DELL SONIC · COMPLETE FABRIC

Dell SONiC: build a complete EVPN fabric

Everything together, from blank switches: two Z9264F-ON spines, two MCLAG leaf pairs of S5248F-ON, and a border pair of S5232F-ON. Tenant T1 has web and app VLANs, tenant T2 a database VLAN, kept apart in their own VRFs. A classic switch is the physical domain. The cables are in, and the configuration is yours.

Dell SONiC track · Dell Enterprise SONiC-style + Cisco switch · 7 objectives

Open in simulator More Dell SONiC labs

Objectives

The simulator ticks each one as soon as the network meets it.

Underlay: loopbacks and BGP on all eight switches, as in the underlay lab. Pairs share an ASN (65001, 65002, 65003) and a VTEP address (10.10.10.1, .2, .3).
Pairs: MCLAG on L1+L2, L3+L4 and B1+B2 (domains 1, 2, 3).
VXLAN: VLANs 10, 20, 30 and 100 mapped to VNIs 10010, 10020, 10030 and 10100 where they are needed. Attach the classic switch PHY1 on port 3 of L1 and L2 as a trunk carrying VLANs 10 and 100.
Tenants: Vrf-T1 (VLANs 10 and 20, L3 VNI 50001) and Vrf-T2 (VLAN 30, L3 VNI 50002), with gateways at .254 on every leaf that has the VLAN.
Border: Loopback 100 in Vrf-T1 (10.100.100.1/24) on B1 and B2 stands in for the outside network, advertised as a type-5 route. WEB1 reaches it.
Tenant routing works: WEB1 reaches APP1 (192.168.20.21), and the two tenants stay apart: WEB1 cannot reach DB1 (192.168.30.31).
The physical domain reaches across: BM1 reaches BM2 (192.168.100.22).

Start this lab

Before you start

Build in the order of the tasks, and check each layer before the next: BGP summary, then show mclag brief, then show vxlan remotevtep, then the VRF routes. A leaf only needs the VLANs it has hosts for. The solution lists every line for every switch.

Concept

A leaf-spine fabric on Dell switches

Every leaf connects to every spine, and no leaf connects to another leaf, so any two leaves are two hops apart over several equal paths. eBGP routes between loopbacks form the underlay, usually with one ASN per leaf pair. EVPN then runs on the same BGP sessions: VTEPs announce their VNIs and hosts, and tunnels form from those routes. SONiC can peer without link addresses: ipv6 enable and neighbor interface are enough.

Concept

VLT and MCLAG: two switches, one LACP partner

A leaf pair joined by a peer link looks like one switch to the device below it. That device bundles one link to each leaf with ordinary LACP, so spanning tree blocks nothing and both links forward. Dell OS10 calls this VLT, and SONiC calls it MCLAG. In a VXLAN fabric, the pair also shares one VTEP address, so the rest of the fabric sees a single tunnel endpoint, and either leaf can take the tunnel.

Concept

Physical domains: joining classic switches to a fabric

Most fabrics must reach racks that know nothing about VXLAN: classic switches and bare-metal servers on tagged VLANs. The fabric treats that network as a physical domain. A leaf pair presents one LACP partner, carries the tagged VLANs on a trunk, and maps each VLAN to a VNI, so a host on a classic switch reaches a host anywhere in the fabric. Only VLANs that are mapped cross, and each stays separate.