Specifications

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McDATA Products in a SAN Environment - Planning Manual
Implementing SAN Internetworking Solutions
• IP - This technology supports low-bandwidth, high-latency
applications with long RTO and RPO requirements. Applications
include asynchronous disk backup or tape vaulting over
metropolitan to extended (intercity) distances. SAN routers are
included in the extended-distance link (iFCP only), so the
technology isolates the connected SANS and prevents disruptions
caused by fabric or link problems.
Table 4-4 compares and contrasts the transport technologies.
Additional factors to consider are:
• Availability of a physical infrastructure - If fiber-optic cable is
available, WDM is a good choice because of high bandwidth, low
cost, and ease of use. SONET and SDH connectivity is generally
available within metropolitan and intercity regions. IP provides
the highest level of long-distance connectivity but supports only
low-bandwidth, high-latency applications.
• Bytes of data requiring backup - The volume of data associated
with the SAN is a consideration in selecting the transport
bandwidth. As an example, the approximate time required to
perform a 60-terabyte backup is:
— 50 days over a single OC-3 connection.
— One week over a single GbE connection.
— Three hours over a 2 Gbps, 32-channel WDM connection.
Table 4-4 Transport Technology Comparison
Requirement Dark Fiber WDM SONET/SDH IP
Bandwidth (native storage) Medium High Medium Low
Extended-link latency Low Low Medium High
Network scalability Fair Good Fair Good
Performance monitoring Average Average Good Good
Extended distance (greater that 120 Km) No No Yes Yes
Security Good Good Good Good
Routed SAN benefits No No No Yes