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20Gb FAQs |
| Is 20Gb Fibre Channel proprietary? |
No. T11-endorsed 20Gb Fibre Channel is simply an extension of the 10Gb Fibre Channel standard using the same physical layer. |
| Does 20Gb require new cabling infrastructure? |
| No. 20Gb Fibre Channel runs on the same XPAK media as 10Gb. You won’t have to touch a cable or change your topology when you upgrade. Activating your 20Gb ISL fabric is like getting an entirely new SAN with the click of a mouse! | |
| Is 20Gb interoperable with 10Gb? |
20Gb Fibre Channel is 100% interoperable with 10Gb. Customers can mix and match 20Gb and 10Gb ports of any SANbox generation within the same stack at any time. The 20Gb ports auto-negotiate back to 10Gb for those connections that require it – always enabling the highest possible data rate. |
| Do I have to upgrade my entire fabric at the same time? |
No. The 20Gb license is applied on a per-switch basis – all four XPAK ports being upgraded with a single key.
This feature lets customers choose whether to activate 20Gb on all or just some of their SANbox 5802V switches in the early stages of 8Gb migration. The upgrade may be deployed selectively to alleviate bandwidth “hot spots” in the SAN environment – allowing customers to phase in 20Gb as they phase in 8Gb. |
| Will I need to reset my switches or disrupt devices? |
No. There is no device disruption or need to reset the switch – only the ISL port itself is reset. |
| How fast is 20Gb, really? |
20Gb Fibre Channel runs at an actual line speed of 25.5 Gbps. That’s three times the speed of the 8Gb device ports – and six times the speed of ports running at 4Gb!
In other words, with a relatively inexpensive 20Gb upgrade, the four stacking ports on each SANbox 5802V provide the bandwidth equivalent of twelve 8Gb ISL ports, or twenty-four 4Gb ports!
And for customers who only need 4Gb device speeds, the “always on” 10Gb stacking ports are like getting twelve extra 4Gb ISLs at no charge with every switch!
BOTTOM LINE: Whether the stacking ports are running at 20Gb or 10Gb, the SANbox 5802V offers more bandwidth and a much simpler, less disruptive method of connecting switches – an unbeatable cost-saving combination! |
| Are distances limited compared with 10Gb? |
As defined by the Fibre Channel standard, faster speeds run over shorter distances. For instance, using the same media, 8Gb will run half as far as 4Gb – therefore, 20Gb runs half the distance of 10Gb. QLogic offers integrated copper XPAK cables in the following lengths. Data can run at full 20Gb speed over any of these cables.
- 3 inches
- 9 inches
- 2 meters (78 inches)
- New! 8 meter (26 feet)
IMPORTANT: The stacking ports on any SANbox product can also communicate over much larger distances using standard 10Gb short-wave (up to 300m) or long-wave (up to 2km) optical transceivers. |
| Do I need 20Gb optics? |
20Gb optics are not yet available in the industry – however, 20Gb Fibre Channel supports distances up to 8 meters (26 feet) over low-cost integrated copper XPAK cables. |
| Is 20Gb more expensive to run than 10Gb? |
No. Since 20Gb uses the same copper media as 10Gb, there are no additional costs beyond the license upgrade. |
| Aren’t stacking cables more expensive than ISLs using device ports? |
Not for equivalent bandwidth. The improved connection density of stacking always saves costs over the long run. Stacking cables are actually cheaper on a per-bandwidth basis than the multiple ISL links required using regular 8Gb device ports. Remember a single integrated copper XPAK cable replaces at least three fiber optic runs – and at least six expensive SFPs!
IMPORTANT: The cost of competitors’ “device port” ISLs goes up with 8Gb, thanks to the higher cost of SFP optics. However, the cost of 20Gb ISL cables remains the same as 10Gb! Stacking makes more financial sense than ever with 20Gb!
Additional benefits:
- The simplicity of stacking reduces management costs.
- The stability of stacking reduces device disruption costs.
- The efficiency of stacking eliminates unnecessary switch purchases to create ISL ports – maximizing return on investment over time.
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| When should I upgrade to 20Gb? |
Running most of your ports at 4Gb? Most customers in this situation will choose to defer costs by leaving their XPAK ports at the default 10Gb setting.
Beginning to populate the majority of your 5802V ports with 8Gb devices – or simply want to have the fastest Fibre Channel network on earth? Apply one or more 20Gb ISL licenses non-disruptively…and let ‘er rip! |