MX84 Warm Spare Setup - 2 Buidlings

[Razoe]

Good Day Everyone,

I'm in need of assistance in regards to setting up a warm spare MX84.

From my understanding via research, it seems that the Warm Spare needs to be directly connected to the Master, a switch on the LAN, and a core switch of sorts?

Please see the diagram of the network i'd like to have https://imgur.com/a/fkrSeep.

There are two sites, an MX84 and MS220-24 in each, with a single fiber cable connecting both sites.

What i would like is for in the case of there being a fire or or issue at Site A, then Site B will still have full functionality (Ignore servers and printers and such, lets just think network connectivity and internet access).

Can i get some guidance please? Also, i have some questions below!

1. Does the WAN1 in Building A and WAN1 in Building be have to be of the same subnet (minimum a /29)? Can they be two /30 IP Addresses (meaning they’re not of the same WAN Subnet).

2. I’ve seen images/diagrams where the MX1 needs to be connected to MX2 as well as MX1 Needs to be connected directly to SW2, and MX2 needs to be connected directly to SW1. Is this all necessary? Or it’s just additional redundancy?

[MacuserJim]

1) They don't have to have to be in the same subnet, I have set them up before where each MX had different ISPs.

2) You don't want your MX appliances connected directly together, just to the switches.

This is a pretty good article to help out and explain some of these in a bit more detail. https://documentation.meraki.com/MX/Deployment_Guides/MX_Warm_Spare_-_High_Availability_Pair

[AjitKumar]

Hi Razoe,

@MacuserJimredirects us to a perfect Url depicting the HA functionality in Meraki.

However allow me summarize this for you.
Your understanding is correct. For HA to work properly VRRP heartbeat shall reach either side ideally via L2 / L3 Core.

Also (expcerpt from the Url)
 *There should be no more than one additional hop between them, and they must be able to communicate on all VLANs.

Your queries.
1. Does the WAN1 in Building A and WAN1 in Building be have to be of the same subnet (minimum a /29)? Can they be two /30 IP Addresses (meaning they’re not of the same WAN Subnet).

We can have WAN Interfaces of MXes on the different sub nets. However ideally we shall have a vIP based configuration. I guess this may not be possible in your case as the MXes are placed in two different buildings.

*/30 When using this option, the current Active MX will use its distinct uplink IP or IPs when sending traffic out to the Internet. This option does not require additional public IPs for Internet-facing MXes, but also results in more disruptive failover because the source IP of outbound flows will change.

*/29: When using this option, both MXes will use a shared virtual IP (vIP) when sending traffic out to the Internet. This option requires an additional public IP per uplink but allows for seamless failover because the IP address the network is using to communicate with the Internet will be consistent. The vIP for each uplink must be in the same subnet as the IPs of the MXes themselves for that uplink, and the vIP must be different from both MX uplink IPs.

 
2. I’ve seen images/diagrams where the MX1 needs to be connected to MX2 as well as MX1 Needs to be connected directly to SW2, and MX2 needs to be connected directly to SW1. Is this all necessary? Or it’s just additional redundancy?

MX1 shall not be directly connected be MX2. This is an old configuration which is not recommended any more as there were Dual Master Issue cropping up.

I have also updated your diagram with few comments.

Hope this help you.