Interface

Interface through which the neighbor is reachable.

All levels

L or Level

Level:

• 1—Level 1 only
• 2—Level 2 only
• 3—Level 1 and Level 2

An exclamation point (!) preceding the level number indicates that the adjacency is missing an IP address.

All levels

Hold (secs)

Remaining hold time of the adjacency.

brief

Expires in

How long until the adjacency expires, in seconds.

detail

Up/Down transitions

Count of adjacency status changes from Up to Down or from Down to Up.

detail

Circuit type

Bit mask of levels on this interface: 1=Level 1 router; 2=Level 2 router; 3=both Level 1 and Level 2 router.

detail

MAC address

MAC address of the interface.

detail extensive

Restart capable

Whether a neighbor is capable of graceful restart: Yes or No.

detail extensive

Adjacency advertisement: Suppress

This neighbor has signaled not to advertise the interface in the routing device's outbound link-state PDUs.

detail extensive

Transition log

List of recent transitions, including:

• When—Time at which an IS-IS adjacency transition occurred.
• State—Current state of the IS-IS adjacency (up, down, or rejected).
  • Up—Adjacency is up and operational.
  • Down—Adjacency is down and not available.
  • Rejected—Adjacency has been rejected.
• Event—Type of transition that occurred.
  • Seenself—Possible routing loop has been detected.
  • Interface down—IS-IS interface has gone down and is no longer available.
  • Error—Adjacency error.
• Down reason—Reason that an IS-IS adjacency is down:
  • 3-Way Handshake Failed—Connection establishment failed.
  • Address Mismatch—Address mismatch caused link failure.
  • Aged Out—Link expired.
  • ISO Area Mismatch—IS-IS area mismatch caused link failure.
  • Bad Hello—Unacceptable hello message caused link failure.
  • BFD Session Down—Bidirectional failure detection caused link failure.
  • Interface Disabled—IS-IS interface is disabled.
  • Interface Down—IS-IS interface is unavailable.
  • Interface Level Disabled—IS-IS level is disabled.
  • Level Changed—IS-IS level has changed on the adjacency.
  • Level Mismatch—Levels on adjacency are not compatible.
  • MPLS LSP Down—Label-switched path (LSP) is unavailable.
  • MT Topology Changed—IS-IS topology has changed.
  • MT Topology Mismatch—IS-IS topology is mismatched.
  • Remote System ID Changed—Adjacency peer system ID changed.
  • Protocol Shutdown—IS-IS protocol is disabled.
  • CLI Command—Adjacency brought down by user.
  • Unknown—Unknown.

extensive