Specifications

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A zoning database is maintained on each switch. Table 3 describes the zoning database limits, excluding
the active zone set.
Performance
The 8/20q Fibre Channel Switch supports class 2 and class 3 Fibre Channel service at transmission rates
of 8-Gb/s with a maximum frame size of 2,148 bytes. Related performance characteristics include the
following:
• Distance, page 20
• Bandwidth, page 20
• Latency, page 21
Distance
Consider the physical distribution of devices and switches in the fabric. Choose SFP transceivers that are
compatible with the cable type, distance, Fibre Channel revision level, and the device host bus adapter.
For more information about cable types and transceivers, see ”Technical specifications” on page 55.
Each Fibre Channel port is supported by a data buffer with a 16 credit capacity; that is, 16 maximum sized
frames. For fibre optic cables, this enables full bandwidth over approximately 3 kilometers at 8 Gb/s (4.8
credits/km).
Bandwidth
Bandwidth is a measure of the volume of data that can be transmitted at a given transmission rate. A Fibre
Channel port can transmit or receive at nominal rates of 8 Gb/s, 4 Gb/s, or 2 Gb/s depending on the
device to which it is connected. This corresponds to full duplex bandwidth values of 1,700 MB, 850 MB,
and 424 MB respectively. Multiple source ports can transmit to the same destination port if the destination
bandwidth is greater than or equal to the combined source bandwidth. For example, two 4 Gb/s source
ports can transmit to one 8 Gb/s destination port. Similarly, one source port can feed multiple destination
ports if the combined destination bandwidth is greater than or equal to the source bandwidth.
In multiple switch fabrics, each link contributes up to 1,700 MB of bandwidth between those switches,
depending on the speed of the link. When additional bandwidth is needed between devices, increase the
number of links between the connecting switches. The switch guarantees in-order delivery with any number
of links.
Table 3 Zoning database limits
Limit Description
MaxZoneSets Maximum number of zone sets (256).
MaxZones Maximum number of zones (2,000).
MaxAliases Maximum number of aliases (2,500).
MaxTotalMembers Maximum number of zone and alias members (10,000) that
can be stored in the zoning database. Each instance of a zone
member or alias member counts toward this maximum.
MaxZonesInZoneSets Maximum number of zones that are components of zone sets
(2,000), excluding the orphan zone set. Each instance of a
zone in a zone set counts toward this maximum.
MaxMembersPerZone Maximum number of members in a zone (2,000).
MaxMembersPerAlias Maximum number of members in an alias (2,000)