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I'm having issues with my router acting very slow (Adtran Netvanta 3458). We have two networks, let's call them A and B. When I run netperf from two servers on network A (no routing) I get speeds along the lines of 900 Mbps. Which makes sense, since we have all 1Gbps switches. When testing A to B (or vice-versa) I get speeds along the lines of 22Mbps. I have also tested connecting my laptop to the switchports on the router, and testing two servers on network A (no routing) and got speeds around 90 Mbps. Which makes sense since the switchports on the router are 100Mbps. Does anyone have any idea why routing would be so slow?

We bought the router over a year ago, and we think it has been doing this since then, but we never actually tested it before. (network B isn't really used much, so we didn't notice much) We were implementing a site-to-site VPN and noticed it was ridiculously slow, so we started testing basic routing performance. I have ruled out cabling and router CPU/memory utilization. Adtran looked at my config, but didn't see anything wrong with it.

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What bandwidth is the link between A and B and what is the latency between A and B? – joeqwerty Mar 30 '12 at 15:36
The bandwidth is 100Mbps (the speed of the switchports on the router). Pinging from A to B I get ~1ms. – reverendj1 Mar 30 '12 at 20:12

The Adtran data sheet for this model makes no claims whatsoever about the routing performance. With this being an access router designed for WAN links, I would assume it is simply limited in its routing / processing capability. This might especially be the case if you are using ACLs or firewalling rules for your traffic (if supported by the router model).

If the vendor is making any kind of performance claims, it would specify the routing throughput as a bandwidth and packets-per-second (pps) figures for the "plain" and "firewalled" scenarios in the data sheet. Or simply claim to have "wirespeed" routing which would mean that it is capable of routing at least as fast as its physical interface(s) can receive/transmit.

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+1 see if you can disable the stateful packet inspection/firewall engine to turn it into a pure router. – gravyface Mar 31 '12 at 12:19
VPN often requires encryption of the data which slows things down even further. If you have a spare PC and NIC(s), you could set up a pfSense box instead of the Adtran to see the performance before deciding on how much to spend on your long term solution. – Robin Gill Mar 31 '12 at 16:22
@syneticon-dj - Adtran hasn't given me any specifics, but they said it should definitely perform better than it is. – reverendj1 Apr 2 '12 at 16:43
@RobinGill - When we started using the VPN is what brought it to our attention, but I'm doing all my testing on routing locally. I have actually played around with the idea of just switching to pfSense, since we have redundant pfSense routers at another site that seem to be working well. – reverendj1 Apr 2 '12 at 16:53
@reverendj1 in this case: have you checked on the interface L2 statistics? Maybe something is wrong there (like a duplex mismatch). – the-wabbit Apr 3 '12 at 11:22
up vote 1 down vote accepted

Well that was incredibly easy. It turned out to be storm control. I'm not sure if Adtran's implementation is broken or if it is just really expensive, but after disabling it, I am now getting near wirespeed routing (~90mbps). Hopefully this helps someone else.

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I haven't heard of Adtran, I tend to work with enterprise class boxes from the likes of HP or Cisco. Without knowing the details of your configuration, it sounds like it might be doing routing in software. If it is built like most home routers used for ADSL, they have relatively slow MIPS or ARM based processors, and don't have any hardware assistance for routing. They tend to top out at the sort of speeds you are experiencing.

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Adtran is enterprise class, similar to Cisco. It cost ~$1500, not one of the cheapos you find in Big Box stores. – reverendj1 Apr 2 '12 at 16:52
Adtran is more well known for making telco grade hardware for T-carrier circuits. – Thomas G Apr 4 '12 at 21:50

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