McDATA StorageWorks 2/140 - Director Switch Planning Manual page 190

Implementing SAN Internetworking Solutions
4
Table 4-4
Requirement
Bandwidth (native storage)
Extended-link latency
Network scalability
Performance monitoring
Extended distance (greater that 120 Km)
Security
Routed SAN benefits
McDATA Products in a SAN Environment - Planning Manual
4-48
• 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
Transport Technology Comparison
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.
compares and contrasts the transport technologies.
Dark Fiber WDM
Medium High
Low Low
Fair Good
Average Average
No No
Good Good
No No
SONET/SDH IP
Medium Low
Medium High
Fair Good
Good Good
Yes Yes
Good Good
No Yes