Solved

switch throughput

Posted on 2011-03-13
10
694 Views
Last Modified: 2012-08-13
If we have a 100M switch, if that every port is providing 100M or sum of all the traffic passing through the switch is 100M? If every port, and is it that uplink on 24-port sw is carrying 23x100M or 2.3G worth of data? Mostly, the uplinks are 1G fiber, can they boost up to 2.3G???
0
Comment
Question by:totaram
  • 4
  • 3
  • 2
  • +1
10 Comments
 
LVL 13

Expert Comment

by:AustinComputerLabs
Comment Utility
A 100m switch has 100m per port, if full duplex (and almost everything is now) 100m up and 100m down.
A 100m hub has 100m total
0
 

Author Comment

by:totaram
Comment Utility
Austin;
If every port is operating @ 100m, will it not slow down the uplink link considerably? Is there way to around it??
0
 
LVL 13

Expert Comment

by:AustinComputerLabs
Comment Utility
That is the max of each, they seldom need or use it.
0
 

Author Comment

by:totaram
Comment Utility
Austin;
We have applications downloading 1 gig on different ports via FTP, and am looking for a suitable solution, for sure 100 meg will be used.
0
 
LVL 50

Expert Comment

by:Don Johnston
Comment Utility
If you have a 24-port, 100mbps switch with a single gig uplink port, then that port will be oversubscribed. (If all 24 ports are sending simultaneously, they will be generating 2.4gbps of traffic.)

On some switches, there will be two gig uplink ports that you can channel so that you end up with 2gbps of uplink throughput. It will still be oversubscribed, but not as much. When you consider the chances of all 24-ports receiving data at max throughput as the same time, the 400mbps of oversubscription isn't that big of a problem.
0
Find Ransomware Secrets With All-Source Analysis

Ransomware has become a major concern for organizations; its prevalence has grown due to past successes achieved by threat actors. While each ransomware variant is different, we’ve seen some common tactics and trends used among the authors of the malware.

 

Author Comment

by:totaram
Comment Utility
donjohnston;
I see your point with oversubscription of 400m, which is not a big deal. But if the switch ports are 10/100/1000 and 2 uplinks are 10g each for 48port switch, it would be considerable oversubscription... is there any way around it?
0
 
LVL 50

Expert Comment

by:Don Johnston
Comment Utility
Nope. You'd be dealing with over 100% over-subscription.  

So it comes down to the traffic patterns. In a situation like this, you would want to know that the devices connected to your switch would not be generating over 20gbps of traffic simultaneously. But even if they did, the traffic would hopefully not exceed the buffer capacity until the utilization dropped back below 20gbps.
0
 

Author Comment

by:totaram
Comment Utility
Is having two uplinks also called dual personality? Was wondering if vendors ever thought of providing 4 uplinks instead of 2???
0
 
LVL 18

Accepted Solution

by:
decoleur earned 25 total points
Comment Utility
the other thing that you should look at is how the interfaces themselves are oversubscribed.

you can have 100M interfaces that are tied 4 to an ASIC with a 4 times over subscription, each ASIC can handle 100M full duplex but all 4 interfaces will not be able to overload the ASIC once the 100M threshold has been reached. Furthermore those ASICs are connected to each other on a bus that has a finite capacity often called a backplane or a switch fabric. in this example you could have 24 ports that are 4 times oversubscribed into 6 asics tied to a common backplane that is limited to 1G total throughput so at every step along the way there is over subscription and the distinct possibility of packet loss as a result of saturation.

this is entirely dependent on the switch hardware architecture. this limits are physical capacity limitations and cannot be overcome.

the hardware that is less over subscribed is more expensive but you can get an indication by the interfaces speeds as they relate to the back plane capacity.

let us know if there is more that you need to assist you in making your decisions.

-t
0
 
LVL 50

Assisted Solution

by:Don Johnston
Don Johnston earned 25 total points
Comment Utility
Yes, some vendors will have four 10 gig ports on a 48-port switch for 1.2:1 oversubscription.
0

Featured Post

How to improve team productivity

Quip adds documents, spreadsheets, and tasklists to your Slack experience
- Elevate ideas to Quip docs
- Share Quip docs in Slack
- Get notified of changes to your docs
- Available on iOS/Android/Desktop/Web
- Online/Offline

Join & Write a Comment

Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
In the world of WAN, QoS is a pretty important topic for most, if not all, networks. Some WAN technologies have QoS mechanisms built in, but others, such as some L2 WAN's, don't have QoS control in the provider cloud.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now