IP Management Gains Favor
Background: For years now, Sonet/SDH networks have been managed with protocols based on Open System Interconnection (OSI), a suite of internetworking protocols originally developed by the International Telecommunication Union (ITU).
Sonet/SDH devices, such as ADMs, use a data communications channel (DCC) carried in the Sonet signal to send information to management and provisioning systems. These DCCs are part of a larger DCN (data communications network) that links the devices with the operations support systems in the carrier's network. This DCN setup lets operators access all Sonet network elements through a single connection into the network, one that allows for remote provisioning and centralized maintenance.
IP network devices, like routers, aren't based on these OSI protocols; instead, they use packet-oriented routing and management protocols established by the Internet Engineering Task Force (IETF). Each router or other IP-based device is managed via an IP-based control plane.
As IP plays an increasingly important role in carrier networks, particularly in metro networks where IP is used within or alongside Sonet/SDH rings, it's getting to be problematic to manage everything in a unified way. According to Chris Murton, founder and director of Murton Consultancy & Design Ltd., which specializes in helping carriers set up metro networks, the discrepancy is a cost factor for carriers, who'd like to start moving everything over to an IP-based management approach that doesn't require as much know-how to maintain as OSI does.
Murton says a suite of ITU protocols called G.7712 holds an answer. G.7712 defines a method of encapsulating OSI in IP and routing that information through a DCN. Over time, as IP devices proliferate, the OSI-based DCC can be removed altogether. But meanwhile, G.7712 provides an automated way to put OSI and IP management together, Murton maintains.
Murton says several vendors are at work on G.7712 code: Atos Origin, based in France, and Vertel Corp. (Nasdaq: VRTL), for example, presently offer software for OEMing by equipment vendors that purports to solve the OSI-to-IP management problem.
Cisco Systems Inc. (Nasdaq: CSCO) is also said to be at work on G.7712 software. But at press time, the vendor hadn't responded to inquiries about the status of its developments.
Vertel's VP of Asia/Pacific sales and operations, Koert Blom, says the market for this kind of software is just starting to form. "But I think by the middle of next year it will be mandatory," he says. Vertel is selling code to a range of equipment providers and has even conducted interoperability tests among its customers, but Blom can't identify who Vertel's worked with.
Using IP in Sonet/SDH management DCCs, the way G.7712 does, is a mixed blessing, according to Scott Clavenna, chief analyst at Heavy Reading, the market research division of Light Reading. "An IP-based DCC does a better job of supporting end-to-end management and provisioning," he says. But the problem is that the approach calls for a routing engine to be placed inside each network element, one that supports G.7712 or another form of OSI-to-IP conversion or encapsulation.
This can make for a "buggy" DCN, since each Sonet box in the network is also a router, and that can make for plenty of hiccups when routing tables aren't updated properly or nodes are added or taken out of service.
While vendors sort out the issues, carriers continue to face the cost of overlaying IP and its management over Sonet/SDH networks. The issues could take a long time to hammer out. In the meantime, the few suppliers presently working on the problem are surely apt to increase in number.
— Mary Jander, Senior Editor, Light Reading
To examine an executive summary of the Heavy Reading Report – "The Future of Sonet/SDH" – click here. The full report is available for $3,950.