Specifications

A-2

Cisco ONS 15530 Planning Guide

OL-7708-01

Appendix A IBM Storage Protocol Support

Supported Protocols

The Cisco ONS 15530 can provide the transport layer for the following IBM storage related protocols:

• ESCON

• FICON

• Coupling Facility

• Sysplex Timer links

The Cisco ONS 15530 can also be used to help implement the high availability features for the following

applications:

• PPRC

• XRC

• GDPS

ESCON

ESCON (Enterprise System Connection) is a 200-Mbps unidirectional serial bit transmission protocol

used to dynamically connect mainframes with their various control units. ESCON provides nonblocking

access through either point-to-point connections or high speed switches, called ESCON Directors. In the

Parallel Sysplex or GDPS environment, ESCON performance is seriously affected if the distance

spanned is greater than approximately 8 km. For instance, measurements have shown that ESCON

performance at 20 km is roughly 50% of maximum performance. Performance degradation continues as

distance is further increased.

Figure A-2 shows an estimate of how the effective data rate decreases as the path length increases. At a

distance of 9 km, performance begins to decrease precipitously. This data point is referred to as the

distance data rate droop point.