Nic teaming - what is dynamic load balancing
When set up nic teaming in Windows 2012 I have the option of selecting "Address Hash", "Hyper-V Port", or "Dynamic" for the load balancing mode. The technet documentation explains "Address Hash" and "Hyper-V
Port" but there is nothing about "Dynamic". Is there anywhere I can find a description of what the "Dynamic" option provides?
Microsoft's official recommendation is to use Dynamic load balancing in most configurations.
Section 3.3 of
the NIC Teaming Deployment Guide explains what Dynamic is. Section 3.4 suggests when to use Dynamic load balancing, and when to use other modes.
I suggest reading the Guide from start to finish. I learn new things every time I look at it.
Similar Messages
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Dynamic Load Balancing vs Static Load Balancing
What do you guys recommend, Dynamic or Static Loading Balancing+Logon Groups? This is to be for 2 instances envoirnment. 1 Central and 1 Dialog.
Thank you,
SamerI would say (as so often) - it depends.
If you CI also carries the batch and update processes and it's not overloaded one could add it to the logon group. If you have a heavy batch load (such as we have) and the CI is already loaded just use the DI for the interactive work.
Markus -
Coherence Extend Address-provider for dynamic load balancing
Hi,
I want to have load balancing across my proxies. so, trying to use <address-provider> feature.
Here is my setup,
I have two proxies and many clients.I am configuring both proxy and the client to use load sharing scheme.
There are implemented classes for the interface AddressProvider. So, i am going to use that.
Here is proxy server settings,
<proxy-scheme>
<service-name>ExtendTcpProxyService</service-name>
<thread-count>10</thread-count>
<acceptor-config>
<tcp-acceptor>
<address-provider>
<class-name>com.tangosol.net.RefreshableAddressProvider</class-name>
</address-provider>
</tcp-acceptor>
</acceptor-config>
<autostart>true</autostart>
</proxy-scheme>
I know there is some silly mistake with that,
I am getting error message in the following log,
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.emc.srm.common.daemon.SrmDaemon.start(SrmDaemon.java:59)
... 5 more
Caused by: (Wrapped: Missing or inaccessible constructor "com.tangosol.net.RefreshableAddressProvider()"
<address-provider>
<class-name>com.tangosol.net.RefreshableAddressProvider</class-name>
</address-provider>) java.lang.InstantiationException
at com.tangosol.util.Base.ensureRuntimeException(Base.java:293)
at com.tangosol.run.xml.XmlHelper.createInstance(XmlHelper.java:2542)
at com.tangosol.run.xml.XmlHelper.createInstance(XmlHelper.java:2426)
at com.tangosol.net.ConfigurableAddressProvider.createAddressProvider(ConfigurableAddressProvider.java:277)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.peer.acceptor.TcpAcceptor.configure(TcpAcceptor.CDB:78)
at com.tangosol.coherence.component.util.daemon.queueProcessor.service.grid.ProxyService.configure(ProxyService.CDB:67)
at com.tangosol.coherence.component.util.SafeService.startService(SafeService.CDB:6)
at com.tangosol.coherence.component.util.SafeService.ensureRunningService(SafeService.CDB:27)
at com.tangosol.coherence.component.util.SafeService.start(SafeService.CDB:14)
at com.tangosol.net.DefaultConfigurableCacheFactory.ensureServiceInternal(DefaultConfigurableCacheFactory.java:1057)
at com.tangosol.net.DefaultConfigurableCacheFactory.ensureService(DefaultConfigurableCacheFactory.java:892)
at com.tangosol.net.DefaultCacheServer.startServices(DefaultCacheServer.java:81)
at com.tangosol.net.DefaultCacheServer.intialStartServices(DefaultCacheServer.java:250)
at com.tangosol.net.DefaultCacheServer.startAndMonitor(DefaultCacheServer.java:55)
at com.tangosol.net.DefaultCacheServer.main(DefaultCacheServer.java:197)
... 10 more
Caused by: java.lang.InstantiationException
at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at com.tangosol.util.ClassHelper.newInstance(ClassHelper.java:587)
at com.tangosol.run.xml.XmlHelper.createInstance(XmlHelper.java:2501)
... 23 more
Cannot start daemon
First question:
1) without address provider section in the proxy server configuration xml, will it use any default address provider implementation?
2) what's wrong with the proxy server settings xml which causes above error?
Thanks
PrabHi LuK,
Sounds like there is no load balancing is happening in my environment.
I didn't use address provider tag since it's mentioned in AddressProvider Interface API that by default it uses ConfigurableAddressProvider implementation.
Here is a xml snippet in remote client cache configuration xml,
<tcp-initiator>
*<remote-addresses>*
*<socket-address>*
*<address>PROXY-A</address>*
*<port>9099</port>*
*</socket-address>*
*<socket-address>*
*<address>PROXY-B</address>*
*<port>9099</port>*
*</socket-address>*
*</remote-addresses>*
<connect-timeout>10s</connect-timeout>
</tcp-initiator>
what i mean by load balancing is,
I will be having lot of web service queries which runs very fast. I would like to see both the proxies serves the web requests.
I am observing, One connection has been made to one proxy when it's starts up and keep hold on to it (no matter whether other proxy is free or not).
is it a bug? or am i doing some mistake?
Thanks
Prab -
We have developed Client Server Communication through Tuxedo Server and Workstation Client. This approach should handle 500 concurrent requests.
We want to configure our Tuxedo Server in such a way that it could handle all the Requests in parallel.
Currently below is our UBB Configuration
WSL SRVGRP="WSLGRP" SRVID=1 RESTART=Y MAXGEN=255 GRACE=3600
##CLOPT="-A -- -n //10.223.26.28:12791 -m 5 -M 10 -x 15 -p 16914 -P 16924"
##CLOPT="-A -- -n //10.223.26.28:12791 -m 2 -M 4 -x 45" ##Minimum 90 ports needs to be available
CLOPT="-A -- -n //10.223.26.28:12791 -m 2 -M 9 -x 60" ##Minimum 120 ports needs to be available
"REQ_HANDLER" SRVGRP="DATA" SRVID=22280
CLOPT="-A -r -e /log/timings/stderr -o /log/tuxlog/req_handler_stdout"
RQPERM=0666 RPPERM=0666 MIN=1 MAX=200 CONV=N
SYSTEM_ACCESS=FASTPATH MAXGEN=255 GRACE=3600 RESTART=Y
The Problem with the above configuration is that, it is not booting another instance of REQ_HANDLER Server when multiple Request receives.
For the Alternative, we have set both MIN and MAX as 10 to make sure it can handle concurrent request.
But We want the Configuration like if there are multiple request received, it will automatically boot the Another instance of the Server and down it(except MIN value) in case of no request.
Please advise.
Thanks in advanceHi Vikas,
It's not really possible to give you an answer just by looking at the config; you will need to observe the queue behaviour to get an idea of what is happening; but perhaps the following will help.
You mention that two servers have booted, so since MIN=1 that does indicate that automatic spawning has taken place. What I think is happening is that the two servers are managing with the workload. When you say you "push 20 requests" how quickly did these arrive, and were the servers able to cope with the workload? You can use the pq command in tmadmin to view the queue "REQ_HANDLER" - based on your config the queue would need to exceed the 50 load for at least 5 seconds to cause another server to start, and you may find that by the time the second server has started up the 20 messages have already been processed (I think I am correct in saying that automatic spawning will only be tested again once the second server has completed it's startup and is able to process messages). Also remember that if the queue depth drops below the level you specified, even briefly, the timer starts again from zero. Do you know how long it takes for the service to execute (you can use the -r CLOPT option and run "txrpt" to determine the execution time)? You can also use the psc and psr commands of tmadmin to see which servers are actually processing the messages.
I notice you have used the "L" option in -p, and are working with service loads rather than number of messages. If the messages all have the same load value then you can simply use the number of messages as an alternative in the -p option.
Regards,
Malcolm. -
Hyper-V NIC Team Load Balancing Algorithm: TranportPorts vs Hyper-VPorts
Hi,
I'm going to need to configure a NIC team for the LAN traffic for a Hyper-V 2012 R2 environment. What is the recommended load balancing algorithm?
Some background:
- The NIC team will deal with LAN traffic (NOT iSCSI storage traffic)
- I'll set up a converged network. So there'll be a virtual switch on top of this team, which will have vNICs configured for each cluster, live migration and management
- I'll implement QOS at the virtual switch level (using option -DefaultFlowMinimumBandwidthWeight) and at the vNIC level (using option -MinimumBandwidthWeight)
- The CSV is set up on an Equallogics cluster. I know that this team is for the LAN so it has nothing to do with the SAN, but this reference will become clear in the next paragraph.
Here's where it gets a little confusing. I've checked some of the Equallogics documentation to ensure this environment complies with their requirements as far as storage networking is concerned. However, as part of their presentation the Dell publication
TR1098-4, recommends creating the LAN NIC team with the TrasportPorts Load Balancing Algorithm. However, in some of the Microsoft resources (i.e. http://technet.microsoft.com/en-us/library/dn550728.aspx), the recommended load balancing algorithm is HyperVPorts.
Just to add to the confusion, in this Microsoft TechEd presentation, http://www.youtube.com/watch?v=ed7HThAvp7o, the recommendation (at around minute 8:06) is to use dynamic ports algorithm mode. So obviously there are many ways to do this, but which one is
correct? I spoke with Equallogics support and the rep said that their documentation recommends TransportPorts LB algorithm because that's what they've tested and works. I'm wondering what the response from a Hyper-V expert would be to this question. Anyway,
any input on this last point would be appreciated.Gleb,
>>See Windows Server 2012 R2 NIC Teaming (LBFO) Deployment and Management for more
info
Thanks for this reference. It seems that I have an older version of this document where there's absolutely
no mention of the dynamic LBA. Hence my confusion when in the Microsoft TechEd presentation the
recommendation was to use Dynamic. I almost implemented this environment with switch dependent and Address Hash Distribution because, based on the older version of the document, this combination offered:
a) Native teaming for maximum performance and switch diversity is not required; or
b) Teaming under the Hyper-V switch when an individual VM needs to be able to transmit at rates in excess of what one team member can deliver
The new version of the document recommends Dynamic over the other two LBA. The analogy that the document
makes of TCP flows with human speech was really helpful for me to understand what this algorithm is doing. For those who will never read the document, I'm referring to this:
"The outbound loads in this mode are dynamically balanced based on the concept of
flowlets. Just as human speech has natural breaks at the ends of words and sentences, TCP flows (TCP communication streams) also have naturally
occurring breaks. The portion of a TCP flow between two such breaks is referred to as a flowlet. When the dynamic mode algorithm detects that a flowlet boundary has been encountered, i.e., a break of sufficient length has occurred in the TCP flow,
the algorithm will opportunistically rebalance the flow to another team member if apropriate. The algorithm may also periodically rebalance flows that do not contain any flowlets if circumstances require it. As a result the affinity
between TCP flow and team member can change at any time as the dynamic balancing algorithm works to balance the workload of the team members. "
Anyway, this post made my week. You sir are deserving of a beer! -
Hello!
There're two physical servers (Hyper-V is not installed) with two nic teams, each consisting of two 1Gb nics:
To test these teams I tried to copy two files from server1 to server2:
1) I started copying the first file and ~20 sec later started copying the second file to the same SSD (from server1 to server2)
2) I copied ~simultaneously two different files to the two different SSDs (from server1 to server2)
As shown in the picture 1 when I added the second copying the first one had stopped completely, although this SSD can tolerate transfer rate up to 350-380MBps.
Both pictures show that the total file transfer speed was less than that of a single team member (1Gbps):
0+112MBps < 1Gbps
57.1 MBps + 56.5MBps < 1Gbps
According to http://technet.microsoft.com/en-us/library/hh831648.aspx
NIC Teaming, also known as load balancing and failover (LBFO), allows multiple network adapters on a computer to be placed into a team for the following purposes:
Bandwidth aggregation
Traffic failover to prevent connectivity loss in the event of a network component failure
Test1 and Test2 show no bandwith aggregation... Are my tests wrong?
Thank you in advance,
MichaelP.S. In a production network it means users would read data from servers using the total amount of a team's bandwidth but write data using the bandwidth of a single team member - that's not I would ever like to have in my network.
And once again: http://technet.microsoft.com/en-us/library/hh831648.aspx
Traffic distribution algorithms
NIC Teaming in Windows Server 2012 supports the following traffic distribution methods:
Hashing. This algorithm creates a hash based on components of the packet, and then it assigns packets that have that hash value to one of the available network adapters. This keeps all packets from the same TCP stream on the
same network adapter. Hashing alone usually creates balance across the available network adapters. Some NIC Teaming solutions that are available on the market monitor the distribution of the traffic and reassign specific hash values to different
network adapters in an attempt to better balance the traffic. The dynamic redistribution is known as smart load balancing or adaptive load balancing.
The components that can be used as inputs to the hashing function include:
Source and destination MAC addresses
Source and destination IP addresses, with or without considering the MAC addresses (2-tuple hash)
Source and destination TCP ports, usually used along with the IP addresses (4-tuple hash)
I don't see in this explanation any reason for not creating balance when the sourses are different but the destination is the same...
Regards,
Michael -
Windows Server 2012/2012R2 NIC Teaming Mode
Hi,
Question 1:
In Windows Server 2012 the following teaming mode was recommended for Hyper-V NIC teams:
Teaming mode: Switch Independent
Load balancing mode: Hyper-V Port
All Adapers Active
In a session at TechEd 2014 it was stated that Dynamic is the new recommendation for Windows Server 2012 R2. However, a Microsoft PFE stated a few weeks ago that he would still recommend Hyper-V Port for Windows Server 2012 R2. What is your opinions around
this?
Question 2:
We have a Hyper-V Failover Cluster which isn`t migrated to 2012 R2 yet, it`s running 2012. In this cluster we use Switch Independent/Hyper-V Port for the team. We also use converged networking, having 2 physical adapters bound to the NIC team, as well as
3 virtual adapters in the management OS for management, CSV and Live Migration. Recently one of the team NICs failed, and this incident also caused the cluster membership on the affected node to go offline even though the other team NIC was
connected. Is this expected behaviour? Would the behaviour be different if 2012 R2 with Dynamic mode was being used?Hello,
As for question number 1:
For Hyper-V workload it's recommended to use Dynamic with
Switch Independent mode. Why?
This configuration will distribute the load based on the TCP Ports address hash as modified by the Dynamic load balancing algorithm. The Dynamic load balancing algorithm will redistribute flows to optimize team member bandwidth utilization so individual
flow transmissions may move from one active team member to another. The algorithm takes into account the small possibility that redistributing traffic could cause out-of-order delivery of packets so it takes steps to minimize that possibility.
The receive side, however, will look identical to Hyper-V Port distribution. Each Hyper-V switch port’s traffic, whether bound for a virtual NIC in a VM (vmNIC) or a virtual NIC in the host (vNIC), will see all its inbound traffic arriving on a single
NIC.
This mode is best used for teaming in both native and Hyper-V environments except when:
1) Teaming is being performed in a VM,
2) Switch dependent teaming (e.g., LACP) is required by policy, or
3) Operation of a two-member Active/Standby team is required by policy.
As for question number 2:
The Switch Independent/Hyper-V Port will send packets using all active team members distributing the load based on the Hyper-V switch port number. Each Hyper-V port will be bandwidth limited to not more than one team member’s bandwidth because the port
is affinitized to exactly one team member at any point in time.
In all cases where this configuration was recommended back in Windows Server 2012 the new configuration in 2012 R2, Switch Independent/Dynamic, will provide better performance.
Microsoft recommend for a clustered Hyper-V deployment
in Windows server 2012 to use Switch Independent/Hyper-V Port as you mentioned and to configure
Hyper-V QoS that applies to the virtual switch. (Configure minimum bandwidth in
weight mode instead of in bits per second and Enable and configure QoS
for all virtual network adapters
Did you apply QoS on the Converged vSwitch after you
created the team?? However Nodes are considered down if they do not respond to 5 heartbeats. The Switch Independent/Hyper-V Port does not cause the cluster to goes down if one NIC failed. The issue is somewhere else and not in the teaming mode
that you choose.
Hope this help.
Regards,
Charbel Nemnom
MCSA, MCSE, MCS, MCITP
Blog: www.charbelnemnom.com
Please remember to click “Mark as Answer” on the post that helps you, and to click “Unmark as Answer” if
a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. -
NIC Teaming on new 2012R2 install IntelX540-T2 Netgear XS712T not functioning properly
I have a new 2012R2 server with an Intel LOM X540-T2 Dual port, 10-gig copper NIC. I'm trying to team both ports to a Netgear 10-gig copper switch (XS712T, CAT6A cables) and not having much luck. Latest firmware/drivers all around. I reset to factory defaults
on the Netgear switch.
From a console, I go to server manager, NIC Teaming, New Team.
When I try Team Mode: Switch Independent / Load balancing mode: Dynamic. Both ports become Active. I understand that now the adapters listed in networking connections are to be left alone, and that configuration should take place on the Microsoft
Network Adapter Multiplexor Driver. The 'Team' adapter is supposed to DHCP, but never does, and ends up with a private 169.254 address. If I manually configure ip4 on the 'Team' adapter, I still have no communication to the network. Both ports are able
to DHCP when un-teamed. Something interesting is that port 1 only shows received packets, and none sent. At the same time, port 2 shows a much smaller number of sent packets, but zero received. Odd.
When I try Team mode: LACP / Load balancing mode: Dynamic. I add two of the Netgear ports to a LAG and enable LACP. One of the ports in Windows will show 'Active' (and has DHCP'd with normal send/receive), and the other port shows 'Faulted LACP Negotiation'
with very few sent packets and zero received.
Any ideas, or places to look next?
Edit: It looks like I can get physical port 1 to join the LACP group, but physical port 2 will not join, even after swapping cables and rebooting the Netgear switch. But port 1 still goes 'active' regardless of the switchport that it's plugged into.Hi,
I agree with SpackTime, please confirm his replay.
Thanks.
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place. -
Hi,
Can someone tell me what has the NIC teaming effect on WAAS.
I was preparing a demo for one of my client but before this they were using another popular WAAS product. According to my client, they had a big network issue with NIC teaming, i.e one ip and 2 mac addresses with server loadsharing.
scenario.
Before the demo i just wanted to confirm that WAAS has nothing to do with the above mentioned problem...can anybody confirm...Hmm... Still not quite sure what your saying. It sounds like by coincidence the other accelerator box got the same IP as one of their servers. They should have been able to fix that quite simple, not to mention test for it by doing the equivalent of "show int" on the box before plugging it in.
Or possibly they had some type of proxy arp configured wrong?
Either way we're running WAAS boxes on our networks that have teaming of NIC's via HP's teaming utility using "Transmit load balancing" on the servers. The WAAS boxes are configured for ether-channeling their NIC's and using WCCP for traffic redirection.
Actually, if you did them using WCCP rather than inline, there definitely shouldn't be a MAC conflict since the WAAS boxes will be on a different subnet at that point. No chance of a problem like that with Layer-3 separation... -
Windows Server 2012 R2 - Hyper-V NIC Teaming Issue
Hi All,
I have cluster windows server 2012 R2 with hyper-v role installed. I have an issue with one of my windows 2012 R2 hyper-v host.
The virtual machine network adapter show status connected but it stop transmit data, so the vm that using that NIC cannot connect to external network.
The virtual machine network adapter using Teamed NIC, with this configuration:
Teaming Mode : Switch Independent
Load Balance Algorithm : Hyper-V Port
NIC Adapter : Broadcom 5720 Quad Port 1Gbps
I already using the latest NIC driver from broadcom.
I found a little trick for this issue by disable one of the teamed NIC, but it will happen again.
Anyone have the same issue with me, and any workaround for this issue?
Please Advise
Thanks,Hi epenx,
Thanks for the information .
Best Regards,
Elton Ji
We
are trying to better understand customer views on social support experience, so your participation in this
interview project would be greatly appreciated if you have time.
Thanks for helping make community forums a great place. -
Round robin DNS for load balancing between multiple network adapters (Xserve)
I'm attempting to use 'round robin' DNS to load balance between the two ethernet adapters of an Xserve.
Both ethernet adapters are connected to the same LAN and have static IP addresses of 192.168.2.250 and 192.168.2.251.
The DNS zone for the server's local domain/host (macserver.private) has a machine record with both IP addresses (set up in the Lion Server UI).
Having read up on round robin DNS, I would have expected DNS requests for 'macserver.private' to be answered with the two IP addresses ordered at random, achiving my aim of requests being served at random via each ethernet adapter.
However this doesn't seem to be the case. Doing a 'nslookup' from any of the network clients results in the two IP addresses being listed in the same order everytime. And pinging 'macserver.private' only ever results in a response from the same address.
Does anyone know why this is the case? Does Lion Server use a non-standard DNS configuration? Are there any additional settings I need to configure in Lion's DNS server to make adopt a round robin approach to responding to requests?
Thanks in advance for any help!Be careful what you wish for
Round Robin DNS is rarely the best option for 'load balancing'. At the very least it's subject to caching at various point on the network - even at the client side, once the client looks up the address it will cache that response - this means that subsequent lookups may be served from the client's cache and not refer back to the server. Therfore any given client will always see the same address until the cache expires.
I suspect this is what you're seeing.
You can minimize this by setting a lower TTL on the records. This should result in the response being cached for a shorter period, meaning the client will make more requests to the server, with a higher change of using the 'other' address.
However, you're also going to run into issues with the server having two interfaces/addresses in the same LAN. This isn't recommended.
As Jonathon mentioned, you may be better off just bonding the two interfaces. This will provide an automatic level of dynamic load balancing without the latency of DNS caches, as well as automatic failover should one link fail (as opposed to round robin DNS which will cause 50% of requests to fail until the client cache expires and a new lookup is performed (and, even then, there's still a chance the client will try to use the failed link). -
WLC - Aggressive Load Balancing?
Hello,
The Wirless LAN Network bulit is as follows -
1. 1 x 4404 WLC
2. 40 x LWAPP 1131AG Access Points
3. Windows Clients used by the Laptop Clients.
4. Only one Wireless VLAN across the Capmus network - hence AP's, WLC & Clients are all in one VLAN / IP Subnet.
5. No Access Point Group is created.
6. Aggressive Load Balancing is enabled allowing 15 Clients as max connection per Access Point.
Problem facing -
1. Tried configuring the Aggressive Loadbalancing allowing only 2 x Clients per AP. But noticed that the 3rd Client connecting to the same AP as of the previous 2 Clients have connected. 3rd client is not associating to a different AP which is nearby.
Please can one help me, if i'm configuring & testing Aggressive Load Balancing in the right way!
Regards,
Keshava RajuAMR is on target. In fact I just completed 20 hours worth of testing with variuos clients with ALB for a white paper I am doing. Code 17 isnt honored by most clients and is only sent 1 time from the AP. The clients will contiue to attempt to associate to the AP and the AP will allow them on.
Here is a peek of my white paper "still in draft"
WLC - Cisco WLC Aggressive Load Balancing; What is it and where did it go in 6.0!
I've spent the majority of my WLC experience at code level 4.2. Not by choice really, more
based on the fact that 4.2 is pretty darn stable and it is the only safe harbor to date for the Cisco WLC. Healthcare and Enterprise enviroments are typically slow to move on upgrades, especially when things are operating fine.
Since my latest project involves the deployment of hundreds of Cisco 1142s @ location grade, it required that I move to later code to support the 1142 access points. After much research, conversations with our
local Cisco Wireless SE, conversation with peers at other healthcare organizations, and direct contact with the aware team I had decided that 6.0.188.0 was a release that was of great interest.
As I start to get fimilar with the new code I am starting to see that things got moved around a little. One of the items is Aggressive Load Balancing. If you aren't fimilar with Aggressive Load Balancing (ALB) you definitly need to be and let me share why.
First lets look at what ALB is and how it works and then we will dive into the differences between the 4.2 code and the new options 6.0 gives us. ALB when enabled, allows the Cisco WLC to load balance wireless clients on access points that are joined to the same controller. “Key word here – same controller”. You can configure the load balancing window globally in the controller. What is the load balancing window you ask? Well is the maximum number of clients that should be allowed on the access point BEFORE it will start to load balance.
Lets assume for a moment you have an access point with 5 clients already attached. When client #6 sends association request to the access point the access point will kindly respond with an associaton response frame with the reason code of 17. The wireless client will see reason code 17 in the association response and will kindly find other access points to associate with. However, some devices will ignore this frame and yet still continue to try and associate to the access point. Note: The Cisco WLC will ONLY send 1 reassociation frame with a reason code of 17. It doesn’t flood the medium / client with multiple frames.
Its up to the client to honor this information and move on. But I can tell you from my experience and testing this isn’t always the case.
By default, 4.2 and 6.x both have a load balancing window of (5). Lets look at an example.
The window setting controls when aggressive load−balancing starts. With a window setting of five, for
example, all clients after the sixth client are load−balanced.
I know, what is the reason code talk, right. Lets cover this as well. If you dive into the 802.11 frames you will see “Reason Codes”. When a client sees the reason code of “17”, it indicates to the client that the access point is busy and the client should look else where.
yada yada yada
I will post the complete paper on my site: my80211.com in the next week or so ... -
Dynamically load a VI by library reference
We are very excited by the introduction of project libraries in LV8 and what it means for project management and building multiple custom distributions using libraries of dynamically called VIs from within a single project. We now have our VIs arranged by VI "type" in the directory structure and by logical "function" with the project libraries that make up the project. It sure wold be nice if we could dynamically load VIs from the library reference rather than trying to keep up with the actual paths. I can get a reference to the library using and invoke node and "open.library" with a path wired in. Is there any way to use this library reference to do an "open vi reference" to a VI within that library?
Hello Lee,
This invoke node returns a reference to the libray, with this you can browse throught the library just like a tree control. It is usefull to open the .lvlib file with a text editor to see what 'Type string' options you have. If you get to the right VI use the 'VI Reference' property from the 'Library Item'-class, this will get you a reference to the VI which you can open, edit, save or whatever VI-server offers you.
Good luck
Ton
PS I'm using in this in a tool to duplicate the .lvproj structue into the hard-drive, I'm not fully done but getting there!
PS This screenshot was made with Starware
Free Code Capture Tool! Version 2.1.3 with comments, web-upload, back-save and snippets!
Nederlandse LabVIEW user groep www.lvug.nl
My LabVIEW Ideas
LabVIEW, programming like it should be!
Attachments:
Example_BD.png 2 KB -
Load Balancing - BSP Applications
Hi All,
Our current system has lot of custom BSP Applications. Recently the basis/network teams have taken up load balancing activities to better manage the workload.
We have observed after the load balancing activity came into play that our BSP calls have been failing(end in ST22 dumps) more frequently then they were happening before.
Failure rate : % of BSP calls ending in ST22 dumps.
Failure rate before load balancing : < 3%.
Failure rate after load balancing : > 25%.
There has been no code change recently.
Dump analysis points to a new line of code each time, also point to standard SAP code most of the times.
Does anyone know what are we doing wrong?
Let me know in case you have more questions.
Regards,
KarthikHi!
In order to really use Load Balancing for BSPs you can
1. install and use SAP Web Dispatcher (no Redirect) or
2. use the SAP Message Server (=Redirect)
In both cases you have to adjust your URLs to the server and port of Web Dispatcher resp. Message Server.
What kind/types of dumps do you get?
Regards,
Volker -
Problem with WLIOTimeoutSecs in weblogic and apche CSS load balancer
Hi,
We are using Weblogic 11g, apache 2.2 and CSS load balancer for load balancing.
we have huge reports which take minutes to generate and hence we need higher value for WLIOTimeoutSecs. This works fine when we use server url but WLIOTimeoutSecs is not working when we use CSS load balancer.
We checked with our load balancing team they said CSS load balancer will not repost the request.
Here is the plugin configuration
<Location /*****>
SetHandler weblogic-handler
PathTrim /
WebLogicHost 'serevrip'
WebLogicPort 'port'
WLIOTimeoutSecs 3600
Idempotent OFF
WLProxySSL ON
DefaultFileName /***/***/index.jsp
Debug On
WLLogFile /***/***/***/***.log
</Location>
Could some please help me on this.
Thanks in advance
Regards,
VenkatHi Tarun,
The problem occurs when the SSL is enabled on apache. If I access the same URL over HTTP, the parameter WLIOTimeOut works fine.
Also I observed that, none of the parameters are getting applied to the plugin. I had switched on 'DebugConfigInfo'. With this the HTTP URL with ?__WebLogicBridgeConfig as query parameter returned the complete configuration. However when accessed with HTTPS the server did not return the configuration.
Is there a specific configuration to be applied when apache is used with SSL?
Thanks for your help,
Shashi
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