Unit 1: Network Infrastructure
This will allow you to demonstrate your networking skills, knowledge, and abilities, with a focus on enterprise-level switching, routing, and multicast components that support cross-platform (inter)operability and integration with the most recent software-defined technologies.
Network devices advertise their identification and capabilities to neighbors on a local area network (LAN) segment using the vendor-independent link layer protocol known as Link Layer Discovery Protocol (LLDP).
Format for LLDP Frames
The devices in LLDP send data in the form of an Ethernet frame from each of their ports at set intervals. One LLDP Data Unit (LLDPDU) is in each frame. There are a number of type-length-value (TLV) objects in each LLDPDU.
- The field for EtherType is set to 0x88cc.
- Every single LLDP frame begins with the mandatory TLVs that are listed below, and these TLVs must remain intact in LLDP implementations.
Chassis ID
Port ID, and
Time-to-Live (TTL)
- After any number of possible TLVs, there are TLVs that must be sent.
- The frame ends with a unique TLV called end of LLDPDU. Its type field is 0 and its length field is also 0.
- Different groups can design and encode their own TLVs using the LLDP specification. These are called Organizationally Specific TLVs. The LLDP TLV Type value for all Organizationally Specific TLVs starts at 127.
|
TLV type – Types |
||
|
TLV type Value |
TLV name |
Usage in LLDPDU |
|
0 |
End Of LLDPDU |
Mandatory |
|
1 |
Chassis ID |
Mandatory |
|
2 |
Port ID |
Mandatory |
|
3 |
Time To Live |
Mandatory |
|
4 |
Port Description |
Optional |
|
5 |
System Name |
Optional |
|
6 |
System Description |
Optional |
|
7 |
System Capabilities |
Optional |
|
8 |
Management Address |
Optional |
|
9-126 |
Reserved |
Undefined |
|
127 |
Organizationally Specific TLVs |
Optional |
Types of LLDPDU 
