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Leading Edge Features

To learn more about our advanced features you can select from the list below, or simply scroll down the page. You can also download our network whitepaper.

TDM & Full VoIP

If you’re running an on site PBX, we have solutions for both Legacy and IP systems. We have years of experience in both areas, and are experts in the set up, configuration, and operations of these systems.

Full VoIP

IP Trunking “Native” provides IP PBX customers with a business grade VoIP alternative versus installing costly TDM gateways and PRI’s. EXCEL supports industry standards including SIP or H.323 and Codec G.711 and G.729.

Legacy TDM

IP Trunking “Legacy” provides a simple solution for converting legacy PBX lines into VoIP with an IAD (Integrated Access Device). The IAD will prioritize all voice calls over data and includes a built-in router to access the network. The standard IAD will support PRI, T1 CAS or POT(s) lines.

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Network Architecture

To learn more about our network architecture, download our network whitepaper.

The Switch

Excel uses a next generation switching platform to facilitate call and data transport across one of the few native nationwide FGD networks deployed today. The switch is true to an IP switch network design and features geographically redundant call processing elements that message via MGCP to media gateways placed at the edge of the network. Also true to classic IP switch design is the decomposition of legacy switch functions and the hardware that supported them. The switch boasts a wide range of value added features that can be supported on board or via out board databases. Service creation is core code independent and thereby makes time to market much shorter than in legacy equipment networks.

Boundary Protection

Excel uses Acme Packet Session Border Controllers (SBC). Acme is an industry acknowledged leader in VoIP security and quality of service (QOS) handling. The SBC’s provide critical protection from Internet Denial of Service attacks at the SIP edge customer interconnect.

Using a “network within a network” architecture, SBC’s are located in all major sites so that traffic can be routed optimally, and if necessary, routed around a problem site. The SBC’s also provide a peering arrangement with various IP networks thereby providing security, QOS and cost control at the ingress and egress access points.


To support customer demand for lower bandwidth cost Excel, also employs state of the art Acme's Transcoders to enable numerous codec’s including G711u, G711a, G729, H323 and T.38. All codec interoperation is performed on a call by call basis at the SBC so any potential transcoding conflicts are handled outside the Excel private network. The SBCs and Transcoders have been strategically deployed at key points in the network to support high availability and geographic redundancy.

The Transportation Network

The Excel transport network provides best-in-class services that are the result of a fully redundant core network of equipment from Cisco and Juniper that is distributed across all switching sites throughout the country. Each site is fully meshed over redundant providers to maximize capacity and network uptime. In addition to the dedicated private network components, Excel peers with multiple DIA providers giving us a redundant DIA presence across the country.

SIP Methods

Session Initiation Protocol (SIP) is a widely used signaling protocol used for the setup and teardown of multimedia communication sessions. It can be use to create, modify and terminate two-party or multi-party sessions consisting of one or several media streams. Modification can involve the changing of ports, invitation of more participants, the addition or removal of media streams, and so on.1

SIP uses a request / response transaction model, where each transaction consists of a client request that invokes a particular method on the server and at least one response. Excel supports many of these methods2 including SIP Info.


G711u and G711a

G.711, also known as Pulse Code Modlation (PCM) is compressed using two main compression algorithms, µ-law and A-law. They encode 14-bit and 13-bit PCM respectively to logarithmic 8-bit samples to create a 64 kbit/s bitstream for a single sampled at 8 kHz. In North America and Japan µ-law is used, and A-law is used in Europe and the rest of the world.3


G729 is an audio compression for voice, compressing audio I packets of 10 milliseconds duration. Music and DTMF tones can only be reliably supported using this codec.4


The H323 codec is an umbrella recommendation from the ITU Telecommunication Standardization Sector (ITU-T) for defining these protocols on any packet network. The H323 codec is used for standard addresses call signaling and control, transport and control of multimedia, and point-to-point and multi-point conference bandwidth control.5


The T.38 codec was developed in 1998 to allow faxes to be transported across IP networks between existing Group 3 (G3) fax terminals.6

Network Operations Center

The Network Operations Center provides support on a 365X24x7 basis. The NOC is responsible for monitoring network alarms including switch elements, IP core switches/routers, SBC/Transcoders and switch site environmental alarms. This dedicated team is key to providing the highest level of responsiveness and shortest path to resolution, enhancing Excel’s ability to provide a high quality and efficient network. Routing updates are performed nightly and repetitive maintenance tasks are undertaken on a scheduled basis. The NOC is the central point of contact for all network activity.

  1. http://en.wikipedia.org/wiki/Session_Initiation_Protocol
  2. http://en.wikipedia.org/wiki/List_of_SIP_request_methods
  3. http://en.wikipedia.org/wiki/G.711
  4. http://en.wikipedia.org/wiki/G.729
  5. http://en.wikipedia.org/wiki/H323
  6. http://en.wikipedia.org/wiki/T.38