According to http://www.cisco.com/en/US/solutions/collateral/ns340/ns517/ns224/ns892/ns894/white_paper_c11-525307.html
Each virtual machine is given a dedicated network interface card. My question is, how do a server containing about 10 virtual machines, ever support 10 NIC's ?
Those NICs are probably virtual. Packets from them are routed to the physical NIC(s) and the other way around. It's pretty much the same thing as you get in modern WiFi routers: at home you only have one Ethernet port from your Internet Service Provider, it's in the modem. You connect your router to it, but your router may have 2+ Ethernet ports to which you can connect multiple PCs.
They can be physical too and either be directly accessible to VMs or indirectly.
Related
Is it possible to connect the Ethernet port (of a Raspberry Pi) directly to a Modbus TCP RJ45 port (such that the devices can talk to each other)? Or is this not possible without a converter?
I am unsure if this is the correct forum, but I believe this should not be specific to the Raspberry pi.
Short answer - Yes... But....
As per the comments this is possible but there are a few things you will need to do (i.e. some configuration will be needed).
I think it's worth nothing that "Modbus TCP RJ45 port" is not really a meaningful term. Modbus is an application layer protocol; this depends upon a number of underlying layers:
Transport layer - TCP
Network layer - IP
Datalink Layer - Ethernet
Physical Layer - Ethernet cable with RJ45 connectors
You don't need to understand this in detail; the point is that before ModbusTCP will work you need to have a working TCP network (which all Modbus-TCP devices will support; generally via an RJ45 Ethernet connection). As such a better question probably is "If I run a CAT-5 cable between a Raspberry Pi and another device (Modbus TCP unit) will I be able to connect via TCP?" (a lot more people know about TCP/IP networking than Modbus!).
The first thing to consider is Ethernet. Running a cable directly between two older devices will often not work because they needed a crossover cable. Almost all modern equipment (including the Pi) supports Auto MDI-X which means the cable will just work. You can also connect the units via a switch (and doing this removes the need for Auto MDI-X).
Next you need to consider the IP layer. When you connect your Pi to your home network it will (usually!) be given an IP address by a DHCP service (usually running on your router). If you are connecting the Pi directly to the device then there will be no DHCP service so you will need to manually assign IP addresses to the devices (and ensure the subnet is correctly configured). A common way to check if an IP connection is working is to use the ping command.
With the lower layers working ModbusTCP will generally 'just work'. Many ModbusTCP devices also offer a browser based configuration and checking that you can access that is a good way to confirm that the network link is working.
One further question is probably "should I do this"; it's OK to hook things up this way to make some quick changes. However generally you will want the Pi to access other network resources so connecting everything to a router (home router will work; for remote devices a cell router is often used). You can either give the Modbus unit a static IP manually or use the routers configuration pages to assign it a static DHCP lease (otherwise it's IP might change from time to time).
I have an Intel 82599ES 10G NIC which supports Intel SR-IOV. I have successfully created 8 virtual functions (VF) of it and assigned to 2 qemu/kvm VMs (2 VFs per each VM). Both of the VMs run DPDK applications (warp17 on one and my custom application on other) using assigned VFs. What I need to do is test my custom DPDK application by sending traffic through it using warp17. My test setup looks like this,
The red arrow represents the traffic path.
My Physical NIC (PF) use dpdk poll mode driver (igb_uio). What I need to do is route traffic between VFs as shown by the red arrows. I think https://doc.dpdk.org/guides/prog_guide/switch_representation.html has explained switching behavior but I cannot understand it. warp17 and my custom dpdk application both works perfectly on physical hardware. What I trying to do is virtualize my test setup to preserve resources. Has anyone tried to do such configuration?
neither X710 fortville and Ninatic 82599ES ASIC does not have internal Bridging or forwarding VERBor feature. The best option is to have software virtual switch like SPP, OVS-DPDK or custom application to forward packets via virtio or tap.
if you still want to use physical NIC or x710 or 82599ES you will need to have connection at other end and run the logic to direct packets to relevant VF (modifying dst mac).
Edit-1: (as per DPDK 20.11) VEB virtual ethernet Bridging is an option, but specific NIC firmware and driver is required to create VEB on PF then propagate to VF. Once done the NIC can not receive packets from the Outside world
I have Windows Server 2008 and Windows 7 on virtual machines (HyperV). Win7 has 2 internal interfaces (Local Area Connection 4 and 5), the same situation is on Server 2008.
All interfaces are using one, the same internal virtual switch.
I thought that they are all in the same subnet now and should ping each other, but the only machines that can communicate are interface 5 (Win7) with interface 4 from Server.
How can I connect them all? Do I understand this interfaces and virtual switches properly?
When I do ping command I get: Reply from ...Server IP adress.. Destination host unreachable.
Virtual switch has static IP adress 192.168.1.1, when I set default Gateway on my interfaces I get error: warning- Multiple default gateways are intended to provide redundancy to a single networ. They will not function properly when the gateways are on two seperate, disjoint networks.
Your internal interfaces are suppose to have one configured for the current network your on and the other interface can be bridged to have the virtual network established. One interface will have the same Local Area network as the machine your using to run the virtual machines which allows your virtual machines to use the network. Also make sure you name your interfaces to keep them distinguished from each other, for example "NAT" and the other "Internalnet" hope this helps.
I have two servers, written in Java, that communicate through sockets and TCP. The servers are both on the same Linux machine. If the servers were on different machines then data would have to go through network adapters and network cables, but since the servers are on the same machine how does the OS actually move data efficiently form one server to the other.
Generally, the messages will be sent over the loopback interface:
In TCP/IP a loopback device is a virtual network interface implemented in software only and not connected to any hardware, but which is fully integrated into the computer system's internal network infrastructure. Any traffic that a computer program sends to the loopback interface is immediately received on the same interface.
However, you can manage to configure your situation so that, for example, the server is referred to via an external IP address so that messages actually go out over the network before being routed back to the same machine.
If two programs are using TCP/IP to communicate on the same machine, they are probably connected through the loopback interface
I want to monitor the HTTP traffic sent/received from my iPhone. The iphone is connected to the Internet via my wifi router.
I want to capture packets from my windows 7 station.
Thanks for your help.
You have a few options here:
If your wireless router has a port mirroring or port spanning feature, turn it on and point it at your workstation's IP. Use Wireshark on your workstation to look at the packets arriving on the interface assigned to that IP.
If your workstation has a wireless card, get Connectify for Windows 7 (turns wireless card into Wifi Hotspot). Connect iPhone through Windows 7 wireless, and workstation through ethernet to the internet. Your workstation will effectively act as a router for your iPhone and you will be able to record iPhone's packets passing through it.
Get an ethernet hub (make sure it is not a switch, you won't see all packets on every interface with a switch), and connect your workstation, wifi router and internet to it.
Get a switch with port mirroring feature, configure port mirroring to forward a copy of all packets to your workstation.
Another option that I wish someone would have mentioned to me is pfSense. This is an operating system based on BSD made to serve as a firewall. Top of the line routers have, say 400 Mhz of processing speed, and unimpressive amounts of ram. The lowest-end computer you'll find these days has better specs than that, and of course, it's upgradeable. You don't have to bother with those terrible Cisco licenses (no DHCP with no license, 20 DHCP users at one license level, 100 users at an higher lever? Ludicrous), etc. Best of all, you have "root' access to the system, so you can run whatever you want on it (including wireshark, say)!!
Make sure you have two sufficiently fast ethernet cards. You'll set your wireless router to not do NAT (because pfSense will be doing that), then you can get to work setting up your VPN server, etc. without thinking about cisco licensing, etc.