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IS-IS BasicS

IS-IS | intermediate systems

  • The IS-IS protocol is an interior gateway protocol (IGP) that uses link-state information to make routing decisions.
  • ISIS Configuration Steps:
    Step 1 – Enabling ISIS on the Router
    Step 2 – IP Address Configuration
    Step 3 – Enabling ISIS on the Router
    Step 4 – Creating Loopback IPs and ISIS NET addresses
    Step 5 – Router Roles (L1/L2 or both)
    Step 6 – Assigning Interfaces under ISIS
    Step 7 – Verifying ISIS on the Juniper Routers

Juniper vMX 14 & EVE-NG Pro is used for this lab.

 Devices Configuration: 

[email protected]> show configuration |display set 
set version 14.1R4.8
set system host-name R1
set system root-authentication encrypted-password "$1$qHZ8BpyI$pPV9o7nXi2d3WdEr9wXZv1"
set system syslog user * any emergency
set system syslog file messages any notice
set system syslog file messages authorization info
set system syslog file interactive-commands interactive-commands any
set interfaces ge-0/0/0 unit 0 family inet address 12.12.12.1/24
set interfaces ge-0/0/0 unit 0 family iso
set interfaces lo0 unit 1 family inet address 1.1.1.1/24
set interfaces lo0 unit 1 family inet address 11.11.11.11/24
set interfaces lo0 unit 1 family iso address 49.0001.0010.0100.1001.00
set protocols isis level 1 disable
set protocols isis interface ge-0/0/0.0
set protocols isis interface lo0.1
[email protected]> show configuration |display set 
set version 14.1R4.8
set system host-name R2
set system root-authentication encrypted-password "$1$uf4lHupy$EIWlSuzoWbVYJ.r/Wy8JQ/"
set system syslog user * any emergency
set system syslog file messages any notice
set system syslog file messages authorization info
set system syslog file interactive-commands interactive-commands any
set interfaces ge-0/0/0 unit 0 family inet address 12.12.12.2/24
set interfaces ge-0/0/0 unit 0 family iso
set interfaces lo0 unit 2 family inet address 2.2.2.2/24
set interfaces lo0 unit 2 family inet address 22.22.22.22/24
set interfaces lo0 unit 2 family iso address 49.0001.0020.0200.2002.00
set protocols isis level 1 disable
set protocols isis interface ge-0/0/0.0
set protocols isis interface lo0.2
— Configuration | Verification —

— ISIS Neighbor:

R1>
set interfaces ge-0/0/0 unit 0 family iso
set interfaces lo0 unit 1 family inet address 1.1.1.1/24
set interfaces lo0 unit 1 family inet address 11.11.11.11/24
set interfaces lo0 unit 1 family iso address 49.0001.0010.0100.1001.00
set protocols isis interface ge-0/0/0.0
set protocols isis interface lo0.1
R2>
set interfaces ge-0/0/0 unit 0 family iso
set interfaces lo0 unit 2 family inet address 2.2.2.2/24
set interfaces lo0 unit 2 family inet address 22.22.22.22/24
set interfaces lo0 unit 2 family iso address 49.0001.0020.0200.2002.00
set protocols isis interface ge-0/0/0.0
set protocols isis interface lo0.2
[email protected]> show isis interface brief 
IS-IS interface database:
Interface             L CirID Level 1 DR        Level 2 DR        L1/L2 Metric
ge-0/0/0.0            3   0x1 R2.02             R2.02                  10/10
lo0.1                 3   0x1 Passive           Passive                 0/0

[email protected]> show isis interface detail 
IS-IS interface database:
ge-0/0/0.0
  Index: 330, State: 0x6, Circuit id: 0x1, Circuit type: 3
  LSP interval: 100 ms, CSNP interval: 10 s
  Adjacency advertisement: Advertise
  Level Adjacencies Priority Metric Hello (s) Hold (s) Designated Router
    1             1       64     10     9.000       27 R2.02 (not us)
    2             1       64     10     9.000       27 R2.02 (not us)
lo0.1
  Index: 326, State: 0x6, Circuit id: 0x1, Circuit type: 0
  LSP interval: 100 ms, CSNP interval: disabled
  Adjacency advertisement: Advertise
  Level Adjacencies Priority Metric Hello (s) Hold (s) Designated Router
    1             0       64      0 Passive
    2             0       64      0 Passive

[email protected]> show isis adjacency brief 
Interface             System         L State        Hold (secs) SNPA
ge-0/0/0.0            R2             1  Up                    8  0:5:86:71:af:0
ge-0/0/0.0            R2             2  Up                    6  0:5:86:71:af:0

[email protected]> show isis adjacency extensive 
R2
  Interface: ge-0/0/0.0, Level: 1, State: Up, Expires in 7 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 01:44:40 ago
  Circuit type: 3, Speaks: IP, IPv6, MAC address: 0:5:86:71:af:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.2
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        

R2
  Interface: ge-0/0/0.0, Level: 2, State: Up, Expires in 7 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 01:44:40 ago
  Circuit type: 3, Speaks: IP, IPv6, MAC address: 0:5:86:71:af:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.2
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        

------

[email protected]> show isis interface brief 
IS-IS interface database:
Interface             L CirID Level 1 DR        Level 2 DR        L1/L2 Metric
ge-0/0/0.0            3   0x2 R2.02             R2.02                  10/10
lo0.2                 3   0x1 Passive           Passive                 0/0

[email protected]> show isis interface detail 
IS-IS interface database:
ge-0/0/0.0
  Index: 330, State: 0x6, Circuit id: 0x2, Circuit type: 3
  LSP interval: 100 ms, CSNP interval: 10 s
  Adjacency advertisement: Advertise
  Level Adjacencies Priority Metric Hello (s) Hold (s) Designated Router
    1             1       64     10     3.000        9 R2.02 (us)
    2             1       64     10     3.000        9 R2.02 (us)
lo0.2
  Index: 326, State: 0x6, Circuit id: 0x1, Circuit type: 0
  LSP interval: 100 ms, CSNP interval: disabled
  Adjacency advertisement: Advertise
  Level Adjacencies Priority Metric Hello (s) Hold (s) Designated Router
    1             0       64      0 Passive
    2             0       64      0 Passive

[email protected]> show isis adjacency brief 
Interface             System         L State        Hold (secs) SNPA
ge-0/0/0.0            R1             1  Up                   20  0:5:86:71:4c:0
ge-0/0/0.0            R1             2  Up                   24  0:5:86:71:4c:0

[email protected]> show isis adjacency extensive 
R1
  Interface: ge-0/0/0.0, Level: 1, State: Up, Expires in 25 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 01:44:40 ago
  Circuit type: 3, Speaks: IP, IPv6, MAC address: 0:5:86:71:4c:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.1
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        

R1
  Interface: ge-0/0/0.0, Level: 2, State: Up, Expires in 19 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 01:44:40 ago
  Circuit type: 3, Speaks: IP, IPv6, MAC address: 0:5:86:71:4c:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.1
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        
  
  
  

— Routing & Overview : 

[email protected]> show route protocol isis 

inet.0: 10 destinations, 10 routes (10 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

2.2.2.0/24         *[IS-IS/15] 02:35:29, metric 10
                    > to 12.12.12.2 via ge-0/0/0.0
2.2.2.2/32         *[IS-IS/15] 02:35:29, metric 10
                    > to 12.12.12.2 via ge-0/0/0.0
22.22.22.0/24      *[IS-IS/15] 02:35:29, metric 10
                    > to 12.12.12.2 via ge-0/0/0.0
22.22.22.22/32     *[IS-IS/15] 02:35:29, metric 10
                    > to 12.12.12.2 via ge-0/0/0.0

iso.0: 1 destinations, 1 routes (1 active, 0 holddown, 0 hidden)

[email protected]> show isis overview 
Instance: master
  Router ID: 1.1.1.1
  Adjacency holddown: enabled
  Maximum Areas: 3
  LSP life time: 1200
  Attached bit evaluation: enabled
  SPF delay: 200 msec, SPF holddown: 5000 msec, SPF rapid runs: 3
  IPv4 is enabled, IPv6 is enabled
  Traffic engineering: enabled
  Restart: Disabled
    Helper mode: Enabled
  Level 1
    Internal route preference: 15
    External route preference: 160
    Wide metrics are enabled, Narrow metrics are enabled
  Level 2
    Internal route preference: 18
    External route preference: 165
    Wide metrics are enabled, Narrow metrics are enabled

— Disable IS-IS levels:

Let's Disable IS-IS level 1: (same process to disable level 2)

— Level 1 Routes — *[IS-IS/15]
— Level 2 Routes — *[IS-IS/18]

[edit protocols isis] + level 1 disable;

- Checked from R1/R2:  
[email protected]> show isis adjacency 
Interface             System         L State        Hold (secs) SNPA
ge-0/0/0.0            R2             2  Up                    8  0:5:86:71:af:0

[email protected]> show isis adjacency extensive 
R2
  Interface: ge-0/0/0.0, Level: 2, State: Up, Expires in 7 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 03:52:38 ago
  Circuit type: 2, Speaks: IP, IPv6, MAC address: 0:5:86:71:af:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.2
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        


[email protected]> show isis adjacency              
Interface             System         L State        Hold (secs) SNPA
ge-0/0/0.0            R1             2  Up                   23  0:5:86:71:4c:0

[email protected]> show isis adjacency extensive    
R1
  Interface: ge-0/0/0.0, Level: 2, State: Up, Expires in 20 secs
  Priority: 64, Up/Down transitions: 1, Last transition: 03:52:25 ago
  Circuit type: 2, Speaks: IP, IPv6, MAC address: 0:5:86:71:4c:0
  Topologies: Unicast
  Restart capable: Yes, Adjacency advertisement: Advertise
  LAN id: R2.02, IP addresses: 12.12.12.1
  Transition log:
  When                  State        Event           Down reason
  Wed May 13 16:17:31   Up           Seenself        

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