services works with each of its customers through authorized dealers to

achieve optimal network performance while providing for flexibility in growth and ease of

maintenance. One goal of nUCaaS is to use NEC’s tenure in the marketplace and experience

gained along the way to provide its Cloud customers the very best experience as they embark

on the challenge of utilizing next generation technology to provide legacy telephony services.

Figure 2

Understanding the infrastructure

The networks that are in place today look very different than the networks of yesterday. It used

to be that small networks only had computers and servers connected to them. The network

was built to be as a best effort delivery mechanism, where delay and loss of information

between devices was something to be dealt with. Today, most networks have an over

saturation of devices needing to gain access to the IP infrastructure. Desktop computers, fax

machines, wireless PDA’s, Servers, home appliances, video servers and numerous types of VoIP

terminals all are fighting for bandwidth, precedence, and addresses on this converged network.

While each and every network functions the same in terms of the sending and the receiving of

traffic (either locally or across the Internet), each network can be routed and switched

differently depending on numerous criteria. When the addition of voice traffic is added to that

switched data network, each end user can also have different expectations when it comes to

voice call communications. In an effort to provide the very best voice communications over the

Cloud, nUCaaS critiques each customer infrastructure so that a solid foundation is built starting

with the deployment of devices on the IP network. When evaluating the existing customer

network design for possible Cloud deployments of 24 voice users or less, nUCaaS has adopted

two physical network design implementations to assist dealers in building solid customer

network bases from which Cloud services and applications can be implemented. Two repetitive

elements of a well functioning voice and data network are segmentation of traffic and quality of

service. Each of these will be further described in the upcoming sections.

Network Considerations

When designing any VOIP network, de facto industry standards suggest that the voice and data

traffic routed across the Local Area Network (LAN) be physically or virtually segmented and

priority given to the transmitting of voice traffic. Because the RTP traffic which carries the voice

packets is never resent over the network it is imperative that this type of traffic reach its

destination in a sequential order and in a timely manner. If this traffic is lost or delayed for any

reason the quality of voice calls over that network suffers (choppiness of conversation, one way

audio conversations, dropped words, etc). To complicate matters, even though the company

internal LAN is optimal in design yet utilizes an Over-The-Top (OTT) solution, the best effort end

to end internet connection may be the bottleneck. Over-The-Top simply refers to the

distribution of media over the Internet without the use of an operator to control content

delivery and is described as “best effort” traffic. Given the challenges of Internet connections

and bandwidth oversubscribing there is little the customer can do short of replacing the

connection with a managed dedicated circuit or obtaining some sort of Service Level

Agreement (SLA) from the provider specifying a guaranteed amount of bandwidth.

Implementing Quality of Service (QoS) on the network is giving some type of priority to the

traffic that is transmitted over the LAN. Most often voice traffic is given QoS over regular data

traffic. This can be accomplished in many different ways with proper design of the network as

well as careful consideration of exactly what traffic is most important. The most common types

of QoS are IP Precedence and Type of Service. Additionally, physical configuration of the ports

on managed switches can also assist with this implementation. NEC Cloud Services is fully

capable of assisting in the proper design or layout of the network to accomplish this task.

There are several network quality requirements that NEC requires be met before deployment

of any hosted VOIP telephony services. In addition to this, once the deployment is

implemented, these parameters need to be periodically monitored so that in the event of any

call quality issues coming forth any one of these items can be quickly dismissed once remote

access to the customer demarc router has been established. At a minimum these criteria

include:

The Local Interface to which the VoIP terminals and/or software terminal connects

must meet 802.3af Ethernet standards (use of PoE L2 / L3 switches)

Sustained packet delay one-way should be less than 100 milliseconds optimal, with a

maximum of 150 milliseconds one-way

Sustained jitter should be between 10-150 milliseconds optimal with maximum of 300

milliseconds

Sustained packet loss of 1% or less is recommended with the maximum of 3% from

end to end

Bandwidth usage will vary depending on the media, payload and audio algorithms

utilized. QoS (IP Precedence /Type of Service) needs to be implemented.

Bandwidth and Latency (ANOP-01-003a) requirements for determining the sustained

amount of bandwidth required (128K per call @G711)

Mean Opinion Score (MOS) voice calls of 4.0 or more

Types of SMB networks

NEC Cloud Services is categorizing SMB networks into three different designs based on how the

customer currently has it deployed. The first design is one which has the voice and data

networks physically separated by switches.

The second design is one that has data devices are plugged into the back of the phones (which

is serving as a switch port) and the phone is cabled to a managed switch again providing PoE.

The managed switch is configured with two Virtual LANS (VLANs) on it; one for voice traffic and

the other for data traffic.

The third design is one which has VLANs set up on a managed switch and uses a dedicated WAN

link from the router through the Internet. Examples of this type of link could be a T1 (1.54Mb)

or an MPLS (1.5Mb or 3Mb) circuit. The additional costs associated with this link provide the

customer with some type of SLA that mandates a specified amount of bandwidth at all times

from the Provider. While this document only covers OTT based solutions, additional specifics

on the nUCaaS hosted MPLS solution can be found in the NEC Cloud Services (nUCaaS) Best

Practices Guide to MPLS Deployments in SMB Markets (document is currently in draft status).

Network Design Option 1

The network design for option 1 typically shows a network that has both voice and data

networks physically separated. Every data device has its own Ethernet cable run back to a non

PoE switch and every phone is cabled into a PoE switch or has an AC adapter supplying AC

power. Every device on the LAN has a separate IP address based on DHCP address schemes and

this can be configured on the demarc router. Traffic from one subnet does not traverse onto

the other and if the switches do not support QoS then it will only be applied as the traffic is

directed in and out the demarc router. The demarc router on site serves to direct any traffic

destined for the Internet out the WAN interface where it then becomes best effort traffic while

traversing the Internet.

Network Design Option 2

The network design for option 2 is configured so that computers are plugged into the back of

the NEC Dterms using the built-in switch port. The Ethernet cable run from the Dterm to the

switch carries both voice and data traffic. At this point the voice traffic can be “tagged” with a

VLAN ID as it enters the managed switch. If this switch is not PoE then all Dterms must have

some sort of AC power adapter to supply power. Any other data devices (printer, DHCP server,

etc) would have a separate connection on the LAN back to the data VLAN. After configuring the

managed switch to provide the rules which regulate the movement of packets across the LAN

(VLAN tags, queue priorities, VLAN trunking, etc) the switch is then cabled to an interface on

the router. A Fast Ethernet interface on the router then serves as the physical link to the ISP.

As traffic enters the managed switch it is queued or managed based on the configuration

programmed on the switch. QoS may be adopted at this point with the voice traffic given a

higher priority. Different switches offer different modes of QoS and it is advisable to discuss

these parameters with nUCaaS prior to deployment. Once the prioritized voice traffic destined

for the NEC NOC enters the demarc router it may also be given some type of priority either

based on Ingress properties (coming in) or Egress (going out) properties out the WAN interface.

Nonetheless, once the traffic (either voice or data) traverses the Internet it all becomes best

effort once again with no QoS implied or given.

Equipment

In an effort to alleviate all possible known or unknown hindrances on a customer’s routed

network and to also verify the network’s ability to support quality Cloud telephony services via

the OTT WAN link, NEC has partnered with Adtran (www.adtran.com) to bring forth a complete

line of high performance routers, switches, and Business gateways at very reasonable prices.

These devices are expected to be implemented into the network where needed to facilitate

routing to the WAN interface. These devices will be implemented into the network with

minimal disruption to the customer and with the full technical support of the NEC dealer and

the nUCaaS team. The nUCaaS team will look at all currently configured devices on the network

to verify that they are able to support the requirements of the network in a hosted

environment.

In addition to the available routers and switches, NEC has implemented a network monitoring

process used to help determine the quality of the network before actual deployment. The

monitor tool (VOIP Analyzer) is able to perform both live and scheduled tests on the network to

assess its overall performance for any specified time duration and is a pass/fail test that

determines the capacity of the network infrastructure’s current configuration to support VoIP

traffic. VOIP Analyzer will be administered as part of every IP Telephony implementation but

will be required for ALL Over-The-Top WAN connections to an ISP. Because of the best effort

“no QoS implied or given” bursty nature of Internet traffic, this requirement has been adopted

to help minimize the trouble-shooting process and lessen the chance of voice issues occurring

after deployment. A failing report on the network means that the network as a whole is not

conducive to support a toll quality VOIP Cloud deployment and must be resolved before

proceeding.

The preconfigured monitoring tool will host a connection from the customers’ on premise

network to a NEC server gathering data in one of NEC’s redundant data centers. The test shows

results for the call quality (MOS) and QoS (jitter, delay, and packet loss) performance of the

expected volume of VoIP Traffic to be supported by the network. The VOIP Analyzer will also

deliver a network speed test, a traffic capacity test and a firewall test. This service however,

does not provide analysis regarding specific network impairments or recommendations for

remediation. If the customer requests this information, they should be encouraged to purchase

a full VoIP Network Assessment. The VOIP Analyzer will be remotely administered for a period

of 7 days on the customer network. The NEC Associate must schedule this monitor service with

NEC’s Cloud Network Operations Center (NOC) a minimum of two weeks prior to any scheduled

customer cut-over.

The currently preferred network hardware devices being offered by NEC for placement on

premise on a customer’s network are listed below. There are other devices available

depending on the needs and requirements of the network and these specific cases should be

discussed with the NEC Associate’s Account team.

Demarc Routers

The demarc router that nUCaaS will be deploying for all OTT deployments where the customer

WAN connection is 20Mbps or greater will be the NetVanta 3140. For any OTT deployment

with a customer WAN connection of 20Mbps or less the NetVanta 3120 will be deployed.

Additional parameters and feature of each router is described in the next section and for more

detailed information of the parameters and feature specifications of each device please refer to

the ADTRAN Hardware Feature Specifications and Matrix Guide for UCaaS Shipped Routers and

Switches document.

NV 3140 (P/N 0410441)

The NV 3140 is a high-performance router supporting three fixed, autosensing LAN or WAN

facing Gigabit Ethernet interfaces. It is ideal for multiple applications where Ethernet

redundancy is needed. This can be achieved with two Ethernet delivered access services

providing immediate failover to the active link anytime a link down event occurs. Also, since

many customer networks still feature separate voice and data network the NV 3140 is a perfect fit

with two Gigabit interfaces routing the LAN voice and data traffic and the third port serving as

the WAN interface connecting to the Internet.

QoS is supported on t he NV 3140 for delay-sensitive traffic like VoIP or video. To prioritize

mission-critical traffic and control network congestion the NV 3140 supports Low Latency

Queuing, Weighted Fair Queuing (WFQ), Class-based WFQ, and DiffServ marking. Also

functionality in the NV 3140 provides for a powerful, high-performance stateful inspection

firewall. The firewall can identify and protect against common Denial of Service (DoS) attacks like

TCP syn flooding, IP spoofing, ICMP redirect, ping-of-death, and IP reassembly problems. The

NetVanta 3140 also supports IPSec compliance for VPN access.

NV 3120 (P/N 0410294)

This access router supports a single 10/100Mb Fast Ethernet interface and a 4-port switch. The

NV 3120 is ideal for Internet access using broadband connectivity such as DSL or cable. The

3120 supports VLAN tagging and trunking, static and default routes, and demand routing, for

fast, accurate network convergence. QoS is also supported for delay-sensitive traffic. It

supports standard queuing mechanisms; LLQ, WFQ, and Class-based WFQ, as well as DiffServ

marking to establish the priority of IP packets.

L2 switches

1234 (P/N 0410078) / 1234P (P/N0410080)

This layer 2 switch comes in both Power-over-Ethernet (PoE) as well as non-PoE flavors. It

includes 24 - 10/100Base-T access ports and 2 - combo 1000Base-T/SFP Gigabit Ethernet Ports

and 2 - Enhanced (1Gbps/2.5Gbps) SFP ports. Features include 32 Static Routes, 802.1Q

VLANs, GVRP, and 802.1p/DiffServ QoS. The devices will provide up to 15.4 watts/port (370

watts) of 802.3af compliant power. 19" Rack mount 1U housing. Current supported SFP

modules include 1000Base-SX, 1000Base-LX and SFP interconnect cable.

1531 (P/N xxxxxx) / 1531P (P/N 0410296)

Both models of the 1531 (PoE and non-PoE) have a 8 -10/100/1000Base-T POE access ports, 2 –

1000Base-T, and 2 - Standard SFP Gigabit Ethernet Ports. Its features include 16 Static Routes,

802.1Q VLANs, GVRP, 802.1p QoS, 802.1w Rapid Spanning Tree, 802.3ad Link Aggregation, Auto

MDI/MDI-X, CLI, HTTP GUI, SSH, SSL, RADIUS, SNMP. The unit’s 8" width allows 2 units to be

mounted side-by-side in a standard 19" Rack. It also supports 1000Base-SX and 1000Base-LX

SFP modules.

VOIP Analyzer Monitor tool (P/N 0410335)

VOIP Analyzer (as previously described) measures the expected call quality (Mean Opinion Score –

MOS, based on modified version of the ITU g.107 standard E-Model equation) and quality of

service (QoS) performance (jitter and packet loss). The objective estimation of a MOS takes into

account important factors that effects call quality in any VoIP implementation, such as codec,

delay, loss data and jitter. A higher MOS estimate indicates higher call quality; a MOS of 5 is

excellent; while a MOS of 1 is unacceptable.

The following table (taken from ITU G.107) summarizes the relationship between the MOS and the

user satisfaction:

Mean Opinion Score

(lower limit)

User Satisfaction

4.34 Very satisfied

4.03 Satisfied

3.60 Some users dissatisfied

3.10 Many users dissatisfied

2.58 Nearly all users dissatisfied

The pass/fail grade is based on the Mean Opinion Score (MOS) of the expected amount of VoIP

calls to be transported over the carrier network. If MOS results show less than 4.03 during the

period of testing, NEC recommends that the customer perform a complete Network VoIP

Assessment to determine the spot(s) in the network that require upgrades or tweaking of the

device’s configuration to guarantee optimum voice quality. If MOS score is less than 4.03, NEC’s

Network Operations Center will fail this test and the project will be placed on hold status until the

network is optimized for voice. The test will need to be re-administered again for a period of 7

days to be scheduled with NEC NOC. Please refer to Figure 2 above to see Cloud connection of the

VOIP Analyzer.

The VOIP Analyzer devices will be pre-configured to find its home server located within the NEC

Cloud Services NOC when the unit is brought online. After order placement the NEC Associate will

place the preconfigured VOIP Analyzer device on to customers’ network. The test will simulate a

number of calls over the customers’ internet circuit every hour for the check period. This will

generate a report that will be evaluated by the NOC to determine if the environment will be able

to support OTT connection adequately. It must be taken into consideration that the test will only

monitor the circuit and determine viability of the customers’ circuit during the period of time that

the test is being administered. It is in no way a guarantee that the customers’ overall network

would not have connectivity issues at any given time based on Internet best effort. OTT is a best

effort SLA from any given provider and NEC does not in any way guarantee the customers’ circuit

stability or bandwidth expectations.

Once the monitoring period has ended and the results gathered, nUCaaS engineers review and

analyze the findings. A failing network would incur several sustained instances of excessively high

jitter rates and / or high percentages of network packet loss. Furthermore, if the averages for the

MOS scores continuously dropped below 3.0 the network would also fail. A passing network

would be produce very minimal jitter or packet loss as well as produce MOS scores of 4.0 or

higher. With test results falling between these two defined outliers or parameters, the Associate

and customer must tweak performance levels on the network and outcome results will be on a

case by case basis. In certain cases the monitor process may be performed a second time once

network tweaking has concluded to verify changes.

Trouble-shooting Suggestions

Over the course of time in dealing with OTT implementations and the plethora of WAN supplied

routing devices installed NEC has gained much insight into necessary changes that need to be

implemented on these devices. By making these changes the quality of voice calls has increased as

well as other trouble issues with calls decreased. Below are some suggestions that NEC suggests

trying if the ISP supplied WAN link router is suspect. As always, with any voice issue or down

system call into the NOC’s support line for immediate assistance.

If you are having issues with dropped or choppy calls, please follow these steps:

1. Reboot the premise gateway router

2. Verify that SIP ALG and or SIP Helper/Fix up is turned off on your gateway router

Having SIP ALG or Helper implemented makes your gateway router attempt to

correct for NAT Traversal difficulties by manipulating the contents of the SIP

Header fields.

Leaving the SIP ALG enabled on your gateway router is most likely going to break

SIP connection between your phones and the NEC Cloud VoIP system. This

happens because your gateway router is rewriting the SIP headers needed to

make the VoIP system work.

Leaving SIP ALG on is not supported on the NEC Cloud VoIP system

3. Common issues related to having SIP ALG turned on your gateway router:

Voice traffic only goes one way (end user can hear you but you can’t hear them)

Strange error messages when attempting to make calls

Incoming calls to users do not connect, go straight to voicemail

The call gets setup but no voice traffic can be heard

IP phones reboot a lot, cannot stay registered to the VoIP PBX

4. To turn off Cisco “SIP Fixup” (SIP ALG)

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat/configuration/15-

mt/nat-15-mt-book/nat-tcp-sip-alg.html

On routers:

no ip nat service sip tcp port 5060

no ip nat service sip udp port 5060

On ASA firewalls

Go to policy-map global_policy > class inspection_default and enter:

no inspect sip

On Pix firewalls

no fixup protocol sip 5060

no fixup protocol sip udp 5060

5. For Adtran routers:

Command line: no ip firewall alg sip

Web Interface:

Under Firewall settings go to Firewall/ACLs,

There's a tab for ALG Settings, under that tab you'll see the following:

SIP ALG – Disable this setting

6. Sonicwall

Uncheck box "Use SIP Header Transformation"

Enable consistent NAT

7. Fortinet

From CLI interface, type the following commands:

config system session-helper

show system session-helper (look for the session instance that

refers to SIP, should be #12)

delete 12 ***** example only, be sure to select the

corresponding number to be deleted *****

Confirm deletion of session-helper entry by running the "show system

session-helper" command again. #12 will be there because #13 moved up in

rank, but no reference to SIP or port 5060 noted.

End

8. Netgear:

http://documentation.netgear.com/dg834n/enu/202-10197-02/Advanced.7.2.html

9. Linksys:

10. For all other manufacturers, please check their documentation to disable any SIP ALG

functionality.

Conclusion

In conclusion, NEC continues to remain a leader in the deployment of voice telephony and

strives to apply the latest industry technology in the marketplace. With over a century of

legacy PBX and telephony application experience NEC Cloud Services (nUCaaS) continues to

build upon this rock solid foundation. NEC is committed to remain being a global partner in the

telephony market and its introduction into hosting Cloud telephony services and applications

brings forth both new rewards as well as new challenges. NEC Cloud Communications

continues to develop and adopt new industry technology as part of its Cloud hosting platform

and is continuously adding service functionality and applications to it platform.

As part of this hosting platform NEC Cloud Communications is committed to bringing toll quality

voice communications to the SMB market. With knowledge gained in the legacy PBX markets,

as one telephony challenge is encountered and overcome that earned experience brings forth

added value to both the nUCaaS platform as well as those that it supports. While the

traditional switched IP networks supporting telephony bring forth many challenges for the

Cloud, the NEC support team and its partners offer the service, the knowledge, and the

commitment to providing the highest level of service.

For additional information or questions please feel free to contact your NEC Account Manager.

For nUCaaS Post-Sale Technical Support please contact:

Project Management

Availability: 8:00 am – 5:00 pm EST

Email: projectmgr@neccloudsupport.com Technical Support

Telephone: (800) 852-4632, Dial (Option 7) Availability: 24/7 x 365

Email: support@neccloudsupport.com

Web: Browse to https://help.neccloudsupport.com

NOTE: If you are a new user click on the “Sign-In” button at the top right of the

page then click the link below the sign in box that says “Sign Up”.