282 Chapter 7: Managed Multiservice Networks and Packet Voice VPNs
Managed Multiservice Networks
An MMS network is essentially an enterprise network that is hosted by an SP on its shared
backbone. The CPE equipment and features are the same as the enterprise would use to
create its own network, but instead they are managed and sometimes owned by the SP.
Instead of maintaining its own WAN, the enterprise uses the SP backbone, which is shared
by many different enterprises, as a virtual WAN. The enterprise’s network thus becomes a
An MMS network has the same conﬁguration, features, and performance issues as any
enterprise network. Additionally, security, billing, network management, compliance with
service-level agreements (SLAs) including trafﬁc policing and shaping, and voice quality
issues must be considered.
An MMS network has the following characteristics:
• Combined services—In addition to managing data trafﬁc between multiple sites for
the enterprise customer, voice services are included in an overall solution managed
and deployed by the SP.
• Tandem/class 4 replacement—SPs offer business connect services that replace those
that would ordinarily connect an enterprise’s telephony equipment to the IXC’s Class
• Not a local services solution—MMS solutions don’t support the features required to
address the residential market (Class 5).
Evolution of Managed Voice Networks
Managed voice networks began with the advent of circuit-switched telephone solutions.
The following is a timeline of the signiﬁcant developments that have occurred:
• Mid-1980s—Sprint USA invented a time-division multiplexed (TDM) voice VPN to
compete against AT&T’s Private Line PBX networks.
• Early 1990s—U.S. long-distance companies such as AT&T and several international
companies such as SITA-Equant started providing Managed Router Services over
• Late 1990s—Fifty international carriers ratiﬁed Circuit-Switched Voice VPN as an
Today, SPs such as AT&T and MCI offer feature-rich, worldwide voice VPN services to
Managed Multiservice Networks 283
The following pressures are driving the industry toward packet-based solutions:
• Competition to duplicate existing services on packet networks.
• Desire to provide advanced, revenue-generating services that can be deployed only
over packet-based networks.
• New entrants want to complement existing packet-based voice services with voice
• Mobile carriers want to interconnect mobile and PBX networks with voice VPNs.
Now that data managed services have matured and become commodities, enterprises can
switch relatively easily among different SP offerings, which are often competitively priced.
By adding voice and other value-added services to their existing data managed service
offerings, SPs can maintain a competitive edge, increase revenues, and encourage customer
MMS Solution Market Drivers
The following factors were the original market drivers for MMS networks:
• To leverage the convergence of data and voice over packet networks, the traditional
data providers had to upgrade their offerings to be multiservice.
• To increase revenues, SPs wanted to attract more trafﬁc onto their packet backbone.
However, simply transporting voice trafﬁc is no longer a cutting-edge service. The industry
is moving toward value-added services and applications leveraging a combined
infrastructure, particularly packet voice VPNs. The factors driving this market include the
• As competitive pressures force enterprise customers to focus on their own business
plans, they are increasingly turning to SPs for network outsourcing.
• Enterprise customers are comfortable with VPNs, because both voice VPN (circuit-
switched) and data VPN services are mature technologies.
• VPNs offer cost-effective communication with remote ofﬁces and business partners.
• For large, multisite enterprises, internal voice trafﬁc typically is greater than external
The following enterprise customers are ideally suited for MMS network solutions:
• Larger enterprise customers who want to interconnect multiple sites (a more
important goal than Internet access or e-business connectivity, although these are
often secondary goals).
• Customers who need to integrate existing dial plans, PBXs, and key systems.