OutLabel: 4294967295 OutLabel flag: N
Total nets: 6
Intra area: 6 Inter area: 0 ASE: 0 NSSA: 0
# Display MPLS LSP information on Router A.
[RouterA] display mpls lsp
FEC Proto In/Out Label Out Inter/NHLFE/LSINDEX
10.0.0.2 Local -/- GE0/0/1
1.1.1.1/32 OSPF 16010/- -
2.2.2.2/32 OSPF 16020/3 GE0/0/1
2.2.2.2/32 OSPF -/3 GE0/0/1
3.3.3.3/32 OSPF 16030/16030 GE0/0/1
3.3.3.3/32 OSPF -/16030 GE0/0/1
4.4.4.4/32 OSPF 16040/16040 GE0/0/1
4.4.4.4/32 OSPF -/16040 GE0/0/1
Example: Configuring an SR-based MPLS TE tunnel over an explicit path
Network configuration
As shown in Figure 21 , Router A, Router B, Router C, and Router D are running IS-IS.
Configure dynamic SID allocation on loopback interfaces of the routers. Then, create an explicit path from Router A to Router D and configure the MPLS TE tunnel interface to use SR to establish an
MPLS TE tunnel over the explicit path.
Figure 21 Network diagram
Loop1 Loop1 Loop1 Loop1
GE0/0/1 GE0/0/2
GE0/0/1 GE0/0/1
Router A Router B
Table 4 Interface and IP address assignment
Router C
GE0/0/2
GE0/0/1
Router D
GE0/0/2
Device
Router A
Router C
Prerequisites
Interface IP address
Loop1
GE0/0/1
Loop1
1.1.1.1/32
10.0.0.1/24
3.3.3.3/32
GE0/0/1
GE0/0/2
11.0.0.2/24
12.0.0.1/24
Device
Router B
Router D
Interface IP address
Loop1
GE0/0/1
GE0/0/2
Loop1
2.2.2.2/32
10.0.0.2/24
11.0.0.1/24
4.4.4.4/32
GE0/0/1
GE0/0/2
12.0.0.2/24
100.1.2.1/24
Configure IP addresses and masks for interfaces.
Procedure
1. Configure IS-IS on the routers to achieve network level connectivity and set the IS-IS cost style to wide:
59
# Configure Router A.
<RouterA> system-view
[RouterA] isis 1
[RouterA-isis-1] network-entity 00.0000.0000.0001.00
[RouterA-isis-1] cost-style wide
[RouterA-isis-1] is-level level-1
[RouterA-isis-1] mpls te enable
[RouterA-isis-1] quit
[RouterA] interface gigabitethernet 0/0/1
[RouterA-GigabitEthernet0/0/1] isis enable 1
[RouterA-GigabitEthernet0/0/1] quit
[RouterA] interface loopback 1
[RouterA-LoopBack1] isis enable 1
[RouterA-LoopBack1] quit
# Configure Router B.
<RouterB> system-view
[RouterB] isis 1
[RouterB-isis-1] network-entity 00.0000.0000.0002.00
[RouterB-isis-1] cost-style wide
[RouterB-isis-1] is-level level-1
[RouterB-isis-1] mpls te enable
[RouterB-isis-1] quit
[RouterB] interface gigabitethernet 0/0/1
[RouterB-GigabitEthernet0/0/1] isis enable 1
[RouterB-GigabitEthernet0/0/1] quit
[RouterB] interface gigabitethernet 0/0/2
[RouterB-GigabitEthernet0/0/2] isis enable 1
[RouterB-GigabitEthernet0/0/2] quit
[RouterB] interface loopback 1
[RouterB-LoopBack1] isis enable 1
[RouterB-LoopBack1] quit
# Configure Router C.
<RouterC> system-view
[RouterC] isis 1
[RouterC-isis-1] network-entity 00.0000.0000.0003.00
[RouterC-isis-1] cost-style wide
[RouterC-isis-1] is-level level-1
[RouterC-isis-1] mpls te enable
[RouterC-isis-1] quit
[RouterC] interface gigabitethernet 0/0/1
[RouterC-GigabitEthernet0/0/1] isis enable 1
[RouterC-GigabitEthernet0/0/1] quit
[RouterC] interface gigabitethernet 0/0/2
[RouterC-GigabitEthernet0/0/2] isis enable 1
[RouterC-GigabitEthernet0/0/2] quit
[RouterC] interface loopback 1
[RouterC-LoopBack1] isis enable 1
[RouterC-LoopBack1] quit
60
# Configure Router D.
<RouterD> system-view
[RouterD] isis 1
[RouterD-isis-1] network-entity 00.0000.0000.0004.00
[RouterD-isis-1] cost-style wide
[RouterD-isis-1] is-level level-1
[RouterD-isis-1] mpls te enable
[RouterD-isis-1] quit
[RouterD] interface gigabitethernet 0/0/1
[RouterD-GigabitEthernet0/0/1] isis enable 1
[RouterD-GigabitEthernet0/0/1] quit
[RouterD] interface gigabitethernet 0/0/2
[RouterD-GigabitEthernet0/0/2] isis enable 1
[RouterD-GigabitEthernet0/0/2] quit
[RouterD] interface loopback 1
[RouterD-LoopBack1] isis enable 1
[RouterD-LoopBack1] quit
2. Configure LSR IDs, and enable MPLS and MPLS TE:
# Configure Router A.
[RouterA] mpls lsr-id 1.1.1.1
[RouterA] mpls te
[RouterA-te] quit
[RouterA] interface gigabitethernet 0/0/1
[RouterA-GigabitEthernet0/0/1] mpls enable
[RouterA-GigabitEthernet0/0/1] quit
# Configure Router B.
[RouterB] mpls lsr-id 2.2.2.2
[RouterB] mpls te
[RouterB-te] quit
[RouterB] interface gigabitethernet 0/0/1
[RouterB-GigabitEthernet0/0/1] mpls enable
[RouterB-GigabitEthernet0/0/1] quit
[RouterB] interface gigabitethernet 0/0/2
[RouterB-GigabitEthernet0/0/2] mpls enable
[RouterB-GigabitEthernet0/0/2] quit
# Configure Router C.
[RouterC] mpls lsr-id 3.3.3.3
[RouterC] mpls te
[RouterC-te] quit
[RouterC] interface gigabitethernet 0/0/1
[RouterC-GigabitEthernet0/0/1] mpls enable
[RouterC-GigabitEthernet0/0/1] quit
[RouterC] interface gigabitethernet 0/0/2
[RouterC-GigabitEthernet0/0/2] mpls enable
[RouterC-GigabitEthernet0/0/2] quit
# Configure Router D.
[RouterD] mpls lsr-id 4.4.4.4
[RouterD] mpls te
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[RouterD-te] quit
[RouterD] interface gigabitethernet 0/0/1
[RouterD-GigabitEthernet0/0/1] mpls enable
[RouterD-GigabitEthernet0/0/1] quit
3. Enable SR-MPLS on the routers:
# Configure Router A.
[RouterA] isis 1
[RouterA-isis-1] address-family ipv4
[RouterA-isis-1-ipv4] segment-routing mpls
[RouterA-isis-1-ipv4] quit
[RouterA-isis-1] quit
# Configure Router B.
[RouterB] isis 1
[RouterB-isis-1] address-family ipv4
[RouterB-isis-1-ipv4] segment-routing mpls
[RouterB-isis-1-ipv4] quit
[RouterB-isis-1] quit
# Configure Router C.
[RouterC] isis 1
[RouterC-isis-1] address-family ipv4
[RouterC-isis-1-ipv4] segment-routing mpls
[RouterC-isis-1-ipv4] quit
[RouterC-isis-1] quit
# Configure Router D.
[RouterD] isis 1
[RouterD-isis-1] address-family ipv4
[RouterD-isis-1-ipv4] segment-routing mpls
[RouterD-isis-1-ipv4] quit
[RouterD-isis-1] quit
4. Configure IS-IS prefix SIDs for the routers:
# Configure Router A.
[RouterA] interface loopback 1
[RouterA-LoopBack1] isis prefix-sid index 10
[RouterA-LoopBack1] quit
# Configure Router B.
[RouterB] interface loopback 1
[RouterB-LoopBack1] isis prefix-sid index 20
[RouterB-LoopBack1] quit
# Configure Router C.
[RouterC] interface loopback 1
[RouterC-LoopBack1] isis prefix-sid index 30
[RouterC-LoopBack1] quit
# Configure Router D.
[RouterD] interface loopback 1
[RouterD-LoopBack1] isis prefix-sid index 40
[RouterD-LoopBack1] quit
5. Configure an explicit path on Router A.
62
# Create an explicit path to Router D and specify the nodes by their prefix labels.
[RouterA] explicit-path 1
[RouterA-explicit-path-1] nextsid label 16020 type prefix
[RouterA-explicit-path-1] nextsid label 16030 type prefix
[RouterA-explicit-path-1] nextsid label 16040 type prefix
[RouterA-explicit-path-1] quit
6. Configure an MPLS TE tunnel on Router A:
# Configure MPLS TE tunnel interface Tunnel 1.
[RouterA] interface tunnel 1 mode mpls-te
[RouterA-Tunnel1] ip address unnumbered interface LoopBack 1
# Set the tunnel destination address to the IP address of the loopback interface on Router D.
[RouterA-Tunnel1] destination 4.4.4.4
# Configure the MPLS TE tunnel interface to use SR to establish a tunnel over the explicit path.
[RouterA-Tunnel1] mpls te signaling segment-routing
[RouterA-Tunnel1] mpls te path preference 1 explicit-path 1
[RouterA-Tunnel1] quit
Verifying the configuration
# Display MPLS LSP information on Router A.
[RouterA] display mpls lsp
FEC Proto In/Out Label Out Inter/NHLFE/LSINDEX
10.0.0.2 Local -/- GE0/0/1
Tunnel1 Local -/- NHLFE6
1.1.1.1/32 ISIS 16010/- -
2.2.2.2/32 ISIS 16020/3 GE0/0/1
2.2.2.2/32 ISIS -/3 GE0/0/1
3.3.3.3/32 ISIS 16030/16030 GE0/0/1
3.3.3.3/32 ISIS -/16030 GE0/0/1
4.4.4.4/32 ISIS 16040/16040 GE0/0/1
4.4.4.4/32 ISIS -/16040 GE0/0/1
1.1.1.1/1/17700 SR-TE -/16030 GE0/0/1
16040
# Display the NHLFE entry information.
[RouterA] display mpls forwarding nhlfe
Total NHLFE entries: 3
Flags: T - Forwarded through a tunnel
N - Forwarded through the outgoing interface to the nexthop IP address
B - Backup forwarding information
A - Active forwarding information
M - P2MP forwarding information
NID Tnl-Type Flag OutLabel Forwarding Info
--------------------------------------------------------------------------------
5 LOCAL NA - GE0/0/1 10.0.0.2
6 SRLSP NA 16030 GE0/0/1 10.0.0.2
16040
268435457 TE TA - 6
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