Dell SmartFabric Services User Guide Release 10.5.3

Internal SFS components

SFS creates a VLT fabric automatically in the leaf and spine environment. VLT fabric is autoassigned with a fabric-ID, a universally unique identifier (UUID). When a VLT fabric is created, the management IP addresses of the VLT peers are used automatically to set up the VLT backup link. If the management IP address of the peers is changed after the fabric is created, the VLT backup link is updated automatically.

SFS creates a network fabric with the leaf and spine switches automatically. The network fabric is autoassigned with a fabric-ID, a name, and description. The fabric name and description are automatically assigned, but can be changed through the SFS GUI. For more information, see Update fabric name and description.

Fabric links create a connection between the switches in a network fabric. ISL is a link formed between a leaf and spine switch. All parallel links with same connectivity are grouped to form a port channel interface. VLT interconnect (VLTi) is a link formed between the two leaf switches in a same rack.

Internal virtual networks

The internal virtual networks created by SFS are:

VLAN 4000 for SFS cluster control

SFS automatically configures VLAN 4000 on all the switches that are discovered in a fabric, and uses the network for all internal fabric operations. When a leaf or spine switch is discovered, the VLTi or ISL ports are automatically added as tagged members.

VLAN 4001 to 4079 for leaf and spine connections

SFS automatically configures the leaf and spine network using eBGP as the underlay routing protocol. SFS uses the reserved VLAN range from 4001 to 4079 with automatic IP addressing to set up the peer connections. When SFS detects an ISL connection on either a leaf or spine switch, it assigns the ISL to the untagged member of this VLAN. IP address from reserved range is used for this VLAN, and an eBGP session is started on the VLAN interface.

VLAN 4080 for Global untagged VXLAN

SFS automatically configures VXLAN overlay networks with EVPN to extend networks between racks in a multirack deployment. VLAN 4080 with automatic IP addresses from the reserved range is used for VLTi links. VXLAN requires one VLAN to be assigned globally for untagged port-scoped VLAN (Port, VLAN) pairs.

VLAN 4089—OS10 internal use

In SmartFabric mode, VLAN 4089 is the default VLAN and is reserved for OS10 internal use.

VLAN 4090—iBGP peering between leaf switches

SFS automatically configures iBGP peering between a pair of leaf switches directly connected over VLTi links. VLAN 4090 is created automatically with IP addresses from reserved range for enabling iBGP sessions between the VLT peer switches.

VLAN 4094—VLT control VLAN

SFS automatically creates VLAN 4094 on all leaf switches. This VLAN is used for all VLT control traffic between two VLT peer switches and is added on the VLTi ports on leaf switches.

VLAN 4091—Default client management network

SFS automatically configures an overlay network that is called a client_Management_Network. When a device is automatically onboarded on to the network fabric, the device uses the VLAN mapped to this overlay network. This network is a native VLAN unless there is a policy specifying a different native VLAN. VLAN 4091 is used as the default client management VLAN for the VXLAN network.

NOTE You can change this VLAN to a specified VLAN through SFS GUI.

VLAN 3939—Default client control network

SFS configures a second overlay network that is called Client_Control_Network for SFS-integrated solutions. When a device such as VxRail is discovered, it is automatically added as a tagged member of this network. SFS enables leader advertisement and fabric discovery by integrated solutions. The SFS leader virtual IP address for VXLAN network is advertised. The VIP address fde1:53ba:e9a0:cccc:0:5eff:fe00:1100 is fixed and not user configurable.

VLAN 3939 is used as the default client control VLAN for this VXLAN network for SFS-integrated solutions including VxRail and PowerScale solutions. Although you can change the VLAN associated with the default client management and control networks, Dell Technologies recommends not to change the VLANs for VxRail deployments.

OS10# show virtual-network 
Codes: DP - MAC-learn Dataplane, CP - MAC-learn Controlplane, UUD - Unknown-Unicast-Drop
Un-tagged VLAN: 4080
Virtual Network: 3939
   Description: In-band SmartFabric Services discovery network
   VLTi-VLAN: 3939
   Members:
      VLAN 3939: port-channel1000, ethernet1/1/12, ethernet1/1/13
   VxLAN Virtual Network Identifier: 3939
      Source Interface: loopback2(172.30.0.0)
      Remote-VTEPs (flood-list): 172.30.0.1(CP)
 
Virtual Network: 4091
   Description: Default untagged network for client onboarding
   VLTi-VLAN: 4091
   Members:
      Untagged: ethernet1/1/12, ethernet1/1/13
      VLAN 4091: port-channel1000
   VxLAN Virtual Network Identifier: 4091
      Source Interface: loopback2(172.30.0.0)
      Remote-VTEPs (flood-list): 172.30.0.1(CP)

Reserved networks

SFS uses the reserved networks internally by default. If these networks conflict with any networks in the existing deployment, change the default networks using the instructions that are provided in Edit Default Fabric Settings.

Domain ID and ASN mapping

After you enable the SFS on the switches, SFS:

• Associates domain ID for the cluster if it is not assigned when enabling SFS. By default, the domain ID is set to 100.
• Autogenerates ASN for the leaf and spine switches in the fabric.
• Autogenerates subnet with prefix from domain ID.

The following table lists the ASN and BGP subnet and VTEP subnet mapped with the domain ID: