Implementation of IP-Centrex in Oki Electric Group of Companies Eiki Ichinohe The Oki Electric Group fully implemented the VoIP voice network (extension network) within the group in 2003. This system dramatically reduced costs by doing away with conventional toll switching equipment and Overseas converting connections between the switches of individual [2] Wide area LAN WAN locations to IP communications. This was performed along with a review of domestic networks. Implementation Internet of the IP-Centrex has been promoted since FY2004 to NOC IDC unify phone numbers within the Oki Electric Group in [1] Ring response to the diversification of terminals, fusing them with information systems and further reducing costs. DC [3] Internet/VPN Activities ranging from the implementation of VoIP to IP- [4] Internet/VPN (closed) Centrex are introduced in this paper. ADSL B-Flets network Conversion from toll switching equipment IDC : Internet Data Center to VoIP networks NOC : Network Operation Center DC : Data Center The conversion of toll switching equipment networks to VoIP for voice connections within the Oki Electric Fig. 2 IP networks of Oki Electric Group Group started in August 1998 and was completed in 2003, when networks at all locations (domestic and overseas) were converted to IP networks (sharing with Furthermore, clarification of the risks as well as a further data systems) (Figure 1). reduction in costs have been promoted through the selection of four network categories suitable for particular situations; backbone networks ([1] Ring), large-scale 442 locations and 1,442 lines As of August 2003 location networks ([2] Wide area LAN), intermediate- Domestic block Kanto District scale networks ([3] Internet/VPN: Closed) and small- locations Shibaura District Locations WAN routers WAN routers scale location networks ([4] Internet/VPN), as shown in Domestic WAN Figure 2. Domestic WAN BV1250 (Wide Area LAN) LS (IP-VPN) BV1250 LS 11 locations and 269 lines 264 locations and 753 lines BV2000 Network evaluation for IP-Centrex Overseas WAN Internet / VPN Major locations implementation Overseas locations (Dedicated lines Gatekeeper in Kanto WAN routers and FR networks) WAN routers A network evaluation, intended to determine the 192 lines effects on internal networks of the Oki Electric Group, as BV1250 BV1500 LS LS well as to secure voice quality, was conducted as advance preparation for the full-scale implementation of 26 locations and 68 lines LS LS LS 140 locations and 140 lines *LS: Private branch exchange (PBX) the IP-Centrex system. For this reason a model was set for each mode of connection for domestic IP networks and verifications were performed for each evaluation item Fig. 1 VoIP network of Oki Electric Group including voice quality, bands used by data, voice and images, as well as responses, priority control and band control for each model. Networks for data systems and voice systems were (1) Wide area LAN model centralized through the conversion of networks to VoIP systems, thereby dramatically reducing network Network loads are not a concern for wide area LAN expenses. However, since the operation of switching the models, since networks are redundantly configured and equipment installed at individual locations continued as it the main lines are used by data systems, the secondary was, a response to new functions, such as IP by voice systems. Since both data systems and voice conversions and wireless conversions within those systems use the same line when network disorders locations, was difficult to achieve. The “IP-Centrex occur, there are no practical problems as long as the Implementation Plan” was formulated and the band control on such occasions is adequately designed. implementation of the IP-Centrex has been promoted (2) Large and intermediate-scale internet/VPN models since FY2004 in order to further reduce operating costs. Large and intermediate-scale locations of the 8 Oki Technical Review April 2006/Issue 206 Vol.73 No.2 Special Issue on Customer Case Examples Internet/VPN models are 100Mbit/second connections Modeling of the selection criteria for implementation with secured practical speeds of approximately 20Mbit/ was performed in consideration for the fact that the second that present no problems with regards to the load functions that can be used differ from terminal to terminal on the network. However, since both data systems and as shown in Table 2, as well as the selection of terminals voice systems use the same line at all times and as the used vary depending on the business operation modes of VPN equipment will be installed on the route, it is individual employees. A trial was then conducted. necessary to have a band control with a thorough consideration for such issues and control the priority. Table 2 Models of terminals implemented (3) Small-scale internet/VPN models Type of Main implementing terminal Reason for selection of terminal corporate organizations Depending on the extent of application use at certain Software An improvement in operational efficiency and a reduction in Back offices locations, there is a slight deterioration in the response phones costs arising from business travel are sought through effective (excluding capability with small-scale internet/VPN models. use of application functions of software phones. manufacturing lines) Although these models are not valid for band controls, as FOMA An improvement in operational efficiency and a reduction in Sales, SE and design phones communication costs are sought using mobile phones that are organizations they are open internet/VPN models, we determined that essential for business operations due to frequent business engagements outside the office and because they can also be coverage should be possible through operations at used as phones for extension lines while moving around within locations with a small number of users. the company. (4) Wireless LAN implementation models WiFi An improvement in operational efficiency is sought by making Design and phones it possible to contact persons in locations where conventional management With regards to voice calls over wireless LAN on the phone lines have been abolished or transitioned to IP phones, organizations premises of locations it is necessary to conduct advance as well as while moving around within the company. surveys, such as the investigation of external PHS Existing wiring is effectively utilized to gain the effects of the Manufacturing plant IP-Centrex, such as mobile environments, at locations where it organizations environments (extrinsic waves), conditions of radio wave is difficult to set up LAN environments. leaks to exteriors, radio interference between wireless IP phones Implemented as phones for receiving incoming calls from external Fixed line phones of applications, as well as adjustments to the number of (e-Sound lines, representative phones for individual corporate organizations, individual corporate connections that can be established simultaneously or phones) as well as phones for receiving calls at branch offices. organizations the verification of handovers. Even if the designing and building of systems are conducted based on such surveys, the radio wave environment will change due to Location implementation model with changes in the external environment, changes with the IP-Centrex layout of the office, etc., therefore, periodical tuning will An evaluation was conducted during the trial also be necessary. implementation and models for the full-scale (5) Mobile environment utilization models implementation of the network as well as the terminals, Since security barriers are high for voice calls in a which do not rely on any network modes, were mobile environment, a thorough study must be formulated for individual locations (Figure 3). conducted and adequate countermeasures need to be Data center Clerical location model (combined model for effective use of location facilities) considered beforehand. Permission to use services in the Existing corporate Office Multi-functional phones extension BV1500 FOMA phone mobile environment is granted only to specific employees Wireless AP network SS9100 Analog phones FAX Monitoring Charging at Oki Electric Group. BV1600 server server AS8700 SS9100 Com@WILL PSTN Feeding switch “050” network network VC-D01 L2 SW IPLTU L2 SW POW Selection of terminals for implementing SS9100 network (Oki Electric Group network) IP-Centrex L2 SW L2 SW L2 SW POW PSTN Feeding switch network IPLTU IPLTU IPLTU IP e-Sound IP The majority of terminal devices connected to PSTN phones network Com@WILL Analog FAX Wireless AP IPLTU IPLTU phones conventional switching equipment were multi-function … IP FOMA Com@WILL e-Sound phones IP Base station PHS telephone sets (including analog phone sets) and Attendant IPLTU Branch office model (full-IP conversion model) consoles Multi-functional phones personal handyphone systems (PHS). In contrast the IP- IP FAX Overseas locations Machine room Office L2 SW Centrex system makes it possible to use new terminals, Com@WILL Manufacturing plant model (model for effective use of existing facilities) Existing VoIP such as IP phones, software phones, WiFi phones and network Switching FOMA phones. The types of terminals that can be equipment connected and the usable functions are listed in Table 1. Fig. 3 Location implementation models Table 1 Usable terminal functions FOMA (1) Manufacturing plant model PHS Software e-Sound FOMA Wireless WiFi (IP base phone This model is for large areas that will be subject to LAN IP phone (mobile (extension stations) (PCs) phones) lines) coverage, with consideration for mobility needs and Web access *1 *1 accommodation for the use of numerous simple phones and a premise of making effective use of existing facilities Videophone to avoid spending more than the necessary costs in order Presence referencing *1 *1 to set up LAN environment due to the conversion to IP- Screen sharing Centrex. Terminals are primarily PHS. Instant messaging (2) Branch office model Voice calls This model is for full-scale IP conversions covering Roaming areas that are not large, which cater to the needs of *1: Available using devices that support browsers.