Dell EMC SmartFabric OS10 User Guide Release 10.5.0

• Two leaf switches with VLT pair without any spine switch
• Two leaf switches with single spine switch or multiple spines switches
• Multiple leaf switches or VLT pairs with single or multiple spine switches
• Leafs without VLT interconnect (VLTi) with single or multiple spine switches

Network fabric is a fabric that consists of switches that are connected in the cluster. The fabric includes leafs and spine switches. Enabling SFS creates a network fabric automatically in a leaf and spine network. The network fabric is autoassigned with a fabric-ID, a name, and description.

VLT fabric is a fabric that is created for a VLT pair. The VLT fabric includes two leaf switches, and 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).

Switch role defines the role of the switch that is deployed in the leaf and spine topology. Spine and leaf are the industry standard terms in any Clos topology. The roles are:

Leaf:

• A switch in a rack that connects to a spine switch. The server or the end device is connected to the fabric through a leaf switch.
• The switch can also be connected to external network using L3 Routed, L3 VLAN, VXLAN, or general-purpose networks.

Spine:

• A switch that connects multiple leaf switches.
• The spine switch can be connected to external network through L3 Routed or L3 VLAN network.

Fabric links

Fabric links create a connection between the switches in a network fabric. The types are:

• Interswitch link (ISL) : A link between a leaf and a spine.

  All parallel links with same connectivity are grouped to form a LAG interface. This link is called ISL.

• Intercluster links (ICL) or VLTi: A link between two leaf switches in same rack.

Internal networks for building a fabric

The VLANs in the range from 4000 to 4094 are reserved for SFS internal use.

• Cluster control VLAN 4000 — SFS automatically configures VLAN 4000 on all the switches in a fabric, and uses the network for all internal fabric operations. When SFS detects an ISL, it assigns the ISL to the tagged member of this VLAN. This VLAN is PVST enabled with root bridge that is forced on one of a spine switch.
• IP-peer VLAN 4001 to 4079 — SFS automatically configures the leaf and spine network using eBGP as the routing protocol. SFS uses the reserved VLAN range from 4001 to 4079 for 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. eBGP session is started on the VLAN interface.
• Global untagged VXLAN VLAN 4080 — 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 leaf-to-leaf ICL links. VXLAN requires one VLAN to be assigned globally for untagged port-scoped VLAN (Port, VLAN) pairs.
• Internal BGP (iBGP) ICL VLAN 4090 — SFS automatically configures iBGP peering between a pair of leaf switches directly connected over ICL links. VLAN 4090 is created automatically with IP addresses from reserved range for enabling iBGP sessions between the VLT peer switches.
• VLAN 4094 — 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 VLT ICL ports on leaf switches.
• Default client management network VLAN 4091 — SFS automatically configures an overlay network that is called client_Management_Network. When a device is connected automatically on to the network fabric, the switch uses the VLAN mapped to this overlay network. VLAN 4091 is used as the default client management VLAN for the VXLAN network.
• Default client control network — SFS configures a second overlay network that is called Client_Control_Network for VxRail integrated solutions. VLAN 3939 is used as the default client control VLAN for this VxLAN network. You can change the VLAN associated with the network, but it is not recommended to change it for VxRail solution 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)