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UCS Reserved VLANs

Anyone that has spent any time with Cisco equipment should just come to expect that there’s a number of VLANs that Cisco reserves for internal use. Cisco UCS is no exception. However, in UCS land, there’s a few curve balls you need to be aware of from version numbers and hardware types.

As I just completed an internal documentation of these VLAN IDs for our department, and since there’s a few places these are documented on Cisco’s web site, I felt it may make sense to just put them here for easy consumption later. In addition to the Cisco official documentation I’ve included my recommendations for reserving additional VLANs to make your life easier.

So, without further blabbering, here’s my current list of reserved VLANs on Cisco UCS, what they’re used for, and whether they can be changed or not..

Official Cisco UCS Port Reservations

VLAN IDDescriptionModifiable
3915-4042Only on Cisco UCS 6454 Fabric Interconnects
Used for internal system communication
See Cisco UCS Configuration Limits
Yes
4030-4047Used for internal system communication
See Cisco UCS Manager Network Management Guide
No
4048Cisco UCS 2.0 and later
Default VSAN’s FCoE VLAN ID
See Cisco UCS Manager Network Management Guide
Yes
4049Cisco UCS 2.0 and later
Default FCoE Storage Port Native VLAN ID
See Cisco UCS Manager Network Management Guide
Yes
4093Cisco UCS 4.0.1(c) and earlier
Used for internal system communication
See Cisco UCS Manager Network Management Guide
No
4094-4095Used for internal system communication
See Cisco UCS Manager Network Management Guide
No

My Bonus Recommended Reservations

Cisco UCS domains that are using Fibre Channel, whether by attaching to an existing Fibre Channel SAN fabric or by having an array directly connected to the Fabric Interconnect, will also require VLAN IDs for the VSANs within UCS. As I always design my storage fabrics as an A and B fabric I also create a separate VSAN ID for them (typically 11 and 12, respectively). Therefore, in my UCS domains I also create two VSANs and assign them unique VLAN IDs for the FCoE to run in.

VLAN IDVSAN IDDescription
321111Fibre Channel Fabric A
321212Fibre Channel Fabric B
321313Direct-Attached Array FI-A
321414Direct-Attached Array FI-B
Published inCisco UCS

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