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Which two pieces of information are communicated by IS-IS TLVs? (Choose two.)

Which two pieces of information are communicated by IS-IS TLVs? (Choose two.)

PrepAway - Latest Free Exam Questions & Answers

A.
network protocols supported

B.
designated router priority

C.
authentication key

D.
PDU Length

Explanation:
Factors for Scaling IS-IS Areas
One reason you might want to consider setting the adjacency types on an L1/L2 router by interface rather than on the entire router is that if the entire router is set to accept both, it will originate both L1 and L2 Hellos on all interfaces. Its L1-only neighbors will reject the L2 Hellos, and its L2-only neighbors will reject the L1 Hellos, ensuring that the right adjacency types are established. But the L1/L2 router is originating twice as many Hellos on its links than it needs to, unnecessarily using up some portion of the link bandwidth. And as stated in Section 7.3.2, network control traffic should normally consume less than 1 percent of a link’s bandwidth and should never exceed 5 percent.

As you learned from Chapter 4, IS-IS messages have a standard 8-byte header. To that, LAN Hellos add 19 bytes of header and Point-to-Point Hellos add 12 bytes of header. The remainder of the Hellos is TLVs, which can be one or more of the following types:[9]

[9] Hellos can actually carry more TLV types than the ones listed here; they are discussed in later chapters in the context of the extensions the TLVs support.

* Area Addresses TLV (type 1)
* Intermediate System Neighbors TLV (type 6)
* Protocols Supported TLV (type 129)
* IP Interface Address TLV (type 132)
* Authentication Information TLV (type 10)
* Padding TLV (type 8)

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