Tuesday, July 9, 2013

NPV & NPIV - (Storage Series Part-9)

Node Port Virtualization & Node Port ID Virtualization (NPV & NPIV)

- FCID is a 3 byte field with Domain ID as first byte

- Fibre Channel forwarding is based on FCID

- Domain ID is used to identify the Switch in the Fabric's SPT

- It implies that hard limit of switches per fabric is 256

- Some IDs are reserved so only 239 are usable but Qualified limit by OSMs 
   (Original Storage Manufacturer) is approx 50

- NPV fixes the Domain ID problem by removing the need for a switch to participate in Fabric Services
  > I.e. no FSPF, FCNS, Zoning etc

- Switches running NPV appears to the rest of the fabric as an end host I.e. a Node Port (N_Port)

- Upstream facing link on the NPV switch is called NP_Port AKA Proxy Node Port

FC Switch/NPV Core Swith (F_Port)----------(NP_Port) NPV Switch (F_Port)----------(N_Port) Initiator

- Switch upstream of NPV switch is the NPV core switch

- NPV Core switch runs NPIV

- NPIV allows multiple FLOGIs and FCID assignments on its F Port facing downstream


NPV/NPIV Configuration

- Enable NPV on NPV Switch (Downstream Switch)

 > feature fcoe
 > feature npv

# After enabling feature NPV,Switch would require reload. Also most of older config 
   including Data Plane will be erased

# On 5500 UP, reallocate ports as FC after first reload which would again require second reload

- Now configure NP Ports on NPV Switch

 > switchport mode np

- Configure F Ports on NPV Switch (Facing Initiator) / NPIV Switch (Facing NPV Switch)

 > switchport mode f

- ENable NPIV on the Core Swith

 > feature npiv

# sh npv flogi-table ( To check Initiators flogi on NPV Switch )

# sh npv external-interface-usage (To check F port to NP Port Mapping on NPV SW to 
   verify static pinning distribution)

- Zoning to be configured on NPIV Switch

Deepak Arora


incisive said...

I'd like to ask you a question about hard limit of domain ID is limited to 239 per fabric. Does this means it is only applicable to that fabric switch only or the entire fabric switching convergence. That being said, as you already know the end host(N port) are connected to the fex or 5k switch, and so the flogi and fcid is between 5k and N_port isn't it, so what would be the use of having NPIV in any given situation. can you elaborate more that could make me to understand much better on NPIV structure.

Thank you
Krishna CCIE Voice.

Deepak Arora said...

Using NPV/NPIV is more of a solution to help fabric grow in large scale SAN designs. Most of SAN vendors though support 239 Fabric enabled devices in theory but not in real design. Also bigger the fabric grown in turn adds bigger SPF table.

Further Readings: