Which two pieces of information are communicated by IS-IS TLVs?

In IS-IS (Intermediate System to Intermediate System), Type-Length-Value (TLV) structures are essential for conveying various types of information during the routing process. The correct choice regarding the pieces of information communicated by IS-IS TLVs is indeed related to the supported network protocols.

IS-IS TLVs allow routers to advertise various capabilities and attributes. One of the critical functions of TLVs is to indicate the network protocols that the routers are capable of supporting. This capability is vital for enabling interoperability between devices that may be using different protocols within the same network.

Using TLVs, routers exchange information about their interfaces and the protocols they can handle, ensuring that all participating devices can communicate effectively, regardless of the specific network-layer technologies they employ.

In contrast, designated router priority, authentication key, and PDU length do not directly fall under the primary functions communicated by TLVs in IS-IS. While designated router priority can influence the routing process, it is not part of the TLV communication. Similarly, while authentication keys might be relevant for security, they are not traditionally expressed as TLVs in the IS-IS protocol. PDU length pertains to the overall size of the protocol data units being exchanged, but this detail does not typically encompass