Verifying the OSPF Protocol
Purpose
After you have verified that the LSP is down, and the cause is not in the physical, datalink, or IP layer, verify the OSPF configuration. Check the routers in your network to ensure that the interfaces and the OSPF protocol are configured correctly, and that the neighbors are established.
Figure 1: MPLS Network Broken at the OSPF Protocol Layer
- Verify the LSP
- Verify OSPF Interfaces
- Verify OSPF Neighbors
- Verify the OSPF Protocol Configuration
- Take Appropriate Action
- Verify the LSP Again
Verify the LSP
Purpose
Confirm that interfaces are configured for OSPF, the OSPF protocol is configured correctly and that neighbors are established.
Action
To verify the LSP, enter the following command on the ingress, transit, and egress routers:
Sample Output 1
user@R1> show mpls lsp extensive Ingress LSP: 1 sessions 10.0.0.6 From: 10.0.0.1, State: Dn, ActiveRoute: 0, LSPname: R1-to-R6 ActivePath: (none) LoadBalance: Random Encoding type: Packet, Switching type: Packet, GPID: IPv4 Primary State: Dn 11 Oct 19 18:06:04 No Route toward dest[78 times] 10 Oct 19 17:08:09 Deselected as active Created: Mon Oct 18 21:48:42 2004 Total 1 displayed, Up 0, Down 1 Egress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 0 sessions Total 0 displayed, Up 0, Down 0
Sample Output 2
user@R3> show mpls lsp extensive Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 0 sessions Total 0 displayed, Up 0, Down 0
Sample Output 3
user@R6> show mpls lsp extensive Ingress LSP: 1 sessions To From State Rt ActivePath P LSPname 10.0.0.1 10.0.0.6 Dn 0 - R6-to-R1 Total 1 displayed, Up 0, Down 1 Egress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 0 sessions Total 0 displayed, Up 0, Down 0
Sample Output 4
user@R1> show mpls lsp extensive
Ingress LSP: 1 sessions
10.0.0.6
From: 10.0.0.1, State: Up, ActiveRoute: 1, LSPname: R1-to-R6
ActivePath: (primary)
LoadBalance: Random
Encoding type: Packet, Switching type: Packet, GPID: IPv4
*Primary State: Up
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt):
10.1.13.2 10.1.36.2
5 Oct 19 10:37:55 Selected as active path
4 Oct 19 10:37:55 Record Route: 10.1.13.2 10.1.36.2
3 Oct 19 10:37:55 Up
2 Oct 19 10:37:10 No Route toward dest[1029 times]
1 Oct 18 21:48:42 Originate Call
Created: Mon Oct 18 21:48:42 2004
Total 1 displayed, Up 1 , Down 0
Egress LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Sample Output 5
user@R3> show mpls lsp extensive Ingress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Egress LSP: 0 sessions Total 0 displayed, Up 0, Down 0 Transit LSP: 1 sessions 10.0.0.6 From: 10.0.0.1, LSPstate: Up, ActiveRoute: 1 LSPname: R1-to-R6 , LSPpath: Primary Suggested label received: -, Suggested label sent: - Recovery label received: -, Recovery label sent: 3 Resv style: 1 FF, Label in: 100368, Label out: 3 Time left: 154, Since: Tue Oct 19 10:25:24 2004 Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500 Port number: sender 1 receiver 47933 protocol 0 PATH rcvfrom: 10.1.13.1 (so-0/0/2.0) 209 pkts Adspec: received MTU 1500 sent MTU 1500 PATH sentto: 10.1.36.2 (so-0/0/3.0) 209 pkts RESV rcvfrom: 10.1.36.2 (so-0/0/3.0) 209 pkts Record route: 10.1.13.1 <self> 10.1.36.2 Total 1 displayed, Up 1, Down 0
Sample Output 6
user@R6> show mpls lsp extensive
Ingress LSP: 1 sessions
10.0.0.1
From: 10.0.0.6, State: Dn, ActiveRoute: 0, LSPname: R6-to-R1
ActivePath: (none)
LoadBalance: Random
Encoding type: Packet, Switching type: Packet, GPID: IPv4
Primary State: Dn
2 Oct 19 13:01:54 10.1.56.2: MPLS label allocation failure [9 times]
1 Oct 19 12:57:51 Originate Call
Created: Tue Oct 19 12:57:51 2004
Total 1 displayed, Up 0, Down 1
Egress LSP: 1 sessions
10.0.0.6
From: 10.0.0.1, LSPstate: Up, ActiveRoute: 0
LSPname: R1-to-R6, LSPpath: Primary
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: -
Resv style: 1 FF, Label in: 3, Label out: -
Time left: 148, Since: Tue Oct 19 10:30:03 2004
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 1 receiver 47933 protocol 0
PATH rcvfrom: 10.1.36.1 (so-0/0/3.0) 206 pkts
Adspec: received MTU 1500
PATH sentto: localclient
RESV rcvfrom: localclient
Record route: 10.1.13.1 10.1.36.1 <self>
Total 1 displayed, Up 1, Down 0
Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Meaning
Sample Outputs 1, 2, and 3 show that the LSP and the reverse LSP are down:
- Sample Output 1 from ingress router R1 shows that LSP R1-to-R6 does not have a route towards the destination (R6).
- Sample Output 2 from transit router R3 shows that there are no LSP sessions.
- Sample Output 3 from egress router R6 also shows that reverse LSP R6-to-R1 is down.
Sample Outputs 4, 5, and 6 show that the LSP is up and the reverse LSP is down:
- Sample Output 4 from ingress router R1 shows that LSP R1-to-R6 is up and there are no egress LSP sessions.
- Sample Output 5 from transit router R3 shows that there is one ingress LSP session (R1-to-R6) and no egress LSP sessions.
- Sample Output 6 from egress router R6 shows that LSP R6-to-R1 is down due to an MPLS label allocation failure.
Verify OSPF Interfaces
Purpose
After you have verified that the LSP is down, and the cause is not in the physical, data link, or IP layer, check the routers in your network to determine that all relevant OSPF interfaces are configured correctly.
Action
To verify OSPF interfaces, enter the following commands from the ingress, transit, and egress routers:
Sample Output 1
user@R1> show ospf interface Interface State Area DR ID BDR ID Nbrs so-0/0/0.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/1.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 user@R3> show ospf interface Interface State Area DR ID BDR ID Nbrs so-0/0/0.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/1.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/3.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 user@R6> show ospf interface Interface State Area DR ID BDR ID Nbrs so-0/0/0.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/1.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/3.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1
Sample Output 2
user@R1> show ospf interface Interface State Area DR ID BDR ID Nbrs lo0.0 DR 0.0.0.0 10.0.0.1 0.0.0.0 0 so-0/0/0.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/1.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 user@R3> show ospf interface Interface State Area DR ID BDR ID Nbrs lo0.0 DR 0.0.0.0 10.0.0.3 0.0.0.0 0 so-0/0/0.0 Down 0.0.0.0 0.0.0.0 0.0.0.0 0 so-0/0/1.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/3.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 user@R6> show ospf interface Interface State Area DR ID BDR ID Nbrs lo0.0 DR 0.0.0.0 10.0.0.6 0.0.0.0 0 so-0/0/0.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/1.0 Down 0.0.0.0 0.0.0.0 0.0.0.0 0 so-0/0/2.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1 so-0/0/3.0 PtToPt 0.0.0.0 0.0.0.0 0.0.0.0 1
Meaning
Sample Output 1 shows that all interfaces on all routers are in the correct area (0.0.0.0), and the loopback (lo0) interface is missing from the list of interfaces on all routers. The missing loopback (lo0) interface is a problem in this configuration.
In an MPLS network configured with OSPF as the IGP, when you manually configure the RID, it is important to explicitly configure the loopback interface at the [edit protocols ospf] hierarchy level. If the RID is not manually configured, OSPF automatically advertises the loopback (lo0) interface. In the configuration of all the routers in this network, the RID is configured manually, therefore, the loopback (lo0) interface must be explicitly configured at the [edit protocols ospf] hierarchy level. In addition, the loopback (lo0) interface is configured with the passive statement to ensure that the protocols are not run over the loopback (lo0) interface and it is correctly advertised throughout the network.
Sample Output 2 shows that all the relevant interfaces on the ingress, transit, and egress routers, including the loopback (lo0) interface, are in the correct area (0.0.0.0). Because the configuration of the interfaces is correct, further investigation is required to determine the reason for the LSP problem.
Verify OSPF Neighbors
Purpose
After you have checked OSPF interfaces, check your network topology to determine that all relevant neighbors are established.
Action
To verify OSPF neighbors, enter the following commands from the ingress, transit, and egress routers:
Sample Output
user@R1> show ospf neighbor Address Interface State ID Pri Dead 10.1.12.2 so-0/0/0.0 Full 10.0.0.2 128 39 10.1.15.2 so-0/0/1.0 Full 10.0.0.5 128 39 10.1.13.2 so-0/0/2.0 Full 10.0.0.3 128 33 user@R3> show ospf neighbor Address Interface State ID Pri Dead 10.1.34.2 so-0/0/0.0 Full 10.0.0.4 128 33 10.1.23.1 so-0/0/1.0 Full 10.0.0.2 128 33 10.1.13.1 so-0/0/2.0 Full 10.0.0.1 128 33 10.1.36.2 so-0/0/3.0 Full 10.0.0.6 128 33 user@R6> show ospf neighbor Address Interface State ID Pri Dead 10.1.56.1 so-0/0/0.0 Full 10.0.0.5 128 30 10.1.46.1 so-0/0/1.0 Full 10.0.0.4 128 38 10.1.26.1 so-0/0/2.0 Full 10.0.0.2 128 34 10.1.36.1 so-0/0/3.0 Full 10.0.0.3 128 35
Meaning
The sample output shows that all neighbors are fully adjacent, indicating that each router has exchanged a full copy of its link-state database with the other routers, passed through several neighbor states, and become fully adjacent. These adjacencies are created by router link and network link advertisements.
Verify the OSPF Protocol Configuration
Purpose
After you have checked interfaces and neighbors, verify the OSPF protocol configuration.
Action
To verify the OSPF protocol configuration, enter the following command from the ingress, transit, and egress routers:
Sample Output 1
user@R1> show configuration protocols ospf
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface so-0/0/1.0;
interface so-0/0/2.0; <<< The loopback interface (lo0) is missing
}
Sample Output 2
user@R3>show configuration protocols ospf
area 0.0.0.0 { <<< traffic engineering is missing
interface so-0/0/0.0;
interface so-0/0/1.0;
interface so-0/0/2.0;
interface so-0/0/3.0; <<< The loopback interface (lo0) is missing
}
Sample Output 3
user@R6> show configuration protocols ospf
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface so-0/0/1.0;
interface so-0/0/2.0;
interface so-0/0/3.0; <<< The loopback interface (lo0) is missing
}
Meaning
All three sample outputs show that the loopback interface is not included on any of the routers. Including the loopback (lo0) interface is important when you have the RID manually configured.
In addition, Sample Output 2 from transit router R3 shows that traffic engineering is not configured. Traffic engineering must be manually enabled when you configure OSPF for an MPLS network.
Because the loopback interface and traffic engineering are missing from the OSPF protocol configuration, the LSP does not work as expected.
Take Appropriate Action
Problem
Depending on the error you encountered in your investigation, you must take the appropriate action to correct the problem. In this example, the loopback (lo0) interface is missing from all routers, and traffic engineering is missing from the transit router (R3).
Solution
To correct the errors in this example, follow these steps:
- Include the loopback (lo0) interface on all routers
that have the RID manually configured. Enter the following configuration
mode commands:[edit]user@R3# edit protocols ospf area 0.0.0.0 [edit protocols ospf area 0.0.0.0]user@R3# set interface lo0 user@R3# set interface lo0 passive
- Move up one level of the configuration hierarchy:[edit protocols ospf area 0.0.0.0]user@R3# up [edit protocols ospf]user @R3#
- Include traffic engineering on the transit router (R3). Enter the following configuration mode command:[edit protocols ospf]user@R3# set traffic-engineering
- On all routers, verify and commit the configuration:user@R3# show user@R3# commit
Sample Output
user@R3> edit
Entering configuration mode
[edit]
user@R3# edit protocols ospf area 0.0.0.0
[edit protocols ospf area 0.0.0.0]
user@R3# set interface lo0
[edit protocols ospf area 0.0.0.0]
user@R3# set interface lo0 passive
[edit protocols ospf area 0.0.0.0]
user@R3# up
[edit protocols ospf]
user@R3# set traffic-engineering
[edit protocols ospf]
user@R3# show
traffic-engineering;
area 0.0.0.0 {
interface so-0/0/0.0;
interface so-0/0/1.0;
interface so-0/0/2.0;
interface lo0.0; {
passive
}
}
[edit protocols ospf]
user@R3# commit
commit complete
Meaning
The sample output shows that the loopback (lo0) interface and traffic engineering are now correctly configured on transit router R3. When traffic engineering is configured, OSPF advertises the traffic engineering capabilities of the links.
In the OSPF configuration, you must manually include the loopback (lo0) interface and set it to passive when you manually configure an RID. Setting the loopback (lo0) interface to passive ensures that protocols are not run over the loopback (lo0) interface and the loopback (lo0) interface is advertised correctly throughout the network.. If you do not manually configure an RID, there is no need to explicitly include the loopback interface because the OSPF protocol automatically includes the loopback (lo0) interface.
For more information about configuring LSPs and MPLS, see the Junos MPLS Applications Configuration Guide.
Verify the LSP Again
Purpose
After taking the appropriate action to correct the error, the LSP needs to be checked again to confirm that the problem in the IS-IS protocol has been resolved.
Action
To verify that the LSP is up and traversing the network as expected, enter the following command from the ingress, egress, and transit routers:
Sample Output
user@R1> show mpls lsp extensive
Ingress LSP: 1 sessions
10.0.0.6
From: 10.0.0.1, State: Up , ActiveRoute: 1, LSPname: R1-to-R6
ActivePath: (primary)
LoadBalance: Random
Encoding type: Packet, Switching type: Packet, GPID: IPv4
*Primary State: Up
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt):
10.1.13.2 10.1.36.2
4 Oct 19 21:22:54 Selected as active path
3 Oct 19 21:22:53 Record Route: 10.1.13.2 10.1.36.2
2 Oct 19 21:22:53 Up
1 Oct 19 21:22:53 Originate Call
Created: Tue Oct 19 21:22:53 2004
Total 1 displayed, Up 1 , Down 0
Egress LSP: 1 sessions
10.0.0.1
From: 10.0.0.6, LSPstate: Up , ActiveRoute: 0
LSPname: R6-to-R1 , LSPpath: Primary
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: -
Resv style: 1 FF, Label in: 3, Label out: -
Time left: 117, Since: Tue Oct 19 21:17:42 2004
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 2 receiver 39064 protocol 0
PATH rcvfrom: 10.1.13.2 (so-0/0/2.0) 10 pkts
Adspec: received MTU 1500
PATH sentto: localclient
RESV rcvfrom: localclient
Record route: 10.1.36.2 10.1.13.2 <self>
Total 1 displayed, Up 1 , Down 0
Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
user@R3> show mpls lsp extensive
Ingress LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Egress LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Transit LSP: 2 sessions
10.0.0.1
From: 10.0.0.6, LSPstate: Up, ActiveRoute: 1
LSPname: R6-to-R1 , LSPpath: Primary
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: 3
Resv style: 1 FF, Label in: 100416, Label out: 3
Time left: 139, Since: Tue Oct 19 21:05:11 2004
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 2 receiver 39064 protocol 0
PATH rcvfrom: 10.1.36.2 (so-0/0/3.0) 11 pkts
Adspec: received MTU 1500 sent MTU 1500
PATH sentto: 10.1.13.1 (so-0/0/2.0) 11 pkts
RESV rcvfrom: 10.1.13.1 (so-0/0/2.0) 11 pkts
Explct route: 10.1.13.1
Record route: 10.1.36.2 <self> 10.1.13.1
10.0.0.6
From: 10.0.0.1, LSPstate: Up, ActiveRoute: 1
LSPname: R1-to-R6 , LSPpath: Primary
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: 3
Resv style: 1 FF, Label in: 100448, Label out: 3
Time left: 135, Since: Tue Oct 19 21:10:22 2004
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 1 receiver 47951 protocol 0
PATH rcvfrom: 10.1.13.1 (so-0/0/2.0) 4 pkts
Adspec: received MTU 1500 sent MTU 1500
PATH sentto: 10.1.36.2 (so-0/0/3.0) 4 pkts
RESV rcvfrom: 10.1.36.2 (so-0/0/3.0) 4 pkts
Record route: 10.1.13.1 <self> 10.1.36.2
Total 2 displayed, Up 2 , Down 0
user@R6> run show mpls lsp extensive
Ingress LSP: 1 sessions
10.0.0.1
From: 10.0.0.6, State: Up, ActiveRoute: 1, LSPname: R6-to-R1
ActivePath: (primary)
LoadBalance: Random
Encoding type: Packet, Switching type: Packet, GPID: IPv4
*Primary State: Up
Computed ERO (S [L] denotes strict [loose] hops): (CSPF metric: 2)
10.1.36.1 S 10.1.13.1 S
Received RRO (ProtectionFlag 1=Available 2=InUse 4=B/W 8=Node 10=SoftPreempt):
10.1.36.1 10.1.13.1
19 Oct 19 21:09:52 Selected as active path
18 Oct 19 21:09:52 Record Route: 10.1.36.1 10.1.13.1
17 Oct 19 21:09:52 Up
16 Oct 19 21:09:52 Originate Call
15 Oct 19 21:09:52 CSPF: computation result accepted
Created: Tue Oct 19 18:30:09 2004
Total 1 displayed, Up 1 , Down 0
Egress LSP: 1 sessions
10.0.0.6
From: 10.0.0.1, LSPstate: Up, ActiveRoute: 0
LSPname: R1-to-R6 , LSPpath: Primary
Suggested label received: -, Suggested label sent: -
Recovery label received: -, Recovery label sent: -
Resv style: 1 FF, Label in: 3, Label out: -
Time left: 120, Since: Tue Oct 19 21:15:03 2004
Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
Port number: sender 1 receiver 47951 protocol 0
PATH rcvfrom: 10.1.36.1 (so-0/0/3.0) 4 pkts
Adspec: received MTU 1500
PATH sentto: localclient
RESV rcvfrom: localclient
Record route: 10.1.13.1 10.1.36.1 <self>
Total 1 displayed, Up 1 , Down 0
Transit LSP: 0 sessions
Total 0 displayed, Up 0, Down 0
Meaning
The sample output from ingress router R1 and egress router R6 shows that the LSP is now traversing the network along the expected path, from R1 through R3 to R6, and the reverse LSP, from R6 through R3 to R1. In addition, the sample output from transit router R3 shows that there are two transit LSP sessions, one from R1 to R6, and the other from R6 to R1.
