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VC-init : use cases
I have a few questions
Currently we have Brocade only equipment with the exception of one NPIV 8gbit uplink coming from a Cisco UCS Blade Chassis
I configured VC-INIT on the Long distance port , connecting 2 sites over an 8gbit LINK on a Connectrix G620
However I want to generalize on VC-init throughout my fabrics.
It unlocks Virtual Channels, and hereby unlock QOS (zones), quarantaining, buffercredits per channel , ... , most of all better flow control
My questions are :
- Suppose I leave it only on my intersite ISL , will VC support only be used for frames threspassing my site over the intersite ISL, but not originating from my initiator path , or over any ISL hops, nor towards my target destination ?
- Suppose I enable VC-INIT on all my E-PORTS (LD0 mode) , will all frames threspassing ISLs use VCs , but Fports still don't use it .
- Suppose I enable it on all my switchports, would then also benefit my Host/Storage Nodes from the use of VCs ?
- Is there a global setting to enable it switchwide ?
- Are there any prerequisites other then that other FC vendors might not support it ? Would it then be ok, that in respect to the intersection with the Brocade equipment , you would simply not enable it on the intersection port with such a solution ?
Ed Schulte
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Posted September 7th, 2020 00:00
Hi,
Virtual channels only E-port to E-port.
On your questions:
Suppose I leave it only on my intersite ISL , will VC support only be used for frames threspassing my site over the intersite ISL, but not originating from my initiator path , or over any ISL hops, nor towards my target destination ?
Ed: Virtual channels is normally used over any E-port to E-port connection.
Suppose I enable VC-INIT on all my E-PORTS (LD0 mode) , will all frames threspassing ISLs use VCs , but Fports still don't use it .
Ed: Correct, f-port don’t use VC. (of course there are exceptions, see below.)
Suppose I enable it on all my switchports, would then also benefit my Host/Storage Nodes from the use of VCs ?
Ed: No. No f-ports.
Is there a global setting to enable it switchwide ?
Ed: No.
Are there any prerequisites other then that other FC vendors might not support it ? Would it then be ok, that in respect to the intersection with the Brocade equipment , you would simply not enable it on the intersection port with such a solution ?
Ed: Brocade HBA’s (F-ports) can avail from virtual channels.
“16 Virtual Channels (VCs) per port. VC-RDY flow control can use these multiple channels for Quality of Service (QoS) and traffic prioritization in physical and virtualized network environments.”
Regards,
Ed