You configure a metric of 200 on an IS-IS enabled interface on Router-1. When you examine the routing table entry for that link on another IS-IS device, you see a metric of 67.
What would explain this behavior?
A.
Router-1 is sending both standard and wide metrics.
B.
Router-1 is sending only wide metrics.
C.
Router-1 has a metric multiplier set.
D.
Router-1 has a configured reference bandwidth.
Explanation:
The default behavior of the JUNOS software is the advertisement of IP routes using both the small metric TLVs (128 and 130) as well as the wide metric TLVs (135). The presence of TLVs 128 and 130 in the received LSP causes the router to ignore the settings located in the extended IP reachability TLV (135).external metric A cost included in a route when OSPF exports route information from external Autonomous Systems. There are two types of external metrics: Type 1 and Type 2. Type 1 external metrics are equivalent to the link-state metric; that is, the cost of the route, used in the internal Autonomous System. Type 2 external metrics are greater than the cost of any path internal to the Autonomous System.
Be able to identify the uses of the various IS-IS PDUs. IS-IS routers use Hello PDUs to form and maintain adjacencies with other routers in the network. Link-state PDUs contain information that populates the database. Each router generates an LSP for each operational level and floods that LSP into the network. Sequence number PDUs are used to request database information from a neighbor and to maintain the integrity of the database.
Be able to list the TLVs used by an IS-IS router. An individual IS-IS uses several TLVs to describe portions of the network. Each PDU contains a separate, and somewhat different, set of TLVs. Some TLVs describe the local configuration of the router, while others advertise adjacencies.Still others include IP routing information advertised to the network by the local router.
Be able to describe the difference between an IS-IS area and an IS-IS level. An IS-IS area only controls the adjacency formation process. A Level 1 router only forms an adjacency with another router in the same area, whereas a Level 2 router forms an adjacency with a router in any area. An IS-IS level controls the flooding of LSPs. Level 2 LSPs are flooded across a contiguous set of Level 2 areas; a Level 1 LSP is normally flooded within its own Level 1 area.
Know the authentication options available for use in the JUNOS software. The JUNOS software supports both plain-text (simple) and MD5 authentication within the confines of the IS-IS protocol. The configuration of authentication at the level hierarchy causes the authentication TLV to be placed into all PDUs generated by the router. The local router can also secure just the Hello PDUs transmitted on a specific interface to control which neighbors it forms an adjacency with.
Be able to describe the operation of a multilevel IS-IS network. Internal Level 1 routes are flooded throughout the area providing each router with knowledge of the Level 1 topology. These routes are advertised by an L1/L2 router into the Level 2 backbone, which provides the entire level with knowledge of all routes in the network. Routers in the Level 1 area reach unknown destinations through a locally installed default route pointing to the metrically closest attached Level 2 router.
These Level 2 routers set the Attached bit in their Level 1 LSPs when they form a Level 2 adjacency across an area boundary.Be able to configure address summarization within IS-IS. To effectively summarize addresses in IS-IS, you use a combination of locally configured aggregate routes and routing policies. Each aggregate route represents the addresses you wish to summarize. You then create and apply routing policies that locate the aggregate routes and advertise