Application viewpoint: FC storage switch partitions and LIP isolation

The FC storage switch has a lot to learn about. Here we mainly introduce the partition and LIP isolation of the FC storage switch. In earlier SAN solutions, most servers were the same operating system, and the security issues in the SAN environment were not prominent. However, in the current scheme, the coexistence of heterogeneous operating systems is everywhere. It is also common for disk array subsystems with multiple sets of disk arrays or with multiple host interfaces.

To ensure that the SAN works normally without destroying data, the FC storage switch-level partitioning can effectively provide a solution-the server can only access devices in the same partition, improves Device Access Security ., Port-based Hardware partitioning of Hardware Zoning can generate intuitive and clear logic division, which is widely used in practice. There is also a Software Zoning Software partitioning) method, that is, based on WWNWorld Wide Name) for partitioning. However, software partitions are rarely used in actual use.

Partitions can overlap, and the same device can belong to different partitions. It can be dynamically divided when the device is running, so that different operating systems can coexist in one SAN. The partition function of the FC storage switch is crucial, but the function of the FC storage switch varies by brand. For example, vswitches of some brands automatically have the Partition Function and do not need to buy software licenses separately. vswitches of other brands need to purchase software licenses separately to implement the corresponding functions.

LIP Isolation)

Many users confuse partition and LIP isolation and think that partition is LIP isolation. In fact, the two are different concepts. When the FC storage switch operates in accordance with the FC-AL protocol, generally all devices negotiate AL_PA addresses or Loop_ID), this process is called loop initialization LIP ). When any new device on the SAN is started, it will cause a LIP. In this case, all machines stop working for address negotiation, so the LIP will interrupt the system.

When the FC storage switch follows the FC-SW protocol, a special service is required to ensure that the SAN works normally. A service similar to the LIP mentioned above is RSCN. After the device completes Fabric Login, it will register a lot of information with the switch. when the device is disabled or restarted, the registration status will change, the RSCN Service is responsible for notifying all devices on the SAN of the registration status change information.

It can be seen that both LIP and RSCN cause damage to the normal operation of SAN, and are even fatal for some special key applications, such as video stream applications and tape library backup applications. According to the FC-AL protocol standard, LIP generally takes 15 milliseconds, while the RSCN following the FC-SW Protocol depends on the complexity of the actual SAN Environment, and even affects normal communication to several seconds. For vswitches with the LIP isolation function, you can set the LIP option based on the port. For important nodes, you can set it to not accept LIP to completely solve the problem. Vswitches that do not have the LIP isolation function can only use the partition method to mitigate the impact of devices in other partitions when solving the RSCN impact problem. However, the actual test results of video stream applications still have a great impact on the performance of devices that communicate normally.

Hardware supports Dolby sound technology

Intel works with the Dolby lab to enable HD Audio to support a wide range of Dolby sound effects, while the ac'97 Audio specification basically does not support sound effects, which is a very important reason for poor reputation. Currently, HD Audio supports Dolby sound effects including: Dolby Headphone, Dolby Virtual Speaker, Dolby ProLogic II, Dolby ProLogic Ⅱ x, and Dolby Digital Live. Through close cooperation between Intel and Dolby, Dolby labs also provides certification for HD Audio of different levels, including Dolby Sound Room, Dolby Home Theater, and Dolby Master Studio, among them, the highest standard Dolby Master Studio defines a wide range of audio encoding, and the signal-to-noise ratio is also up to 95dB, which is comparable to the high-end sound cards on the market.

Human Design and audio input progress

User-friendly design is another highlight of HD Audio specifications. Nowadays, sound cards often have different interfaces with different functions, and their physical shapes are the same. Even if they are defined by different colors, they are easy to connect to complicated interfaces, in the HD Audio specification, Intel leverages the internal routing function of the high-end sound card and works with the automatic monitoring function to determine whether an input or output terminal is inserted, the prompt on the driver software interface fundamentally solves the problem that has plagued users for many years. HD Audio uses the Echo elimination technology Acoustic Echo Cancellation for recording input through a microphone to achieve high-quality input signals. It also supports multiple Microphone Arrays, to adapt to different users and scenarios. For ordinary PC users, it means that they can hear clearer voices from afar during video/Voice chats.

Nowadays, it is common practice to develop dedicated drivers for each CODEC, so the drivers of the ac'97 soft sound card are also varied. Since the launch of HD Audio, it will all become a history. In the HD Audio specification, to improve the ease of use of the system, Intel introduced the Audio Architecture Universal Audio Architecture, UAA). This bus driver can support any CODEC Chip that complies with the HD Audio specification. At present, Intel is cooperating with Microsoft. Microsoft will introduce the UAA function in Windows 2000, Windows XP SP2, Windows Server 2003, And the LongHorn operating system in the future. In the near future, you can use the HD Audio Sound card after installing the operating system.

In order to test and experience the rich and powerful features of HD Audio, we tested and tried it on platforms 915 and 925 respectively, in addition, he solicited an Inspire T7700 7.1 speaker as an audio output device from innovative companies. Due to the relatively tight time, we tested CODEC's ability by playing video and Audio files of different encoding on the test disc. HD Audio can perfectly support various Dolby sound effects, but for home entertainment, it is a pity that DTS sound effects are not supported. In the sound effects supported by the product, the Creative Inspire T7700 speaker can reproduce the effects of various sound effects, easily surpassing the common multi-channel sound cards on the market. In general, the multi-channel audio system seems to be more entertaining, while the appreciation of music is less important, and a richer entertainment experience is the future direction of PC development. HD Audio presents attractive prospects for PC Audio systems. With the release of Intel 915/925 chipset, HD Audio is coming to people step by step.