（双语）目录允许网络

Almost three years ago, cisco and microsoft annouced the directory enabled network(DEN)initiative, which sought to develop a standard for storing information about network devices, applications and users in a single directory.

　　This directory would bind a user's name and network resource access profile to policies for granting or restricting that access, and delegating bandwidth priorities and privileges.work on standardizing specifications for the directory were handed off to the distributed manage-ment task force (DMTF).

　　In march, the DMTF announced it had completed work on a new version of the common infor-mation model that facilitates the mapping of the CIM schema into a lightweight directory access protocol(LDAP)-compliant directory. CIM defines how to represent network device, system and application data in a directory so it can be easily shared for DEN and enter-prise management purposes.

　　By mapping the CIM schema into an LDAP directory, users will be able to further integrate directory information into an overall enterprise management system, the DMTF says.

　　Customers will make DEN-compliant products a priority once the DMTF makes a little more progress on DEN specifications-such as defining a pollicy schema that would specify data structures for binding directory profiles to network security and quality-of-service (QOS)policies and products soon follow.

　　Perhaps, vendors still have to determine how to use directories to prompt network and applications to configure themselves based on business policies. For example, when a user logs on to a network, the directroy would recognize the user's name, department, location and rank within the company, and bind this information with the user's network access or restriction policies. then the IT infrastructure would configure itself accordingly to enable or disable that a access.

　　One of the killer applications for DEN when it was announced was the ability to link QoS policies to users via dircetories. But bandwidth has become cheaper and more plentiful in the LAN over the past two years, and that's made QOS much less of an issue.

　　Instead of prioritizing bandwidth allocation, users can inexpensively overprovision band-width when they need to support delay-sensitive traffic such as voice and video. Also, simple mechanisms such as setting 802.1p bits on ethernet frame or type-of -service bits in IP headers are enough for LAN QOS.

　　Nonetheless, there 's still a huge demand among enterprise users for directories to enable self-configuring networks based on business policy.

　　DEN for QOS may still apply for WAN applications, edholm says. Indeed cisco has made more strides with DEN in the service provider market than in the enterprise arena.

　　Service providers are looking to DEN to integrate multivendor products into an interoperable operational support system.

　　So despite the silnece, progress on DEN is being the silnece, progress on DEN is being made and activty is expected to pick up once standards become a little more solidiffed.