Configuring Vsan; Overview; Vsan Fundamentals - HP 5920 series Configuration Manual

Configuring VSAN

Overview

The virtual storage area network (VSAN) technology breaks a physical SAN into multiple VSANs, and
provides more secure, reliable, and flexible services.
Devices in a VSAN cannot get information about any other VSAN and devices in any other VSAN. Each
VSAN performs the following operations independently: selecting a principal switch, assigning domain
IDs, running routing protocols, maintaining routing table and FIB table, and providing services.
The VSAN technology delivers the following benefits:
Improved security—VSANs are isolated from each other.
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• Improved adaptability—Each VSAN independently runs and provides services. Different VSANs
can use the same address space so that network capacity is improved.
Flexibility—You can assign interfaces to different VSANs without changing the physical
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connections of the SAN.

VSAN fundamentals

VFC interfaces can only work as trunk ports. A trunk port can belong to multiple VSANs.
Trunk VSAN in an FC network
The trunk VSAN technology implements logical isolation among VSANs. The trunk VSAN works as
follows: The trunk VSAN adds a Virtual Fabric Tagging Header (VFT_Header, also known as VSAN tag)
to the FC frames. The VFT_Header contains a VF_ID (also known as "VSAN ID") field to indicate the
VSAN of the FC frames. In this way, FC frames within different VF_IDs are contained in their respective
VSANs, and different VSANs cannot communicate with each other. VSAN tags are added to and
removed from an FC frame during transmission. A switch supports multiple VSANs one physical interface,
thus reducing physical connections and implementing logical isolation in a physically connected SAN.
Figure 16 shows a typical trunk VSAN. The F_Ports in blue on switches are configured as trunk ports and
assigned to VSAN 1, and the F_Ports in purple are configured as trunk ports and assigned to VSAN 2.
The E_Ports are configured with trunk VSANs 1 and 2.
When servers read the disks, the N_Ports of different servers send FC frames without VFT_Headers to the
F_Ports on FC switch Switch A. Switch A searches for the outgoing interfaces in the FIB table of the VSAN
that each F_Port belongs to. These F_Ports use the same E_Port as the outgoing interface. When the
frames are forwarded out of the E_Port, they are tagged with the VFT_Header of VSAN 1 and VSAN 2
and travel across multiple VSAN-capable switches to the E_Port of FC switch Switch B.
According to the VFT_Headers, Switch B searches for the outgoing interfaces in the FIB tables of the
VSANs, and forwards them to the F_Ports. Then, the F_Ports remove the VFT_Headers and send the
frames to the N_Ports of different disk devices. The frames from the disk devices to the server are
processed in the same way and finally reach the servers.
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