r/Arista

Have CE routers connecting via individual links to each leaf in an MLAG pair — exclusive VLANs, PE-CE eBGP, /32 loopbacks advertised as EVPN Type-5. With anycast VTEP, inbound VXLAN for these Type-5 routes can land on either peer causing peer-link traversal.

Is it worth introducing Multi-VTEP MLAG to solve this, or is the peer-link traversal acceptable in practice?

720XP Switches with 4GB DRAM

722XPM Switches with 4GB DRAM

7050SX3-48YC12

7050SX3-48YC8 and 7050SX3-48C8

7060SX2-48YC6

7060CX and 7060CX2

We are quiet new to Arista and currently having this setup and use L3 VXLAN over MLAG:

After moving some SVI from our old network to Arista, we noticed an increase in CPU load to about 80-90%.

MLAG domain 1: LEAF-DC1-01, LEAF-DC1-02

interface Loopback1

ip address 100.64.1.1/32

ip address 100.64.1.100/32 secondary

ip virtual-router mac-address 00:1c:72:00:00:11

interface Vxlan1

vxlan source-interface Loopback1

vxlan virtual-router encapsulation mac-address mlag-system-id

vxlan udp-port 4789

vxlan vlan 1 vni 20001

vxlan vlan 2 vni 20002

vxlan vlan 3 vni 20003

MLAG domain 2: LEAF-DC2-01, LEAF-DC2-02

interface Loopback1

ip address 100.64.2.1/32

ip address 100.64.2.100/32 secondary

ip virtual-router mac-address 00:1c:72:00:00:11

interface Vxlan1

vxlan source-interface Loopback1

vxlan virtual-router encapsulation mac-address mlag-system-id

vxlan udp-port 4789

vxlan vlan 1 vni 20001

vxlan vlan 2 vni 20002

vxlan vlan 3 vni 20003

So the TAC figured out that the high CPU usage was because different VVTEP-IPs on each MLAG which cause loops on ARP sync. Which means we have to change this in MLAG domain 2 so that VVTEP matches the one in MLAG domain 1:

interface Loopback1

no ip address 100.64.2.100/32 secondary

ip address 100.64.1.100/32 secondary

Does anyone know how this will affect traffic?

Also is it neccessary to add

vxlan vtep flood

to interface vxlan 1? How would it look like? Like this?

MLAG domain 1: LEAF-DC1-01, LEAF-DC1-02

interface Vxlan1

vxlan vtep flood 100.64.2.1, 100.64.2.100

MLAG domain 2: LEAF-DC2-01, LEAF-DC2-02

interface Vxlan1

vxlan vtep flood 100.64.1.1, 100.64.2.100

Started using ANTA for post-deploy validation, pre/post change snapshot.
Now wondering if people are doing more with it - scheduled health polling or something else entirely ?

Deploying a new Arista L3LS EVPN/VXLAN fabric with AVD. Two design decisions:

- BGP unnumbered underlay — operational/troubleshooting pain vs numbered /31s?
- EVPN AA ESI MH vs MLAG — convergence, reliability, any regrets?

Thanks.