Using an old router as a switch

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Kookoo

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#154129 18-Oct-2014 19:36

Hi all

I've got a FritzBox on ADSL, and quickly running out of LAN ports. So I figured I could use an ancient Netgear WNR614 router as a switch to connect all the devices in the entertainment cabinet.
So I followed the following steps:
1) Wiped the dust off the Netgear router, and got rid of the ants that seemed to have built a nest inside. No, really.
2) Turned off Wireless AP, DHCP and the firewall on the Netgear
3) Connected one of the FritzBox LAN ports to the Netgear WAN
4) Hung 4 devices off the the Netgear LAN ports

Problem is - it works! I mean it's a good problem to have, but every guide I read states that I need to use one of the Netgear LAN ports (not the WAN port) to connect to the first router.

So I guess the questions are:
1) If my Netgear isn't set up as a switch in this configuration, what exactly does it act as?
2) Why does it work and what are the downsides of this setup?

Any ideas anyone?

Hello, Ground!

kiwigeek1

637 posts

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#1157597 18-Oct-2014 20:06

I havent netgear..

I wouldnt of thought the wan port would of worked.. but some routers hardware
and firmware are clever and can work out its connected to another
router/switch and route the packets I suspect what has happened?
some even can work with cross over cable and normal utp cable
it auto detects.

normally you do connect to 1 of the 4 lan ports and then connect
other devices to the remaining 3

is the wan port is 1gb and the other 4 100mbit?

if it works it works.. I cant see a down side.. but would check the
settings in firmware/web page and have a look
you might need to turn of some extras in it.

update.. of course the downside is multiple hubs cause more packet conflicts

sometimes its better to buy a 1gig or better switch.with more ports.. to keep up the speed

switch is intelligent it figures out the data per port and hubs just split it to
all ports.

kiwigeek1

637 posts

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#1157604 18-Oct-2014 20:28

I just read this on web. about using wan ports on routers. which I think would apply to you.. you can use either it seems WAN uses more overhead to convert between the 2 devices... if I read this right,..

-----

What you possess are routers with integrated switches. Normally these
would be separate devices with separate functions.

You are using the integrated switch (LAN ports) to extend your switched
network.

If you need routing functionality, you use a LAN port connected to one
network, and the WAN port connected to a different network.

The two networks use different IP address space.

When a host needs to connect to a resource on another system, it applies
the network mask to it's own IP address, and the IP address of the
destination resource, and then compares the results to determine whether
the destination resource is on the local LAN, or another LAN.

If the resource is on the local LAN, a router is not needed. The packets
are framed with the MAC address of the destination resource and placed
on the wire.

If the resource is on another LAN, the host needs the assistance of a
router. The packet is forwarded to the router, the router then uses its
knowledge of adjacent routers to determine the next hop. One router
passes data to the next, and so on, and so on, until it reaches a router
directly connected to the LAN where the destination host resides.

Your host would frame the packet with the MAC address of the router's
LAN interface. When that router places the packet onto the WAN, it is
framed with the MAC address of the next hop router.

Forgetting about issues such as NAT for a moment, the source and
destination IP addresses in the IP header remain the same as the packet
traverses the Internet. However, the source and destination MAC
addresses with which the packet is framed are constantly changing hop by
hop.

Two devices on the same segment use the Address Resolution Protocol
(ARP) to resolve an IP address into the MAC address needed to forward
the traffic. Communication occurs at Layer 2 (MAC). IP addresses are
logical, they really exist to facilitate getting from one network to
another.

richms

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#1157608 18-Oct-2014 20:37

Just buy a switch. Ive tried this before and the router would occasionally reboot and the switch would reset and things would lose connectivity briefly. 8 port gigabit switches are dirt cheap now, not like the several 100 the first one I bought cost.

Richard rich.ms

Sideface

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#1157613 18-Oct-2014 20:45

richms: Just buy a switch. ...

+1 Switches are dirt cheap. Get one.

Sideface

richms

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#1157614 18-Oct-2014 20:50

TP links from PB tech work mint and are $32.14 inc GST with free freight.

Richard rich.ms

Kookoo

787 posts

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#1157632 18-Oct-2014 22:01

Hmm, true, but if the old router has the same functionality as the switch, why spend the $33?

Hello, Ground!

Sideface

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#1157633 18-Oct-2014 22:05

Kookoo: Hmm, true, but if the old router has the same functionality as the switch, why spend the $33?

Because it's bigger and uglier and draws more power and has only 3 usable ports.

Sideface

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kiwigeek1

637 posts

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#1157635 18-Oct-2014 22:08

its not a switch though.. its a router. it wont be as good as a 1gigbit 8 to 12 port switch

router connects one lan to another (as per article above) or WAN to LAN or (lan extender for 3 ports with less overhead if not using wan port)

Switch learns and route packets to the correct port for speed

and a basic Hub routes all packets to all ports.. doesnt learn and more conflicts

(once HUBs were what people could afford and switches companies could afford
but now days they cheap enough to get one for home)

so yeah

depends if it does the job for you and doesnt have issues like they said above about dropping out

Kookoo

787 posts

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#1157644 18-Oct-2014 22:57

Ok, I was wrong - this setup does have issues - it times out occasionally, and then takes too long to reconnect for my liking.
Off to PBTech to get the TL-SG1005D tomorrow. Thanks for your help guys!

Hello, Ground!

linw

2849 posts

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#1158085 19-Oct-2014 20:58

Way to go. I use one of those gigabit switches - works great. Nothing like having the right tools!!