Q: Sizes of Existing and Planned Fully Meshed IPSEC VPN (Tunnel Mode)

Joe Rhett jrhett at isite.net
Sun Nov 4 00:52:36 UTC 2001

> I assume "fully meshed" means each node connects to each other
> node, so each node has 109 tunnels (110 total).
> I also assume "Cisco IPSEC based VPN" means IPsec (rfc 2401/2411/etc.)
> and not MPLS-only.
> In that case, 120 is not 'large' according to the vendor
> community -- 'large' starts at around 5000 tunnels.  I suspect that,
> in nature (or in the land of the Nanogians) that under 1000 is
> more like a 'large' one.
Hardly. Until the very latest T-code releases, there was a hard limit of
200 on the number of open SAs any IPSec router could have open. 200 routers
talking fully meshed is impossible, nevermind 5000. If communications are
opened in 2 directions, 100 routers with a single access-list entry
identifying the other site was the max.

Joe Rhett                                                      Chief Geek
JRhett at ISite.Net                                      ISite Services, Inc.

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