Re: Performance of CentOS as a NAT gateway

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]



Bart Schaefer wrote:

Or are you saying that LAN-to-LAN traffic maxs out at 10Mbps, it is
a little vague.

LAN-to-gateway traffic (e.g., a test FTP of a large file from the
gateway to a machine on one of the LANs) begins to degrade as the
LAN-to-internet traffic increases.  That's not surprising, but it
degrades disproportionately, i.e. when the FTP begins to show
intermittent stalls, the total traffic visible at the router on the
internet side of the gateway is only in the just-over-10Mb/s range.

Once we get to this point, no matter how many more LAN-to-internet
connections become active, the router on the internet side never sees
much over 10Mb/s of traffic.  We're not losing data or having an
unusual number of connection timeouts; each connection just slows
down.  We figured on some slowdown for NAT, but not 80%+.

LAN-to-LAN traffic that doesn't involve the gateway behaves more like
we'd expect, but I'm not sure that eliminates the switch as the
culprit.

How much 'other stuff' is happening on these networks (either side) that might be passed by the switches? It's a long shot but if you've assigned multiple IP addresses to the interface, the card is probably going into promiscuous mode to accept them all and then there will be interrupts and a small amount of CPU work to discard the ones you don't need. It might be worth firing up something like ntop for a while to categorize what's really going by - and you might find something like a virus trying to make connections as fast as it can.

--
  Les Mikesell
   lesmikesell@xxxxxxxxx

_______________________________________________
CentOS mailing list
CentOS@xxxxxxxxxx
http://lists.centos.org/mailman/listinfo/centos

[Index of Archives]     [CentOS]     [CentOS Announce]     [CentOS Development]     [CentOS ARM Devel]     [CentOS Docs]     [CentOS Virtualization]     [Carrier Grade Linux]     [Linux Media]     [Asterisk]     [DCCP]     [Netdev]     [Xorg]     [Linux USB]
  Powered by Linux