Warm Spare and redundant internet

[IvoBiermans]

Hi Guys,

Sorry for have yet another topic on this, but have not found a clear solution for my scenario.

Looking to have an MX in Warm Spare setup and MS in stack. ISP provided 2 links (physically separate). 

Based on this the best setup seems to be the following topology.

However, the issue in my scenario, the ISP ONLY provides a /30 WAN address PER link. 😒

They will not provide a /29, so I cannot do a VIP on the WAN.

In this setup would I configure WAN1 on MX1 & 2 with the same /30 IP of Internet 1 and WAN2 of MX1 & 2 with the /30 IP of Internet 2?

Thanks in advance!

[DarrenOC]

Hi @IvoBiermans , that isn’t going to work with having the same WAN IP on both MX’s. Each IP needs to be unique.

Without the VRRP address you can still have an MX HA pair but you’ll hit the issue highlighted below.  You’re paying the ISP so pushback and demand a bigger subnet

Use MX uplink IPs: 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 MXs, but also results in more disruptive failover because the source IP of outbound flows will change.

[IvoBiermans]

Thank you @DarrenOC for your reply, much appreciated.

I agree with you regarding the ISP, however they have already clearly stated that the only way to get more IP's is to buy an additional block and it being delivered by way of framed route...

Which means I would need more equipment in front of the MX's, which will complicated matters further, financially and technically.

What about the scenario where I would connect Link1 to WAN1 on MX1(Active) and Link2 to WAN1 on MX2(Warm Spare). What would happen in the case where Link1 link fails. Would the MX failover functionality be smart enough to fail over and for traffic to start flowing through the warm spare MX2 and in turn utilize Link2?

I understand there will be some disruption due to the public IP changing.

Again, thank you for your help.

[DarrenOC]

Hi @IvoBiermans 

The scenario you describe will work. As highlighted there would be some disruption to traffic flows as they’ll be using a different Public IP.

[PhilipDAth]

When my contract expired, I'd change ISPs.  Talk about inflexible.

[IvoBiermans]

Agreed, and this coming from the biggest ISP in Australia...

I guess Meraki is probably using VRRP with object tracking to make the type of fail over I would require work.