session management in an enterprise comunication ... - Genband

SESSION MANAGEMENT IN AN ENTERPRISE COMUNICATION NETWORK
Introduction
Enterprise Chief Information Officers (CIOs) are increasingly
aware that growing demand for information and collaboration
at anytime, from anywhere is placing enormous burden
on network infrastructure. What was once a secure voice
network is now becoming a converged voice/data network
supporting multiple IP interfaces and services. CIOs are
pushed to their limits when confronted with questions such as:
• How to support a multi-vendor network and guarantee
interoperability
• How to securely convert their existing public voice access
from costly PRI trunks to inexpensive IP trunks
• How to guarantee quality voice, video and multimedia
services on a common IP infrastructure
• How to introduce new SIP services into the network without
affecting existing infrastructure
• How to meet important E911 and CALEA requirements
with the new VoIP network
Enterprises need to harness the flexibility of the converged
IP network to deliver voice and multimedia services but must
do so without creating complex overlays for each specific
service. Such convergence naturally brings to the forefront
challenges of ensuring network security and service visibility.
Clear demarcation of enterprise and service provider
networks is mandatory to manage services across the demarcation
and accounting for resource usage. The need for
visibility into the behavior of the network, the user, and the
performance of the services carried over a converged IP infrastructure
supersedes traditional Time Division Multiplex (TDM)
network management approaches. The emphasis becomes
more on gaining visibility and control over the individual
multimedia sessions that ride over the IP infrastructure.
While IP networks provide many capabilities to define Virtual
Private Networks (VPNs) and prioritize different multimedia
traffic, they are not designed to be session-aware and they
provide few capabilities to manage and control end-user
sessions; a session being the IP-equivalent of a phone call. To
illustrate this key point, many times users complain about call
quality across a voice over IP (VoIP) enterprise network while
the IP/MPLS network layer is working properly. This is a void
in current IP network solutions and has the potential to impact
converged IP-PBX installations.
GENBAND’s session management solution complements
enterprise routers, switches, IP PBXs and application servers,
delivering the information and control necessary to guarantee
quality sessions and services while customers realize both operational
and capital expense savings. This paper discusses
GENBAND’s unique approach to session management that
enables enterprises to set up, secure, monitor, manage and
account for IP-based sessions, both Session Initiated Protocol
(SIP) and H.323.
GENBAND’s solution enables network administrators to
• Establish Public Switched Telephone Network (PSTN)
like the granular control required for centralized session
management, monitoring and accounting in a highly
distributed converged IP network
• Architect real-time dynamic policy based control of the
end-to-end performance of each session
• Flexibly meet enterprise service requirements without
building separate overlay networks
• Cost-effectively operate a converged communication
network for the delivery of real-time IP services
Session Management Challenges
In the converged rich-media enterprise, service support requires
traffic management on a session-by-session
basis. Unlike the PSTN, which offers predictable resource
utilization and guaranteed service levels, the IP network is
inherently a multi-service and best-effort network. A new approach
is required to derive PSTN-like controls and real-time
service predictability. The IP-layer offers Quality of Service
(QOS) and security features such as VLAN tagging and
MPLS. However, even with these lower layer features, session
quality is not guaranteed nor reported on an individual
session basis; voice quality of a VoIP session may be poor
while the IP layer is working properly. This problem is more
apparent as IP sessions travel outside the enterprise via direct
IP trunks to the service provider. While service providers
may provide Service Level Agreements (SLA) within their own
network, SLAs are difficult to guarantee as sessions traverse
multiple and worldwide IP networks. Network administrators
require added session specific control and intelligence that
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