Cisco Systems DSC9148D8G48PK9 manual Extended Credits, Port Virtualization, FlexAttach

Chapter 1 Interfaces Overview

Extended Credits

Extended Credits

Full line-rate Fibre Channel ports provide at least 255 buffer credits standard. Adding credits lengthens distances for Fibre Channel SAN extension. Using extended credits, up to 4095 buffer credits from a pool of more than 6000 buffer credits for a module can be allocated to ports as needed to greatly extend the distance for Fibre Channel SANs.

N Port Virtualization

Cisco NX-OS software supports industry-standard N port identifier virtualization (NPIV), which allows multiple N port fabric logins concurrently on a single physical Fibre Channel link. HBAs that support NPIV can help improve SAN security by enabling zoning and port security to be configured independently for each virtual machine (OS partition) on a host. In addition to being useful for server connections, NPIV is beneficial for connectivity between core and edge SAN switches.

N port virtualizer (NPV) is a complementary feature that reduces the number of Fibre Channel domain IDs in core-edge SANs. Cisco MDS 9000 family fabric switches operating in the NPV mode do not join a fabric; they only pass traffic between core switch links and end devices, which eliminates the domain IDs for these switches. NPIV is used by edge switches in the NPV mode to log in to multiple end devices that share a link to the core switch. This feature is available only for Cisco MDS Blade Switch Series, the Cisco MDS 9124 Multilayer Fabric Switch, and the Cisco MDS 9134 Multilayer Fabric Switch.

FlexAttach

Cisco NX-OS supports the FlexAttach feature. One of the main problems in a SAN environment is the time and effort required to install and replace servers. The process involves both SAN and server administrators, and the interaction and coordination between them can make the process time consuming. To alleviate the need for interaction between SAN and server administrators, the SAN configuration should not be changed when a new server is installed or an existing server is replaced. FlexAttach addresses these problems, reducing configuration changes and the time and coordination required by SAN and server administrators when installing and replacing servers. This feature is available only for Cisco MDS 9000 Blade Switch Series, the Cisco MDS 9124, and the Cisco MDS 9134 when NPV mode is enabled.

	Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
1-2	OL-29284-01, Release 6.x