Cisco UCS

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