http://support.citrix.com/servlet/KbServlet/download/17424-102-671540/Xen_Networking_in_Linux_final.pdf

brctl show

arp -a

ifconfig xenbr0

http://discussions.citrix.com/topic/246981-how-to-pass-a-trunked-interface-to-a-vm/

http://support.citrix.com/article/CTX123489

• VLANs allow a single physical network to support multiple logical networks.
• To use VLANs with XenServer, the host's NIC must be connected to a VLAN trunk port (switch or router).
• Creating a VLAN in XenServer is done through the process of creating additional virtual interfaces that correspond to a specific VLAN tag. This is done through the XenCenter Host Network tab by adding an External network name and assigning an NIC with a VLAN number.
• XenServer VLANs are represented by additional PIF objects representing VLAN interfaces corresponding to a specified VLAN tag.
• XenServer networks can then be connected to the PIF representing the physical NIC to see all traffic on the NIC, or to a PIF representing a VLAN to see only the traffic with the specified VLAN tag.
• When using VLANs the XenServer host handles all interpretation of the VLAN tags and strips the VLAN tags before routing packets to VMs.
• If the XenServer host has one or more VLAN networks configured on an interface or bond, it will perform the VLAN tag/untag operations for all packets that enter/leave that interface/bond.
• However, if no VLAN networks/bridges/whatever-the-term-may-be are configured on the interface/bond, then XenServer leaves 802.1q VLAN tags alone and passes the packets straight to the VM.
• If there are any VLAN interfaces configured on top of the base interface (either a simple physical interface or a non-tagged bond), XenServer strips off the tags, as it is responsible for both tagging and untagging of packets on that base interface.
• XenServer will leave 802.1q VLAN tags alone if there are no VLAN networks configured on top of your base interface, be that a single physical interface or a logical interface such as a bond.

http://support.citrix.com/article/CTX137599

http://support.citrix.com/servlet/KbServlet/download/34969-102-704897/reference.pdf

Whenever possible, create NIC bonds as part of initial resource pool creation prior to joining additional hosts to the pool or creating VMs. Doing so allows the bond configuration to be automatically replicated to hosts as they are joined to the pool and reduces the number of steps required. Adding a NIC bond to an existing pool requires one of the following:

• Using the CLI to configure the bonds on the master and then each member of the pool.
• Using the CLI to configure the bonds on the master and then restarting each member of the pool so that it inherits its settings from the pool master.
• Using XenCenter to configure the bonds on the master. XenCenter automatically synchronizes the networking settings on the member servers with the master, so you do not need to reboot the member servers.