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---
lastproofread: '2023-04-10'
---
(examples-segment-routing-isis)=
# Segment-routing IS-IS example
When utilizing VyOS in an environment with Cisco IOS-XR gear you can use this
blue print as an initial setup to get MPLS ISIS-SR working between those two
devices.The lab was build using {abbr}`EVE-NG (Emulated Virtual
Environment NG)`.
:::{figure} /_static/images/vyos-sr-isis.webp
:alt: ISIS-SR network
ISIS-SR example network
:::
The below configuration is used as example where we keep focus on
VyOS-P1/VyOS-P2/XRv-P3 which we share the settings.
## Configuration
- VyOS-P1:
```none
set interfaces dummy dum0 address '192.0.2.1/32'
set interfaces ethernet eth1 address '192.0.2.5/30'
set interfaces ethernet eth1 mtu '8000'
set interfaces ethernet eth3 address '192.0.2.21/30'
set interfaces ethernet eth3 mtu '8000'
set protocols isis interface dum0 passive
set protocols isis interface eth1 network point-to-point
set protocols isis interface eth3 network point-to-point
set protocols isis level 'level-2'
set protocols isis log-adjacency-changes
set protocols isis metric-style 'wide'
set protocols isis net '49.0000.0000.0000.0001.00'
set protocols isis segment-routing maximum-label-depth '8'
set protocols isis segment-routing prefix 192.0.2.1/32 index value '1'
set protocols mpls interface 'eth1'
set protocols mpls interface 'eth3'
set system host-name 'P1-VyOS'
```
- XRv-P3:
```none
hostname P3-VyOS
interface Loopback0
ipv4 address 192.0.2.3 255.255.255.255
!
interface GigabitEthernet0/0/0/1
mtu 8014
ipv4 address 192.0.2.6 255.255.255.252
!
interface GigabitEthernet0/0/0/2
mtu 8014
ipv4 address 192.0.2.18 255.255.255.252
!
router isis VyOS
is-type level-2-only
net 49.0000.0000.0000.0003.00
log adjacency changes
address-family ipv4 unicast
metric-style wide
segment-routing mpls
!
interface Loopback0
passive
address-family ipv4 unicast
prefix-sid index 3
!
!
interface GigabitEthernet0/0/0/1
point-to-point
address-family ipv4 unicast
!
!
interface GigabitEthernet0/0/0/2
point-to-point
address-family ipv4 unicast
!
!
!
```
- VyOS-P2:
```none
set interfaces dummy dum0 address '192.0.2.2/32'
set interfaces ethernet eth2 address '192.0.2.17/30'
set interfaces ethernet eth2 mtu '8000'
set interfaces ethernet eth3 address '192.0.2.26/30'
set interfaces ethernet eth3 mtu '8000'
set protocols isis interface dum0 passive
set protocols isis interface eth2 network point-to-point
set protocols isis interface eth3 network point-to-point
set protocols isis level 'level-2'
set protocols isis log-adjacency-changes
set protocols isis metric-style 'wide'
set protocols isis net '49.0000.0000.0000.0002.00'
set protocols isis segment-routing maximum-label-depth '8'
set protocols isis segment-routing prefix 192.0.2.2/32 index value '2'
set protocols mpls interface 'eth2'
set protocols mpls interface 'eth3'
set system host-name 'P2-VyOS'
```
This gives us MPLS segment routing enabled and labels forwarding :
```none
vyos@P1-VyOS:~$ show mpls table
Inbound Label Type Nexthop Outbound Label
-----------------------------------------------------------------
15000 SR (IS-IS) 192.0.2.6 implicit-null
15001 SR (IS-IS) 192.0.2.22 implicit-null
15002 SR (IS-IS) fe80::5200:ff:fe04:3 implicit-null
16002 SR (IS-IS) 192.0.2.6 16002
16003 SR (IS-IS) 192.0.2.6 implicit-null
16011 SR (IS-IS) 192.0.2.22 implicit-null
vyos@P2-VyOS:~$ show mpls table
Inbound Label Type Nexthop Outbound Label
-------------------------------------------------------
15000 SR (IS-IS) 192.0.2.18 implicit-null
16001 SR (IS-IS) 192.0.2.18 16001
16003 SR (IS-IS) 192.0.2.18 implicit-null
16011 SR (IS-IS) 192.0.2.18 16011
RP/0/0/CPU0:P3-VyOS#show mpls forwarding
Tue Mar 28 17:47:18.928 UTC
Local Outgoing Prefix Outgoing Next Hop Bytes
Label Label or ID Interface Switched
------ ----------- ------------------ ------------ --------------- ------------
16001 Pop SR Pfx (idx 1) Gi0/0/0/1 192.0.2.5 0
16002 Pop SR Pfx (idx 2) Gi0/0/0/2 192.0.2.17 0
16011 16011 SR Pfx (idx 11) Gi0/0/0/1 192.0.2.5 0
24000 Pop SR Adj (idx 1) Gi0/0/0/1 192.0.2.5 0
24001 Pop SR Adj (idx 3) Gi0/0/0/1 192.0.2.5 0
24002 Pop SR Adj (idx 1) Gi0/0/0/2 192.0.2.17 0
24003 Pop SR Adj (idx 3) Gi0/0/0/2 192.0.2.17 0
```
VyOS is able to check MSD per devices:
```none
vyos@P1-VyOS:~$ show isis segment-routing node
Area VyOS:
IS-IS L1 SR-Nodes:
IS-IS L2 SR-Nodes:
System ID SRGB SRLB Algorithm MSD
---------------------------------------------------------------
0000.0000.0001 16000 - 23999 15000 - 15999 SPF 8
0000.0000.0002 16000 - 23999 15000 - 15999 SPF 8
0000.0000.0003 16000 - 23999 0 - 4294967295 SPF 10
0000.0000.0011 16000 - 23999 15000 - 15999 SPF 8
vyos@P2-VyOS:~$ show isis segment-routing node
Area VyOS:
IS-IS L1 SR-Nodes:
IS-IS L2 SR-Nodes:
System ID SRGB SRLB Algorithm MSD
---------------------------------------------------------------
0000.0000.0001 16000 - 23999 15000 - 15999 SPF 8
0000.0000.0002 16000 - 23999 15000 - 15999 SPF 8
0000.0000.0003 16000 - 23999 0 - 4294967295 SPF 10
0000.0000.0011 16000 - 23999 15000 - 15999 SPF 8
```
Here is the routing tables showing the MPLS segment routing label operations:
```none
vyos@P1-VyOS:~$ show ip route isis
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, F - PBR,
f - OpenFabric,
> - selected route, * - FIB route, q - queued, r - rejected, b - backup
t - trapped, o - offload failure
I>* 192.0.2.2/32 [115/30] via 192.0.2.6, eth1, label 16002, weight 1, 1d03h18m
I>* 192.0.2.3/32 [115/10] via 192.0.2.6, eth1, label implicit-null, weight 1, 1d03h18m
I 192.0.2.4/30 [115/20] via 192.0.2.6, eth1 inactive, weight 1, 1d03h18m
I>* 192.0.2.11/32 [115/20] via 192.0.2.22, eth3, label implicit-null, weight 1, 1d02h47m
I>* 192.0.2.16/30 [115/20] via 192.0.2.6, eth1, weight 1, 1d03h18m
I 192.0.2.20/30 [115/20] via 192.0.2.22, eth3 inactive, weight 1, 1d02h48m
I>* 192.0.2.24/30 [115/30] via 192.0.2.6, eth1, weight 1, 1d03h18m
vyos@P2-VyOS:~$ show ip route isis
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, F - PBR,
f - OpenFabric,
> - selected route, * - FIB route, q - queued, r - rejected, b - backup
t - trapped, o - offload failure
I>* 192.0.2.1/32 [115/30] via 192.0.2.18, eth2, label 16001, weight 1, 1d03h17m
I>* 192.0.2.3/32 [115/10] via 192.0.2.18, eth2, label implicit-null, weight 1, 1d03h17m
I>* 192.0.2.4/30 [115/20] via 192.0.2.18, eth2, weight 1, 1d03h17m
I>* 192.0.2.11/32 [115/40] via 192.0.2.18, eth2, label 16011, weight 1, 1d02h47m
I 192.0.2.16/30 [115/20] via 192.0.2.18, eth2 inactive, weight 1, 1d03h17m
I>* 192.0.2.20/30 [115/30] via 192.0.2.18, eth2, weight 1, 1d03h17m
RP/0/0/CPU0:P3-VyOS#show route isis
Tue Mar 28 18:19:16.417 UTC
i L2 192.0.2.1/32 [115/20] via 192.0.2.5, 1d03h, GigabitEthernet0/0/0/1
i L2 192.0.2.2/32 [115/20] via 192.0.2.17, 1d03h, GigabitEthernet0/0/0/2
i L2 192.0.2.11/32 [115/30] via 192.0.2.5, 1d02h, GigabitEthernet0/0/0/1
i L2 192.0.2.20/30 [115/20] via 192.0.2.5, 1d03h, GigabitEthernet0/0/0/1
i L2 192.0.2.24/30 [115/20] via 192.0.2.17, 1d03h, GigabitEthernet0/0/0/2
```
Information about prefix-sid and label-operation from VyOS
```none
vyos@P1-VyOS:~$ show isis route prefix-sid
Area VyOS:
IS-IS L2 IPv4 routing table:
Prefix Metric Interface Nexthop SID Label Op.
----------------------------------------------------------------------
192.0.2.1/32 0 - - - -
192.0.2.2/32 30 eth1 192.0.2.6 2 Swap(16002, 16002)
192.0.2.3/32 10 eth1 192.0.2.6 3 Pop(16003)
192.0.2.4/30 20 eth1 192.0.2.6 - -
192.0.2.16/30 20 eth1 192.0.2.6 - -
192.0.2.20/30 0 - - - -
192.0.2.24/30 30 eth1 192.0.2.6 - -
vyos@P2-VyOS:~$ show isis route prefix-sid
Area VyOS:
IS-IS L2 IPv4 routing table:
Prefix Metric Interface Nexthop SID Label Op.
-----------------------------------------------------------------------
192.0.2.1/32 30 eth2 192.0.2.18 1 Swap(16001, 16001)
192.0.2.2/32 0 - - - -
192.0.2.3/32 10 eth2 192.0.2.18 3 Pop(16003)
192.0.2.4/30 20 eth2 192.0.2.18 - -
192.0.2.16/30 20 eth2 192.0.2.18 - -
192.0.2.20/30 30 eth2 192.0.2.18 - -
192.0.2.24/30 0 - - - -
```
Ping between VyOS-P1 / VyOS-P2 to confirm reachability:
```none
vyos@P1-VyOS:~$ ping 192.0.2.2 source-address 192.0.2.1
PING 192.0.2.2 (192.0.2.2) from 192.0.2.1 : 56(84) bytes of data.
64 bytes from 192.0.2.2: icmp_seq=1 ttl=63 time=3.47 ms
64 bytes from 192.0.2.2: icmp_seq=2 ttl=63 time=2.06 ms
64 bytes from 192.0.2.2: icmp_seq=3 ttl=63 time=3.90 ms
64 bytes from 192.0.2.2: icmp_seq=4 ttl=63 time=3.87 ms
^C
--- 192.0.2.2 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3004ms
rtt min/avg/max/mdev = 2.064/3.326/3.903/0.748 ms
vyos@P2-VyOS:~$ ping 192.0.2.1 source-address 192.0.2.2
PING 192.0.2.1 (192.0.2.1) from 192.0.2.2 : 56(84) bytes of data.
64 bytes from 192.0.2.1: icmp_seq=1 ttl=63 time=2.91 ms
64 bytes from 192.0.2.1: icmp_seq=2 ttl=63 time=3.23 ms
64 bytes from 192.0.2.1: icmp_seq=3 ttl=63 time=2.91 ms
64 bytes from 192.0.2.1: icmp_seq=4 ttl=63 time=2.85 ms
^C
--- 192.0.2.1 ping statistics ---
4 packets transmitted, 4 received, 0% packet loss, time 3005ms
rtt min/avg/max/mdev = 2.846/2.972/3.231/0.151 ms
```
|
