BGP

[mscotto]

I have two ISP's right now however I do not have load balancing enabled.  Do you guys know if load sharing will accomplish the same thing as BGP?  Are any of you running BGP on your MX's and do you experience any issues?

[ww]

Not sure what load balancing you are trying  to achieve

Are you running routed mode? It does not support bgp.  Bgp is only for one armed concentrator. 

[mscotto]

It is in routed mode. If I moved to one arm concentrator I assume I would have to change all my routing in terms of having the core switches do NAT and DHCP? 

[GreenMan]

If you have a site with an MX acting basically as a firewall/UTM + you have two WAN links and you want to share Internet-bound traffic across them, use load balancing configured in Security appliance > Configure > SD-WAN & traffic shaping:   https://documentation.meraki.com/MX/Firewall_and_Traffic_Shaping/MX_Load_Balancing_and_Flow_Preferen...

If you add no other configuration (indicating preferences of which specific WAN links you want identified traffic streams to take) flows will be allocated based upon the bandwidths you configure for each WAN uplink.

If VPN of some kind is involved, it gets a bit more exciting

[mscotto]

Got it thank you, im trying to understand the difference between that and BGP, would BGP be more route specific and load balancing does not handle routes?

[GreenMan · Accepted solution]

You need to explain what you are looking to do more fully, to answer this but...

BGP is always route specific - it’s a dynamic routing protocol.  It exchanges information with other BGP routers.

Load balancing does not handle routes - in the MX implementation it knows there are potentially two paths available for certain outbound traffic flows:  via WAN1, or via WAN2.  (In pure routing terms, there are two equal cost routes & they are not learned from anywhere else).  It can allocate flows to each, based on how you configure it.  Because MX NATs outbound traffic, the return traffic uses the same WAN link.

[mscotto]

Got it that makes more sense, I wanted to do routing so it seems like BGP would be more robust for this.  Thanks!

[GreenMan]

Are you using AutoVPN on your MX?

[GreenMan]

The BGP available from Meraki MX may not be what you're thinking it is.    E.g. you can't hook up an MX to an Internet link and simply learn the Internet routing table (or a subset thereof, controlled by the eBGP peer).

Instead BGP is used only to exchange routes in and out of Meraki AutoVPN.  It's basically used in the Data Centre, to allow the branch SD-WAN to let the DC know which sites / subnets are reached via a particular Hub MX.  It also allows a new service to be deployed in the DC and made readily reachable by all the branches on the SD-WAN.

Of course, the fact that it performs peer monitoring and provides dynamic updates also offers other benefits, in terms of solution resilience.   If you want to do very clever route manipulation, you are likely to need to implement this within the upstream eBGP routers, with which the Hub MXs are peering.

https://documentation.meraki.com/MX/Networks_and_Routing/BGP