DMVPN Spectrum Business SLOW

[brent.gunn@warrenaverett.com]

We  have DMVPN with about 10 spokes primary carrier is Level3/Centrurylink and various internet providers.

We are seeing an issue with 2 offices on Spectrum Business internet 300/20 where transfer speeds wont go above 20Mbps.

Has anyone seen any issues overlaying DMVPN on Spectrum business - This is in Alabama and Tampa florida.

Swapped Routers, configs, TAC has reviewed everything - Spectrum CLAIMS they arent limiting ike traffic, but i cant help but think they are.

Bypass the tunnel and things are pretty good.

[Damien Miller]

It sounds like the slowness is unique to only two sites of your dmvpn so I think we could probably rule out the hub(s).

I would confirm that you are not maxing out the cpu on the spokes. Beyond that I would also perform some more thorough testing, if you see the issue with a TCP bandwidth test but not UDP, it would likely indicate packet loss or fragmentation issues. Since the vast majority of our user facing apps use TCP, this would obviously have a high impact. It doesn't take a high % of drop/loss to slow TCP to a crawl.

A packet capture on a machine would indicate packet loss quite visibly with TCP retransmissions, they light the wireshark screen up like the world is ending, red+black.