In the last newsletter, we discussed Visual Networks' revamped a la carte capabilities and pricing structures.  We also mentioned our frustration and amazement at the relatively low penetration that these devices have made into the marketplace in spite of their obvious value.  We think a part of this low penetration comes from the historical conundrum of having a separate yet highly intelligent DSU/CSU as opposed to an integrated unmanaged DSU/CSU in the router.

But this landscape is rapidly changing.  For some time, suppliers such as QuickEagle have provided routers integrated with managed DSU/CSUs.  Also, the combination of management functions that were previously available only in stand-alone devices with the router took a giant step forward when Cisco and Visual Networks began offering Visual's capabilities integrated into Cisco's routers.  Even though the availability of a given level of software on the routers seems to lag just a little behind the stand-alone devices, the same functions are now available with integrated DSU/CSUs.

While this integration is a great move forward overall, it does bring up a fascinating question.  In addition to the obvious option of deploying these devices as a discrete piece of customer premise equipment (CPE), all of the major service providers have offered enhanced frame, ATM, and IP-based services where they also supply a managed DSU/CSU as a part of the service.  But the DSU/CSU-to-router physical interface has been the demarcation point between the carrier service and the CPE.  And while the router with the integrated managed DSU/CSU could be provided as a part of a managed router service, we're not seeing a wholesale movement to this level of managed services.

So here's the dilemma.  The benefits of having your service provider monitor and maintain the managed DSU/CSU function are obvious, but there are also strong benefits of having DSU/CSU integrated into your customer-supplied router.  So this means having the demarcation point between your service and your CPE being somewhere inside your router.  And we're not sure most users are ready for this level of "virtual" interface.

We'd like to hear your thoughts on this.  From a theoretical viewpoint, letting the service provider have access to some - but not all - router software makes a lot of sense.  But we're not sure whether you're ready to take this step.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.