Need Help Visualising A Switch Role On A Network

[RebelFox]

We have a small network and I am looking into increasing performance. One possibility is using a switch.
I just need to make sure my understanding of a switch is accurate.

Does a switch merely service the segment it is connected too? In other words, does it improve performance by increasing direct communication between PC's/devices that exist on the same segment as the switch only?

Example:-

Segment 1 Segment 2
--------- ---------

PC 1------ -------PC 4
| |
PC 2-----HUB----SWITCH----ROUTER----HUB-----PC 5
| |
PC 3------ -------PC 6


The segments are divided by a router.
The switch increases traffic performnace between PC 1, PC 2
and PC 3 but not traffic between PC 4, PC 5 and PC 6. Also
Traffic between PC 4 and PC 1 is only better on Segment 1?


Many thanks.

 

[edfair]

Probably best described as keeping segment1 traffic away from segment2 and segment2 traffic away from segment1 while allowing required cross segment traffic.

It doesn't affect the individual segments except by reducing clutter.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[jimbopalmer]

The switch is not doing much useful in this diagram because the router is even more thorough at seperating Segment 1 traffic from Segment 2 traffic.

The switch learns which traffic is destined for its segment 1 port and and sends only those packeets to segment 1. and learns which traffic is only destined for segment 2 and sends only those packets., but the switch allows broadcasts to use both ports.

The router also restricts packets to those destined for segment 1 and those destined for segment 2 but also eliminates broadcasts between them.

Whichever hub is properly sized and highest use would be replaced by the switch for the most impact in your network, as shown, at reducing traffic WITHIN a segment.

I tried to remain child-like, all I acheived was childish.

 

[bcastner]

[tt]
Router - Switch - PC #1 - #3 (Cross over cabling or Uplink)
Router - Switch - PC #4 - #6 (Cross over cabling or Uplink)
[/tt]

And yes it will help.

 

[edfair]

In the diagram as shown I would question the purpose of the router and/or hub unless there is a distance problem.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[bcastner]

Edfair,

Yes,
But as it is there, he might find it of help.
(I suspect it acts as a wiring hub, rather than router).

 

[salmans]

Is there a reason why there are two segments? Security? You could put all 6 users on a single switch and separate the segments with a VLAN (inside the switch) and then you would'nt need the hubs at all. You would still have two separate broadcast domains (using VLAN) and all users would be direcly connected to the switch providing dedicated bandwith to each user and every user would be in his/her own collision domain...this would all improve performance. If the two segments didnt need to be separated then there is no need for the VLAN, just connect all users to the single switch and the switch to the router. Hope this helps!!!!

"Do it right the first time, and there won't be a second time!"