NewBWiFiGuy
03-01-2003, 03:44 AM
Here is a question I've got. First for those of you that aren't familiar with the difference between a hub and a switch here is what they are supposed to do (I think):
The evil cheap network hub:
Say you plug 10 computers into a hub. Each time one of these computers sends data over your network each and every computer sees that packet and has to do a little bit of calculation to figure out if it was for that given computer. In other words, "Hey computer 1 your talking to me (computer 5), I will deal with this packet" Or "I am computer #5 and I got a packet but it was destined for computer 8. I will ignore it"
Our friend the network switch:
You're probably familiar with a cross over cable right? This is where you run a crossed over cable directly between the network interface cards (NICs) in computer 1 and computer 2. All the packets going out should be destined for either of these computers. Now picture if you had the same 10 computers above and you could manually, within nanoseconds, switch that cable between each set of computers as needed to get the proper packet from computer x to computer x. In other words, no packets going to the wrong computer so that computer doesn't have to deal with it. You'd be using your superman brain to save your computers the trouble.
Ok, so that long lame explaination basically turns into what a switch does. A real time routing of that data to the correct computer and only the correct computer. So for wireless lans (WLANs) and networks where you really really don't want to be tossing around unneeded data and letting collisions ruin your day, a switch should really help I'd think. This is assuming the switch is not a super el-cheapo model.
Ok, so what did I just order? 6 Dlink DSS-24+ switches (http://www.dlink.com/products/switches/dss24+/) ($120ea) to build out my WiFi network backbone. So what the theory here is; The switch should help out a little bit by not sending data thru interfaces and APs that don't need to see it. I also liked:
* "The DSS-24+ 24 10/100 Mbps ports adheres to IEEE 802.3, 802.3u, and 802.3x standards, which specify 10Base-T, 100Base-TX and 100BASE-FX Ethernet technologies. With the DSS-24+ switching function, Store and Forward is implemented with Rate Adaptation Protocol. (RAP) is an end-to-end rate-based congestion control mechanism, which ensures data integrity when packets are transmitted. The switching capability of the DSS-24+ allots 256Kbytes of allocated memory buffer per 8-ports. As a result, a complete frame checking and error-filtering scheme helps prevent any packets with errors from being transmitted among any broadcast segments. The DSS-24+ also supports Backpressure and pause frame-based flow control at half duplex mode schemes to ensure zero packet loss by sending out collision signals when the port's receiving buffer is full under heavy traffic congestion."- Hey, this all sounds cool and I was told much of these class of technologies have only recently become available in the cheaper Small Office Home Office (SOHO) switches. Maybe this will help if I get a few wacky packets or congestion by making sure things get sent that need sent. Or maybe I am clueless.
This switch is also apparently smart and learning so it gets better and knowing where to send things. I quote "As a switching solution, the DSS-24+ initiates a MAC address-learning table aging features. MAC addresses are automatically updated reducing any broadcast among network segments, which provides dynamic filtering through auto-learned MAC addresses and static filtering. " If I am reading this right, these switches tend to be a little smarter and not to do things like send out bogus broadcast packets to every AP on your subnode. I'd guess this is one more step to a cleaner network. Or it might squirt frozen yogert out the RJ-45's.
BTW, I chose the DSS-24+. There are tons of great switches out there that are probably as good or better. So don't think of my post as a product endorsement. I haven't even connected one up yet.
So anyway - for those of you with serious techie coolness, I have a theory that I'd love to get some input on. Initially I'll have a single linksys AP at point A and another linksys AP at point B. These will run in bridge mode and each be connected to a DSS-24+ switch at each end. Then several 802.11b radios will be attached to those switches to provide the local "hot spot" style access. Ok, so this is pretty simple. The two bridges should connect my two disparet networks and transfer data accordingly.
Now with a 802.11g bridge (I'm using linksys WAP54g) I'll probably get 25-30mbit at the best with the bridge. So what if I wanted to use two or more bridges at point A and point B that connected up these two networks. Since every port on the DSS-24+ can act as an uplink port, I'm am theorizing I can just link this 2nd pair of bridges in and the switch will route data over both bridges as needed. For instance say I have users moving more than 50mbit over my backbone - wouldn't the switch automatically kind of split that traffic between the two bridges?
One reason I am thinking about this is for now I'd like to build out cheap 802.11g bridges then add 802.11a bridges (see
thread1 (http://forums.80211-planet.com/showthread.php?s=&threadid=1049) and thread2 (http://forums.80211-planet.com/showthread.php?s=&threadid=1048)) to this backbone to expand its capacity.
I'm also wondering if I can just use a signal combiner and, for instance, have two APs sending their data over the single point to point antenna pair. Technically since they are on different channels they should be able to stay clear of each other...??
So can a good switch actually "combine" multiple bridges? Eitherway, does anyone have comments/ideas/etc regarding my above statements? Am I on track or way off? Is this crazy?
The evil cheap network hub:
Say you plug 10 computers into a hub. Each time one of these computers sends data over your network each and every computer sees that packet and has to do a little bit of calculation to figure out if it was for that given computer. In other words, "Hey computer 1 your talking to me (computer 5), I will deal with this packet" Or "I am computer #5 and I got a packet but it was destined for computer 8. I will ignore it"
Our friend the network switch:
You're probably familiar with a cross over cable right? This is where you run a crossed over cable directly between the network interface cards (NICs) in computer 1 and computer 2. All the packets going out should be destined for either of these computers. Now picture if you had the same 10 computers above and you could manually, within nanoseconds, switch that cable between each set of computers as needed to get the proper packet from computer x to computer x. In other words, no packets going to the wrong computer so that computer doesn't have to deal with it. You'd be using your superman brain to save your computers the trouble.
Ok, so that long lame explaination basically turns into what a switch does. A real time routing of that data to the correct computer and only the correct computer. So for wireless lans (WLANs) and networks where you really really don't want to be tossing around unneeded data and letting collisions ruin your day, a switch should really help I'd think. This is assuming the switch is not a super el-cheapo model.
Ok, so what did I just order? 6 Dlink DSS-24+ switches (http://www.dlink.com/products/switches/dss24+/) ($120ea) to build out my WiFi network backbone. So what the theory here is; The switch should help out a little bit by not sending data thru interfaces and APs that don't need to see it. I also liked:
* "The DSS-24+ 24 10/100 Mbps ports adheres to IEEE 802.3, 802.3u, and 802.3x standards, which specify 10Base-T, 100Base-TX and 100BASE-FX Ethernet technologies. With the DSS-24+ switching function, Store and Forward is implemented with Rate Adaptation Protocol. (RAP) is an end-to-end rate-based congestion control mechanism, which ensures data integrity when packets are transmitted. The switching capability of the DSS-24+ allots 256Kbytes of allocated memory buffer per 8-ports. As a result, a complete frame checking and error-filtering scheme helps prevent any packets with errors from being transmitted among any broadcast segments. The DSS-24+ also supports Backpressure and pause frame-based flow control at half duplex mode schemes to ensure zero packet loss by sending out collision signals when the port's receiving buffer is full under heavy traffic congestion."- Hey, this all sounds cool and I was told much of these class of technologies have only recently become available in the cheaper Small Office Home Office (SOHO) switches. Maybe this will help if I get a few wacky packets or congestion by making sure things get sent that need sent. Or maybe I am clueless.
This switch is also apparently smart and learning so it gets better and knowing where to send things. I quote "As a switching solution, the DSS-24+ initiates a MAC address-learning table aging features. MAC addresses are automatically updated reducing any broadcast among network segments, which provides dynamic filtering through auto-learned MAC addresses and static filtering. " If I am reading this right, these switches tend to be a little smarter and not to do things like send out bogus broadcast packets to every AP on your subnode. I'd guess this is one more step to a cleaner network. Or it might squirt frozen yogert out the RJ-45's.
BTW, I chose the DSS-24+. There are tons of great switches out there that are probably as good or better. So don't think of my post as a product endorsement. I haven't even connected one up yet.
So anyway - for those of you with serious techie coolness, I have a theory that I'd love to get some input on. Initially I'll have a single linksys AP at point A and another linksys AP at point B. These will run in bridge mode and each be connected to a DSS-24+ switch at each end. Then several 802.11b radios will be attached to those switches to provide the local "hot spot" style access. Ok, so this is pretty simple. The two bridges should connect my two disparet networks and transfer data accordingly.
Now with a 802.11g bridge (I'm using linksys WAP54g) I'll probably get 25-30mbit at the best with the bridge. So what if I wanted to use two or more bridges at point A and point B that connected up these two networks. Since every port on the DSS-24+ can act as an uplink port, I'm am theorizing I can just link this 2nd pair of bridges in and the switch will route data over both bridges as needed. For instance say I have users moving more than 50mbit over my backbone - wouldn't the switch automatically kind of split that traffic between the two bridges?
One reason I am thinking about this is for now I'd like to build out cheap 802.11g bridges then add 802.11a bridges (see
thread1 (http://forums.80211-planet.com/showthread.php?s=&threadid=1049) and thread2 (http://forums.80211-planet.com/showthread.php?s=&threadid=1048)) to this backbone to expand its capacity.
I'm also wondering if I can just use a signal combiner and, for instance, have two APs sending their data over the single point to point antenna pair. Technically since they are on different channels they should be able to stay clear of each other...??
So can a good switch actually "combine" multiple bridges? Eitherway, does anyone have comments/ideas/etc regarding my above statements? Am I on track or way off? Is this crazy?