IS-IS help (no default route)

loloski · August 29, 2023, 3:09pm

I try to setup a simple IS-IS topology like PE1 → P2 → P3 → PE2 with P2 and P3 as level 1-2 router and PE1 and PE2 as level-1 router

vyos@PE1# run show configuration commands
set interfaces ethernet eth0 hw-id '0c:c3:aa:33:00:00'
set interfaces ethernet eth1 address '10.10.10.1/30'
set interfaces ethernet eth1 hw-id '0c:c3:aa:33:00:01'
set interfaces ethernet eth2 hw-id '0c:c3:aa:33:00:02'
set interfaces loopback lo
set protocols isis interface eth1
set protocols isis level 'level-1'
set protocols isis net '11.1111.1111.1111.1111.00'
set system config-management commit-revisions '100'
set system conntrack modules ftp
set system conntrack modules h323
set system conntrack modules nfs
set system conntrack modules pptp
set system conntrack modules sip
set system conntrack modules sqlnet
set system conntrack modules tftp
set system console device ttyS0 speed '115200'
set system host-name 'PE1'

vyos@P2# run show configuration commands
set interfaces ethernet eth0 address '192.168.100.1/30'
set interfaces ethernet eth0 hw-id '0c:31:29:ec:00:00'
set interfaces ethernet eth1 address '10.10.10.2/30'
set interfaces ethernet eth1 hw-id '0c:31:29:ec:00:01'
set interfaces ethernet eth2 hw-id '0c:31:29:ec:00:02'
set interfaces loopback lo
set protocols isis interface eth0
set protocols isis interface eth1
set protocols isis level 'level-1-2'
set protocols isis net '11.1111.2222.2222.2222.00'
set system config-management commit-revisions '100'
set system conntrack modules ftp
set system conntrack modules h323
set system conntrack modules nfs
set system conntrack modules pptp
set system conntrack modules sip
set system conntrack modules sqlnet
set system conntrack modules tftp
set system console device ttyS0 speed '115200'
set system host-name 'P2'


vyos@P3# run show configuration commands
set interfaces ethernet eth0 address '192.168.100.2/30'
set interfaces ethernet eth0 hw-id '0c:10:cd:41:00:00'
set interfaces ethernet eth1 address '10.10.20.1/30'
set interfaces ethernet eth1 hw-id '0c:10:cd:41:00:01'
set interfaces ethernet eth2 hw-id '0c:10:cd:41:00:02'
set interfaces loopback lo
set protocols isis interface eth0
set protocols isis interface eth1
set protocols isis level 'level-1-2'
set protocols isis net '22.2222.3333.3333.3333.00'
set system config-management commit-revisions '100'
set system conntrack modules ftp
set system conntrack modules h323
set system conntrack modules nfs
set system conntrack modules pptp
set system conntrack modules sip
set system conntrack modules sqlnet
set system conntrack modules tftp
set system console device ttyS0 speed '115200'
set system host-name 'P3'

vyos@PE2# run show configuration commands
set interfaces ethernet eth0 hw-id '0c:20:c3:65:00:00'
set interfaces ethernet eth1 address '10.10.20.2/30'
set interfaces ethernet eth1 hw-id '0c:20:c3:65:00:01'
set interfaces ethernet eth2 hw-id '0c:20:c3:65:00:02'
set interfaces loopback lo
set protocols isis interface eth1
set protocols isis level 'level-1'
set protocols isis net '22.2222.4444.4444.4444.00'
set system config-management commit-revisions '100'
set system conntrack modules ftp
set system conntrack modules h323
set system conntrack modules nfs
set system conntrack modules pptp
set system conntrack modules sip
set system conntrack modules sqlnet
set system conntrack modules tftp
set system console device ttyS0 speed '115200'
set system host-name 'PE2'

vyos@PE2# run show isis topology
Area VyOS:
IS-IS paths to level-1 routers that speak IP
Vertex               Type         Metric Next-Hop             Interface Parent
PE2
10.10.20.0/30        IP internal  0                                     PE2(4)
P3                   TE-IS        10     P3                   eth1      PE2(4)
PE2
192.168.100.0/30     IP TE        20     P3                   eth1      P3(4)
10.10.20.0/30        IP TE        20     P3                   eth1      P3(4)

IS-IS paths to level-1 routers that speak IPv6
Vertex               Type         Metric Next-Hop             Interface Parent
PE2
P3                   TE-IS        10     P3                   eth1      PE2(4)
PE2

[edit]
vyos@PE2#

vyos@PE2# run show isis route
Area VyOS:
IS-IS L1 IPv4 routing table:

 Prefix            Metric  Interface  Nexthop     Label(s)
 -----------------------------------------------------------
 10.10.20.0/30     20      eth1       10.10.20.1  -
 192.168.100.0/30  20      eth1       10.10.20.1  -

IS-IS L1 IPv6 routing table:

vyos@PE2# run show ip route
Codes: K - kernel route, C - connected, S - static, R - RIP,
       O - OSPF, I - IS-IS, B - BGP, E - EIGRP, N - NHRP,
       T - Table, v - VNC, V - VNC-Direct, A - Babel, D - SHARP,
       F - PBR, f - OpenFabric,
       > - selected route, * - FIB route, q - queued, r - rejected, b - backup

I   10.10.20.0/30 [115/20] via 10.10.20.1, eth1 inactive, weight 1, 00:45:09
C>* 10.10.20.0/30 is directly connected, eth1, 01:52:27
I>* 192.168.100.0/30 [115/20] via 10.10.20.1, eth1, weight 1, 00:45:09
[edit]
vyos@PE2#

vyos@PE2# run show version

Version:          VyOS 1.3.2
Release train:    equuleus

Built by:         vyos-build-action@github.com
Built on:         Sat 10 Sep 2022 15:49 UTC
Build UUID:       8b5b1d8c-41bf-4b62-ab5c-19777e686f47
Build commit ID:  7ce86511888635

Architecture:     x86_64
Boot via:         installed image
System type:      KVM guest

Hardware vendor:  QEMU
Hardware model:   Standard PC (i440FX + PIIX, 1996)
Hardware S/N:
Hardware UUID:    9120c365-358c-4b0e-9d30-afda90885387

Copyright:        VyOS maintainers and contributors
[edit]
vyos@PE2#

I’m expecting that on PE2 there’s is a default route but routing table clearly says there’s no entry, could anyone help or shed some light on this please

JoeN · August 30, 2023, 4:15pm

Hi @loloski,

Based on the provided information, this could be due to a configuration oversight or a specific routing behavior within your setup.

You can try a few steps to help troubleshoot the issue:

Check to see if all the IS-IS configurations are correct on all devices and ensure that the devices can reach each other.
Run the command ‘show isis neighbor’ to make sure the adjacencies are established between the devices.
Make sure the IS-IS configuration on P2 and P3 are correctly configured as level-1 and level-2 routers.
Check to make sure the NET address are correct.

loloski · August 31, 2023, 12:01pm

Hi @Joen,

Thanks for a reply yes P1 and P2 is level-1-2 router while PE1 and PE2 is level-1 router only, I have IP reachability in all routers involved in the setup and adjacencies is formed between (PE1,P2),(P2,P3),(P3,PE2) from P2 I can reach P3 and PE2 and from P3 I can reach P2 and PE1 but from PE1 and PE2 they can’t reach each other because there’s no default route on both PE1 and PE2 respectively. But if i Manually set default route on both routers PE1 and PE2 both of this router can reach each other

I’m pretty sure i covered the basics, because the same lab settings is working fine for me in cisco labs, thank you so much for your time and effort

vyos@PE1:~$ show isis neighbor
Area VyOS:
  System Id           Interface   L  State        Holdtime SNPA
  P2                  eth1        1  Up            27       0c31.29ec.0001
vyos@PE1:~$

vyos@P2:~$ show isis neighbor
Area VyOS:
  System Id           Interface   L  State        Holdtime SNPA
  P3                  eth0        2  Up            30       0c10.cd41.0000
  PE1                 eth1        1  Up            30       0cc3.aa33.0001
vyos@P2:~$
vyos@P3:~$ show isis neighbor
Area VyOS:
  System Id           Interface   L  State        Holdtime SNPA
  P2                  eth0        2  Up            29       0c31.29ec.0000
  PE2                 eth1        1  Up            28       0c20.c365.0001
vyos@P3:~$

vyos@PE2:~$ show isis neighbor
Area VyOS:
  System Id           Interface   L  State        Holdtime SNPA
  P3                  eth1        1  Up            29       0c10.cd41.0001
vyos@PE2:~$


vyos@PE1:~$ show isis neighbor detail
Area VyOS:
  P2
    Interface: eth1, Level: 1, State: Up, Expires in 29s
    Adjacency flaps: 1, Last: 5m5s ago
    Circuit type: L1L2, Speaks: IPv4, IPv6
    SNPA: 0c31.29ec.0001, LAN id: 1111.1111.1111.03
    LAN Priority: 64, is not DIS, DIS flaps: 1, Last: 5m ago
    Area Address(es):
      11.1111
    IPv4 Address(es):
      10.10.10.2
    IPv6 Address(es):
      fe80::e31:29ff:feec:1

vyos@PE1:~$

vyos@P2:~$ show isis neighbor detail
Area VyOS:
  P3
    Interface: eth0, Level: 2, State: Up, Expires in 30s
    Adjacency flaps: 1, Last: 6m31s ago
    Circuit type: L1L2, Speaks: IPv4, IPv6
    SNPA: 0c10.cd41.0000, LAN id: 2222.2222.2222.02
    LAN Priority: 64, is not DIS, DIS flaps: 1, Last: 6m25s ago
    Area Address(es):
      22.2222
    IPv4 Address(es):
      192.168.100.2
    IPv6 Address(es):
      fe80::e10:cdff:fe41:0

  PE1
    Interface: eth1, Level: 1, State: Up, Expires in 27s
    Adjacency flaps: 1, Last: 6m32s ago
    Circuit type: L1, Speaks: IPv4, IPv6
    SNPA: 0cc3.aa33.0001, LAN id: PE1.03
    LAN Priority: 64, is DIS, DIS flaps: 1, Last: 6m26s ago
    Area Address(es):
      11.1111
    IPv4 Address(es):
      10.10.10.1
    IPv6 Address(es):
      fe80::ec3:aaff:fe33:1

vyos@P3:~$ show isis neighbor detail
Area VyOS:
  P2
    Interface: eth0, Level: 2, State: Up, Expires in 29s
    Adjacency flaps: 1, Last: 7m52s ago
    Circuit type: L1L2, Speaks: IPv4, IPv6
    SNPA: 0c31.29ec.0000, LAN id: P2.02
    LAN Priority: 64, is DIS, DIS flaps: 1, Last: 7m47s ago
    Area Address(es):
      11.1111
    IPv4 Address(es):
      192.168.100.1
    IPv6 Address(es):
      fe80::e31:29ff:feec:0

  PE2
    Interface: eth1, Level: 1, State: Up, Expires in 27s
    Adjacency flaps: 1, Last: 7m52s ago
    Circuit type: L1, Speaks: IPv4, IPv6
    SNPA: 0c20.c365.0001, LAN id: PE2.03
    LAN Priority: 64, is DIS, DIS flaps: 1, Last: 7m47s ago
    Area Address(es):
      22.2222
    IPv4 Address(es):
      10.10.20.2
    IPv6 Address(es):
      fe80::e20:c3ff:fe65:1

vyos@PE2:~$ show isis neighbor detail
Area VyOS:
  P3
    Interface: eth1, Level: 1, State: Up, Expires in 28s
    Adjacency flaps: 1, Last: 8m16s ago
    Circuit type: L1L2, Speaks: IPv4, IPv6
    SNPA: 0c10.cd41.0001, LAN id: 4444.4444.4444.03
    LAN Priority: 64, is not DIS, DIS flaps: 1, Last: 8m10s ago
    Area Address(es):
      22.2222
    IPv4 Address(es):
      10.10.20.1
    IPv6 Address(es):
      fe80::e10:cdff:fe41:1

vyos@PE2:~$

loloski · September 1, 2023, 8:24pm

I’ll lab the same config and setup using vyos-1.4 rolling release and it work as expected this is 1.3.2 issue

fernando · September 4, 2023, 11:35am

try to use this command : set protocols isis set-attached-bit in l1l2 .

although , part of this scenery can be affected with this problem :

loloski · September 8, 2023, 12:03pm

I did try that but it doesn’t work on 1.3.2