https://mannit.com.au/posts/Recent content in Posts on MannIT BlogHugoen-usMon, 20 Oct 2025 13:23:48 +0800https://mannit.com.au/posts/ospf_redist/Mon, 20 Oct 2025 13:23:48 +0800https://mannit.com.au/posts/ospf_redist/Redistributing OSPF into EVPN I was recently working on a lab for VXLAN/EVPN and was trying to simulate a connection to the outside world. For the lab, I was using OSPF to connect to the pretend ISP router, and wanted to redistribute that route into the EVPN-based fabric for a customer using our fabric. I got most of this to work fairly simply, but ran into issues redistributing the Gateway of last resort.https://mannit.com.au/posts/troubleshoot_evpn/Tue, 07 Oct 2025 09:06:04 +0800https://mannit.com.au/posts/troubleshoot_evpn/Troubleshooting EVPN This is a page which shows some troubleshooting tips for EVPN. The strategy I like to use is “Local,Spine,Remote”, or ‘LSR’ to make it easy to remember. Before you get too far into the weeds, always first verify that you have BGP & EVPN neighborships. The below steps are useless if you do not have those fundamental pieces in place. Troubleshooting EVPN has similar steps to troubleshooting standard networking problems.https://mannit.com.au/posts/evpnconfig/Sun, 05 Oct 2025 11:53:16 +0800https://mannit.com.au/posts/evpnconfig/EVPN Config Examples Leaf1 & Leaf2 (MLAH/iBGP Pair) Leaf 1 vlan 10 rd 65001:10010 route-target both 10010:10010 redistribute learned ! vlan 20 rd 65001:10020 route-target both 10020:10020 redistribute learned ! vlan 30 rd 65001:10030 route-target both 10030:10030 redistribute learned ! address-family evpn neighbor SPINEOVERLAY activate ! address-family ipv4 neighbor 10.10.1.1 activate neighbor 10.10.2.1 activate neighbor 172.16.4.2 activate network 1.1.1.1/32 ! vrf CUST1 rd 1.1.1.1:20010 route-target import evpn 20010:20010 route-target export evpn 20010:20010 redistribute connected !https://mannit.com.au/posts/intvxlan/Thu, 02 Oct 2025 21:26:17 +0800https://mannit.com.au/posts/intvxlan/VXLAN Interface Sample Config Leaf1 Leaf1#show run int vxlan1 interface Vxlan1 vxlan source-interface Loopback0 //bind to lo0 vxlan udp-port 4789 //declare udp port vxlan vlan 10 vni 10010 vxlan vlan 20 vni 10020 // vlans 10,20,30 mapped to appropriate vni's vxlan vlan 30 vni 10030 vxlan vrf CUST1 vni 20010 //mapping the VRF's to a VNI vxlan vrf CUST2 vni 20020 Verification The VNI’s must match on each leaf, or you will end up with massive issues.https://mannit.com.au/posts/underlay/Thu, 02 Oct 2025 20:53:08 +0800https://mannit.com.au/posts/underlay/BGP/EVPN Underlay Example Spine 1 router bgp 65000 router-id 5.5.5.5 no bgp default ipv4-unicast distance bgp 20 200 200 maximum-paths 3 ecmp 3 neighbor 10.10.1.2 remote-as 65001 neighbor 10.10.1.2 description Leaf1 neighbor 10.10.1.2 maximum-routes 12000 neighbor 10.10.1.6 remote-as 65001 neighbor 10.10.1.6 description Leaf2 neighbor 10.10.1.6 maximum-routes 12000 neighbor 10.10.1.10 remote-as 65002 neighbor 10.10.1.10 description Leaf3 neighbor 10.10.1.10 maximum-routes 12000 neighbor 10.10.1.14 remote-as 65003 neighbor 10.10.1.14 description Leaf4 neighbor 10.10.1.14 maximum-routes 12000 address-family ipv4 neighbor 10.https://mannit.com.au/posts/evpn_overlay/Thu, 02 Oct 2025 20:23:35 +0800https://mannit.com.au/posts/evpn_overlay/EVPN Overlay Example Spine 1 router bgp 65000 router-id 5.5.5.5 no bgp default ipv4-unicast distance bgp 20 200 200 maximum-paths 3 ecmp 3 neighbor LEAFOVERLAY peer group neighbor LEAFOVERLAY next-hop-unchanged neighbor LEAFOVERLAY update-source Loopback0 neighbor LEAFOVERLAY ebgp-multihop neighbor LEAFOVERLAY send-community neighbor LEAFOVERLAY maximum-routes 0 neighbor 1.1.1.1 peer group LEAFOVERLAY neighbor 1.1.1.1 remote-as 65001 neighbor 1.1.1.1 description Leaf1 neighbor 2.2.2.2 peer group LEAFOVERLAY neighbor 2.2.2.2 remote-as 65001 neighbor 2.2.2.2 description LEAF2 neighbor 3.https://mannit.com.au/posts/addressing/Thu, 02 Oct 2025 17:47:05 +0800https://mannit.com.au/posts/addressing/If possible, allocate a /24 for each Spine, and it’s correspinding Spine-Leaf Uplink. For example; * Spine1 = 10.10.1.0/24 * Spine2 = 10.10.2.0/24 * Spine3 = 10.10.3.0/24 * etc. Following this, a best practice is to make the uplinks /30’s, and make the spine have the first address in that /30. i.e, for 10.10.1.0/30 , the spine would have the .1 address and the leaf would have the .2 address. This allows for uniformity of the spines (i.https://mannit.com.au/posts/mlagibgp/Thu, 02 Oct 2025 17:44:13 +0800https://mannit.com.au/posts/mlagibgp/Expanded notes for MLAG / iBGP Config See below config vlan 4093 name Mlag_iBGP trunk group MLAG vlan 4094 name MLAG_HB trunk group MLAG interface Vlan4093 no autostate ip address 172.16.4.1/30 //4.2 on adj leaf interface Vlan4094 no autostate ip address 172.16.40.1/30 //40.2 on adj Leaf ip virtual-router mac-address 00:1c:73:00:00:99 mlag configuration domain-id DomainLeaf1Leaf2 local-interface Vlan4094 peer-address 172.16.40.2 peer-link Port-Channel100 interface Port-Channel100 description Peer Link Leaf 1 and Leaf 2 switchport mode trunk switchport trunk group MLAG // matches trunk grou spec'd in vlan creation int e3-4 mtu 9214 channel group 100 mode active router bgp 65001 .https://mannit.com.au/posts/vxlan_evpn_outline/Wed, 01 Oct 2025 21:33:06 +0800https://mannit.com.au/posts/vxlan_evpn_outline/EVPN/VXLAN Config Structure/ Skeleton 0 Enable EVPN with the following command service routing protocols model multi-agent 1. Add the Addresses to the devices / configure ports. The first step is to add the addresses to the appropriate locations. Each devices will need; Address on uplinks/downlinks Loopback0 address for EVPN overlay MLAG Devices will need additional addresses; 1 x VLAN SVI (normally 4094) for MLAG Heartbeat 1 x VLAN SVI (use 4093) for iBGP peering over the MLAG peer-link Additionally, you need to ensure the MTU is set to 9214 on ports, and they are set as ’no switchport’.https://mannit.com.au/posts/evpntypes/Wed, 01 Oct 2025 20:52:24 +0800https://mannit.com.au/posts/evpntypes/EVPN Route Types Questions about the EVPN Route Types are pretty good interview questions for Network Engineers/ Architects. I keep forgetting the EVPN route types, so here is the EVPN route types explained so I can review them before an interview. I will separate them into their respective categories: “Standard” and “Multihoming” Standard Route-Type 2: The bread and butter of EVPN, EVPN Route Type 2 is used to advertise the MAC address of a host.https://mannit.com.au/posts/ospfinterviewquestions/Fri, 19 Sep 2025 08:50:17 +0800https://mannit.com.au/posts/ospfinterviewquestions/OSPF Interview Questions A page to visit to refresh the brain about OSPF stuff before you go for an interview LSA Types & Description LSA’s 1. Router LSA Each router genererates this to describe its own interface (inluding address/mask, cost, etc). Flooded within the OSPF Area 2. Network LSA Generated by a DR, and lists all the routers in an OSPF area. Flooded within an area 3. Summary LSA Created by the ABR, summarizes network information from one area and advertise to another.