Featurenet is a British Telecom Centrex VPN service. This white paper discusses featurenet and related design issues. This page discusses BT Featurenet, the Centrex / VPN service offering from British Telecom in the UK. Westplan is a voice network design modelling tool which will help you design economical carrier networks, private networks or VPN access arrangements. * Purpose * Description of Featurenet * Tariff options * Applying Westplan to Featurenet + Featurenet 5000 with Usage Based Charging + Featurenet 5000 with National Networking + Featurenet 1000 with Usage Based Charging + Featurenet 1000 with National Networking * About Westplan * Conclusion Purpose Featurenet is the UK managed voice network offering from British Telecom. There are two types of Featurenet Service. These are Featurenet 1000 which is a VPN service and Featurenet 5000 which is a combined centrex and VPN based service. The complexity of the tariffing structures for Featurenet can make an analysis of the financial benefits of the services a daunting task. The methods of applying Westplan to the analyse of VPN networks are described in the Westplan User Guide. This paper discusses the differences between Featurenet and conventional VPN networks, and the ways in which the use of Westplan can be modified to take account of these differences. Description of Featurenet Featurenet is a managed network offered by BT in the UK. Customers connecting to Featurenet can choose between two service offerings. Featurenet 1000 Featurenet 1000 is a VPN network which, as described in Chapter 2 of the Westplan User Guide, is a modern alternative to private voice networking. VPN requires only a single group of trunks to be connected to each PABX. The VPN switches the calls based on the dialled digits offered and so alleviates the requirement for tandem switching in a private network resulting in a saving on PABX hardware costs. The connection of smaller sites whose connection to a traditional private network could not be justified can often become financially viable using VPN. Featurenet 5000 Featurenet 5000 is a centrex solution. Customers connecting to Featurenet 5000 do not have PABXs installed in their buildings. Their telephones are connected directly to Featurenet public exchanges via concentrating devices called Small Remote Units. All switching, even desk to desk calls within the same building, is achieved using the serving Featurenet public exchange. The use of Featurenet 5000 avoids the large capital investment required when purchasing PABXs and offers an upgrade path to Voice Mail and ACD, all charged on a revenue basis. Featurenet 5000 customers are also offered desk to desk dialling between their offices using a dial plan with unique site codes. This network is very similar in nature to VPN. Tariff options To appreciate the Featurenet tariffing options, the two types of calls which can be offered to a VPN network should be understood: On-net These are calls made between two locations which are both connected to a VPN network. Off-net These are calls which are made from locations connected to a VPN network and whose destinations are sites not connected to a VPN network. In addition, there are two main tariffing options associated with Featurenet: Usage based charging This is the charging option adopted by most VPN network providers. Charges are applied to both on-net and off-net calls. Both charges are usually lower than the equivalent PSTN costs and on-net calls are always lower in cost than off-net calls. National Networking With National Networking, links are installed WITHIN the VPN network for the customer's exclusive use. Distance related rental charges are incurred for these National Networking Channels (NNCs). On-net calls are carried using these NNCs and are free of charge. Charges are made for off-net calls and on-net calls which overflow from NNCs. Network wide features such as Calling Line Identity and Call Back When Free require National Networking. Applying Westplan to Featurenet Featurenet 5000 with Usage Based Charging With this combination, there are no PABXs installed and no National Networking Channels. Westplan cannot be used to analyse such installations. Featurenet 5000 with National Networking Westplan can be used to design National Networking Channels (NNCs). The steps required to set up a project for this type of analysis are detailed below. Sites configured in network drawings One site should be entered for each Featurenet 5000 site. The sites actually represent the Featurenet public exchanges (DMS). Each site should have the following properties: * Analogue private circuits should be enabled. * Digital private circuits should be disabled. * NNCs can be engineered to allow peak calls to overflow to off-net and so save money on NNC rental. The disadvantage of this strategy is that overflowed calls do not allow the passing of network facilities such as Calling Line Identity and Call Back When Free. To allow overflow, enable PSTN overflow at each site. Analogue circuit costs The annual rental charges for NNCs between each site should be entered in this table. This information should be available from BT account representatives. P.S.T.N. Table The per minute charges for off-net calls should be entered into this table. This is only required if overflow has been enabled (see Sites configured in network drawings). Traffic Table Network traffic between each Featurenet site should be entered into this table. If these figures are not available, then reasonable estimates should be made from your understanding of the business for which you are designing the network. Having set a new project up in this way, new networks can be set up within that project to analyse different NNC configurations. Links should be added in the usual way, each link representing a NNC link between two Featurenet exchanges. When a network has been entered, it should be optimised using the Optimum network option on the Networks menu. This will change the NNCs to their optimum number of trunks. Returning to the Networks Index will show all defined networks; the lowest cost network will be displayed in blue. When studying the cost summary, some figures have slightly different meanings than they do when analysing private voice networks: * Private circuit costs - These are the rental costs associated with National Networking Channels * PSTN costs - These are the off-net call charges for calls which have overflowed from NNCs Featurenet 1000 with Usage Based Charging Westplan can be used to design the access links to the VPN network. Featurenet 1000 with Usage Based Charging is very similar to other vendors' VPN offerings. In addition to the network locations, an additional site should be added to represent the VPN network. The costs of circuits from this site to the network locations should reflect the monthly cost of Featurenet 1000 access lines. The traffic figures to and from the VPN site should be zero as the VPN network effectively acts as a tandem switch and does not generate or receive traffic. Featurenet 1000 with National Networking Westplan can be used to design access links and National Networking Channels (NNCs). As there are two networks involved (end sites / VPN and NNCs), each Featurenet site needs to be represented by two sites in the Westplan Sites Table. The first site represents the site where the PABXs are installed and the second site represents the Featurenet public exchange (DMS). The steps required to set up a project for this type of analysis are detailed below. Sites configured in network drawings Two sites should be entered for each Featurenet 1000 site. Imagine that there are four sites connected to Featurenet 1000. Create four new sites called A, B, C and D; these represent the end sites with PABXs installed. Then, create four additional sites called VA, VB, VC and VD; these represent the Featurenet exchanges between which NNCs are installed. Each end site (A..D) should have the following properties: * Analogue private circuits should be enabled. * Digital private circuits should be enabled. * PSTN overflow should be disabled. Each VPN exchange site (VA..VD) should have the following properties: * Analogue private circuits should be enabled. * Digital private circuits should be disabled. * NNCs can be engineered to allow peak calls to overflow to off-net and so save money on NNC rental. The disadvantage of this strategy is that overflowed calls do not allow the passing of network facilities such as Calling Line Identity and Call Back When Free. To allow overflow, enable PSTN overflow at each Featurenet exchange site. Analogue circuit costs Two types of line rentals should be entered in this table: * Enter rentals for VPN access lines between end sites and their Featurenet exchanges (A to VA, B to VB etc). * Enter rentals for NNC circuits between each combination of Featurenet exchange sites (VA..VD). P.S.T.N. Table The per minute charges for off-net calls should be entered into this table. This is only required if overflow has been enabled (see Sites Table). Traffic Table Network traffic between each Featurenet end site should be entered into this table (A to B, A to C etc). If these figures are not available, then reasonable estimates should be made from your understanding of the business for which you are designing the network. In addition, Featurenet may be used for off-net calling as a cheaper alternative to PSTN. Traffic relating to these calls should be entered in the Traffic Table from each end site to its corresponding Featurenet exchange site (A to VA, B to VB etc.). Having defined a new project up in this way, new networks can be set up within that project to analyse different NNC configurations. Create the first network with links between each end site and its associated Featurenet exchange (A to VA, B to VB etc.). These links represent the VPN access circuits and with this type of project can only be analogue lines. This is because entry of digital lines is only allowed in multiples of 24 or 30. If digital lines are to be analysed, the costs per channel should be entered into the Analogue PW Costs Table and the lines should be drawn on the network as analogue. Conventional links can also be added between end sites if required. Links should be added between the Featurenet exchanges in the usual way, each link representing an NNC between two Featurenet exchanges. When a network has been entered, it should be optimised using the Optimum network option on the Networks menu. This will change the NNCs and access circuits to their optimum number of trunks. Because only analogue lines can be entered into these drawings, in this mode, Westplan cannot be used to work out the break-even point between providing analogue and digital access lines. VPN analysis in its usual form (see Featurenet 5000 with National Networking) can make these calculations. When studying the cost summary, some figures have slightly different meanings than they do when analysing private voice networks: * Private circuit costs - These are the rental costs associated with National Networking Channels and VPN access links. * PSTN costs - These are the off-net call charges for calls to other Featurenet end sites which have overflowed from NNCs