Concept Guide

Appendix
This chapter covers additional information that can support you with the fabric configuration tasks.
Internal fabric components and networks
SFS automatically creates the following components and networks:
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 LAG interface. ICL or 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 ICL 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 ICL
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 ICL
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 VLT ICL 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.
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