We can't comment on what we do not know. DWDM is better than everything else that has gone before and enhancements to it are certainly welcome. The article expresses that
"MetroFusion will allow carriers' fiber infrastructures to achieve an unprecedented low-cost high-performance ratio."
This may be true only up to a certain limit of scale and then it may be a far higher cost than it's worth. The marginal advantage may inflect. There is the concern of utility also.
Current proposals by other vendors' DWDM ring architectures provide only point-to-point connectivity between all nodes on a ring, limiting the implementation of networks on such systems. Each node on the ring can only communicate with other nodes using the same wavelength as assigned to it.
This seems to be an advantage, but what manages which data stream goes to which node? The company uses Metro Core to coordinate signals to and from the Metro Edge nodes. Metro Core thus needs robust switching power. There are tbit switches, but it would seem something far more scale dynamic would be needed since under expansion the stress is multiplied at the core. This may be where costs accelerate especially if DD works as advertised and so becomes over utilized.
So to communicate with all nodes on a ring, a given node must be able to receive and transmit all wavelengths used. This translates to a complete DWDM system at each node, with a full set of lasers and receivers at each node, a very expensive proposition for a multi-node ring. In contrast, any node on the MetroFusion ring can directly communicate with any other node, as well as to a high bandwidth uplink out of the ring, using only a single wavelength per node.
In a caching redundancy demanding environment as is found in public ISP transfers, this facility is advantageous since there is a minimal amount of traffic control needed. Metro areas have a high density caching redundancy requirement, so as the traffic increases this enhancement may be critical. The question is then will Metro Core handle extra growth or short term volume fluctuations and be able to remain mission critical regardless of the redundancy protection?
Nonetheless, DD seems like a very attractive metro solution. In light of
MetroFusion is the first DWDM system that allows for the management of VLANs, priority levels, QoS, and RMON statistics.
I suggest that you get as much info on MetroFusion from next week's Comnet if you attend and post your findings on the MRVC thread with a reference here. We will see if we can get a better handle on this exciting development. |
