User`s guide

3 – Planning
Device Access
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Device Access
Consider device access needs within the FC and iSCSI SANs. Access to an FC
device is controlled by mapping FC device to specific iSCSI initiators. FC devices
may be mapped to more than one initiator. Giving multiple initiators access to an
FC device requires access management.
Fibre Channel
The Fibre Channel ports automatically discover all FC target devices, whether
connected directly (loop) or by fabric (switch).
iSCSI
When an iSCSI initiator logs on, the router records the initiator’s iSCSI name and
IP address. The management interface (command line interface [CLI] or
SANsurfer Router Manager) uses the initiator’s information to simplify the
mapping process.
FC Performance
The SANbox 6142 router supports Fibre Channel service at transmission rates of
1 Gbps or 2 Gbps with a maximum frame size of 2148 bytes. It supports Ethernet
service at transmission rates of 1000-, 100- or 10-Mbps with a maximum
transmission unit (MTU) size of 1500 or 9000 (jumbo frames). Related
performance characteristics include the following:
 Distance (see page 3-2)
 Bandwidth (see page 3-3)
 Latency (see page 3-3)
Distance
Consider the physical distance between Fibre Channel devices. Choose SFP
transceivers that are compatible with the cable type and distance you need.
Each Fibre Channel port is supported by a data buffer with a three-credit capacity;
that is, three maximum sized frames. For fibre optic cables, this enables full
bandwidth over the following approximate distances:
 5 kilometers at 1 Gbps (0.6 credits/Km)
 2.5 kilometers at 2 Gbps (1.2 credits/Km)
Transmitting data beyond these distances reduces efficiency because the
transmitting port must wait for an acknowledgement before sending the next
frame.