Chapter 3. Data center environment 47
The IBM 2029 supports both single-mode and multimode ESCON links, however,
only multimode ESCON links are supported by the 4TDM OCI card. This allows
you to configure 4 ESCON links on a single IBM 2029 channel using Time
Division Multiplexing. This makes the use of multimode ESCON channels in a
IBM 2029 network far more cost-effective than single-mode.
3.2 Fiber Connection (FICON) channels
Fiber Connection (FICON) is a high-bandwidth channel type that uses a new
mapping protocol (Layer FC-4) to take full advantage of the unique
characteristics of the ANSI Fiber Channel Standard:
• Layer FC-0 Interface/Media
• Layer FC-1 Transmission Protocol
• Layer FC-2 Signaling Protocol
• Layer FC-3 Link Services
• Layer FC-4 Mapping (IPI, SCSI, IP, HIPPI, SERIAL BYTE CONN.)
FICON channels offer a more efficient and faster data transfer. There are two
types of FICON channel cards available on both the IBM 9672 G5/G6 processors
and the IBM ^ zSeries 900:
• Long Wavelength (LX)
• Short Wavelength (SX)
FICON LX channels without repeaters support link distances up to 10 km (20 km
with RPQ 8P1984) using 9-micron single-mode fiber, and 550 meters using 50
micron or 62.5-micron multimode fiber. Note that multimode fiber can only be
used for the LX FICON channel via mode conditioning cables.
FICON SX without repeaters supports link distances up to 550 meters using 50
micron fiber and 250 meters using 62.5 micron fiber.
Each FICON channel is capable of supporting up to 4000 I/O operations per
second. This allows each FICON channel to provide the same I/O concurrency as
up to 8 ESCON channels. This capability allows customers the option of channel
to control unit consolidation.
FICON implementation has taken place in three separate phases:
• The first phase is the FICON Bridge (FCV, also known as FICON conversion),
in which a FICON channel in a CPC connects to a 9032 Model 5 ESCON
Director with a Bridge Card. This enables existing ESCON control units,
without any changes, to exploit the FICON channel.
The 9032 Model 005 Director was the first device to support FICON, and is
intended to provide investment protection for currently installed ESCON
control units. Up to 16 Bridge Cards are supported on a single 9032 Model
005, with each card capable of supporting up to eight concurrent ESCON
control unit connections. Control units can be connected to the system using a
combination of FICON (through the Bridge Card) and ESCON paths,
preserving the customer’s investment in ESCON Directors, as well as the
investment in the existing fiber infrastructure.
48 Fiber Saver (2029) Implementation Guide
• The second phase of implementation is native FICON Direct Attachment (FC).
The FICON channel plugs directly into a native FICON control unit. Some IBM
control units that support native FICON attachment are 3590-A60,
2105-F10/F20 Enterprise Storage Server and 3170-005 (Infoprint).
• The third phase of implementation is FICON Director connectivity. The FICON
Directors (IBM 2032 and 2042) enable full dynamic switching of a FICON
control unit between multiple channels, as well as multiple FICON control units
on a single FICON channel. The FICON Directors support both LX and SX
ports. Note that the distance limitation for SX ports using multimode 62.5
micron fiber is reduced to 175 m.
Figure 35 shows the physical connections and distance limitation associated with
each of the 3 phases of FICON implementation for both LX and SX FICON
Figure 35. FICON connections
FICON channels have data rates of up to 100 MB/s, using full-duplex data
transfer. It is possible to send data in both directions simultaneously—unlike
ESCON, which is a half-duplex protocol. FICON channels can also execute
multiple concurrent I/Os on a single channel.
The data rate droop which impacts ESCON channels at distances of around 9km
does not occur with FICON channels. The data rate droop point for FICON
channels is 100 km. Therefore, there is negligible performance degradation at
distances up to 100 km.
Both long wavelength (LX) and short wavelength (SX) FICON channels can be
connected directly to an IBM 2029 shelf. The maximum end-to-end distance
supported for FICON channels is 100 km. This can be achieved by cascading two
IBM 2029 point-to-point networks.
<= 10 km Unrepeated
<=250m 62.5 micron, <=550m 50 micron
<= 100 km Repeated
Note: Each connection line represents a fiber pair
SM or MMSM
SM or MM
<= 10 km Unrepeated)
SM or MMMM
SM or MM
<= 500m 50 micron
<=175m 62.5 micron
<= 10 km Unrepeated
FICON Bridge Card
<= 3 km