ISR1117-4P - Failover - GRE Throughput

[Juan-Carlos Perez]

Hello,

I need to setup a Failover on an ISR1117-4P router  using GRE Tunnels.  The WAN1  Connection is 500/500M, can the GRE tunnels give that much througput or  will they become a bottleneck?  Thank you.. 

[Joseph W. Doherty]

If the routers are capable (I haven't checked that model's performance specs) pushing a gig+, GRE doesn't have to be a major impediment.

You'll lose bandwidth to GRE overhead (becomes more significant as the packet becomes smaller), but the real threat to GRE is fragmentation, more so in a failover role impacting already active flows.