In a recent project, I have been told to consider four Hubs (two in HQ, and two in DR), where each branch will have EIGRP neighborships with all four, as part of a DMVPN based WAN. I have tested this in my lab and found that the branch learns the same routes from all the hubs with the same metric, causing it to load balance traffic which is undesirable. As per my knowledge, EIGRP has 3 ways of metric manipulations :
- Delay change
- Offset list to directly manipulate the composite metric
However, since DMVPN utilises a GRE multipoint concept, I cannot make any changes to B/W or Delay on the Spoke side (and all servers lie in the DCs behind the hubs). Offset lists works well, but don't seem to be a good solution (uses an access-list as a reference which needs to be changed again once customer has more servers).
Another idea I have is to just send a default route to the spokes, with summary-metric set and then use that metric to influence traffic.
I would appreciate any other suggestions, and if there are none, can anyone confirm if I am thinking in the right direction (pros and cons of the default route method).