However, I am not convinced it applies to BaseTX. After reading the replies here, I did a little digging. It is not easy finding definitive rules, but what research I have done leads me to believe in this lower 2 hub rule in a BaseTX lan, when hubs are simply connected by cat5. I understand some hubs are 'stackable', connect differently than a simple patch cable, and are then treated as one unit.
You may have meters of network cable between a hub and an end node. Hubs classified as Class I repeaters can't be cascaded at all using Fast Ethernet. Class II repeaters can be cascaded once--for a total of two per segment--but the two hubs must be within 5 meters of each other. For 10 Mbps, the limit is four; for Mbps, the limit is two. Attention reader! Types of Hub. Skip to content.
Change Language. Related Articles. Computer Network Fundamentals. Physical layer. Data Link layer. Network layer. One could argue that the essentiality of a PPI may be due to its special location in the network and that removing an essential PPI may disturb the network architecture more than removing a nonessential PPI.
Unfortunately, it is unknown with certainty which PPIs are essential in the yeast network. However, no such trend is found Figure 3 A. This is probably because IBEPs tend to occur between highly connected nodes, which are less affected than lowly connected nodes by the loss of an edge. Thus, there is no evidence that essential PPIs are more important than nonessential PPIs in maintaining the network architecture.
A Effects on network diameter, which is the mean shortest path length among all reachable pairs of nodes in the network. B Effects on the proportion of unreachable pairs of nodes in the network. Note that the total number of IBEPs is in the network. It is often said that scale-free networks are robust against random removals of nodes, because the majority of nodes are poorly connected, and they play relatively unimportant roles in organizing the global network structure [ 3 ].
Since in PPI networks the only factor determining protein essentiality is essential PPIs, it is possible to examine if the PPI network is structured in a particularly robust fashion. If we randomly assign essential edges in the yeast PPI network, on average nodes become essential Figure 4 A. In fact, the expected number of essential nodes generated by a given number of essential edges is always lower in scale-free networks than in ER networks Figure 4 B.
This may suggest that the scale-free network is more robust than the ER network, even when we consider the underlying mechanism of node essentiality. Note that the above interpretation of network robustness is different from previous analyses. In previous investigations, robustness is measured in terms of network structure [ 3 ], but here it is measured by network function.
We caution that the higher robustness of the scale-free yeast PPI network than ER networks does not imply that the robustness originated from natural selection for robustness [ 6 ]. More likely, robustness emerged as a byproduct of other evolutionary processes or contingencies. Furthermore, it is interesting to note that the yeast PPI network is far from the most robust network possible.
For instance, one can design a network in which essential edges link 22 essential nodes Figure 4 A. Obviously, evolution did not work in that way. A Numbers of essential nodes generated by essential edges in various networks. Black and gray bars depict the distribution of the number of essential nodes from 10, replications of random assignments of essential edges to the real yeast PPI network and simulated ER networks, respectively.
An ER network has the same number of nodes and edges as in the real network, but the distribution of node connectivity follows a Poisson distribution. Also shown are the minimal and maximal numbers of essential nodes produced by essential edges in any possible network that has the same numbers of nodes and edges as the yeast PPI network.
B Proportions of essential nodes generated by given numbers of essential edges in scale-free power-law and ER networks.
Both networks contain 4, nodes and 4, edges. The ER network has a connectivity distribution following the Poisson distribution with mean connectivity per node being 2. To examine whether our results are similar when different yeast PPI datasets are used, we tried two other datasets, one with many more nodes and edges [ 24 ] and the other with much fewer nodes and edges [ 21 ]. These results are not unexpected, given that the three datasets we used vary greatly in the numbers of nodes and edges, mean connectivity, and proportion of essential nodes.
These variations reflect different numbers of false-negative and false-positive data about protein essentiality and PPI among different datasets. The noise and incompleteness of the data could potentially undermine our ability to predict P E.
However, as long as essential PPIs are randomly distributed among edges and the other essentiality-causing factors affect all nodes equally in a random fashion, our Equation 1 should work. A recent study of pure high-throughput yeast two-hybrid data of PPIs showed a weaker centrality-lethality relationship than previously found from better corroborated data [ 25 ]. It is well known that singleton genes are more likely to be essential than duplicate genes [ 4 , 27 , 28 ].
It is interesting to ask whether singletons are more likely than duplicates to engage in essential interactions. Furthermore, potential functional compensations between duplicates could mask the true essentiality of a duplicate gene. That is, many nonessential duplicate genes may actually have essential PPIs. To avoid these problems, we classify genes into singletons and duplicates and examine their interaction partners, while ignoring the essentiality of these genes themselves.
We found that yeast duplicate genes have on average 0. On the contrary, yeast singletons have on average 1. This analysis suggests that essential PPIs potentially contribute to the higher essentiality of singletons than duplicates, supporting the view that singleton genes are intrinsically more important than duplicate genes [ 29 ].
In biological networks as well as in other networks, different edges may be of different levels of importance. Treating these edges in a quantitatively or qualitatively different way may reveal previously unknown patterns and provide new insights. In this work, we propose the concept of essential protein interactions and demonstrate by computational network analysis that a large faction of gene essentiality is due to essential PPIs.
It is important to stress that using essential PPIs to explain gene essentiality is not tautological, because the explanation provides a molecular understanding of why certain genes are essential and offers a conceptual framework for future experimental proofs. Logically, the next question is why essential PPIs are essential. Thus, the essentiality of a PPI does not seem to be determined by network structures but rather by the particular functions of the interaction.
Alternatively, the influence of the network architecture may be more subtle and thus require further scrutiny of larger and more accurate PPI data. Similarly, our results suggest a simpler explanation of the centrality-lethality rule that does not invoke the role of protein hubs in organizing the global network structure.
Furthermore, our hypothesis quantitatively explains the centrality-lethality rule, whereas the network architecture hypothesis lacks such a quantitative model. Our finding appears to argue against the biological significance of the PPI network architecture. However, it should be pointed out that although gene essentiality is an important phenomenon because it determines organismal survival and reproduction, the significance of the network architecture may lie in other aspects of the cellular life that have yet to be explored.
Furthermore, our analysis focuses on PPI networks, and it is unclear whether our results extend to other biomolecular networks. Therefore, the role of network architecture in biology cannot and should not be dismissed at this time.
Rather, more studies are needed in the nascent field of systems biology to address such important questions as the biological meaning and evolutionary origin of the architecture and robustness of biological networks [ 7 , 30 — 32 ]. Although self- interactions may contain important biological information, they were not considered in our analysis, mainly because our approach of using IBEPs to infer essential interactions would not work for self-interactions.
Because the centrality-lethality rule is observed when self-interactions are excluded, our analysis should still be biologically meaningful.
We also excluded from our analysis 43 interactions involving Ty elements and six involving mitochondrial genes, resulting in 7, non-redundant PPIs linking 4, yeast nuclear genes, of which genes are essential. The mean connectivity per protein is 3. There were genes in our protein network that lacked the essentiality information and were treated as nonessential in the analyses.
All of our results were virtually identical when these genes were excluded from the protein network. Essential genes are those indispensable for the growth of yeasts in the YPD-rich media. This set of genes is apparently fundamental to the cellular processes of the yeast, although additional genes may become indispensable in adverse conditions [ 33 ].
Singleton genes and duplicate genes were defined by all-against-all BLASTP searches of yeast proteins, following [ 34 ]. The fruit fly PPI network [ 35 ] included 4, proteins connected by 4, non-self high-confidence interactions. To control for the fact that essential genes tend to be evolutionarily conserved, we examined only those yeast PPIs for which both partners have orthologs in the fruit fly. In most cases, you can return the device to the manufacturer who will, or should, replace it for free.
You will have to pay for shipping, however. Well… they can. You can connect a switch to a hub, a hub to a router, or a switch to a router. This is how many large networks connect all of their devices to the internet. They usually have a single router with several switches attached to it which have switches of their own, and so on. Usually the computers themselves are connected to a hub that connects to a switch. Of course it all depends on the amount of network-requiring devices. Maybe like 5 switches one for every 10 , or something.
Maybe even less. It all depends on how fast the connection needs to be and how much money the IT department has lol. Will a switch or router solve the problem.
But you have not indicated that we also have layer 3,4 and 7 switches which can in some respect replace routers. They are even smarter than routers.
Hub is take a data and sending to all conneted networks but 2 Swich is unicast sending data only one machin to connected switch.
I have a very interesting setup that I am working on for a client right now. The client has a network of about 25 users. They are experiencing very very slow internet load times slower than one would expect even if the slow connection is shared over 25 computers. The DSL modem is connected to a switch provided by the ISP which is then connected to a 24 port switch, which is then connected to a wireless switch.
Most computers are connected directly to the 24 port switch and a few connect to the linksys wireless access point. The large switch is full and the wireless hub has about 5 laptops connected plus a few desktops. The first switch after the modem only connects to the second large 24 port switch.
Quick question. Thank You Leo!! I am having problems with all the terminology in my networking class. I appreciate your simplicity with such complex issues. I finally understand! My networking connection is modem from the ISP is connected to a 24 port switch,and all the 10 system connected to the switch. I have a broadband router for my network. For your article it would be good to note whether adding a switch for additional network devices is sufficient, or whether the intellegence of an additional router is an advantage.
I took a lightning hit damaging my hub, and now I cannot get all workstations up, with a new HUB, and I even tried a switch. I then run each cat 5 cable out of the few working ports. Any ideas why a new hub would not work? I am last year computer science graduate…. For this I need the master PC switched on, always.
I have one IP with one connection. I came to this site looking for differences between the equipments, but could not make out and hence this post. I have a 4 port linksys wireless router. What can I add to this router to expand my ports. I need another 2 for network printing eithernet. I have a 16 port d-link switch that will only work behind my linksys router, but not when hooked directly from the modem…is this normal, or is there something wrong with my switch?
Anyway, am I just screwed, or is there something Comcast or me can do for me? How does one physically differentiate between a router and a switch? If the switch is not as intelligent as a router, then how come a network can be fully switched? Or, would a fully switched network eventually connect to a router? We have a cisco switch at the end of our network connected to the wireless router connected to the modem. Nothing about the network has changed re: set up or provider, yet the dropping is becoming more of a problem as time wears on.
Do you think we have a switch issue? Any suggestions? I have a LAN which is connected to a router. My Internet modem with inbuilt router is now connected to this router.
In a domain using the username and paswd any one can log into any system so if the router that is a system then i know how to stop simply changing permissions to login will stop access but if in case of routers, configuration has to be made through commands using some interface.
Is the way to share same speed all the systems? Hello Mr. Can I connect both to a single router and enjoy the sum of both connection speed from that router when only 1 PC connected to that router? I have a 5 port switch, and a linksys wireless hot spot with only one port which is the ethernet input. The problem is I can ony get one thing to work at a time, I connect my VoIP, and it works great but no enternet, and so on.
Can I use a switch in this way or will I need a roughter? Thanks in advance for you time. One thing that is cool is that the cookies are browser specific. If you want to try an experiment: go to the computer that remembers you signed in with gmail, and then try it from a different browser and see if it still remembers. For instance, if you usually use IE, then use Chrome or Firefox. Well Explained and informative, even i found this link helpful..
Thanks for the excellent explanation. If you mean safe from hackers accessing your computer, then, yes. How does a VPN protect me? Can I daisy chain a router? My hub has no more room and I have an extra Linksys router. The main router is the same make and model. This Leo has just come in perfect for me. I do voluntary work for a charity helping network the building. I wanted to give the Hp printer a static ip address. I realised that each time the printer was switched on a different ip address was given by the DHCP server.
We then deadicated a pc as a server to increase the speed of printing mainly for Coral draw , also to stop people from having to ask for the printer back. It worked brilliently until the printer was switched off. This has angered us somewhat. I thank you sir and your continued articles. This is 1 of d best explanation hav ever gotten and i realy thank you for that. I shall be searching for more answers on your site. Many thanks. But if i use the laptop of my friend on that wifi it is not showing the error of limited and there is no need to disconnect with internet.
Can u help me out how to solve this issue? I have a problem, im running a hostel n running a cat5e cable from my modem to a 15port router, and from the 15port router to every tenants rooms. I have a switch whose two ports are called in the same vlan.
I connect a device to one port with IP I have a switch whose two ports are called in the different vlans. I connect a device to both the ports with devices in I have a switch port connected to a hub in a port called in an access vlan x. The HUB connects to two end devices one in My two grandsons like to play Minecraft on their devices and love to see each other in their world.
At my summer home, my internet connection is via a cell tower and very expensive. I bought a router last summer naively thinking I could link the two devices together without incurring data charges from my provider. Nothing I tried seemed to do the trick.
Is this even possible to set up and bypass the internet? Most multi-player games communicate not with each other but with a central server on the internet that handles all the inter-player communication and visibility. By splitter, I believe you mean a router. You should be able to use a router to share your internet connection on more than one machine. You may experience some slowdowns if both are accessing the internet at the same time, but other than that, it should work.
IP like It really depends on how your network is configured. If your router is assigning those IP addresses, then sure — you can use a switch. This article explains how to do that: How do I best extend my wireless network for laptop access?
If you have already answered my question in a different way, please refer me to the specific answer. Q2: Will the NAT port forwarding still be possible?
Or does the router simply see the switch and not the individual cameras? They are updated by the AD DC at set intervals. How r u? My self Jamshed…. Sir can u please tell me if my laptop shows the blue screen than how should I take the backup of my data from laptop??
Is there any solution on this? Thanks Regards! First, you should have had a backup — so learn from this and start backing up in the future when things are working again.
Some backup programs like Macrium will allow you to create a backup using the recovery disc — boot from that, create a backup image of the computer, then fix the computer and you can access your data from that backup image. Another approach — particularly if the computer is damaged or not worth repairing — is to take the hard disk out and put it into an external enclosure.
COnnect that now external hard disk to another computer to access the data. One runs on XP other on 8. HI sir fantastic articles i want 2 know if a router IP address changed 4 example …x,…2 this is router IP address and we want to talk with other computers ad there ip address dont have similarity would router or computer accept there request in other side there ip address are different.
Assume you are five other devices in your home. If you have a router then it is a NAT router. Any device on the Internet will only see your router.
Leo — this blog has gone on for years — impressive. And I feel for Leo — people asking the same question s that have already been answered in this blog yes its getting long. If it does wireless too, it also includes a WAP. POP is NOT a term others use — it is my stupid attempt to explain that that piece of plastic you thought was only a Router is in fact, a combination of devices. May help others understand. Just to be completely sure… 1 I have only 1 ip address from my provider.
It sounds wrong from what is written in the blog. If it is the case, can you suggest me a place where I can get the right set up I require? You need a router to share a single IP address among multiple computers. It handles it automatically. Is there an application where you would require in conjunction a hub and router. Great job on this thread. My question: I recently installed a new router in my office.
My modem is bridged to the router. My router is connected to a zygel switch. My switch handles about 30 devices. I noticed during install my router, and switch, have the same default ip address. At times typing in the ip will give me the router, and sometimes the switch, it seems whichever was the last device to be powered on and off.
Should I leave this the same, or change the ip of the switch? And if I change the ip, do I just randomly pick the last number? Second question: In trying to set up Qos in my router, when I apply it, it shuts down all my devices. Any clue why this occurs? Modems often act as routers, and hence you may actually have two routers, which is bad and could lead to all sorts of network issues.
Hi Leo, great work, thank you for doing this. My question. I have iptv tv supplied over the internet I want to add a switch after my cable modem to split the data between my router and my TV Box. Hi Leo, i have a net port comming from a router and i want that this port will be shared by three computer by a hub. Hi According to me the backbone of a computer network relies on 3 types of devices to interconnect computers: 1 Hubs, 2 Switches and 3 Routers.
In fact, the devices are quite different. Hubs are used to simply interconnect individual computers. Switches do the same but more efficiently. However, routers interconnect different networks as opposed to individual machines. I would like to say thank you that have shared this technical info with us.
I am sure many people like me who are not tech savvy will able to better understand the difference between the three in far better way. Hey Leo!!! Your explanations were really good. Regards, Hussain. S Hope to get your reply soon. So you said that switch will dynamically learn about the device addresses on different ports. After switch gathers this information for the first time, it makes a table and etc.
My question is what happens when after this job is finished by switch and two computers of the network swap their ports.? How will switch avoid the mistake of communicating to wrong computer? In response to John, January 8 , you said that the router would have to have the ip address of the computer. I have 3 computers with 3 separate static ip addresses.
This is a Western Digital N with 7 ports. Is this always true? A very clean and helpful explanation. One thing that I want to point out though, maybe you should use Mbps instead of mbps, as upper-case M refers to Mega and lower-case m refers to mili 0. Other than that, thanks for clearing everything out!
Its a typical cottage that will see most of it use in summer and probably none during winter months. Having said this because l checked different options and a hub type internet is least expensive as its a user based pricing. The more you use the you pay. A router has monthly rent costs on top of the data costs.
Also do you know the range of these hubs how far from hub can you go with laptop and get signal etc. Maybe a switch is what l need but my provider never suggested this and do they have flexible plans. A wireless router is the simplest way to connect your laptop via WiFi. There are relatively inexpensive WiFi routers you can purchase. I have one question that I really need help with. I currently live in a dorm with two other roommates and there are only 2 Ethernet ports on the wall.
What should I get in order to get access to the Ethernet? There are simply 2 wall ports that Ethernet cables connect to. I have their single port modem connected to a switch and behind that switch I have 5 routers each with the WAN port IP address that matches each of the 5 public IP addresses assigned by the IP. Recently one of these routers, the last one I added, keeps disconnecting the WAN port, so users behind it lose internet access but can still hit the router and have to power off and on the router to regain internet access.
Tried replacing the router twice, with same result, replaced the switch, cable and connectors, same result. Scratching my head for ideas on what the problem is and how to resolve it. Diagnose by swapping ports on the switch with another router, and see if the problem travels to that other router or not. Leo Hi Leo. These computers sending and receiving messages.
Please tell me the problem. Based on what you already know about networks, what are the different layers you think would be necessary for communication to be mapped to a model? Consider direct connections between host devices and connection that require other routing equipment, such as a hub, switch, or router.
I double checked to ensure that the protocols are supported by the router, and Asus AC powered by Sabai OS, but still no luck. Any idea how to diagnose the issue? A switch is what you need. Comments violating those rules will be removed. Comments that don't add value will be removed, including off-topic or content-free comments, or comments that look even a little bit like spam.
All comments containing links and certain keywords will be moderated before publication. I want comments to be valuable for everyone, including those who come later and take the time to read.
Search Ask Leo! Switches are semi-intelligent devices that learn which devices are on which connection. Routers are essentially small computers that perform a variety of intelligent tasks. I'll see you there! Slow Computer? Podcast audio. Where Can I Download Windows 11? Or 10? If you have a legal retail product key, this could be your replacement media. How Do Outlook and Outlook.
I'll clarify the difference between Outlook and Outlook. Leo Reply. Thanks Reply. Thanks for your time, much appreciated Reply. Good luck! Prat Reply. Thanks, Gary Reply. What is the difference between a router and a gateway! I think that a router will enable us to be a separate, independent network, right?
Or maybe I was doing something wrong… 6. Does a router need an IP address? Thanks in advance for your reponse, and congrats for a great site. Very enlightening! Best of luck! Thank you very much for your time Herbey Reply. Ray Morris Reply. Basically for gaming purposes Thank you very much LEO.
Your help is very VERY much appreciated. Thank you again, and apologize for the unclear questions. Hey Leo, Thanks a lot for this explaination.
This is a great resource site, Leo. Thanks for all your very helpful advice. Ed Reply. Thanks Ed Nick Reply. Hello, Can you have hubs and switches in your network at the same time, or do you need one or the other? Am I doing something wrong? Those are the top items that come to mind. Great site and very informative and very quick with your responses!
Thanks for any help! Thanks again Reply. But your milage may vary. Bob Reply. Thanks guys Reply. Probably not. You really want a router. Thanks, that is what I meant. But does it mattter if I use a switch or hub in this scenario? Please help me Thanks Eduardo Reply. Thanks a Bunch, David Reply. Thank you Reply.
I would get a router.
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