BGP-EVPN-VXLAN Draining Scenarios

-

 Draining Scenarios


A. Draining a Leaf Switch (Most common)

1. Reduce local-pref on EVPN routes

2. Check that MAC/IP routes from this leaf are not being used

3. Ensure all flows use other VTEPs

4. Then safely disconnect leaf from fabric


B. Draining a Spine

Lower underlay cost

ECMP routes move to other spines

IP reachability shifts fast (typically <50ms)

No EVPN changes required.


C. Draining a VTEP for a specific VLAN

Withdraw MAC/IP routes for that VLAN

Gateway anycast moves traffic to other leaf


⭐ Summary (Very Simple)


Draining Level How When Used


Underlay Higher metric, OSPF/ISIS/BGP preference Spine/leaf upgrade

EVPN Control Plane Lower local-pref for Type-2/5 Leaf maintenance

L2/MAC Withdrawal Stop advertising MAC/IP routes Drain specific VLAN/server

Anycast Gateway Shift Move SVI or ARP/ND Host/VM migration

Comments

Post a Comment

Popular posts from this blog

gNMI_with_grafana on containerlabs

-
Image
  root@digi-oss:/home/labadmin/mohan/2jan26_grafana# cat sr_lab.clab.yml name: sr_lab topology:   nodes:     sr1 : {kind: nokia_srlinux, image: ghcr.io/nokia/srlinux:latest, startup-config: sr1.cfg}     sr2 : {kind: nokia_srlinux, image: ghcr.io/nokia/srlinux:latest, startup-config: sr2.cfg}     # gNMIc Collector     gnmic:       kind: linux       image: ghcr.io/openconfig/gnmic:latest       binds: [gnmic-config.yml:/app/gnmic-config.yml:ro]       cmd: "--config /app/gnmic-config.yml subscribe"     # Prometheus TSDB     prometheus:       kind: linux       image: prom/prometheus:latest       binds: [prometheus.yml:/etc/prometheus/prometheus.yml:ro]       ports: ["9090:9090"]     # Grafana Visualization     grafana:       kind: linux       image: grafa...
Read more

EVPN Route type-1 & type-4 in action

-
Image
 Route Type 1: Ethernet Auto-Discovery (A-D) A Type 1 route is advertised by a PE router on a per-Ethernet Segment Identifier (ESI) basis. It is triggered by the presence of a multihomed connection.  Purpose of Type 1 routes Aliasing:  In an all-active multihoming setup, a Type 1 route informs remote PE routers that an Ethernet segment is reachable via multiple PEs. This allows for load-balancing traffic to the same customer device over multiple paths. Fast convergence (Mass MAC Withdrawal):  If a local link to a multihomed customer device fails, the PE sends a withdrawal message for the Type 1 route. Remote PEs can then withdraw all MAC addresses associated with that Ethernet segment, instead of waiting for individual MAC withdrawals, which speeds up convergence. Split-horizon filtering:   The route carries an ESI label to prevent traffic loops in all-active mode. A PE router won't forward broadcast, unknown unicast, and multicast (BUM) traffic back to its sour...
Read more

Network Automation with ROBOT Framework

-
Image
  Folder-structure Scripts testcase_with_keywordsLibrary.robot *** Settings *** Documentation    Test Case With Keyword Resource         Resources/Keywords/common.robot Resource          Resources/Keywords/vxlanInstance.robot Test Setup        Open Connection Test Teardown    Close Connection *** Test Cases *** [Documentation] Step 1: Verify VXLAN Interface Status     VXLAN Interface Status [Documentation] Step 2: Verify VXLAN VNI to VLAN Mapping     VXLAN VNI to VLAN Mapping Resources/Keywords/common.robot *** Settings *** Documentation    Common Keyword Library Library          ../../Libraries/commonLib.py Variables        ../Variables/veosLeaf01.yaml *** Variables *** ${devType}         ${virtualBox}[vmType] ${ipAddr}          ${virtualBox}[vmManagement][hostIp] ${po...
Read more