Tip

This is the documentation for the 25.06 version. Looking for the documentation of the latest version? Have a look here.

IS-IS Status

TNSR supports several commands to display information about the IS-IS daemon configuration and its status.

See also

For more general dynamic routing status information, see Dynamic Routing Manager Status

The general form of the command to view IS-IS state information is show route dynamic isis <options>. Output includes all VRFs by default, but may be restricted to a single VRF by using show route dynamic isis vrf <vrf-name> <options> instead. The list of options is the same in both cases.

Configuration Information

To view the IS-IS configuration:

tnsr(config)# show route dynamic isis config
frr version 10.3+tnsr-v25.06
frr defaults traditional
hostname hq.example.com
log file /var/log/frr/dynamic.log critical
log syslog warnings
service integrated-vtysh-config
!
interface CCLINK
 ip router isis exco
 isis hello-interval level-1 1
 isis hello-interval level-2 3
exit
!
interface LAN
 ip router isis exco
 isis passive
exit
!
router isis exco
 is-type level-1
 net 49.0001.0100.0200.0001.00
exit
!
end

Status Information

Neighbors and Adjacencies

To view information about current IS-IS neighbors and adjacencies:

tnsr# show route dynamic isis neighbor
Area exco:
 System Id           Interface   L  State         Holdtime SNPA
 ro.example.com      CCLINK      1  Up            10       90ec.7747.5e5d

Add the detail keyword to the command to display more detailed, verbose information for all neighbors.

tnsr# show route dynamic isis neighbor detail
Area exco:
 ro.example.com
    Interface: CCLINK, Level: 1, State: Up, Expires in 9s
    Adjacency flaps: 1, Last: 18m16s ago
    Circuit type: L1, Speaks: IPv4
    SNPA: 90ec.7747.5e5d, LAN id: ro.example.com.0d
    LAN Priority: 64, is DIS, DIS flaps: 1, Last: 18m13s ago
    Area Address(es):
      49.0001
    IPv4 Address(es):
      10.127.0.2

Use show route dynamic isis neighbor <name> to show more detailed, verbose information for one specific neighbor.

Routes

To view information about current IS-IS routes:

tnsr# show route dynamic isis route
Area exco:
IS-IS paths to level-1 routers that speak IP
 Vertex             Type          Metric  Next-Hop          Interface  Parent
 --------------------------------------------------------------------------------------------
 hq.example.com
 10.2.0.0/24        IP internal   0                                    hq.example.com(4)
 10.127.0.0/30      IP internal   0                                    hq.example.com(4)
 ro.example.com     TE-IS         10      ro.example.com    CCLINK     hq.example.com(4)
 ro.example.com     pseudo_TE-IS  20      ro.example.com    CCLINK     ro.example.com(4)
 10.127.0.0/30      IP TE         20      ro.example.com    CCLINK     ro.example.com(4)
 10.30.0.0/24       IP TE         20      ro.example.com    CCLINK     ro.example.com(4)

IS-IS L1 IPv4 routing table:

 Prefix         Metric  Interface  Nexthop     Label(s)
 --------------------------------------------------------
 10.2.0.0/24    0       -          -           -
 10.30.0.0/24   20      CCLINK       10.127.0.2  -
 10.127.0.0/30  20      CCLINK       10.127.0.2  -

The output can be changed by using the following modifiers:

backup:

Show backup routes.

level-1:

Show IS-IS paths to level-1 routers.

level-2:

Show IS-IS paths to level-2 routers.

prefix-sid:

Show prefix-SID information

Interfaces

To view information about interfaces participating in IS-IS:

tnsr(config)# show route dynamic isis interface
Area exco:
  Interface   CircId   State    Type     Level
  LAN            0x0      Up     lan        L1
  CCLINK        0x12      Up     lan        L1

Add the detail keyword to the command to display more detailed, verbose information for all interfaces.

tnsr# show route dynamic isis interface detail
Area exco:
  Interface: LAN, State: Up, Passive, Circuit Id: 0x0
    Type: lan, Level: L1, SNPA: 0000.0000.0000
    Level-1 Information:
      Metric: 10
    IP Prefix(es):
      10.2.0.1/24
    IPv6 Link-Locals:
      fe80::290:bff:fe7a:8a65/64
    IPv6 Prefixes:
      2001:db8:f0::1/64

  Interface: CCLINK, State: Up, Active, Circuit Id: 0x12
    Type: lan, Level: L1, SNPA: 0090.0b7a.8a6a
    Level-1 Information:
      Metric: 10, Active neighbors: 1
      Hello interval: 1, Holddown count: 10, Padding: yes
      CNSP interval: 10, PSNP interval: 2
      LAN Priority: 64, is not DIS
    IP Prefix(es):
      10.127.0.1/30
    IPv6 Link-Locals:
      fe80::290:bff:fe7a:8a6a/64

Use show route dynamic isis interface <name> to show more detailed, verbose information for one specific interface.

Summary

To view a summary of the IS-IS daemon status:

tnsr# show route dynamic isis summary
vrf             : default
Process Id      : 2420
System Id       : 0100.0200.0001
Up time         : 00:34:12 ago
Number of areas : 1
Area exco:
  Net: 49.0001.0100.0200.0001.00
  TX counters per PDU type:
     L1 IIH: 2151
     L1 LSP: 4
   LSP RXMT: 0
  RX counters per PDU type:
     L1 IIH: 2147
     L1 LSP: 6
    L1 CSNP: 226
  Drop counters per PDU type:
  Advertise high metrics: Disabled
  Level-1:
    LSP0 regenerated: 6
         LSPs purged: 0
    SPF:
      minimum interval  : 1
    IPv4 route computation:
      last run elapsed  : 00:04:45 ago
      last run duration : 72 usec
      run count         : 11

Hostname to System ID Mappings

To view a list of mappings the IS-IS daemon has made between system IDs and hostnames:

tnsr# show route dynamic isis hostname
vrf     : default
Level  System ID      Dynamic Hostname
1      0100.3000.0001 ro.example.com
     * 0100.0200.0001 hq.example.com

Fast Re-route

To view information about current IS-IS fast re-route data:

tnsr# show route dynamic isis fast-reroute
Area exco:
 IS-IS L1 IPv4 Fast ReRoute summary:

 Protection \ Priority     Critical  High      Medium    Low       Total
 -------------------------------------------------------------------------
 Classic LFA               0         0         0         0         0
 Remote LFA                0         0         0         0         0
 Topology Independent LFA  0         0         0         0         0
 ECMP                      0         0         0         0         0
 Unprotected               0         0         0         2         2
 Protection coverage       0.00%     0.00%     0.00%     0.00%     0.00%

Add the level-1 or level-2 modifier to restrict the output to only L1 or L2 routers.

SPF Backoff Delay

To view IS-IS SPF backoff delay (RFC 8405) information:

tnsr# show route dynamic isis spf-backoff-delay
vrf    : default
Area exco:
  Level-1:
    SPF delay status: Not scheduled
    Using legacy backoff algo