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Dell Enterprise SONiC Networking Use Case Guidebook
Overview Dell Enterprise SONiC Data Center Networking Deployments
Dell Enterprise SONiC Data Center Networking Deployments
Layer 2 fabric deployment
Layer 3 fabric deployment
GenAI fabric
BGP EVPN VXLAN deployments
BGP EVPN VxLAN EVPN Multihoming Data Center Interconnect (DCI) Routing on the Host Multitenant Bridging: Q-in-Q and VLAN Translation
Dell Enterprise SONiC Edge Networking Deployment Dell Enterprise SONiC solutions deployments (RoCE, VxRail, NVMe/TCP, PowerFlex) References

Layer 2 fabric deployment

Home > Networking Solutions > Enterprise/Data Center Networking Solutions > Enterprise SONiC Networking Solutions > Guides > Dell Enterprise SONiC Networking Use Case Guidebook > Layer 2 fabric deployment

Layer 2 fabric deployment

  • The Dell Enterprise SONiC offering provides basic Layer 2 fabric deployment.

    Layer 2 fabric benefits:

    • Simplicity
    • Cost-Effectiveness
    • Compatibility
    • Open standards integration

    The following figure shows the leaf and spine structure to form a Layer 2 fabric. In this topology, the leaf layer facilitates Layer 2 connections to provide a scalable and flexible solution with simplified configurations, allowing for easy network management and expansion.

    The links between the leaf and spine switches are pure Layer 2. Spanning-tree is enabled, and the links are configured as trunks carrying tagged VLANs.

    Multi-chassis Link Aggregation Group (MC-LAG) peer link is deployed on the leaf pair switches. Simultaneously, default gateways for each subnet or VLAN is deployed on the leaf pair switches. The gateways are used to provide subnet or VLAN routing capabilities inside the fabric and Layer 3 connectivity with the external network.

    The connections from the edge or border leaf switch to the external network are Layer 3.

    Figure 1. Scalable Layer 2 fabric for data center
    Scalable Layer 2 fabric for data center

    Deployment best practices

    Whenever deploying a Layer 2 fabric, the following best practice guidelines should be followed:

    • Enable Rapid per VLAN Spanning-tree (RPVST) as the spanning-tree mode. Each VLAN creates its own spanning-tree instance. However, if the number of VLANs grows exponentially, scalability can become an issue.
    • As a minimum, two active links between leaf and spine switches should always be used to ensure link redundancy.
    • Pay close attention to port channel mode (LACP or Static). The default mode is LACP. This means LACP must be configured at both ends of the port channel.
    • When deploying the companion default gateways for each VLAN or subnet, make the description of the gateways clear.
    • Configure jumbo frames (9000-9216 bytes) for fabric and host pot interfaces to address any potential issues with packet size.
    • Configure all port channels or LAGs as trunks to carry all tagged traffic.
    • Use the edge or border leaf pair as a gateway for North-South data traffic.
    • Be aware that by using spanning-tree, network loops are avoided, however, half of the interlinks will be blocked to avoid network loops.