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JD1's avatar
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Feb 18, 2015

LTM - IP Fowarder Performance issues (Stateless Router config)

Hi All,


Wondering if anyone else has issues with using an IP Forwarder in the manner described in this article (Specifically - Emulating stateless IP routing with BIG-IP LTM forwarding virtual servers):


Here's the scenario....


VLAN attached behind the BIG-IP, which has the web servers on.


MSSQL servers sat on a VLAN reachable through the BIG-IP.


The connections all work, just if SQL traffic isn't routed through the BIG-IP, it works fine. Otherwise, behind the BIG-IP, there is severe delays.


I'd suggest it be a good idea not to route this through the BIG-IP, but I wondered what the F5 communities' take on this would be.


In short....Simple IP Forwarder (Stateless) for mssql traffic... Good or bad idea?






4 Replies

  • Hi JD, i know the issue you posted was like forever ago. I'm migrating traffic over to an F5 and I noticed the exact thing you posted in relation to L3 Forwarding Virtual Servers. I can reach web pages but only the super simple ones behave, the more complex ones barely load and do not function. Did you ever figure it out? Did you end up doing a Simple IP Forwarder?

  • giltjr's avatar
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    Have you done a packet capture when the F5 is not in the middle to see if there are any differences on the network flow?


    Have you verify that the F5 interfaces are connection at the highest possible speed?


    What is the NIC speed on the SQL and web servers? Do the SQL server, web servers, and all network equipment have jumbo frames enabled?


    If the SQL and web servers have 10Gbps Ethernet and the F5 is only 1 Gbps, then things will go slower.


    IF the SQL and web servers are configured to use jumbo frames and the network supports it, the F5 will introduce delays, as I don't believe any F5 devices support jumbo frames.


  • JD1's avatar
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    Severe delays - In excess of 20 second page loads where SQL calls are made. Without BIG-IP in the way, no such delay. SQL DBA's checked out SQL to ensure no issues. tcpdump shows data flowing through like crazy for tcp/1433. Config extract below, this is from Big-IP VE 11.3.0 HF5: *** ltm virtual Forwarder { destination ip-forward mask any profiles { fastL4-Stateless { } } source translate-address disabled translate-port disabled vlans { external internal internal-ref } vlans-enabled } ltm profile fastl4 fastL4-Statelsss { app-service none defaults-from fastL4 idle-timeout 300 loose-initialization enabled reset-on-timeout disabled } ***
  • I've performance tested this quite thoroughly with Ixia performance test hardware and have never observed an unexpected performance impact when using ip-forwarding virtual servers that was not explained by some other factor in the environment. Could you elaborate on what 'severe delays' you have seen? Long transfer times? Slow connection setup/handshake? Would you be able to post the virtual server configuration? --jesse