SIP Trunk – Northwest Branch Training
April 2013
Todd Kawamura
CenturyLink Sales Engineer
SIP Trunk – Northwest Branch Training
What we should all know about SIP Trunk
•What is SIP & brief history
•Primary advantages & benefits of SIP
•Sweet spot for SIP opportunities – What to look for
•Configuration Elements
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SIP Trunk – Northwest Branch Training
What we should all know about SIP Trunk
• What is SIP & Brief History
 SIP stands for “Session Initiation Protocol”
 It’s an IETF standard RFC3261 first published in 2002
 Based on many of the features in HTTP and SMTP protocols
 SIP is the signaling protocol to setup and process VoIP calls
 RTP is SIP’s companion protocol that’s used to carry the audio
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SIP Trunk – Northwest Branch Training
What we should all know about SIP Trunk
• Primary Advantages & Benefits of SIP
 Fault-Tolerance: Ability to build in different levels of diversity
 Cost-Effectiveness: Barrier to entry is low, as is marginal expense
 Scalability: Easy to add more capacity with SIP
 Flexibility: Lots of options to adjust call bandwidth, call flow, etc.
 Manageability: QControl gives users lots of control over SIP service
 Centralizability:
 One vendor to deal with for PSTN
 Consolidation of PSTN access lines
 Centralized TN management
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SIP Trunk – Northwest Branch Training
What we should all know about SIP Trunk
• Sweet spot for SIP opportunities: Customer...
 Has QoS-enabled IP WAN now
 Already has a VoIP solution in place
 Has multiple remote/branch locations with traditional PSTN access
 Views telephony as business-critical to enterprise (e.g., call center)
 Has seasonal fluctuations or other unanticipated call-flow variations
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SIP Trunk – Northwest Branch Training
SIP Trunking Configuration Elements
•SIP engineering considerations
•Session sizing
•Bandwidth sizing
•Session-by-type sizing (Usage and Flat session quantity)
•SIP Diversity options (Enterprise, Switch)
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SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 1
TOTAL SESSIONS REQUIRED
 Determine total session (i.e., trunking) requirements for enterprise
 Methods include:
o Peg counts from traffic study
o CDR data from customer’s PBX
o Rule of thumb method agreed to by customer
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 2
SESSIONS REQUIRED BY TYPE
Determine how many sessions by type (Flat or Usage)
o Flat Inbound Call Types (from PSTN) : Local TN, DID
o Flat Outbound Call Types (to PSTN): Local (including 411, 711, 911)
 Usage Inbound Call Types (from PSTN): 8xx, RDID
 Usage Outbound Call Types (to PSTN): LD, Alien TN (non-SIP TN)
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 4
TOTAL VOIP BANDWIDTH REQUIRED
 For each access line, determine max sessions
 Determine circuit type / L2 protocol (HDLC, PPP, Ethernet)
 Determine VoIP packet sample size
 Determine Qty of G.711 calls
 Determine Qty of G.729 calls
Determine % of IQ circuit that is for P1 traffic
 Determine % of P1 bandwidth that is VoIP (QVUR)
SIP Trunk – Northwest Branch Training
What we should all know about SIP Trunk
• Diversity Options Simplified (I hope)
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SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 6
DIVERSITY STRATEGY
ENT. SESSION POOLING, ENT. DIVERSITY, SW DIVERSITY
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 6
DIVERSITY STRATEGY
ENT. SESSION POOLING, ENT. DIVERSITY, SW DIVERSITY
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 6
DIVERSITY STRATEGY
ENT. SESSION POOLING, ENT. DIVERSITY, SW DIVERSITY
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 6
DIVERSITY STRATEGY
ENT. SESSION POOLING, ENT. DIVERSITY, SW DIVERSITY
SIP Trunk – Northwest Branch Training
ENGINEERING CONSIDERATION 6
DIVERSITY STRATEGY
ENT. SESSION POOLING, ENT. DIVERSITY, SW DIVERSITY