ISIS + Segment Routing

Owned by Jean-luc KRIKER
Last updated: Dec 17, 2023
4 min read


ISIS + SR ConfigurationLink
router isis
router isis
R2#show running-config router isis
!
router isis 1
 metric-style wide
 mpls traffic-eng level-1
 mpls traffic-eng level-2
 dynamic-hostname
 net 49.0000.0000.0001.00
 segment-routing mpls
!
interface lo
interface lo 
R2#show running-config interface lo
!
interface lo
 ip address 127.0.0.1/8
 ip address 10.1.1.1/32 secondary
 ipv6 address ::1/128
 prefix-sid index 100
 ip router isis 1
!
interface eth1
interface eth1 
R2#show running-config interface eth1
!
interface eth1
 ip address 10.1.1.100/31
 label-switching
 ip router isis 1
!


Show commands
capability

show isis segment-routing capability

show isis SR 
R2#show isis segment-routing capability

Tag 1  Segment-Routing:
-----------------------------------------------------
Advertisement Router Capability   :10.1.1.100
Algorithm0                        :0
SRMS Preference                   :0
SR ERLD                           :0
Total SID'S Supported             :8000
SID Range List Count              :1
SID's Range                       :16000 - 23999
Total SID'S Supported (SRLB)      :0
SRLB Range List Count             :0
-----------------------------------------------------
Advertisement Router Capability   :10.1.1.101
Algorithm0                        :0
SRMS Preference                   :0
SR ERLD                           :0
Total SID'S Supported             :8000
SID Range List Count              :1
SID's Range                       :16000 - 23999
Total SID'S Supported (SRLB)      :0
SRLB Range List Count             :0
-----------------------------------------------------
state
state 
R2#show isis segment-routing
capability     mapping-table  state
R2#show isis segment-routing state

Tag 1  Segment-Routing:
SR State:  SR_ENABLED
SRGB Start: 16000,  SRGB Range: 8000
Operational state:  enabled
mapping-table
SR 
R2#show isis segment-routing mapping-table ipv4
active    inactive
R2#show isis segment-routing mapping-table ipv4 active
Tag 1  Segment-Routing:
Conflict Resolution Policy: Quarantine

Prefix              SID Index      Range       Flags
10.1.1.1/32         100            1
10.1.1.2/32         200            1

Number of mapping entries in Active IPv4 Table: 2

show mpls forwarding-table

show mpls forwarding-table detail

mapping 
R2#show mpls forwarding-table
Codes: > - installed FTN, * - selected FTN, p - stale FTN, ! - using backup
       B - BGP FTN, K - CLI FTN, (t) - tunnel, P - SR Policy FTN, (b) - bypass,
       L - LDP FTN, R - RSVP-TE FTN, S - SNMP FTN, I - IGP-Shortcut,
       U - unknown FTN, O - SR-OSPF FTN, i - SR-ISIS FTN, k - SR-CLI FTN

Code    FEC                 FTN-ID    Nhlfe-ID  Tunnel-id   Pri   LSP-Type     Out-Label    Out-Intf    ELC   Nexthop
   i>   10.1.1.2/32         1         2         0           Yes   LSP_DEFAULT  3            eth1        No    10.1.1.101


R2#show mpls forwarding-table detail
FEC prefix: 10.1.1.2/32, FTN-ID: 1
  Owner: ISIS-SR, FTN type: Regular, State: Installed
  Tunnel-Name: N/A, Tunnel-id: N/A, Color: N/A
  LSP-ID: N/A, LSP-type: Primary
  NHLFE-id: 2
  Out-Label: 3, Out-Intf: eth1, Nexthop: 10.1.1.101
  Exp-bits: 0x0, Incoming DSCP: none, QoS Resource id: 0
  ELC: No