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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
4
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
5
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
7
QoS absolutely critical tosuccessful quality of experience
Personal oversubscription requires “managed” use of services
DSL
Voice
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
10
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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12
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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