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Diffstat (limited to 'qemu-doc.texi')
| -rw-r--r-- | qemu-doc.texi | 51 |
1 files changed, 23 insertions, 28 deletions
diff --git a/qemu-doc.texi b/qemu-doc.texi index 715bd336b4..0e0e0ae72b 100644 --- a/qemu-doc.texi +++ b/qemu-doc.texi @@ -715,20 +715,12 @@ state is not saved or restored properly (in particular USB). @node pcsys_network @section Network emulation -QEMU can simulate several network cards (PCI or ISA cards on the PC -target) and can connect them to an arbitrary number of Virtual Local -Area Networks (VLANs). Host TAP devices can be connected to any QEMU -VLAN. VLAN can be connected between separate instances of QEMU to -simulate large networks. For simpler usage, a non privileged user mode -network stack can replace the TAP device to have a basic network -connection. - -@subsection VLANs - -QEMU simulates several VLANs. A VLAN can be symbolised as a virtual -connection between several network devices. These devices can be for -example QEMU virtual Ethernet cards or virtual Host ethernet devices -(TAP devices). +QEMU can simulate several network cards (e.g. PCI or ISA cards on the PC +target) and can connect them to a network backend on the host or an emulated +hub. The various host network backends can either be used to connect the NIC of +the guest to a real network (e.g. by using a TAP devices or the non-privileged +user mode network stack), or to other guest instances running in another QEMU +process (e.g. by using the socket host network backend). @subsection Using TAP network interfaces @@ -764,7 +756,7 @@ network). The virtual network configuration is the following: @example - QEMU VLAN <------> Firewall/DHCP server <-----> Internet + guest (10.0.2.15) <------> Firewall/DHCP server <-----> Internet | (10.0.2.2) | ----> DNS server (10.0.2.3) @@ -799,11 +791,23 @@ When using the @option{'-netdev user,hostfwd=...'} option, TCP or UDP connections can be redirected from the host to the guest. It allows for example to redirect X11, telnet or SSH connections. -@subsection Connecting VLANs between QEMU instances +@subsection Hubs + +QEMU can simulate several hubs. A hub can be thought of as a virtual connection +between several network devices. These devices can be for example QEMU virtual +ethernet cards or virtual Host ethernet devices (TAP devices). You can connect +guest NICs or host network backends to such a hub using the @option{-netdev +hubport} or @option{-nic hubport} options. The legacy @option{-net} option +also connects the given device to the emulated hub with ID 0 (i.e. the default +hub) unless you specify a netdev with @option{-net nic,netdev=xxx} here. -Using the @option{-net socket} option, it is possible to make VLANs -that span several QEMU instances. See @ref{sec_invocation} to have a -basic example. +@subsection Connecting emulated networks between QEMU instances + +Using the @option{-netdev socket} (or @option{-nic socket} or +@option{-net socket}) option, it is possible to create emulated +networks that span several QEMU instances. +See the description of the @option{-netdev socket} option in the +@ref{sec_invocation,,Invocation chapter} to have a basic example. @node pcsys_other_devs @section Other Devices @@ -2846,15 +2850,6 @@ with ``-device ...,netdev=x''), or ``-nic user,smb=/some/dir'' (for embedded NICs). The new syntax allows different settings to be provided per NIC. -@subsection -net vlan (since 2.9.0) - -The ``-net vlan=NN'' argument was mostly used to attach separate -network backends to different virtual NICs. This is the default -behavior for ``-netdev'' and ``-nic''. You can connect multiple -``-netdev'' and ``-nic'' devices to the same network using the -"hubport" network backend, created with ``-netdev hubport,hubid=NN,...'' -and ``-nic hubport,hubid=NN''. - @subsection -drive cyls=...,heads=...,secs=...,trans=... (since 2.10.0) The drive geometry arguments are replaced by the the geometry arguments |