If you are working with a network that has a small number of infrequent users on a small network (10Mbps or less), here are some tuning recommendations that will help you to optimize your network use. These recommendations came out of a discussion with one of our customers. Their environment is a 40 person company on a 10Mbps pipe (normal amount of users on a small network), and then converts over at night to a network with only one user.
The following recommendations will help to alleviate the situation where a small network with a small number of infrequent users has a user get knocked down to a less than 1Mbps with a PENALTY while there is more than enough bandwidth to sustain their download at a higher rate.
Summary of Recommendations (listed in priority order):
1) (best option) Put a hard limit somewhere below RATIO (typically 85%) on each IP address on the network. So, for a 10Mbps network with RATIO = 85%, your hard limits should be below 8.5Mbps for each IP address.
2) Put a “day configuration” and a “night configuration” in place. The process to do this is described in the Changing Configurations by Time of Day section of our Advanced Tips & Tricks guide.
3) Change the PENALTY unit sensitivity, to make the penalty less restrictive.
4) Raise the value of HOGMIN from 12,000 bytes/second anywhere up to 128,000 bytes/second.
The philosophy behind each is described in detail in the following sections.
1) Adding Hard Limits on each IP address
We recommend putting Hard Limits on each IP address. Hard Limits will keep any one user from consuming the entire network bandwidth. If you prefer not to have Hard Limits on all IP addresses, you can set the Hard Limit only for the infrequent users.
For example, on a 10Mbps network, you can put a Hard Limit of 4-5Mbps on every user, which will prevent any one user from tripping equalizing, but will allow all of them to sustain a 5 Mbps download on your lightly loaded network.
If a user starts a large download, it will consume network bandwidth up until the network reaches a point of congestion (at 85% with RATIO set to 85). Once that point is reached, equalizing will kick in and start penalizing the traffic. In cases where the network has a normal number of users on it, this works very well to provide fairness across the available bandwidth.
When the one network user spikes the entire network to above 85% congested, a Penalty kicks in. The result of the penalty is that the file download gets throttled back to 500kbs or maybe less – almost instantly. Once the penalty is removed, the file download will again consume all the network bandwidth until another penalty is applied. This cycle repeats itself every few seconds until the download completes.
On a system with more than one user, and typically one that is very busy with 100’s of users or 1000’s, the pipe is usually always near capacity, so penalties being applied are not as dramatic, and ensure that all other users do not experience “lockup”.
2) Change your Configuration by Time of Day
You can also change your NetEqualizer to use two separate configuration files, so that you can apply different rules at various times of day – for example, rules for “off-hours” (typically nighttime) versus another set for “on-hours” (typically daytime). This would be beneficial if you want to open up the amount of bandwidth available per user at night. For example, you could set your off-hours hard limits to 8 Mbps, and lower your on-hours hard limits to 4Mbps.
Note that it is still important to keep your hard limits below RATIO, so that you do not trigger equalizing based on one data flow.
3) Change the PENALTY unit sensitivity, to make the penalty less restrictive
Networks much larger than 45 megabits may require a PENALTY UNIT resolution smaller than 100ths of seconds. In the NetEqualizer Web GUI, the smallest penalty that can be applied to an IP Packet is 1/100 of a second. If you are finding that a default PENALTY of 1 is putting too much latency on your connections then you can adjust the PENALTY unit to 1/1000 of second with the following command:
From the Web GUI Main Menu, Click on ->Miscellaneous->Run a Command
Type in: /bridge/bridge-utils/brctl/brctl rembrain my 99999
Note: For this change to persist you will need to put it in the /art/autostart file.
4) Raise the value of HOGMIN, anywhere up to 128,000 bytes/sec
HOGMIN is used to determine what traffic should be penalized on a congested network. One way to get traffic to not be penalized, then, is to raised the value of HOGMIN (default is 12,000 bytes per second). For a lightly-loaded network you could consider HOGMIN = 50,000 bytes/sec and may even go as high as 128,000 bytes/sec.
Taken as a whole, this is how our four recommendations would work in the example we have described…
Hmm… I have a 10 megabit pipe and I have 40 users during the day and 1 user at night. No user should be able to take the whole pipe all day, but I want my 1 user to get more bandwidth at night.
- I’ll create two configuration files: one with 4Mbps hard limits on all my users during the day (4 megabits is relatively fast service for the average and nobody would complain) and another with 8Mbps hard limits for my night user(s).
- In addition, I would like the penalty to be less harsh at night, so I’ll change the PENALTY=1/1000 of a second in my night configuration file.
- I also would like HOGMIN to be raised at night. I will set it to 50,000 in my night configuration file.
During the day, when every once in a while we get 2 or 3 users downloading at once, it will no longer kill the entire pipe. And during the night, my user can download larger files without being restricted. So, with 4Mbps/8Mbps restrictions plus Equalizing, I get the best of both worlds – pretty fast downloads when the pipe is empty and I am protected against peak time crashes! People get fast downloads and if there is a peak I am protected from system gridlock. Now there is nothing anybody can do to crash the system at random times.
I hope you find this tuning suggestion helpful for your situation. If you would like additional help, please contact our Support Team at firstname.lastname@example.org or 303.997.1300 x102 to discuss tuning for your specific configuration.
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