Which of the following descriptions about configuring the set-overload command in IS-IS is correct?

Question

Options

• AThis command is used to enable IS-IS to automatically calculate the interface cost according to the bandwidth
• BThis command is used to set the overload flag bit of non-pseudo-node TLV
• CThis command allows the device to set 0x1 in the IS-IS system, to maintain the overload flag according to the state of BGP convergence
• DThis command is used to specify that the Hello message sent after the device restarts carries the SA bit

• A
  13% (4)
• B
  77% (24)
• C
  6% (2)
• D
  3% (1)

Explanation

Option B is correct because the set-overload command directly sets the overload (OL) flag bit within IS-IS non-pseudonode LSPs (Link State PDUs). Non-pseudonode LSPs are originated by routers themselves, as opposed to pseudonode LSPs generated by a Designated Intermediate System on broadcast networks. When this bit is set, other routers in the IS-IS domain treat the advertising router as a transit-path of last resort, routing traffic to it only if no alternative exists.

Option A is wrong because automatic interface cost calculation based on bandwidth is controlled by a bandwidth-reference or auto-cost command, not set-overload. Option C is partially misleading: while IS-IS implementations do offer a variant (set-overload on-startup wait-for-bgp) that ties overload behavior to BGP convergence, the description of set-overload itself as a command specifically designed to track BGP state is inaccurate and incomplete. Option D is wrong because the SA (Suppress Advertisement) bit in Hello PDUs relates to graceful restart mechanisms, not to the overload flag.

Memory tip: Anchor the command to LSPs, not Hellos -- set-overload stamps a bit on the router's own LSP (non-pseudonode) to signal overload to the rest of the topology, which rules out D immediately and keeps your focus on B.

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