VoIP Clearing & Peering
Agenda Definitions Interconnect Models and Technologies
Traditional Telephone (The early days) VoIP (What is the future?)
Summary and Conclusions
Definitions
Peering Bilateral interconnection
No Financial Implications (Bill and Keep) Settlement (Interconnect Billing)
Clearing Multilateral Interconnection
Settlement (Interconnect Billing)
Interconnect Business Model Drivers
Market Factors Fair allocation of costs (free resources get abused)
Big is better (network externalities)
Competition / RegulationTechnical Factors Route Discovery (Scalability, Bilateral vs Multi-
Lateral) Access Control Accounting
Interconnect in the Early Days
Market Factors High growth Lots of new entrants Fragmented market Highly competitive Unregulated
Interconnect Model Bill and Keep
LEC Interconnect – Bill and Keep
LocalTelco
LocalTelco
LocalTelco
$
LocalTelco
$
LEC – Bill and Keep
LECs bill their subscribers and keep all the money Interconnect trunks among LECs Simple – low overhead Works well for rural ILECs (no competition) Lack of settlement can lead to economic
distortions Does not scale
Users ModelTechnolog
y
Route Discover
yAccess Control
Accounting
LECs Bill & KeepInter-office
TrunksN Y N
The Telephone Market Matures
Bill & Keep model does not scale.
Market Consolidation. Regulation and market
stability Interconnect is managed
by a dominant inter-exchange carrier
Inter-Exchange Carrier
Inter-exchange
Carrier
LocalTelco
LocalTelco
LocalTelco
Interconnect access & billing occurs at adjacent networks
$
$
$
Inter-Exchange Carrier
IXC has Bilateral Settlement agreements with many networks
Interconnect to IXC provides global routing Tandem switch provides total call control
Access control and accounting Tandem switch creates a network bottleneck
Users Model Technology
Route Discover
yAccess Control Accounting
IXCsMulti-lateral Settlement
Tandem Switch – SS7 signaling
Y Y Y
Interconnect Future for VoIP?
Market Factors High growth Lots of new entrants Fragmented market Highly competitive Unregulated
Trend toward deregulation Natural trunking of IP mesh
different from switched star network
Interconnect Model?
ITSP – Bill and Keep
IP Network
ITSPITSP
ITSP
IP Phone
PC Phone
ENUM
$
$
DirectoryServer
RouteLook-up
ITSP – Bill and Keep
Removes network bottlenecks – enables peer to peer routing
Excellent technical solution for route discovery and scalability (DNS works!)
No access control or accounting – free resources could be abused.
Best for equal sized networks or in a regulated environment.
Users Model TechnologyRoute
DiscoveryAccess Control Accounting
Directory Svc
Free VoIP ENUM Y N N
DUNDi – Bill and Keep
$ $
DUNDi – Bill and Keep
New interconnect model being used by Asterisk users No central authority – enables peer to peer routing General Peering Agreement
Each peer has a bilateral agreement with adjacent peer GPA links all peers for global route discovery
No networks bottlenecks - Potential for high scalability No access control or accounting – free resources could
be abused.
Users Model TechnologyRoute
Discovery
Access Control
Accounting
Asterisk Bill & Keep DUNDi Y Y N
VoIP Peering
IP Network
ITSPITSP
ITSP
$
$
SBC
SBC
SBC
Interconnect access & billing occurs at Border Controllers
VoIP Peering
Bilateral agreement to peer VoIP networks Session Border Controller provides total call control
Bilateral Access control and accounting Settlement billing or Bill and Keep
Session Border Controller creates a network bottleneck
Scalability limited by bilateral agreements
Users Model TechnologyRoute
DiscoveryAccess Control
Accounting
VoIP PeeringBilateral B&K or Settlement
Session Border Controller
N Y Y
$
VoIP Clearinghouse
Certificate Authority andSettlement Clearinghouse
IP Network
ISPISP
ITSP
$
OSP
Interconnect access & billing occurs at
VoIP Domains
Route Look-up& Authorization
CDR
CDR$
VoIP Clearinghouse
Similar to ENUM - Removes network bottlenecks Excellent technical solution for route discovery and
scalability (DNS works!) Public Key Infrastructure (PKI) services ensure
secure multi-lateral peer to peer access control Standards based accounting records ensure simple,
real time settlement (no monthly CDR disputes)
Users Model TechnologyRoute
DiscoveryAccess Control
Accounting
VoIP Clearinghouse
Multi-Lateral Settlement
OSP Y Y Y
Summary of Interconnect Models
Users Model TechnologyRoute
DiscoveryAccess Control
Accounting
LECs Bill & KeepInter-office
TrunksN Y N
IXCsMulti-lateral Settlement
Tandem Switch – SS7 signaling
Y Y Y
Directory Svc Bill & Keep ENUM Y N N
ITSPs Bill & Keep DUNDi Y Y N
VoIP PeeringBilateral B&K
or Settlement
Session Border Controller
N Y Y
VoIP Clearinghouse
Multi-Lateral Settlement
OSP Y Y Y
ConclusionsReliable
Settlement
Bill & Keep
Bilateral GlobalRoute Discovery
Acc
ess
Co
ntr
ol
& A
cco
un
tin
g
Tandem Switch
ENUM
OSP
Inter-OfficeTrunks
SessionBorder
Controller
DUNDi
How Interconnect Technologies Compare