SNMP responses very slow WHEN multiple WAN links

Question

Have have just configured a new XG115 device. 
 There are 2 DSL links on the device, one is a very good vdsl link (90Mbps). 
 Everything works great : very good ping time, very good troughput. 
 But, when I make a SNMP request, the response take about 2 seconds to come back. When I make a SNMP walk from my monitoring server to gather interfaces descriptions, it tooks more than 1 seconds per line so about 20 seconds to end. 
 SFOS is 16.05.1 MR-1 and I have other XG appliances that do not have this issue (even with very smallest Internet links) 
 I cannot figure what can be the problem, the configuration is very basic, no anti dos, no anti spoofing ...

Federico Pancani · Accepted Answer

We just found a workaround for this awesome bug. 
 You just need to create a static route like this: 
 Destination IP / Netmask: x.x.x.x (where x.x.x.xisy the IP of your SNMP collector) 
 Gateway: y.y.y.y (where y.y.y.y is the gateway of the wan interface you want to use to talk with your SNMP) 
 Interface: y.y.y.z (y.y.y.z is the "exiting" interface) 
 Distance: 0 
 
 By doing this you'll enable the packet directed to your SNMP collector to "pass" from the selected interface, removing the high response time problem. 
 Enjoy 
 Digital Network, Florence, Italy

EddyMinet · Answer

Thanks for help, this workaround works ! 
 For a PPP Gateway, /32 adressed, left the 'gateway' field empty