Is network speed depending on number of crossing routers/switches?

[colicab]

I know this is a very general question.

We have several routers in our network who are actually used as APs and also have some switches. All routers/switches are at least of the 100Mbit category and cabling is mixed (mostly standard CAT5).

I'm wondering if the speed you can transfer files from PC A to PC B depends greatly on how many routers/switches it had to traverse to meet its destination?
I guess to short answer will be 'yes' but my question is more: is the difference significant? For example: would it takes a lot more time to copy 100GB of data between A & B if 4 routers are between them or only 3?

 

[CaptainSTX]

The impact on speed depends on if the link between routers and/or switches is fully loaded.

If throughput for transfers on your LAN is important here are a couple of design rules I try to adhere to.

1. Use gigabyte ports on both ends to link from the main router to other switches and routers in your network.

2. Avoid, particularly if you don't have gigabyte ports, stringing devices together (Router1 ------ Switch 1 ------AP 1 ) instead where possible home run all devices back to the primary router.

3. Where possible hook heavy data users onto the same switch or router. For instance if you are streaming uncompressed video than it would ideal to have the media server and the home theater on the same switch.

4. Finally be sure you have good cables and connectors. Your network is only as fast as your slowest link and a bad cable will kill network speeds as data packets are constantly being resent. Route your cables to avoid electrical interference and be careful about long cable runs.

 

[colicab]

Hi CaptainSTX,

thanks for your clear reply and good advise. Just what I wanted to know.

I have an additional question.
For the AP routers, I just disable DHCP so it acts as an AP because my older routers don't have an explicit 'use as AP' option.
Routers configured like this, do they have residual router activity that affects speed/reliability of data transfer? In other words: if you only need AP function, is it better to use an actual AP? Does it make a lot of difference?

Why do I use my routers like this? Just the gear I have. Everytime I needed an additional network device, I went for a router because they can by used for different purposes compared to APs.

 

[azazel1024]

No, it won't impact anything. Just disable DHCP and connect them through the LAN port. If you connect through the WAN port, then all firewall rules, NAT, etc go in to effect. You deffinitely don't want that.

The above explination is correct, depending on how it is all connected will determine maximum speed between two computers. If you have one computer connected to a router, which is connected back to the switch, which is then connected to your other PC and that router also has, say, a laptop connected wireless streaming video, the throughput between the two PCs is limited by the connection pipe minus what the laptop is using, since it is using part of the same backhaul that the PCs are using.

If the PCs were instead connected to the switch directly, the laptop connected through the AP streaming video wouldn't impact speed at all, as none of the same backhaul is in use. Well...so long as the switch has an appropriate switching fabric to handle it (most modern switches generally have a switching fabric capable of handling all ports at maximum speed at once, so the switching is generally not the limitation, just what is traveling over each wire connected the switch).

 

[CaptainSTX]

The router being used as an AP is just loafing and only has to handle the radio traffic. The router being used as a router on the other hand has to handle some or all of the following:

DHCP
Static IP
Firewall QOS
Parental Controls
Site blocking
VPN

Unless you need and can afford to pay for commercial grade APs there is no reason to buy one of the few SOHO APs available. The only problem with reusing old routers is the technology is also old. Love my Linksys 54Gs are great but they can't handle my FIOS 75/35 connection and they are G only.