Useful information I have gathered regarding setting up Citrix XenServer 6.0 networking:
1. Bond two NICs dedicated for Management Traffic. Since there will be an IP address assigned to the NICs, the bond can only operate on an active/passive basis. This management bond will also be used for pool communication and live migrations.
2. Bond two NICs for VM traffic, this L2 bond should be set to active/active for maximum bandwidth usage.
3. Bond two NICs for iSCSI storage traffic. Since this will be an L3 IP interface, the bond will active/passive. If you need additional bandwidth, implement multi-pathing or high bandwidth NICs (10G)
4. Bond two NICs for Provisioning services (assuming you are running a XenDesktop environment) This is a great article (http://blogs.citrix.com/2011/02/22/xenserver-for-xendesktop-how-many-network-cards-do-i-need/) which states that “PVS typically streams 166MB of data across the network during the boot process of a single Windows 7 x86 desktop”.
On your physical switch network, make sure you enable portfast on the interfaces connecting to your XenServer hosts, and disable port security and BPDU Guard. You can enable trunking on the ports you need, but I would make the management interfaces access ports.
All information was taken from this very useful guide (http://support.citrix.com/servlet/KbServlet/download/28782-102-666382/XS-60-design-network_advanced.pdf) and the aforementioned XenDesktop guide.