GTM Topology Load Balancing - Order of Operation
Two-part question:
1.) For wide IP-level topology load balancing, what takes precedence: order, weight, or prefix length? (Assuming topology load balancing is choosing between pools based on source IP subnet).
2.) This question came about due to a situation in which I'm seeing some unexpected LB results. Given the below topology configuration (11.x)
1 IP Subnet is 10.0.1.0/29 Pool is West_DC_Pool 1
2 IP Subnet is 10.0.1.0/24 Pool is West_DC_Pool 150
3 IP Subnet is 10.0.0.0/24 Pool is East_DC_Pool 1
4 IP Subnet is 10.0.0.0/16 Pool is East_DC_Pool 100
The LDNS server IP is 10.0.1.5 (there's only one LDNS server at the moment)
The East_DC_Pool is being chosen every time. Based on the logs, it seems to be comparing 1 (10.0.1.0/29 with a weight of 1) to 4 (10.0.0.0/16 with a weight of 100) and therefore 4 is winning based on a weight of 100. No mention of 2 (10.0.1.0/24 with a weight of 150) in the logs.
If I delete 1, then 2 (10.0.1.0/24 with weight of 150) wins so traffic is then sent to West_DC_Pool. Now re-adding 1 (10.0.0.0/29 with weight 1) causes 4 (East_DC_Pool) to win again. Is this expected behavior??? I would have expected in all cases (with a LDNS IP of 10.0.1.5) that traffic would be routed to the West_DC_Pool based on either longest prefix match(1 would win), weight(2 would win), or order (again 1 would win). But maybe there's something about the order of operation that I'm unaware of.
Thanks in advance, Dave