Hi All
I am landing now come from Benguela (Fanta Dj tour), i want to make sure i will write a post per week because of time consumed on designing/writing/testing. Let focus on how MPLS Tunnel LSP works, this is our diagram.
The goal is to have end to end connectivity between IWS remote Sites, we need only to check the LSP between PE1 and PE2.
PE1:
PE1#show mpls forwarding-table 55.5.5.2
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or VC or Tunnel Id Switched interface
19 17 55.5.5.2/32 0 Se1/0 point2point
PE1#
We see that to going to loopback of PE2 its gonna use Label 19.
At this point the both P’s perform PHP operations
P1:
P1#show mpls forwarding-table 55.5.5.2
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
17 Pop tag 55.5.5.2/32 4873 Se1/0 point2point
Doesn’t need to check on PE2 because its direct connected.
P2
P2#show mpls forwarding-table 55.5.5.2
Local Outgoing Prefix Bytes tag Outgoing Next Hop
tag tag or VC or Tunnel Id switched interface
18 Pop tag 55.5.5.2/32 0 Se1/0 point2point
Ping to IWS remote site with success,
PE1#ping vrf IWS 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/16/28 ms
PE1#
The MPLS is working properly, let says that we want to prefer link for PE1->P2->P1->PE2 for the customer IWS which is simulate on loopback on both PE1 and PE2. So our tunnel will end at the P1, due to prevent misrouting if P1 become PE.
First we gonna trace from PE1 to PE2 to check which path the traffic takes.
PE1#traceroute 55.5.5.2
Type escape sequence to abort.
Tracing the route to 55.5.5.2
1 55.5.1.2 [MPLS: Label 17 Exp 0] 68 msec 12 msec 12 msec
2 55.5.1.10 12 msec * 16 msec
PE1#
Traffic is going from PE1 -> P1 -> PE2. At now all the thing is good and properly work!
Let setup unidirectional Tunnel LSP between P1 and PE2, check the config:
P1 and P2 Configs:
mpls traffic-eng tunnels
!
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
!
interface Ethernet0/0
mpls traffic-eng tunnels
ip rsvp bandwidth
!
interface Serial1/0
mpls traffic-eng tunnels
ip rsvp bandwidth
end
PE2:
mpls traffic-eng tunnels
!
router ospf 1
mpls traffic-eng router-id Loopback0
mpls traffic-eng area 0
!
interface Serial1/0
mpls traffic-eng tunnels
ip rsvp bandwidth
!
interface Serial1/1
mpls traffic-eng tunnels
ip rsvp bandwidth
!
interface Tunnel0
ip unnumbered Loopback0
tunnel destination 55.5.5.3
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng path-option 1 explicit name P2->P1
tunnel mpls traffic-eng path-option 2 dynamic
!
ip explicit-path name P2->P1 enable
next-address 55.5.1.13
next-address 55.5.1.5
next-address 55.5.5.3
!
end
At this point the Tunnel is up and working as u see on the outputs
PE2#show mpls traffic-eng tunnels brief | in PE2_t0
PE2_t0 55.5.5.3 – Se1/1 up/up
PE2#show mpls forwarding-table 55.5.5.1 | in Tu0
18 No Label [T] 55.5.5.1/32 0 Tu0 point2point
At this time the Label Switched Path was broken, as u can see on the ping output. There is No Label for the specific FEC …
PE2#ping vrf IWS 1.1.1.1 source lo1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
Packet sent with a source address of 2.2.2.2
…..
Success rate is 0 percent (0/5)
Unidirectional TE will not work, we must setup another TE Tunnel from P1 to PE2 and enable MPLS on the tunnels link to form a LSP Tunnel.
P1:
P1#sh run int tun0
interface Tunnel0
ip unnumbered Loopback0
mpls ip
tunnel destination 55.5.5.2
tunnel mode mpls traffic-eng
tunnel mpls traffic-eng autoroute announce
tunnel mpls traffic-eng path-option 1 explicit name P2-PE2
tunnel mpls traffic-eng path-option 2 dynamic
no routing dynamic
end
P1#sh run | se ip expli
ip explicit-path name P2->PE2 enable
next-address 55.5.1.6
next-address 55.5.1.14
next-address 55.5.5.2
PE2: just enable the mpls
interface Tunnel0
mpls ip
Now packet is Label Switched out Tunnel
PE2#show mpls forwarding-table 55.5.5.1 | in Tu0
18 18 [T] 55.5.5.1/32 0 Tu0 point2point
Trying ping now …
PE2#ping vrf IWS 1.1.1.1 source lo1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
Packet sent with a source address of 2.2.2.2
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/36/56 ms
PE2#
So we conclude with this post, this post achieve an in-depth knowledge how MPLS LSP work and advanced concept about MPLS TE on the Field. Keep u understand the concepts and post a comment.
//Jeriel Atienza
