ISDN router and bridge lineup

Pipeline 50 HX

Ascends Pipeline 50 HX is a single-user product that supports IP routing and bridging with IPX spoofing. It is part of a family of compatible products that includes hubs that can support from four Basic Rate Interfaces (eight B channels) to four Primary Rate Interfaces (92 B channels). It is the best product of the group for Internet access as well as for IP router-based corporate work-at-home programs.

The strength of Pipeline 50 HX is its ability to do IP routing from remote workstations or PCs to a central site. It supports four remote site profiles, each of which defines a remote site's IP address and authorization requirements. Pipeline 50 HX uses the IP address in the remote site profile to automatically make a call to that site when the product sees packets containing its IP address. These remote site profiles support connections to two sites at the same time.

Combinet 2060 SOHO

The Combinet 2060 SOHO is the best product of the group where the Point-to-Point Protocol is required for the peer-to-peer interconnection of remote offices.

With support for as many as four local users for branch office or telecommuting applications, it is part of a product line that includes the 2060 RO, which supports an unlimited number of users. The 2060 RO can be placed in a large network to support multiple 2060 SOHOs. The 900, which supports a single PRI (23 B channels), can also be used to support larger networks.

The 2060 SOHO uses profiles for all aspects of its configuration. There are three permanent profiles that define its basic behavior. The LAN Profile defines the 2060 to the local LAN, including its IP address. The System Profile defines global parameters such as PPP authentication and default parameters for connecting to remote sites. The Standard Profile is the default profile for incoming ISDN connections that do not have their own profiles defined.

In addition, users can set up as many as 16 external profiles for remote sites. The 2060 can connect to two sites simultaneously. While setting up all of this is complex, it provides a lot of flexibility. Users can define the default behavior of the box to be routing or bridging in the System Profile. They can then define profiles for each remote site either using the defaults set in the System Profile or defining new values.

The 2060 has nearly as many lights as the other three products combined, making it easy to see what's going on just by looking at the box. One light indicates that the ISDN line has initialized correctly, while additional lights show the connection and indicate data being transmitted and received on each B channel.

Gandalf 5242i

The Gandalf 5242i is an ISDN bridge targeted to the small-office market. It is the best choice of the group for telecommuting or small-office applications where bridging rather than IP routing is used. It supports as many as 10 workstations on the local LAN as well a standard analog telephone for voice communications.

Because it handles both voice and data calls, the 5242i can make intelligent decisions on how to allocate B channels. It uses both B channels for a data connection if they are needed. If someone picks up the phone to make a call, the 5242i drops one of the data calls and makes the B channel available for voice. If both B channels are being used for a data call and a voice call comes in, the 5242i disconnects one of the data calls to make the B channel available for the incoming voice call. In either case, it reestablishes the second B channel data call, if appropriate, when the voice call is completed. This is a nice approach. If you are talking on the phone, you probably don't mind if the data transfer slows down.

The 5242i supports only bridging, which may limit its application. Bridging is a good way to support small remote offices and workers at home. Interconnecting larger sites, or interconnecting different companies, is likely to require routing in order to keep the administration of their network addresses separate. The 5242i can support connections to as many as 10 remote sites, one at a time.

Symplex Direct Route RO-1

The Symplex Direct Route RO-1 is the only product of the group that does not limit the number of workstations that it supports. Symplex is targeting its RO-1 to companies that want to create a low-cost network of smaller offices, and it is indeed the best product in this group for this kind of networking, as long as there is no need to use PPP for compatibility with other manufacturers' products.

Symplex has taken advantage of its proprietary protocol on the ISDN line to make it easy to interconnect its products. To set up remote sites, users just enter their ISDN numbers. The RO-1 automatically makes a call to each new remote site to trade information. Each unit learns the IP and media access control addresses of the remote network from the remote unit.

Administrators also enter the characteristics of the telephone usage billing algorithm to each remote site. The RO-1 automatically makes and breaks the ISDN calls on the first and second B channels based on this information. The theory is that if you're going to be billed for a whole minute, you might as well use it.

Even with all this sophistication, Symplex does not handle the usage-charging rules in its home state of Michigan, where you pay $.09 for the first 10 minutes and $.09 for each five minutes thereafter. In Michigan, you should disconnect just before the first 10 minutes are up and then call back immediately to keep your costs to a minimum.

But the RO-1, which is another very new product, is a little too automatic for our taste. We would like to have more control over connection management because there is a trade-off between responsiveness and cost. There are times when we are willing to pay more usage charges to keep the line up to eliminate the 10-second or so delay it takes to get data to the other side when there is no ISDN connection. We would also like to see more information in the log.