Is this an equivalent setup? (small router + switch, big router)

[joe.pelayo]

Hello everybody.

I am planning to build a large wired network (15 machines) and am currently checking the price of the devices I need. I found a router big enough (16 ports) to accommodate all the machines, but I find it a little pricey, on the other hand I've seen that switches are cheaper, as well as smaller routers.

I was wondering, would it work if, instead of getting the big router I only get a small one along with a big enough switch? (the combo is still cheaper than the big router) Would I see any difference performance wise?

Thanks.
Joe.

[Evil_Bert]

Hello everybody.

I am planning to build a large wired network (15 machines) and am currently checking the price of the devices I need. I found a router big enough (16 ports) to accommodate all the machines, but I find it a little pricey, on the other hand I've seen that switches are cheaper, as well as smaller routers.

I was wondering, would it work if, instead of getting the big router I only get a small one along with a big enough switch? (the combo is still cheaper than the big router) Would I see any difference performance wise?

Thanks.
Joe.
Most routers are router+switch, as you probably know. Within the router, the link between router and switch is just one more switch connection, so I personally don't think you'll see any practical performance penalty.

Edit: Plus you will probably not need to update the switch for a very long time, but you may wish to replace the router to get access to new features.

[joe.pelayo]

Most routers are router+switch, as you probably know. Within the router, the link between router and switch is just one more switch connection, so I personally don't think you'll see any practical performance penalty.

Edit: Plus you will probably not need to update the switch for a very long time, but you may wish to replace the router to get access to new features.
And would the router assign ips for all connectors in the switch attached?

I want to assume from your answer that the big router is equivalent to the small one plus a switch.

Thanks.
Joe.

[Evil_Bert]

And would the router assign ips for all connectors in the switch attached?
Yes, if they request that from the router via an appropriate protocol, such as DHCP, or if they've been manually assigned one and exchange/update it via Address Resolution Protocol (ARP).

Here are a few links on DHCP and ARP:
ARP 1 (http://www.tildefrugal.net/tech/arp.php)
ARP 2 (http://www.juniper.net/techpubs/software/erx/erx50x/swconfig-routing-vol1/html/ip-config8.html)
DHCP 1 (http://www.cisl.ucar.edu/nets/presentations/DHCP-in-SCD/sld010.htm)
DHCP 2 (http://www.ehsco.com/reading/19960515ncw3.html)

In short, yes. :)

I do it this way. I have a router with an internal 4-port switch, and have an 8-port switch plugged into one of the router's switch ports. It works fine - no configuration required.

If you want to watch ARP working, just flash up WireShark in promiscuous mode.

[joe.pelayo]

Yes, if they request that from the router via an appropriate protocol, such as DHCP, or if they've been manually assigned one and exchange/update it via Address Resolution Protocol (ARP).

Here are a few links on DHCP and ARP:
ARP 1 (http://www.tildefrugal.net/tech/arp.php)
ARP 2 (http://www.juniper.net/techpubs/software/erx/erx50x/swconfig-routing-vol1/html/ip-config8.html)
DHCP 1 (http://www.cisl.ucar.edu/nets/presentations/DHCP-in-SCD/sld010.htm)
DHCP 2 (http://www.ehsco.com/reading/19960515ncw3.html)

In short, yes. :)

I do it this way. I have a router with an internal 4-port switch, and have an 8-port switch plugged into one of the router's switch ports. It works fine - no configuration required.

If you want to watch ARP working, just flash up WireShark in promiscuous mode.
I just wanna link together the machines in a network so they share internet access and resources, from what you wrote I guess that can be done.

Thanks.
Joe.

[Iron_Mike]

Hello everybody.

I am planning to build a large wired network (15 machines) and am currently checking the price of the devices I need. I found a router big enough (16 ports) to accommodate all the machines, but I find it a little pricey, on the other hand I've seen that switches are cheaper, as well as smaller routers.

I was wondering, would it work if, instead of getting the big router I only get a small one along with a big enough switch? (the combo is still cheaper than the big router) Would I see any difference performance wise?

Thanks.
Joe.


Your correct, connect a router to 16 or 24 port switch , set the switch to DHCP so it will assign network info to your 15 clients. The performance issue would be how much bandwidth you have on the WAN side of the router....

[stevea]

Ehhh maybe but .... I am not an IT guy but I designed and implemented switches, routers, enterprise - mostly RT-kernel stuff but some work in the protocol stack. You'll get a different and probably more relevant opinion on usage from an IT/Server guy.

EvilB is right that most routers consist of an N-way switch connected to a basic gateway, with varying amounts of services implemented.

A few hot button items for me ....

If you are buying gigabit (GigE) you really want support for jumbo packets ... I'm not terribly concerned whether the packet limit if 9kB or if it's higher. The GigE packets require too much interpacket delay and you'll never approach the theoretical limit w/ tiny packets.

You can and should read through the manual (maybe on-line) to verify that it has the services you need. Today even a cheap switch will have dhcp service and dns forwarding. Firewalls are common on the WAN connection, but some firewalls have very flexible exceptions & rules and poor ones are basically on/off with a very few port forwarding options. You may want more - perhaps VPN or dns name resolution.

If you were buying a professional switch/router you might find a rating for "oversubscription". The question is ... can all ports operate at full speed, or 90% of full speed or 80% of full speed. Routers for the home market are often vastly oversubscribed ... that is you may only be able to run all 16 ports + wan port at 20% speed at any instant, but for home use that never really happens. Most home/soho routers have a lot of the traffic through the WAN (maybe limited to 3-10mbit total) and maybe a comparable amount of internal traffic at any instant. Router/switches with more storage (like 128kb per port) may produce better throughput, but also may not; it's sort of an indirect measure.

Almost all pro-routers are "managed" meaning they serve SNMP(simple network management protocol) and you could use this to both collect network statistics and maybe re-balance your network or even change some of the management parameters for better performance.

It's NOT a recommendation but I've recently seen a D-Link/Cisco managed switch (only) with 16 GigE ports for only ~$275-$300USD, rack mount possible but not required. I assume these are similar in performance to inexpensive soho switches but with an SNMP service. Would require a separate router, but not a bad choice for expansion.

[Evil_Bert]

It's NOT a recommendation but I've recently seen a D-Link/Cisco managed switch (only) with 16 GigE ports for only ~$275-$300USD, rack mount possible but not required. I assume these are similar in performance to inexpensive soho switches but with an SNMP service. Would require a separate router, but not a bad choice for expansion.
I have a managed switch (Netgear), but it's a bit more than just SNMP added on. You also get syslog logging, VLAN, port security, MAC-security, QoS/throttling and so on. It's about an extra AUD$100 over the equivalent non-managed version, but I like that kind of fine-grained control over network traffic. I particularly like the VLAN feature, so I can setup and internal virtual "private" network that isn't allowed any internet connectivity.