Citrix Systems 4.2 Managing Networks and Traffic

Chapter 16.
147
Managing Networks and Traffic
In a CloudPlatform, guest VMs can communicate with each other using shared infrastructure with the
security and user perception that the guests have a private LAN. The CloudPlatform virtual router is
the main component providing networking features for guest traffic.
16.1. Guest Traffic
A network can carry guest traffic only between VMs within one zone. Virtual machines in different
zones cannot communicate with each other using their IP addresses; they must communicate with
each other by routing through a public IP address.
See a typical guest traffic setup given below:
Typically, the Management Server automatically creates a virtual router for each network. A virtual
router is a special virtual machine that runs on the hosts. Each virtual router in an isolated network has
three network interfaces. If multiple public VLAN is used, the router will have multiple public interfaces.
Its eth0 interface serves as the gateway for the guest traffic and has the IP address of 10.1.1.1. Its
eth1 interface is used by the system to configure the virtual router. Its eth2 interface is assigned a
public IP address for public traffic. If multiple public VLAN is used, the router will have multiple public
interfaces.
The virtual router provides DHCP and will automatically assign an IP address for each guest VM within
the IP range assigned for the network. The user can manually reconfigure guest VMs to assume
different IP addresses.
Source NAT is automatically configured in the virtual router to forward outbound traffic for all guest
VMs
16.2. Networking in a Pod
The figure below illustrates network setup within a single pod. The hosts are connected to a pod-level
switch. At a minimum, the hosts should have one physical uplink to each switch. Bonded NICs are
supported as well. The pod-level switch is a pair of redundant gigabit switches with 10 G uplinks.