On Fri, 11 Jan 2008 11:45:50 +0000, Invisible wrote:

> A hub is little more than an amplifier. A switch contains actual control
> electronics. That much is true. However, a switch still does the same
> *job* as a hub - it just does it better. There still isn't anything that
> needs to be "configurated". [But, as I found out, these switches are
> actually routers.]

A switch limits the collision domain, which is good for performance but 
bad for network monitoring tasks.  Many of the Cisco switches of the last 
several years (and other "smart" switches, for that matter) have 
management interfaces that let you view traffic counters and other 
diagnostic information to help you isolate problems.  Not to mention port 
mirroring (as Cisco calls it) to allow you to use your copy of Wireshark 
to view all the traffic seen on another port on the switch for diagnostic 
purposes.

Because the collision domain is restricted, there's also buffering 
components and elements to eliminate collisions nearly completely (or 
completely).

A lot of the newer switches on the market also include authentication 
smarts, so only authorized devices can be plugged into the network.  
802.11x authentication (I think is what is used) can be used against 
directory service data stores as well, providing a high degree of 
security in environments that need it.

What kind of switches are they?  Some switches identify as being layer 3 
switches (in the OSI model), but some newer ones will also do layer 4 
switching, which also increases the complexity of the component.  Many 
times, a L4 switch can be thought of as a router, even though it really 
isn't (a router connects one subnet to another).

Some switches also include smarts for VLANs, which limit the broadcast 
domain as well as the collision domain limiting that a dumb switch will 
do.

Jim

Post a reply to this message