[c-nsp] EIGRP on mGRE/DMVPN

[Steve Housego]

Hi all,

Has anyone ever put more than 500 eigrp nieghbours over an mGRE(DMVPN) interface? If so on what hardware? Any issues encountered?

Were looking at either a 3845 or an ASR1002, with approximatly 500 neighbors on a single mgre interface but with potental to grow, we want to standardise our config so would prefer one tunnel endpoint.

Based on the DMVPN design guide (see extract below) it suggests well under 500 as a maximum, but is dated in 2008... 5 years later and ASR's are reasonbly priced..


http://www.cisco.com/en/US/docs/solutions/Enterprise/WAN_and_MAN/DMVPN_2_Phase2.html#wp38036

"If the DMVPN subnet is configured with a /24 network prefix, the neighbor count is limited to 254, which is a safe operational limit. Beyond this number, a compromise is required to balance re-convergence with recovery. In very large EIGRP networks, it may be necessary to adjust the EIGRP hold time to allow the hub more time to recover without thrashing. However, the convergence time of the network is delayed. This method has been used in the lab to establish 400 neighbors. "
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