JUNOS Enterprise Switching

Case Studies

We will now examine a few quick case studies with a very simple topology, depicted in Figure 10-7. Several phones are connected off Cisco switch Schnapps, and due to port capacity issues, new phones are connected off Ethanol. The current call manager (Cisco Express Call Manager) is connected off Rum. The goal is to make a phone call from the IP phone at Ethanol to a phone located at Schnapps. It also should be noted that many of the IP phones will have a PC connected to it at a later time. We will look at two different scenarios off Ethanol. In the first scenario, LLDP-MED is not supported on the phone, and in the second it is supported.

Figure 10-7. IP telephony topology

Without LLDP-MED Support

First, let’s examine the current network and the VLANs that are being used. VLAN 100 is defined as the voice VLAN, in which all traffic for call setup and voice bearer traffic is placed. VLAN 200 is used for all other non-voice-related traffic, and is called the data VLAN. Rum is connected to the call manager for the IP telephony network. This is implemented on a Cisco 2811 router running IOS 12.4(15)T4 using Call Manager Express 4.2. The call manager acts as the controller for the IP telephony network, controlling the phone configuration, call routing, and call setup. In this network, it is also acting as a Dynamic Host Configuration Protocol (DHCP) server to avoid any static IP ...