The OS's built in security measures. But let's say that somehow you've socially engineered some credentials. It's not unheard of. So, you're unhappy and you want to send a page print job at a. Or let's say you want to try to hack an HR workstation for which you obtained the password. Without VLANs you would just log onto your laptop in your office.
Or if you're an attacker, you would use the lobby's Wireless AP - or even in your car across the street. And then you'd send the print job - with the stolen credentials. Or you'd start your hack to the HR workstation with your stolen credentials. Also, that eliminates use of that really really expensive printer because that printer and the two workstations that can print to it are wired directly to a switch and they're all in the same VLAN - and you're not.
How about that HR workstation. Again, you're not in the right VLAN and unless you start physically breaking into offices or network closets to get access to a port that is in the right VLAN, you're out of luck. I hope that explains the basics of added security with a VLAN. There's more to it, and I'm leaving some things out, but you get the idea. Zak, thank you for your post. I am going to give it another read in a little while. I first wanted to mention that we have a gigabit network. Does that further the need for me to use VLANs?
If you ask me, vs mbps really shouldn't even factor into a VLAN-ing conversation. If you're saturating a mbps switch you either need a bigger switch or to go to gigabit. Adding VLANs adds complexity for sure, but lets you segregate and control traffic far more effectively. The security aspects as outlined above are also very useful.
The cumulative bandwidth of a LAN imho can have an determinative effect on the decision to implement and how to implement VLANs only after you consider what kinds of traffic are taking up what percentage of the bandwidth. You have a megabit network running on CAT5 with 8 users, 3 of which are using a video conferencing solution 6 hours a day.
The other 5 users will never use this application. Certainly this scenario would is a good fit for VLAN. You can immediately increase the available cumulative bandwidth for the 5 users without upgrading to Gbit.
There are other scenarios that shouldn't be too hard to come up with, but reality is the best teacher. I'm sure some users here on Spice Works can relate anecdotal stories. In my network, consisting of several satellite offices connected through a "metro-ethernet" setup from a local provider which has each office is on a separate VLAN which comes to our main office with some more beefy equipment.
The main office has an additional VLAN piped in on the same cable that gives us Internet connectivity. This allows us to have one content filter at our main office to manage which prevents people at all offices from going to sites that are We are also in the process of implementing MAC authentication. The configurations of tables are shared among all device ports. Skip to content. What is VLAN? How to Increase Upload Speed. Report a Bug. Previous Prev. Next Continue.
Home Testing Expand child menu Expand. SAP Expand child menu Expand. The network traffic typically is all handled by a single device that performs several functions: wireless access point, Internet router, NAT Network Address Translation , and Ethernet switch. In a nutshell, VLANs allow a group of Ethernet devices subnet to be physically separated by many Ethernet switches but communicate as if they were all connected to the same physical Ethernet switch.
In the example below, the three VLANs have devices located on separate floors. For the Engineering computers to be on the same network across multiple building floors, VLANs are used to isolate this traffic from marketing and accounting computers.
Devices in different VLANs cannot communicate when only using layer 2 switches. Layer 2 devices only inspect the destination MAC media access control addresses of Ethernet frames.
A MAC address is tied to a physical piece of hardware. In other words, a layer 2 switch allows devices in the same VLAN or subnet to communicate. Also, keep in mind, modern Ethernet switches often blur the lines between layer 2 and layer 3 capabilities. What benefits do VLANs have over making it all one large subnet? Splitting into VLANs and using an appropriate variant of spanning tree protocol can allow different trees to be used for each VLAN better utilising links.
On the flip-side though having multiple VLANs can force local traffic to take circuitous routes via a router. Handling overlapping IP addresses. In an ideal world you wouldn't have these but if you must then VLANs give you a way to isolate them. Peter Green Peter Green Sagar Uragonda Sagar Uragonda Sign up or log in Sign up using Google.
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