Background: Know: LLDP messages Recognize:

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Figure 1: LLDP example

The principle of LLDP is that devices periodically announce themselves, the parameters of this announcement/advertisement could be found in previous slide LLDP messages. An example of LLDP is shown in this slide.

The example (Figure 1) shown in this slide is a screenshot of a LLDP packet in Wireshark, which is a well-known tool for the packet analyzer, it could capture the packets RMON packet capture & filtering and ananlyse them. The LLDP packet could be found in Tim's packet zoo.

This slide shoud be referred with the LLDP messages' parameters in previous slide LLDP messages.

Notes on this example:

: The destination of this packet is "LLDP_Multicast", which is the multicast address of "01:80:c2:00:00:0e", that is memtioned by the previous slide LLDP messages .

From this screenshot, it contains almost every parameter of previous slide, such as,

  • Chassis ID = 00:01:30:f9:ad:a0 (which is a Chassis Subtype of MAC address)
  • Port ID = 1/1 (which is a Port Subtype of Interface name)
  • TTL = 120 sec
  • Four 802.1 VLAN info, includes Port VLAN ID, Port and Protocol VLAN ID, VLAN Name and Protocol Identity
  • Four 802.3 info, includes Power Via MDI, MAC/PHY Configuration/Status, Link Aggregation and Maximum Frame Size
  • An End of LLDPDU to indicate the finish point of this unit.

The detail information about every parameter could be displayed by click the "+" in Wireshark.

**Note that the example here is the packet of "From an Extreme Networks Summit 300 switch" in Link-layer discovery protocols section of Tim's packet zoo. Numbers of more other LLDP example packets could be found in Tim's packet zoo.