SCTE VoIP Technical Session May 17th , 2006 Brian Page Network Architect Nortel

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SCTE VoIP Technical Session May 17th ,
2006Brian PageNetwork ArchitectNortel
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Agenda

• Network reference configurations high level
• Trends SIP interworking
• Border gateways SBC
• Other devices such as enterprise PBXs
• SIP Interconnection to other applications
• Issues that impact Voice Quality
• PacketCable Architecture DQoS
• Call Flows
• Issues more common problems
• Packet networks
• Troubleshooting Techniques and Monitoring
• Sample traces
• SS7 and IP traces

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The IP Voice Quality Puzzle
Speech codec quality
End-to-end delay
Transmissionlevels
Echo control
Lost/late packets
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CS2000 PacketCable Cable VoIP Complete Solution
DOCSIS
CS2000 IEMS Probe
SNMP
SNMP
Choice of SCC2 or SNMP for Succession and
Syslog
PSTN
SS7
MAS
Call Server
SDM
CS2000- Compact
GWC SC
Servord Plus
Cable Access
Packet Network
HFC
CMTS
eMTA/SMTA
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SN09 CS2000 Integrated Access Base Solution
VoIP
HIT/HDT
CS 2000
HFC
CS 2000
SIP Interworking - LD
NIU
ESMA
Long Distance E-911 Operator Services Fully
Featured Mobility
SIP Trunking Server
SPM
IW SPM
PP8600

• SIP Services
• Voicemail
• Unified Messaging
• Feature Servers

Managed Packet Network
IP Interconnect to other Carriers
SBC
Shared Trunk Gateway to TDM
Hosted PBX
Business VoIP
Cable Access
CMTS
Media Gateways Open Standards
H.323 SIP
4, 12, 30 Port Analog GW MGCP
H.248
LAN
Embedded MTA - NCS
PRI
PSTN
IP PBXs
PRI
PBX
M1, BCM CS1000 Cisco
Askey, Audio Codes, Carrier Access, Mediatrix,
Others
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DMS and VoIP Switches SIP Mesh LD trunking
Chesapeake
Hybrid
Dual Gateways not Shown Phoenix SIP Servers
Planned WIP Not All routes are shown
simplicity Atlanta Call Server under discussion
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CS 2000 SIP Lines Multimedia Features

• Many Media types from VoIP to point-to-point
  video
• Client types through PoR or BPP
• Hard clients Videophones, SIP MTA, SIP IAD,
  SIP ONT
• Soft clients Nortel PC client
• Multimedia Applications including
• Address Book / Directory ? Click to Call
• Clipboard ? Do Not Disturb
• File Exchange ? Friends Online/Presence
• Outlook Integration ? Inbox / Outbox Call Logs
• Instant Message (IM) ? Picture ID
• Quality of Service (QoS) ? Search (directory)
• Video (H.263, DIVX) ? Web push co-browsing
• Whiteboard ? Search (directory)
• Screening and Routing Rules (follow me,
  sequential ringing)
• Multimedia Web Client

SIP Service Differentiation
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Topics that affect Subscribers

• Bearer Path and Signaling paths can be different
• Different troubleshooting procedures depending on
  issue
• Delayed audio cut through
• Fax super G3 packet cable IP
• Alarm and surveillance systems
• Problems with dial pulse systems
• ECHO control
• Should be enabled in IP packet networks even for
  local systems
• Features interaction
• SCWID and caller ID on call waiting

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Echo Control Considerations
Network Circuit-switched Call type local
Delay 1-2 ms Echo path loss needed lt 10 dB
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Echo Control via the Fixed Loss Plan
Talker echo tolerance curves (from ITU G.131)
10
20
30
Echo path loss
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Limiting case
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Acceptable echo
60
300
250
200
150
100
50
0
One-way delay
Network Circuit-switched Call type short-haul
toll Delay 20-22 ms Echo path loss needed
25-30 dB
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Echo Control Requirements for All IP Calls
Talker echo tolerance curves (from ITU G.131)
10
20
Objectionable echo
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Echo path loss
Limiting case
40
50
Acceptable echo
60
300
250
200
150
100
50
0
One-way delay
Network IP Call type local Delay 200
ms Echo path loss needed 50 dB
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Late/lost Packets in IP

• Where do packets get lost
• Packets may be too late getting to the decoder
• Packets may be lost when router queues overflow
  or are flushed
• Errors and corruption in network devices
  asymmetrical routing
• What can be done to minimize lost packets?
• QoS classification to expedite voice packets
• Longer jitter buffer (need to balance this
  against end-to-end delay)
• What can be done to minimize degradation?
• Use one frame per packet
• Interleaving of frames across packets to reduce
  loss of sequential packets
• What can be done to recover?
• Degradation to output speech quality can be
  reduced through a packet loss concealment (PLC)
  algorithm
• Some codecs have these built in, others need an
  external PLC
• Loss of signaling Packets
• Can result in delays in audio being cut through

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Lost Packets vs. Voice Quality
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Sample E-Model results
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E-Model Output for Various Scenarios
0
0
0
4
0
4
Packet Loss ()
Framing Delay (ms)
0
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98
10
Network Delay (ms)
100
100
100
0
G.723.1 VAD
G.729A VAD
G.711
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PacketCable Architecture

• Security
• DQoS

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Security Architecture
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PacketCable Security

• Spans all interfaces in the PacketCable
  architecture
• Provides confidentiality for media packets and
  for signaling communication across the network
  via authentication, encryption, and key
  management.
• Ensures that unauthorized message modification,
  insertion, deletion and replays anywhere in the
  network are easily detectable without affecting
  network operation
• Security is interface specific, but the majority
  of signaling interfaces are secured using IP
  security (IPSec). The media stream is secured by
  encrypting and authenticating the payload
  directly.
• PacketCable also defines a corresponding key
  management mechanism in addition to defining the
  security protocol that will be applied to each
  interface. There are three basic key management
  mechanisms defined
• Kerberized Key Management
• Internet key exchange (IKE) with either
  pre-shared keys or X.509 digital certificates
• Randomly generated keys exchanged within secured
  signaling messages.
• Encrypted messages are difficult to troubleshoot
• Look at Null Encryption as an option

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Dynamic QOS

• DQoS value
• Security
• DQoS protects against hacker attacks impacting
  the network performance stealing service
• Per-Call Capacity Management
• DQoS enables bandwidth-based access control on a
  per call basis
• Differentiated Service
• DQoS enables Cable VoIP customers to experience
  varying levels of QoS (and for the Cable
  operators to charge for those experiences)

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DQoS Walkthrough
1. The Cable VoIP user attempts to originate a
call, MTA signals CMS using NCS (Network-Based
Call Signaling).
PDP Policy Decision Point
2. The CMS makes a policy decision should this
call be allowed - e.g too many calls from this
MTA a possible denial of service attack If it
decides the call should be allowed, it instructs
the PEP to allow the call via COPS signaling.
3. The PEP creates a gate for this call using
this policy decision and returns the GateID to
the CMS.
PEP Policy Enforcement Point
4. The CMS passes the GateID to the MTA via NCS.
5. The MTA uses this GateID to request QoS
admission from the PEP (using DOCSIS).
6. The PEP admits the flow based on available
bandwidth and authorization envelope provided in
the previous decision. The call can then proceed
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Sample Call Traces
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Backup Material
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Primary Development Platform - Cable VoIP
SN09/(I)SN09FF Line-Up
CALEA Announcements Conferencing
Network Intelligence/ Voice Services
Element Management
SS7 Network Signaling
Back Office
OR
USP/ USP-C
CS 2000 Compact
CS 2000 Hybrid
Back Office and Network Management Systems
SS7 network
MS
SS7
H.248
M3UA
SIP SMDI over IPMWI over SIP BPP
CS LAN
Packetcable OSS Back Office Servers And
Applications
IPUnity Voicemail
C-Cor Cisco (Optional)
Nortel ERS 8600 Cisco 6509
Nortel Border Control Point 7220
Camiant QBUS PacketCable Multimedia Policy
Server(SN09FF)
PKT-MM3
NSF 6614 Firewall
PKT-MM2
Cisco BACC Bigband FFBPM
Access Network Options
Hosted Access
Juniper M40 (Edge) Avici QSR (Core)
Packet Network
ACME SD
Network Interconnect Options
Enterprise
Arris C4 Cisco uBR10012
SIP / SIP-T
H.248 IUA/SCTP IPSec
H.248 IUA/SCTP IPSec
TGCP IPSec
DQoS with IPSec
MG 15000
Other VoIP Networks (Reference Interop to CS
2000 and MCS)
Euro/DOCSIS
NCS with IPSec
NCS
Packet Network
OR
Arris TTM 202/402 Moto SBV5120SBV5229
(09FF) SIP EMTA BPP
SIP
ISUP Trks
ISUP, ltES/OPgt Trks
ISUP, PTS Trks
Unistim
H.323
PRI
V5.2
PRI
i200x
DLC
Centrex IP Clients
BPP
PSTN
IP PBX
TDM PBXs
BPP indicates elements integrated via Nortel
Business Partner Program
Note This is a superset view and interworking
between all gateways may not be supported. Refer
to Gateway Interworking Matrix for supported
interworkings
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Cox TDM Trunking with LD CS2000 Call ServerVoIP
LD handled off to Local IXC -SN09 Configuration
Las Vegas
ALISO VIEJO, CA
CS 2000
NCS
TGCP
H.248/
Nuera
Nuera
Nuera GWY
Nuera GWY
SIP Loop around Signaling EANT ATC Between 100
and 250
ATC/IMT
LEC
IXC -Williams
GWC Signaling Links
Bearer Path
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Cox TDM Trunking with LD CS2000 Call ServerCox
VoIP Voicemail -SN09 Configuration w/ NGSS
Las Vegas
Glenayre IP Voicemail
SIP
CA
NGSS-T
NCS
CS 2000
TGCP
Nuera
H.248/ASPEN
Nuera
Nuera GWY
IT
LEC
IXC
SIP Trunking is required for communication with
Glenayre Session server is required SMDI over
IP converter to RS232 is required for MWI
integration with Hybrid Bearer paths for LD, PSTN
and Voicemail remain local
GWC Signaling Links
Bearer Path
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XA Core/Call Server VoIP Capability

Glenayre Voicemail Currently Connected via TDM
trunk
TDM
SPM
IP IWSPM Port per line 61 trunking ratio
Support Approx 24K customers with out LD
IP IW SPM
SPM Port per line 81 trunking ratio
CSLAN
ESMA
VoIP NCS PacketCable
CMTS

• VoIP Bearer Trunks can go through TDM SPM via IP
  IWSPM
• Takes advantage of TDM pool for efficiency for
  trunking
• VoIP subs can be added by enabling RTU in 6400
  line increments

eMTA
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XA Core Call Server VoIP Remote Market Nuera GW

Glenayre Voicemail Currently Connected via TDM
trunk
TDM
GWC SC
Nuera GW Port per line 61 trunking ratio
CSLAN
CMTS

• VoIP subs can be added by enabling RTU in 6400
  line increments

eMTA