kony said:
They filter and forward network traffic. Essentially, in
simplest terms for your use, plugging a switch into your
router is the equivalent of the router having more ports.
No, each machine does. If you plugged them into a switch,
Each "network interface" has an IP address (and can have more
than one too), and a "machine" (host) may have multiple network
interfaces. But there can be many "ports" on each interface
too, which is where hubs and switches come into the picture.
The context here has been to call the RJ-45 jack a "port", but
keep in mind one or many such ports might be associated with a
single "network interface". I.e., several RJ-45 jacks can be
associated with the same IP address(es). (And for the most
part, in this discussion, IP addressing can be ignored.)
they will still either receive DHCP configuration from your
router or retain their otherwise-assigned IP addresses the
same as if any/all were directly connected to the router
(actually it's the router's integral switch) port.
No, you can even daisey-chain switches. Don't think of a
port having an IP number, it is the host that just (happens
to be) connected to that port that has the IP number and
thus, so long as it's connected in your local lan still, the
rules for it having (whichever IP number and however it got
it) remain the same.
There are some caveats that need to be explained though.
That's fine, use the hub instead since you already have it.
The difference is that the hub doesn't do the filtering, it
broadcasts traffic on all ports instead of only the one
route to the destination. That can be a performance problem
when several systems are connected and simultaneously
"needing" high throughput but for your purpose it will work
fine.
Lets restate that in a different way, and point out the
significance of how hubs and switches differ.
A /hub/ has multiple ports, and every Ethernet frame received
on any one port is transmitted on all of the others. There is
no *isolation* between the ports. Hence a 5 port hub with four
devices connected to it sends all data to all devices. If a
packet sniffer, a wireless device, or whatever unsecure device
is connected to the 5th port, it can see *all* traffic.
A /switch/ has multiple ports, but it switches packets only to
appropriate ports, each of which knows the unique MAC address of
the Ethernet device connected to it. Only Ethernet frames
addressed to that MAC address will be sent on that port. Hence
traffic for each port is isolated from the others, and cannot be
"sniffed" on ports other than the incoming and outgoing pair.
All of the above is done at the *Ethernet* *frame* level, and
does not involve IP addressing or routing at all.
There is one other catch to extending the number of router ports
that needs to be kept in mind when laying out network
topography. A ten port switch or hub connected to a 4 port
router is fine... *if* the aggregate traffic going to the
router port is less than the bitrate of the single port! Hence
if 1 port goes to the router and 9 ports go to
devices/hosts/whatever that typically generate large amounts of
traffic to the router, that 1 port will be a bottleneck.
The devices are able to use their full bitrate to each other
without causing a bottleneck.
Hence if you have a file server that is heavily used by all of
the devices on the switch, it should (all other things being
equal) be connected to a switch port rather than a router port.
Put things like bandwidth limited WAN connections, Internet
connections, print servers, and the like on those extra router
ports, and keep all of the high bandwidth devices on ports of
the *same* switch.
Routing, which involves IP addresses, does not happen in a hub
or a switch, and will only be seen between *interfaces* on the
router (as opposed to between "ports"). Many of the Wireless
router/access-points being sold have *two* interfaces, labeled
WAN and WLAN/LAN. The WAN has one port, which is connected to
the Internet modem and the WLAN/LAN has 4 or more ports. There
is *routing* between the WAN and the other ports, but no routing
takes place between the WLAN/LAN ports (which are actually on a
6 port switch, with one port connected internally to the
WLAN/LAN interface, one port connected to the wireless, and 4
ports with RJ-45 connectors).
Some units allow the internal switch configuration to be
modified, and in fact each LAN port *can* have an IP address,
with routing between them. But don't assume that without
verifying it.
