A problem now exists when LLDP is used with a 2-port phone, because this protocol has not yet been standardized for this scenario.
Piggy port map Pc#
One of the challenges in this area is that LLDP-MED does not adequately specify how the PC port on the phone fits into the overall LLDP-MED architecture. The phone uses the protocol to support these applications. An endpoint connected to a Cisco phone-A PC connected to a Cisco phone can support Cisco Discovery Protocol that is, some applications that can run on a PC (example Cisco VT Advantage) do support this protocol.
That is, LLDP-MED defines how a switch port transitions from LLDP to LLDP-MED if it detects an LLDP-MED-capable endpoint.įigure 1 depicts scenarios of how these protocols can be used and where (if any) challenges lie, as follows:ġ. It should be noted that either LLDP or LLDP-MED-but not both-can be used at any given time on an interface between two devices. Was enhanced to specifically address the voice application this extension to LLDP is called LLDP-MED or LLDP for Media Endpoint Devices. LLDP, which defines basic discovery capabilities, Cisco has been working with other leaders in the Internet and IEEE community to develop a new, standardized discovery protocol, 802.1AB (Station and Media Access Control Connectivity Discovery, or Link Layer Discovery Protocol ). Therefore, to allow inter-working between vendor equipment, it has become necessary to have a single, standardized discovery protocol. Applications (such as voice) have become dependent on these capabilities to operate properly, leading to interoperability problems between vendors. Over time, enhancements have been made to discovery protocols to provide greater capabilities. Because automatic device discovery is so helpful for network administration, many vendors in the data networking industry have subsequently implemented their own discovery protocols to manage their devices. With this capability in the network, Cisco customers can introduce a new network management application that can discover and display an accurate topology of all the Cisco devices active on the network. Because Cisco Discovery Protocol runs over Ethernet, ATM, and Frame Relay links, it is independent of network protocol (for example, TCP/IP, Internetwork Packet Exchange, AppleTalk, etc.). Using Cisco Discovery Protocol, network devices periodically advertise their own information to a multicast address on the network, making it available to any device or application that wishes to listen and collect it. Cisco Discovery Protocol runs on Cisco devices (routers, switches, phones, etc.) and is also licensed to run on some network devices from other vendors. Cisco Systems ® introduced the Cisco ® Discovery Protocol in 1994 to provide a mechanism for the management system to automatically learn about devices connected to the network.
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