HCIP-DATACOM · EVPN

Huawei: EVPN all-active with an anycast gateway

Six Huawei PEs with dual MPUs carry VLANs 10 and 20 across an MPLS core between three sites. The core (IS-IS and LDP), the BGP sessions and Sites 2 and 3 are already configured, so you build Site 1 end to end. Each site has two PEs and two Cisco CE switches. Each CE has one LACP bundle to both of its PEs: the shared ESI makes the two PEs look like one partner. Every PE has the same gateway IP and MAC on a Vbdif, so hosts always use a gateway at their own site, and the gateway MACs must stay local.

HCIP-Datacom track · Huawei VRP + Cisco switches · 7 objectives

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Objectives

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

On S1-CE1 and S1-CE2, build Port-channel 1 with LACP: four members, trunking VLANs 10 and 20, and the host port in its VLAN.
On S1-PE1 and S1-PE2, build Eth-Trunk 1 (to CE1) and Eth-Trunk 2 (to CE2) in mode lacp-static, each with one member on card 0/0 and one on 0/1. Add .10 and .20 mode l2 sub-interfaces with encapsulation dot1q vid.
Give each Eth-Trunk its ESI: 0000.1100.0000.0000.0101 for CE1 and 0000.1100.0000.0000.0102 for CE2, the same on both PEs.
Create EVPN instances E10 and E20 in bd-mode (route-distinguisher, vpn-target 65000: both) and bridge domains 10 and 20 bound to them, joining the sub-interfaces.
Build Vbdif10 and Vbdif20: 192.168.10.1/24 and 192.168.20.1/24, with MACs 0000-5e00-0110 and 0000-5e00-0120, the same on every PE.
Filter the gateway MACs, so no PE learns them from another PE (mac-address blackhole bridge-domain ).
Ping from S1-PC1 to its gateway, to S2-PC1 at another site, and to S1-PC2 in the other subnet.

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Before you start

The ESI is what makes all-active work: without the same ESI on both PEs, the CE keeps only the links to one of them. A DF election picks one PE per VLAN to send flooded traffic to the CE. Huawei needs evpn source-address (already set) and vpn-targets you write yourself. display mac-address bridge-domain shows a gateway MAC learned from another PE as a move. On real routers, the exact command for this MAC filter varies by release, so check yours.

Concept

EVPN all-active: one bundle to two PEs

EVPN joins sites at Layer 2 with BGP routes instead of pseudowires. A CE can bundle links to two PEs, because the PEs share an Ethernet Segment Identifier (ESI): LACP sees one partner, and all links carry traffic. Route type 4 lets the PEs of a segment find each other and elect a designated forwarder (DF) per VLAN, which alone sends flooded frames to the CE. Split horizon stops a frame going back to the segment it came from.

Concept

Anycast gateway: one gateway on every PE

Each PE has a routed interface on the bridge domain (a BVI on IOS XR, a Vbdif on Huawei), and all of them use the same IP and MAC. A host always reaches a gateway at its own site, and keeps the same gateway if it moves. But the same MAC on every PE must not travel as an EVPN route: a PE would then see its own gateway MAC behind another PE, as if it had moved.