What an aggrivation.
I've spent the last day and a half trying to get Broadcom Advanced Control Suite to team four links together, turns out, the issue may be my OS.
Some time ago, for reasons only known to broadcom, they decided to disable teaming functions on all SBS servers. I'm quite baffled as to why.
Turns out that when BACS installer detects SBS, it disabled the option to install Broadcom Advanced Server Program; this BASP program is used to create the virtual interface for a team, that dictates the IP settings across the entire team.
So, anybody have a hacked BACS install that overrides the check for SBS?
Showing posts with label network. Show all posts
Showing posts with label network. Show all posts
Tuesday, June 18, 2013
Tuesday, January 17, 2012
MIMO the best thing ever?
I've just been studying wireless a lot in the last little while and I was considering how MIMO could be one of the best innovations since 802.11a.
For those that don't know, MIMO, or Multi-in, Multi-out (to paraphrase), is a transceiver method that uses multiple radios for a single line to enhance throughput and clarity of signal, being able to be fine tuned to even make reflections and phase shifting due to environmental disturbances, helpful to your wifi signal.
That being said, a lot of newer, mid to high end wireless b/g/n and a/b/g/n cards are coming out with multiple radio chains. The 802.11n standard supports up to 4x4 radio chains, but I have yet to see anything utilize that. Most commercial grade hardware has a max of 3x3 radio chains, which is to say 3 full transceivers in a single card. A good example of this would be the Intel 4965, 5300, and 6300 cards; all of which, I believe, are 3x3 radio chains for a/b/g/n wireless at 2.4ghz and 5ghz. The maximum rates differ, but that's another matter entirely.
My thought is, how useful is this? I mean that. It's beyond what I thought could be useful, but it really depends on what the hardware, driver, and software is capable of. I havn't checked into this, but if you have 3 almost entirely independent radio chains on a single card, would that not mean that you could, in theory, develop a WDS where roaming is entirely seamless? Having all wifi distribution traffic go through a single vlan to a central server that switches the 802.11 traffic into the 802.3 backbone? Then the question becomes, would you be able to separate a single radio chain for roaming and connection discovery? It could have the new connection, to a new AP, with better signal, fully authenticated before the previous (poorer signaled) connection is interrupted. Furthermore, you could simply configure it for a layer 2 notification, to now send all layer 2 packets destined for this layer3 address through this route instead (maybe by a gratuitous ARP or a ping type packet to the WDS Server?) - Meaning no more interruptions while roaming between nodes....
That is, provided the wireless nodes in your network support it.
Furthermore, network troubleshooting and analysis would be further simplified. Considering that you require 2 full channels on either side of the centre channel in order to not interfere with neighbouring networks, that interference could work in your favour when doing network analysis. With a 4x4 radio chain, you could potentially configure each radio chain to listen to a different channel, and catch all overlapping channel traffic too, getting a much faster, much clearer picture of the entire topology of the area that updates more frequently with less work on the hardware side.
I mean, the possibilities here are awesome. No more frequency hopping and incessant probing to try and find your AP.
Of course, the beamforming and everything else included in the 802.11n specification are also nice; and yes, they rely on the MIMO underpinnings to work, but that type of benefit, I believe, would be second to this... at least from a network adminstration point of view.
That's just my thoughts on it. I might be way off base or key, but I find this to be rather exciting. I know they're already working on the next standard, so we'll see.
For those that don't know, MIMO, or Multi-in, Multi-out (to paraphrase), is a transceiver method that uses multiple radios for a single line to enhance throughput and clarity of signal, being able to be fine tuned to even make reflections and phase shifting due to environmental disturbances, helpful to your wifi signal.
That being said, a lot of newer, mid to high end wireless b/g/n and a/b/g/n cards are coming out with multiple radio chains. The 802.11n standard supports up to 4x4 radio chains, but I have yet to see anything utilize that. Most commercial grade hardware has a max of 3x3 radio chains, which is to say 3 full transceivers in a single card. A good example of this would be the Intel 4965, 5300, and 6300 cards; all of which, I believe, are 3x3 radio chains for a/b/g/n wireless at 2.4ghz and 5ghz. The maximum rates differ, but that's another matter entirely.
My thought is, how useful is this? I mean that. It's beyond what I thought could be useful, but it really depends on what the hardware, driver, and software is capable of. I havn't checked into this, but if you have 3 almost entirely independent radio chains on a single card, would that not mean that you could, in theory, develop a WDS where roaming is entirely seamless? Having all wifi distribution traffic go through a single vlan to a central server that switches the 802.11 traffic into the 802.3 backbone? Then the question becomes, would you be able to separate a single radio chain for roaming and connection discovery? It could have the new connection, to a new AP, with better signal, fully authenticated before the previous (poorer signaled) connection is interrupted. Furthermore, you could simply configure it for a layer 2 notification, to now send all layer 2 packets destined for this layer3 address through this route instead (maybe by a gratuitous ARP or a ping type packet to the WDS Server?) - Meaning no more interruptions while roaming between nodes....
That is, provided the wireless nodes in your network support it.
Furthermore, network troubleshooting and analysis would be further simplified. Considering that you require 2 full channels on either side of the centre channel in order to not interfere with neighbouring networks, that interference could work in your favour when doing network analysis. With a 4x4 radio chain, you could potentially configure each radio chain to listen to a different channel, and catch all overlapping channel traffic too, getting a much faster, much clearer picture of the entire topology of the area that updates more frequently with less work on the hardware side.
I mean, the possibilities here are awesome. No more frequency hopping and incessant probing to try and find your AP.
Of course, the beamforming and everything else included in the 802.11n specification are also nice; and yes, they rely on the MIMO underpinnings to work, but that type of benefit, I believe, would be second to this... at least from a network adminstration point of view.
That's just my thoughts on it. I might be way off base or key, but I find this to be rather exciting. I know they're already working on the next standard, so we'll see.
Tuesday, June 29, 2010
How the internet works
Understanding all the nuances of technology, from how a computer encodes a single bit onto a wire for transmission, all the way up to the protocols everyone knows about, like HTTP and HTML, it's amazing to me that we don't have more connection issues.
I was seriously deliberating this, in my head, a few days ago, and an issue I dealt with today, reminded me of all those things and how the simplest thing can make the whole system go away.
The issue I was trying to resolve for a customer was that a particular webpage refused to load... The cause, as I had determined it, was that an administrator for that webpage had disallowed access from that particular address for whatever reason.
Going through the steps though, I checked through all the different layers and made sure the connection was going okay, that the DNS resolution was working correctly, and that the IP settings were correct.
To think of it, when we type google.com into a browser address bar, the browser instructs the system to establish a connection, the system, knowing it has to resolve the name, examines it's DNS settings, if the DNS servers are not listed as a connected route in the routing tables, it then needs to connect to the default gateway on the default route, in which case, it needs to ARP the default gateway for it's MAC address.
After resolving the mac address of the default gateway, it has to assemble a UDP DNS lookup request for the server, with the default gateway's MAC address, the DNS server's IP address, and the request information containing google.com.
After it receives a response, it need to then check the resulting IP for google, and compare that to local routing tables. It then needs to determine whether it needs to send out the SYN request on the same adapter to the same default gateway, and initiate the TCP session.
All this in approximately 1/10th of a second or less.
That's a lot of things to do in so little time... but we do it so often, without thinking, that the relevance of everything gets lost in translation. This process, and appreciation of it is definitely lost on end-users.
Oh well, I appreciate my DHCP and DNS servers, as well as my local default gateway for everything they do for me, each and every nanosecond.
I was seriously deliberating this, in my head, a few days ago, and an issue I dealt with today, reminded me of all those things and how the simplest thing can make the whole system go away.
The issue I was trying to resolve for a customer was that a particular webpage refused to load... The cause, as I had determined it, was that an administrator for that webpage had disallowed access from that particular address for whatever reason.
Going through the steps though, I checked through all the different layers and made sure the connection was going okay, that the DNS resolution was working correctly, and that the IP settings were correct.
To think of it, when we type google.com into a browser address bar, the browser instructs the system to establish a connection, the system, knowing it has to resolve the name, examines it's DNS settings, if the DNS servers are not listed as a connected route in the routing tables, it then needs to connect to the default gateway on the default route, in which case, it needs to ARP the default gateway for it's MAC address.
After resolving the mac address of the default gateway, it has to assemble a UDP DNS lookup request for the server, with the default gateway's MAC address, the DNS server's IP address, and the request information containing google.com.
After it receives a response, it need to then check the resulting IP for google, and compare that to local routing tables. It then needs to determine whether it needs to send out the SYN request on the same adapter to the same default gateway, and initiate the TCP session.
All this in approximately 1/10th of a second or less.
That's a lot of things to do in so little time... but we do it so often, without thinking, that the relevance of everything gets lost in translation. This process, and appreciation of it is definitely lost on end-users.
Oh well, I appreciate my DHCP and DNS servers, as well as my local default gateway for everything they do for me, each and every nanosecond.
Wednesday, June 23, 2010
Network Speeds - GBe, Wireless N and how they affect you.
A very significant debate in my mind, between different wireless (and wired) network technologies has been relating to effective speed.
What I mean by effective speed is two things; first, the speed you can literally get from the network (after overhead, crosstalk, and other factors). Second, the speed that's useful to the end-user.
Because of this, I end up in quite a conundrum... with server and back-end topologies and technologies, you generally know what kind of speed you'll need and what you can use. When connecting servers together, whether from scratch or to an existing network, you can surmise whether you'll need GBe, 802.2ad linked GBe, or a multi-GB connection (or even a 100MBit connection) for your server, depending on application. For example, a high-performance file server or database, you may want to put some of the more expensive connections onto, especially if the system will be used concurrently by many users, and the drive array can handle multiple gigabits of sustained simultaneous output to multiple destinations...
For servers, the job is pretty easy to deduce what you need, the hard part is not only finding the hardware you need (since 90% of computer shops carry consumer oriented products only), but getting management to sign-off on the purchase...
For client access roles and points, you really have to start debating, is one technology really better than another? let's review.
Almost all network access by end users (or consumers) is internet bound. not many people exist in a world where an intranet even exists, nevermind having servers setup on it, or accessing any "local" resources. With this in mind, I quickly begin to consider two things, first, how many people will be using the service, and what is the WAN speed?
WAN speed: most consumer based systems are using consumer based internet lines, which are generally not terribly fast. In North America, most consumer based broadband lines are between 3Mbit and 15Mbit. There are some exceptions to this, in cases of extremely fast or extremely slow internet lines, but for the most part, they fit into this model. In these cases I have to debate on the validity of buying the latest GBe router or switch, or the newest fanciest dual-band Wireless N router or AP. Since 90% of traffic is going to be internet bound, the fastest any one users connection will go, is 3-15Mbit. Current standards for wired internet technology is 100Mbit full duplex (or 100BaseTX), and currently the standard for wireless is 802.11g (or Wireless G) which runs at 54Mbit. Both of these show standard connection speeds that are 3-8 times FASTER than current internet speeds.
Factor all that into the fact that consumer based internet lines don't really seem to be getting any significant bump in speed, neither now, or in the near future, and you've found yourself in my debate.
If you're not using any resources on your local network, why do you need anything more than a 100BaseTX or 802.11g network? ... to be fair, wireless technologies will never run as fast as advertised, due to the fact that the send and receive happens on the same frequency, making the system half-duplex by nature (meaning you can only send OR receive, not both) but still, a half duplex connection can still sustain, even in high-traffic situations, something near 30-40% of it's maximum bandwidth (except in extreme scenarios).
Additionally, a lot of the technology that is touted as "Wireless N" is really just a beefed up Wireless G, that's been given similar encoding technology to Wireless N (making it possible to encode more data per wavelength of transmission, and therefore increasing throughput)... What I mean is that: 802.11n is designed to run on (or was originally designed to run on) higher frequencies, with shorter wavelengths (eventually, they settled on 5.8Ghz). With shorter wavelengths, and better encoding, it became possible to encode a significant amount of extra data into the stream than wave previously possible.
Allowing Wireless N on the same frequency as Wireless G, causes additional interference, since wireless G would take more time to transmit, and create more noise on the channels that Wireless N would be trying to use, and at the same time, Wireless N would be unintelligible noise to any Wireless G implementations nearby. The real conundrum is that to use Wireless N on 2.4Ghz effectively, you have to bump the channel width from 20Mhz, to 40Mhz. While using 'Channel 6' (the midpoint in N.America for wireless), with a "fat channel" (40Mhz), the radio then crosses over into almost every other wireless frequency, causing interference on every wireless "channel".
The bottom line with 2.4Ghz Wireless N, is that it would only really work in a controlled environment, where there is nearly no other 2.4Ghz networks or devices (this includes cordless phones).
Add that to the fact that the extra speed isn't making anything go faster, because you're using the 150-300Mbit 2.4Ghz Wireless N to access the internet, and you end up with this mis-mash of different, competing technologies, that completely ruin the experience for everyone (since they cause so much interference).
The only true benefit you could ever obtain from Wireless N, is in it's intended implimentation at 5.8Ghz (where there's very little demand, aka interference currently), while using dedicated 5.8Ghz ONLY devices and nodes. Additionally, you would have to use that wireless for accessing local resources; not just that, but you would have to make sure that your AP, and every link between you and the system you're talking to, is GBe, since Wireless N can fully saturate 100Mbit Ethernet... Then, on top of that, you almost have to be accessing an array of drives to really take full advantage of the throughput, since, even good conventional drives max out around 400ish MBit... That's not even touching how useless GBe would be to most users...
Yeah, I understand that, despite the bandwidth being not really necessary, GBe can reduce ping times because the speed of the transaction to transmit each packet is so short, however, the difference in real-world scenarios is negligible at best.
The real baffling thing, for me, is when there's respectable companies, that actually have intranets, with dozens of client systems, roaming profiles, network shares, VoIP, Internet, etc, all connected to the same network fiber, and they're still running on MB Ethernet. Thats. Just. Amazing. Upgrading to GBe in those scenarios would have massive impact, and the upgrade costs would be minimal at best. Since a lot of unmanaged switches are rather cheap, even with massive numbers of ports... Managed switches aren't too far behind in cost.
And really, in those scenarios, isn't the cost of the switch far outweighed by the increase in productivity of the workers? since now they don't have to wait forever for a roaming profile to load before they can actually do some work?
Food for thought.
What I mean by effective speed is two things; first, the speed you can literally get from the network (after overhead, crosstalk, and other factors). Second, the speed that's useful to the end-user.
Because of this, I end up in quite a conundrum... with server and back-end topologies and technologies, you generally know what kind of speed you'll need and what you can use. When connecting servers together, whether from scratch or to an existing network, you can surmise whether you'll need GBe, 802.2ad linked GBe, or a multi-GB connection (or even a 100MBit connection) for your server, depending on application. For example, a high-performance file server or database, you may want to put some of the more expensive connections onto, especially if the system will be used concurrently by many users, and the drive array can handle multiple gigabits of sustained simultaneous output to multiple destinations...
For servers, the job is pretty easy to deduce what you need, the hard part is not only finding the hardware you need (since 90% of computer shops carry consumer oriented products only), but getting management to sign-off on the purchase...
For client access roles and points, you really have to start debating, is one technology really better than another? let's review.
Almost all network access by end users (or consumers) is internet bound. not many people exist in a world where an intranet even exists, nevermind having servers setup on it, or accessing any "local" resources. With this in mind, I quickly begin to consider two things, first, how many people will be using the service, and what is the WAN speed?
WAN speed: most consumer based systems are using consumer based internet lines, which are generally not terribly fast. In North America, most consumer based broadband lines are between 3Mbit and 15Mbit. There are some exceptions to this, in cases of extremely fast or extremely slow internet lines, but for the most part, they fit into this model. In these cases I have to debate on the validity of buying the latest GBe router or switch, or the newest fanciest dual-band Wireless N router or AP. Since 90% of traffic is going to be internet bound, the fastest any one users connection will go, is 3-15Mbit. Current standards for wired internet technology is 100Mbit full duplex (or 100BaseTX), and currently the standard for wireless is 802.11g (or Wireless G) which runs at 54Mbit. Both of these show standard connection speeds that are 3-8 times FASTER than current internet speeds.
Factor all that into the fact that consumer based internet lines don't really seem to be getting any significant bump in speed, neither now, or in the near future, and you've found yourself in my debate.
If you're not using any resources on your local network, why do you need anything more than a 100BaseTX or 802.11g network? ... to be fair, wireless technologies will never run as fast as advertised, due to the fact that the send and receive happens on the same frequency, making the system half-duplex by nature (meaning you can only send OR receive, not both) but still, a half duplex connection can still sustain, even in high-traffic situations, something near 30-40% of it's maximum bandwidth (except in extreme scenarios).
Additionally, a lot of the technology that is touted as "Wireless N" is really just a beefed up Wireless G, that's been given similar encoding technology to Wireless N (making it possible to encode more data per wavelength of transmission, and therefore increasing throughput)... What I mean is that: 802.11n is designed to run on (or was originally designed to run on) higher frequencies, with shorter wavelengths (eventually, they settled on 5.8Ghz). With shorter wavelengths, and better encoding, it became possible to encode a significant amount of extra data into the stream than wave previously possible.
Allowing Wireless N on the same frequency as Wireless G, causes additional interference, since wireless G would take more time to transmit, and create more noise on the channels that Wireless N would be trying to use, and at the same time, Wireless N would be unintelligible noise to any Wireless G implementations nearby. The real conundrum is that to use Wireless N on 2.4Ghz effectively, you have to bump the channel width from 20Mhz, to 40Mhz. While using 'Channel 6' (the midpoint in N.America for wireless), with a "fat channel" (40Mhz), the radio then crosses over into almost every other wireless frequency, causing interference on every wireless "channel".
The bottom line with 2.4Ghz Wireless N, is that it would only really work in a controlled environment, where there is nearly no other 2.4Ghz networks or devices (this includes cordless phones).
Add that to the fact that the extra speed isn't making anything go faster, because you're using the 150-300Mbit 2.4Ghz Wireless N to access the internet, and you end up with this mis-mash of different, competing technologies, that completely ruin the experience for everyone (since they cause so much interference).
The only true benefit you could ever obtain from Wireless N, is in it's intended implimentation at 5.8Ghz (where there's very little demand, aka interference currently), while using dedicated 5.8Ghz ONLY devices and nodes. Additionally, you would have to use that wireless for accessing local resources; not just that, but you would have to make sure that your AP, and every link between you and the system you're talking to, is GBe, since Wireless N can fully saturate 100Mbit Ethernet... Then, on top of that, you almost have to be accessing an array of drives to really take full advantage of the throughput, since, even good conventional drives max out around 400ish MBit... That's not even touching how useless GBe would be to most users...
Yeah, I understand that, despite the bandwidth being not really necessary, GBe can reduce ping times because the speed of the transaction to transmit each packet is so short, however, the difference in real-world scenarios is negligible at best.
The real baffling thing, for me, is when there's respectable companies, that actually have intranets, with dozens of client systems, roaming profiles, network shares, VoIP, Internet, etc, all connected to the same network fiber, and they're still running on MB Ethernet. Thats. Just. Amazing. Upgrading to GBe in those scenarios would have massive impact, and the upgrade costs would be minimal at best. Since a lot of unmanaged switches are rather cheap, even with massive numbers of ports... Managed switches aren't too far behind in cost.
And really, in those scenarios, isn't the cost of the switch far outweighed by the increase in productivity of the workers? since now they don't have to wait forever for a roaming profile to load before they can actually do some work?
Food for thought.
Wednesday, May 12, 2010
Trying to Untangle the Tubes
Hello Internet!
or as some of us like to call it, the tubes.
This is, of course, my very first posting here and I would like to start with a statement of intent. This, is my very own tech-blog. This will be where I talk about technical matters of grave importance to me, and give my opinions on a vast array of topics, from network security, system security, server setup, network topology, microtechnology, robotics, cell phones, operating systems, applications, and hardware... there's probably more, but you get the idea.
Currently, I'm working on embedding all of my current endeavours into a single unified webspace, and, if you're reading this significantly after I've posted it, it may already exist; you may have even been referred here from it. In either case, I welcome you to my thoughts.
Personally, I am interested in a wide array of technologies, including microsystems and robotic, though my experience in that field is limited. I have also taken some time to get to know various types of cellphones, and their associated embedded applications, and have recently begun branching out into smartphone technologies. I've been slowly reading up on the CCNA tests, and I've been making my way though self-study books. I've also been working through A+ certification books, mostly for fun, since I don't seem to be learning anything from them. With over 10 years in computers, this field is very natural to me, and never ceases to engage my mind with interest, intrigue, and curiosity.
Currently, I run several systems, including a few laptops for personal use, I sacrificed my desktop to use as a server, and maintain several servers, some for use by 3rd party organizations, some belonging to party organizations. I also have a number of electronics, routers, switches, as well as the usual banter for someone in the field (storage, flash drives, external drives, monitors, keyboards... even a PDA (Dell Axim x51v)).
All this aside, I hope you understand and learn something new.
or as some of us like to call it, the tubes.
This is, of course, my very first posting here and I would like to start with a statement of intent. This, is my very own tech-blog. This will be where I talk about technical matters of grave importance to me, and give my opinions on a vast array of topics, from network security, system security, server setup, network topology, microtechnology, robotics, cell phones, operating systems, applications, and hardware... there's probably more, but you get the idea.
Currently, I'm working on embedding all of my current endeavours into a single unified webspace, and, if you're reading this significantly after I've posted it, it may already exist; you may have even been referred here from it. In either case, I welcome you to my thoughts.
Personally, I am interested in a wide array of technologies, including microsystems and robotic, though my experience in that field is limited. I have also taken some time to get to know various types of cellphones, and their associated embedded applications, and have recently begun branching out into smartphone technologies. I've been slowly reading up on the CCNA tests, and I've been making my way though self-study books. I've also been working through A+ certification books, mostly for fun, since I don't seem to be learning anything from them. With over 10 years in computers, this field is very natural to me, and never ceases to engage my mind with interest, intrigue, and curiosity.
Currently, I run several systems, including a few laptops for personal use, I sacrificed my desktop to use as a server, and maintain several servers, some for use by 3rd party organizations, some belonging to party organizations. I also have a number of electronics, routers, switches, as well as the usual banter for someone in the field (storage, flash drives, external drives, monitors, keyboards... even a PDA (Dell Axim x51v)).
All this aside, I hope you understand and learn something new.
Subscribe to:
Posts (Atom)