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.

[Joseph W. Doherty · Accepted solution]

BTW, your model's performance:

Table 26.     Cisco 111x ISR Autonomous Mode (non-SD-WAN) performance specifications – 17.9 Release (Bidirectional)

Feature	C111x-8P	C111x-4P
IPv4 forwarding throughput (IMIX)	1673 Mbps	1372 Mbps
IPsec throughput (multi tunnel, IMIX)	468 Mbps	370 Mbps
Number of IPsec IPv4 tunnels	100	100

As long as tunnel is just GRE, not GRE/IPSec, looks adequate for 500/500.