QoS:Don’t try VoIP without it

Jonathan ZarkowerDirector, Product Marketing

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Enterprise & contact center transition to IP interactive communications

TDM-to-IP transition well underway

– Reduce costs, improve communications efficiency – Mobility, collaboration, presence and

video drive IP transition and complexity– Compliance – call recording, emergency services,

domain separation– IP PBX extensively deployed but exist as islands

Unified Communications (UC) is the new focus

– Migrate mission critical applications onto IP network – Integrate chat, voice and video into contact center

and business applications– Introduce presence and mobility into application delivery process– Transition call centers to multimedia customer care centers

Enhanced communications efficiency

– Enables intelligent call routing based on business rules/processes (cost, availability, skills, etc.)

– Integrate remote workers/agents seamlessly– Distribute call processing to eliminate single point of failure

Voice and data convergence based on IP telephony

will be under way in more than 95 percent of large companies

by 2010

Gartner Group

SLA requirements forsuccessful UC deployment

Session admission control– Capacity polices for link utilization– Monitor real-time bandwidth utilization– Accept/reject calls based upon capacity & utilization– Prioritize interactive communications traffic over other traffic – Report on observed QoS metrics and accept/reject calls

based upon observed QoS

Traffic controls– Failure detection and re-route– Failure recovery control– Session capacity and rate limiting– Session load balancing– Registration controls

QoS – Capacity guarantee - # of sessions– Bandwidth guarantee – Quality guarantee – delay, jitter, loss

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Session admission control requirements

Establish capacity polices for link utilization including aggregated links

Monitor real-time bandwidth utilization

Accept/reject calls based upon capacity & utilization

Prioritize interactive communications traffic over other traffic

Report on observed QoS metrics and accept/reject calls based upon observed QoS

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Boston

HeadquartersIPT

AccessX

X

X

Traffic control requirements

Failure detection and re-route

Failure recovery control

Session capacity and rate limiting

Session load balancing

Registration controls

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Access

PSTN

Peer

SIP

H.323

SIP

Other IPsubscribers

Regionaloffice

Branchoffice

BO

SOHO Mobileuser

Nomadicuser

HeadquartersCCIPT

UC

RO

Peer

Other IPsubscribers

Capacity guarantee - # of sessions

Bandwidth guarantees

Quality guarantee – delay, jitter, loss

QoS monitoring and reporting

Based on policy, session media traffic gets directed to traffic engineered MPLS pipe

QoS requirements

6Acme Packet proprietary & confidential

Best Effort

Media

Expedited Forwarding

Media

MPLS tagdirective

PremiumLabelSwitchRouter

Best Effort

Media

MPLS taginsertion

QoSmarking

QoS absolutely critical to successful VoIP/UC deployment

Effective bandwidth without QoS much less than rated bandwidth– Less than 15% for toll quality – 250 Kbps of T1

– Less than 33% for cell phone quality – 666 Kbps of T1

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QoS absolutely critical tosuccessful quality of experience

Personal oversubscription requires “managed” use of services

DSL

Voice

Email

Tim

JimBostonMinneapolis

8

HeadquartersIPT

Internet

Today’s QoS mechanisms don’t solve this problem

No QoS mechanism can control call set-up

ToS and DiffServ – packet prioritization only

MPLS – prioritization, and quality & capacity-based routing typically only internal to single network, not between networks

NONE – “Network Overprovision Nearly Everywhere” – never on access links

RSVP – “sorry, no group reservations”prioritization and resource reservation on a per flow basis, not a session consisting of six flows

SIP signaling

RTP media

RTCP control

SIP signaling

RTP media

RTCP control

RouterRouter

9

Session border controllers (SBCs) provide SLA assurance for UC traffic

Session admission control– Perform signaling (call rating,

max sessions, etc.) and/or media (bandwidth) based admission control

– Supports local and/or external policy decision function(PDF)

Traffic controls– Fine-grained session

rate control settings– Per signaling element, per

interface enforcement

Quality of Service (QoS) – Marking and mapping– QoS & ASR-based routing– Monitoring and reporting

Monitor and report quality on both sides

of the session.

Managed network Internet

SIPcaller

H.323caller

Contact center site A

Callers

MPLS VPN

CCSite B CC

Site C

Serviceproviders

PSTN

CSR

ACD IVR AS MSCSRCSR CSR

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SLA assurance benefitsin enterprise/CC

Hosted services/IP contact center ASP

PSTN

Serviceproviders

SIPH.323 SIP

Other IPsubscribers

Regionaloffice

Branchoffice

BO

MPLS VPN Internet

SOHO Mobileuser

Nomadicuser

Headquarters

CC IPTUC

RO

Optimizes HQ-based resources – Ensures consistent resource &

bandwidth availability– Leverages internal and external

policy capabilities

Minimizes costs associated with service outages– Balances traffic across multiple

upstream resources– Provides geographic redundancy

by avoiding out of service devices

Maximizes user quality of experience (QoE)– Defined QoS marking and mapping– Prioritization of traffic on ingress– Reporting of actual session quality

for SLA/admission control use

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SLA assurance to guarantee quality & availability

Function FeaturesSession admission control

Signaling & bandwidth constraints per user, network or session agent to ensure resource availability

Overload protection & control

Traffic load balancing based on max allowed sessions, per session rate capacity, registration rate policing, code gapping, sustained rate and burst rate limits protect core from overload and service disruption due to mass calling events

Failure detection and traffic re-route

Network element (L3 router, registrar, session agent) health and availability monitoring, detection of device failure or performance degradation; traffic re-routing and re-distribution

Failure recovery control Registrar failure detection, controlled endpoint re-registration and registration re-routing reduce duration of service outage

Transport control Differentiated classes of service enabled by QoS marking/VLAN mapping based on application, source/destination addressPeer-peer media release between endpoints

Quality-based routing Session routing based on observed QoS – jitter, loss, latency – or answer seizure ratio (ASR)

Quality reporting Measure QoS (latency, jitter and packet loss) and ASRreport on a per application, per session basisAppend QoS and ASR information to CDR

The leader in session border control

for trusted, first class interactive communications

Session – real-time, interactive communications – voice, video& multimedia - using SIP, H.323,MGCP/NCS, H.248

Border – IP-IP network borders

1. Interconnect border2. Access – trusted3. Access – untrusted4. Hosted/ASP

Control

1. Security 2. Service reach maximization3. SLA assurance 4. CAPEX/OPEX minimization5. Regulatory compliance

What is a session border controller?

Hosted services/IP contact center ASP

PSTN

Serviceproviders

SIPH.323 SIP

Other IPsubscribers

Regionaloffice

Branchoffice

BO

MPLS VPN Internet

SOHO Mobileuser

Nomadicuser

Headquarters

CC IPTUC

RO

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