Distance Topology Example - EMC Connectrix EC-1200 Planning Manual

Connectrix Topologies
4
longwave/singlemode for mission-critical business environments,
EMC advises customers to hire a fiber cable specialist who can
measure the quality of the fiber cable and compare it to expected
standards.
Shortwave
Server
Connectrix
Fibre Channel
Longwave
Symmetrix
Fibre Channel
Shortwave
Fabric
Connectrix
Fibre Channel

Distance Topology Example

Figure 4-11
In the early years of ESCON, both multimode for short distances and
single mode for long distances were offered. However, it was found
that most data centers did not want their long distance links to
terminate at their mainframes or storage equipment. For both
availability and resource management reasons, they preferred to
terminate the long distance links on an ESCON director, then
implement a connection to another ESCON director.
Access to the long distance right-of-way by multiple mainframe
connections and multiple storage connections increases availability.
In addition to availability, significant performance gains can be
achieved with a switch-to-switch topology. The ED-140M, ED-64M,
DS-32M, DS-32M2, DS-16M, and DS-16M2 each provides up to 60
Buffer-to-Buffer Credits on any or all ports. These credits ensure there
will be no rate droop as the distance between the two data centers
extends up to 100 kilometers. With the extended credit capability,
full-duplex 100 MBps throughput is achieved at the extended
distances.
Figure 4-9 on page 4-12 and Figure 4-10 on page 4-13 show the effect
of BB_Credit on performance as a function of distance. For more
detail, refer to Bandwidth on page 2-17.
4-14
Connectrix v6.02 Planning Guide