IMS fixed line enterprise services

As currently defined, the next generation architectures—3GPP IMS, ETSI TISPAN, and others —have yet to satisfy all the requirements associated with delivering services to fixed line-connected enterprises, often the most profitable customer segment for service providers. Acme Packet, with IMS Enterprise (IMS-E), delivers the most comprehensive collection of capabilities to enable the delivery of IP Multimedia Subsystem (IMS) services to fixed line enterprise customers.

IMS-E on our Net-Net session border controller, supplies the missing capabilities for enterprise IMS service delivery with support for eight enterprise-specific requirements:

  • Surrogate registration of IP PBX & IAD phones—IMS assumes that each SIP endpoint (e.g., fixed line phone, mobile phone, PC) is capable of registering itself with its Serving-CSCF (S-CSCF). However, many phones in enterprises are connected to SIP IADs or SIP/H.323 IP PBXs. Acme Packet performs SIP registration on behalf of each individual phone without any changes to the IP PBXs, IADs or IMS core elements. Acme Packet also supports the IETF’s IPTEL trunk group URI mechanism for optimized routing of calls from these aggregated devices.
  • H.323 IP PBX—SIP IMS interworking—The vast majority of installed enterprise IP PBXs from vendors such as Avaya, Cisco, Siemens and others use H.323 as the trunking signaling protocol to connect with the outside world. Acme Packet’s H.323-SIP IMS interworking capabilities enables service providers to interwork these IP PBXs with their SIP-based IMS core. This includes support for H.323 supplementary services, number normalization and translation to support overlapping private dial plans, IMS SIP headers and proven interoperability with many H.323 IP PBXs.
  • SIP IP Centrex service support—The alternative to an IP PBX in the enterprise is the use of IP Centrex services hosted by their service provider. Acme Packet is widely deployed by service providers around the world using Broadsoft, Sylantro SIP-B and many other vendors for the delivery of their hosted services.
  • VPN bridging—Many large enterprises use private IP address spaces that often overlap with other enterprises or use service provider supplied MPLS VPNs defined by IETF RFC 2547 to securely interconnect many office locations. Our IMS Access SBC supports the bridging of MPLS VPNs and overlapping IP address spaces, enabling SIP and H.323 devices to connect to an IMS core for hosted IP Centrex services or IP PBX trunking while maintaining tight enterprise security.
  • Adaptive NAT/firewall traversal—IMS assumes NAT/firewall devices are not present between subscriber endpoints and the IMS core. Enterprises, however, use NAT/firewalls to secure their networks, thus blocking all incoming calls. Acme Packet’s adaptive NAT traversal feature enables trusted sessions to most efficiently traverse enterprise-based NAT/firewalls by adapting the SIP registration frequency to the time-to-live value for pinholes in each individual firewall. An Acme Packet IMS Access SBC, represented by a single well-known IP address in a trusted service provider’s network, is much more secure from an enterprise perspective than using alternative methods such as multiple STUN and TURN servers.
  • DoS/DDoS protection for SBC and IMS core elements—Denial-of-service (DoS) and Distributed DoS (DDoS) protection from both malicious attacks and non-malicious overloads is a functional requirement absent from both 3GPP and ETSI TISPAN architectures. Acme Packet fills this huge void with proven, robust capabilities for SBC DoS protection and IMS core DoS prevention.
  • Overload protection for IMS core elements—Mechanisms for preventing overloads on S- & I-CSCF functions are also missing from IMS. Acme Packet’s P-CSCF in its IMS Access SBC uses configurable local policies to perform call rate limiting or code gaping for each CSCF based upon the number of sessions or session establishment rate. Selective admission control based upon destination or source telephone numbers is also supported to ensure valuable enterprise calls are always accommodated even in the presence of high-volume, low-value consumer televoting, such as American Idol.
  • Transcoding—The G.711 and G.729 codecs defined by the ITU are the de-facto standards used by IP phones and PCs in enterprises today. Acme Packet’s transcoding support in the Net-Net 9200 platform enables these enterprise endpoints to communicate with mobile and fixed line endpoints that use different codecs. A broad selection of mobile codecs such AMR, EVRC, SMV and QCELP and other fixed line codecs such as iLBC, G.723.1, G.726 and G.728 are supported.