Avoiding the domino effect

Replicating data to another site is an important part of an insurance policy for business continuity. Network equipment vendors and carriers are jumping into the network storage extension space. There are basically three ways - WDM, SONET and IP - to extend a storage area network (SAN), or four, if...

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Bibliographic Details
Published in:Telecommunications Americas 2003-11, Vol.37 (12), p.14
Main Author: Masud, Sam
Format: Article
Language:English
Subjects:
Carriers
Credit management
Data replication
Disaster recovery
Ethernet
Network storage
Network topologies
Product management
Storage area networks
Technological planning
Wave division multiplexing
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Summary:Replicating data to another site is an important part of an insurance policy for business continuity. Network equipment vendors and carriers are jumping into the network storage extension space. There are basically three ways - WDM, SONET and IP - to extend a storage area network (SAN), or four, if you consider ATM. BellSouth and Verizon claim to support all three transport options both within their footprints and also out of region using either their long-distance service or partnering with an IXC. However, depending on a customer's distance requirements, IXCs might possibly have an advantage here because of the larger reach of their networks. The challenge for equipment vendors and carriers is to offer a Fiber Channel extension capability that can extend the protocol beyond approximately 10 km - or about 8 km for ESCON and 100 km for FICON. To compensate for Fibre Channel's flow control mechanism and ensure that there is no loss of Fibre Channel frames, the industry has developed a buffer-to-buffer credit management system for throttling back the transmission of frames so end stations can confirm the successful transfer of data-a concept analogous to the TCP window. Currently, DWDM seems to be the lead technology for SAN extension in the metro. In addition to offering high fiber capacity, DWDM supports transparent transport of SAN protocols at line rates as well as other services such as GigE, voice and video. Due to the popularity of IP and Ethernet, the interesting development has been the transport of Fibre Channel over IP, or FCIP, as it's called. An alternative is to do away with Fibre Channel entirely and transport SCSI over IP (iSCSI).
ISSN:1534-956X