Networking Virtual Computers
Virtual computers need a way to communicate by using virtual network components. Virtualization is the creation software-based representations of devices, such as servers, storage and networks. While they have the benefit of being on one server, the problem is there is only one network interface card. So rather than installing multiple NIC, we use virtual switching devices, which allow us to set up things like VLANs.
Why Would I Use A Virtual Switch?
- Switch like connectivity
- Allow for the same functionality as a physical switch. Our virtual switch allow our virtual computers to communicate with one another like they are using a regular switch.
- Communicate over Layer 2
- Set up VLAN
- Allow for segmentation of our networks, so our virtual machines don’t communicate with all of our physical servers.
- Utilize a single NIC as a trunk port.
In the image below, all of the virtual machines are sitting on a single server with its own IP address, but we will not be paying attention to that here. Looking at the virtualized devices sitting on the server, we have:
- A virtual switch in the middle;
- The “192.168.2.x” VLAN with the “red” devices; and
- The “192.168.1.x” VLAN with the “black” devices.
If we just had a single NIC, it would be difficult to set up a VLAN this because a NIC only sends data to a single port on an external switch.
- To overcome this issue, we use a virtual switch inside of the server in order to identify which VLAN the virtual devices are a part of.
- The virtual switch then talks out over the NIC to the physical switch as a trunk port, tagging the packets with the appropriate VLAN identification.
- The same process happens in reverse, with the physical devices passing packets to the physical switch, which tags the packets and passes them over the trunk port back to the virtualized environment.
As an example, say the device at “192.169.1.3” functions as a DHCP server and we are just plugging in the device we’ve identified as “192.169.1.7” in the image above (except that it doesn’t have an IP address yet). We have already identified the port on the physical switch that it is plugging into as part of the black VLAN, so the computer sends out a DHCP request when we plug it in to the switch. This request goes over the physical switch, across the NIC, to the virtual switch and on to the devices at “192.169.1.3” and “192.169.1.4”. Since “192.169.1.4” is not a DHCP server, it does nothing, “192.169.1.3” responds with an IP address offer and then assign it “192.169.1.7”
What is a Virtual Desktop
There are two types of virtualization, remote and local
- Remote Desktop Virtualization
- Virtual Desktop with Remote data
- An alternative to using a VPN to tunnel into a server to retrieve files.
- Consistent folders everywhere
- Remote data execution. This is helpful when your local machine has much less power than the server running the virtualized machine.
- Requires a constant network connection for remote data execution
- Local Desktop Virtualization
- Virtual machine runs locally and uses computers resources
- Virtual disk/image synced to a server.
- Does not require a constant network connection to run.
- Works well with high powered computer and low power server.
How Do Virtual Servers Work
- Servers that provide a full service (DHCP, file server, etc)
- Full physical server may not be needed. Can buy a really good physical server and put logical servers on it.
- Allows for logical distribution/scalable resources
- Communicate over Physical Network Interface Card
- May install more NICs, so that virtual servers can connect directly to physical VLANS
- May install virtual switch if we just want to use one NIC
How Does a Virtual PBX Work?
BPX stands for a Private Branch Exchange
- Telephone switch/Call Manager
- Establish connections
- Maintain connections
- Disconnect connections
- Provide call info
- Virtual PBX Replaces Hardware
- Still need call agent, a device that manages the calls
- Useful for VOIP
- Small office —> Large call center.
In the image above, picture an office environment with 500 workers and then a few offsite home workers. The home workers need to be able to communicate with workers and clients from home, while looking like they are in the office.
The answer is an internet based PBX and you set your infrastructure up to connect to the PBX over the internet. Our physical phones connect with an ethernet cable and are assigned a phone number/extension (Extensions #1, #2 and #3 in the image above). They connect out to the internet via a switch and router to the virtual PBX, which acts as a call manager.
The person at extension #3 is working at home today, so how does she get calls from work? Installed on her computer is a virtual phone, whose MAC address is assigned extension #3. The PBX will then route the calls to the virtual phone rather than the office phone.
What Are The Advantages of Onsite vs Offsite Hosting
- The main differentiating point is that having your servers “on” or “off” premises.
- Might refer to the location of data backups, but even off site data backup location may still be managed by your company.
- Benefits of Onsite Hosting
- Faster response and more control
- Business continuity implications
- Staffing/training requirements
- Offsite
- Connection delays
- Information control, need a high degree of trust. May need to encrypt data.
- Better resources for business continuity, back ups and ongoing support
What is a NaaS?
Network as a Service
- Just need computer, link to ISP and a NaaS service.
- Host your apps, data and servers.
- Benefits of NaaS
- Less management
- Business continuity
- Business resources
- Scalable, good for companies that have offices spread out across a wide geography.
- Cost of Naas
- Less control/security issues
- Connectivity issues
