Transcript Don`t Try VoIP Without It

QoS:
Don’t try VoIP without it
Jonathan Zarkower
Director, Product Marketing
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
Gartner Group
Voice and data convergence
based on IP telephony
will be under way in more than
95 percent of large companies
by 2010
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
2
SLA requirements for
successful UC deployment
Session admission control
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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
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–
–
–
–
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
Boston
Headquarters
IPT
X
Access
X
X
4
Traffic control requirements
Failure detection and reroute
Other IP
subscribers
Other IP
subscribers
PSTN
Failure recovery control
Session capacity and rate
limiting
Session load balancing
Peer
Peer
Headquarters
IPT
CC
UC
Registration controls
Access
H.323
RO
SIP
SIP
BO
Regional
office
Branch
office
SOHO
Mobile
user
Nomadic
user
5
QoS requirements
Capacity guarantee - # of sessions
Bandwidth guarantees
Quality guarantee – delay, jitter, loss
QoS monitoring and reporting
QoS
marking
Best Effort
Expedited Forwarding
Media
Media
Based on policy, session media
traffic gets directed to traffic
engineered MPLS pipe
MPLS tag
insertion
MPLS tag
directive
Media
Acme Packet proprietary & confidential
Best Effort
Label
Switch
Router
Premium
6
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 to
successful quality of experience
Personal oversubscription requires “managed” use
of services
Tim
Boston
Headquarters
Minneapolis
Voice
Jim
IPT
Internet
DSL
Email
8
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
RTCP control
RTP media
SIP signaling
Router
Router
SIP signaling
RTP media
RTCP control
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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)
CC
Site B
PSTN
Service
providers
CC
Site C
MPLS VPN
Contact center
site A
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
CSR
Monitor and
report quality
on both sides
of the
session.
CSR
CSR
ACD
Managed
network
AS
MS
Internet
CSR
Callers
IVR
SIP
caller
H.323
caller
10
SLA assurance benefits
in enterprise/CC
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
PSTN
Service
providers
Headquarters
UC
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
Hosted services/
IP contact center ASP
Other IP
subscribers
CC
MPLS VPN
H.323
IPT
Internet
SIP
SIP
RO
BO
Regional
office
Branch
office
SOHO
Mobile
user
Nomadic
user
11
SLA assurance to guarantee quality &
availability
Function
Features
Session 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 rerouting and re-distribution
Failure recovery control
Registrar failure detection, controlled endpoint re-registration and registration rerouting reduce duration of service outage
Transport control
Differentiated classes of service enabled by QoS marking/VLAN mapping based
on application, source/destination address
Peer-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 ASR
report on a per application, per session basis
Append QoS and ASR information to CDR
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The leader
in session border control
for trusted, first class
interactive communications
What is a session border controller?
Session – real-time, interactive
communications – voice, video
& multimedia - using SIP, H.323,
MGCP/NCS, H.248
Hosted services/
IP contact center ASP
Other IP
subscribers
PSTN
Service
providers
Border – IP-IP network borders
1. Interconnect border
2. Access – trusted
3. Access – untrusted
4. Hosted/ASP
Headquarters
UC
CC
IPT
Control
1. Security
2. Service reach maximization
3. SLA assurance
4. CAPEX/OPEX minimization
5. Regulatory compliance
MPLS VPN
H.323
Internet
SIP
SIP
RO
BO
Regional
office
Branch
office
SOHO
Mobile
user
Nomadic
user
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