HP StorageWorks 2/32 common software and switch options version 3.0.x/4.0.x re - Page 8

Switch Options Descriptions and Requirements The maximum number of 'HOPS' or inter-switch links allowed in a Fabric is seven and only one of these links can be a very long Extended Link (> 10 kilometers). The maximum distance for a very long Extended Link 1 Gigabit Link is 100 kilometers. Given these limits the maximum of 160 kilometers is possible with one 100-kilometer link and six 10-kilometer links. Extended Fabric Compatibility Support HP has three series of switches as listed above; these switches can be divided into two classes based on the internal ASIC technology used in the switch. The two classes are switches limited to 1 Gigabit and those that are 2 Gigabit capable. An extend fabric link can only exist between two switches of the same technology, meaning a StorageWorks 1 Gigabit SAN series switch can only have an extended fabric link to another StorageWorks 1 Gigabit SAN series switch. The StorageWorks 2 Gigabit SAN series switch can only have an extended fabric link to another StorageWorks 2 Gigabit SAN series or a HP StorageWorks Core Switch 2/64 switch. A StorageWorks 2 Gigabit SAN series or a HP StorageWorks Core Switch 2/64 switch cannot a have an extended fabric link to a StorageWorks 1 Gigabit SAN series switch. PortcfgLongDistance Setting Extended Fabric optimizes the internal buffering algorithm for StorageWorks switches, which results in line speed performance of close to full Fibre Channel speed. The "PortcfgLongDistance" setting is used to configure the port with the appropriate amount of buffers based on the speed and distance of the extended link. The possible settings are: • L0: 1 Gigabits links up to 10 kilometers or 2 Gigabit links up to 5 kilometers No Extended Fabric license required (Also referred to as an "E-Port") • LE: 2 Gigabit links between 5 and 10 kilometers No Extended Fabric license required • L1: Extended Links greater than 10 kilometer but not more than 50 kilometers Extended Fabric license required • L2: Extended Links greater than 50 kilometer but not more than 100 kilometers Extended Fabric license required These port settings modify the number of Buffer-To-Buffer credits a particular port is allocated and there are limited numbers of these credits available. Buffer-To-Buffer credits are allocated to a group of 4 ports or what is referred to as a "Quad". A quad consists of ports 0 through 3, 4 through 7, 8 through 11, 12 through 15 and so on. The following table lists the configuration limits for a "Quad". 8 Common Software and Switch Options Version 3.0.x/4.0.x Release Notes