All the IP phones belong to this VLAN, regardless of the department.

This includes making a single physical resource (such as a server, an operating system, an application, storage device, or network) appear to function as multiple logical resources; or it can include making multiple physical resources (such as storage devices or servers) appear as a single logical resource.

Fundamentally, virtual networks all provide a mechanism to deploy what looks and operates like multiple networks, and are actually all using the same hardware and physical connectivity.

Routers use IP addresses to direct the data to the correct destination.

When an IP packet is received the destination address is looked up in a route table to determine the next hop to send the packet to.

Normally all packets within a physical router use the same route table or global table.

They may still be using a shared Layer 2 or Layer 1 infrastructure, however at Layer 3 they are not connected and do not form a network.

The global table contains all IP interfaces that are not part of a specific virtual network and route tables are for each unique virtual network assigned to an IP interface.

Packets arriving on FastEthernet 00 are only forwarded to other interfaces in virtual network 10 and do not use FastEthernet 01, because it is not in its virtual network: virtual network 10 has no routing knowledge of other virtual networks.

For a FastEthernet physical port, the use of multiple virtual LANs (VLANs) allows each VLAN to use a different virtual network.

VLAN is the existing virtualization technique that is used to separate voice networks from data networks.

As a result, it creates a potential security threat since the voice VLAN is now visible from the data network.

A customer talking to an agent on a voice network has no access to the data world of that agent.

However, with IP communications, since both are on the same network, security is a significant concern.

VRF technology can be used with the rules and policies so that each VRF network achieves the expected level of security.

The system allow only the softphone application to talk to the hard-phone in a voice VRF, or allow different soft phones within data VRF resources to talk to each other, however, do not allow other applications to communicate with each other.

In this deployment, we see both PSTN and WAN connectivity, allowing for interbranch communication through the WAN link.

In a real life deployment, we may not see that all the phones and PCs directly connected to Ethernet ports of the Cisco Unified CME router.

There may be a lot of Ethernet switches in between the Cisco Unified CME and IP devices.

Usually, all the IP phones are part of the voice VLAN and all other IP devices are in the regular data VLAN.

IP phones are not accessible from the data network, although they may share the same physical layers.

To accommodate multiple departments, multiple VLANs are created for security purposes.

Change Between Vrf Routing