CNV-21839: MTU configuration

Author: Shikha Jhala

modules/virt-jumbo-frames-vm-pod-nw.adoc

@@ -0,0 +1,20 @@
+// Module included in the following assemblies:
+//
+// * virt/virtual_machines/vm_networking/virt-using-the-default-pod-network-with-virt.adoc              
+
+:_content-type: CONCEPT                                            
+[id="virt-jumbo-frames-vm-pod-nw_{context}"]                                   
+= About jumbo frames support          
+
+When using the OVN-Kubernetes CNI plugin, you can send unfragmented jumbo frame packets between two virtual machines (VMs) that are connected on the default pod network. Jumbo frames have a maximum transmission unit (MTU) value greater than 1500 bytes.
+
+The VM automatically gets the MTU value of the cluster network, set by the cluster administrator, in one of the following ways:
+
+* `libvirt`: If the guest OS has the latest version of the VirtIO driver that can interpret incoming data via a Peripheral Component Interconnect (PCI) config register in the emulated device. 
+
+* DHCP: If the guest DHCP client can read the MTU value from the DHCP server response.
+
+[NOTE]
+====
+For Windows VMs that do not have a VirtIO driver, you must set the MTU manually by using `netsh` or a similar tool. This is because the Windows DHCP client does not read the MTU value.
+====

virt/virtual_machines/vm_networking/virt-using-the-default-pod-network-with-virt.adoc

@@ -6,8 +6,15 @@ include::_attributes/common-attributes.adoc[]
 
 toc::[]
 
-You can connect a virtual machine to the default internal pod network by configuring its network interface to use the `masquerade` binding mode
+You can connect a virtual machine to the default internal pod network by configuring its network interface to use the `masquerade` binding mode.
 
 include::modules/virt-configuring-masquerade-mode-cli.adoc[leveloffset=+1]
 
 include::modules/virt-configuring-masquerade-mode-dual-stack.adoc[leveloffset=+1]
+
+include::modules/virt-jumbo-frames-vm-pod-nw.adoc[leveloffset=+1]
+
+[role="_additional-resources"]
+.Additional resources
+* xref:../../../networking/changing-cluster-network-mtu.adoc#changing-cluster-network-mtu[Changing the MTU for the cluster network]
+* xref:../../../scalability_and_performance/optimizing-networking.adoc#optimizing-mtu_optimizing-networking[Optimizing the MTU for your network]