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Example: Configuring Remote LFA over LDP Tunnels in OSPF Networks

In an OSPF network, a loop free alternate(LFA) is a directly connected neighbor that provides precomputed backup paths to the destinations reachable through the protected link on the point of local repair (PLR). A remote LFA is not directly connected to the PLR and provides precomputed backup paths using dynamically created LDP tunnels to the remote LFA node. The PLR uses this remote LFA backup path when the primary link fails. The primary goal of the remote LFA is to increase backup coverage for the OSPF networks and provide protection for Layer 1 metro-rings. This example shows how to configure remote LFA for LDP tunnels in an OSPF network for extending backup protection.

Requirements

This example uses the following hardware and software components:

One ACX5000 router and eight other routers with OSPF protocol and LDP enabled on the connected interfaces.
Junos OS Release 15.1X54–D60 running on ACX5000 routers.
Junos OS Release 14.2 or later running on other supporting devices.

Before you configure remote LFA over LDP tunnels in an OSPF networks, make sure of the following:

LDP is enabled on the loopback interface. Without a loopback interface, LDP targeted adjacency cannot be formed. Remote LFA cannot be configured without LDP targeted adjacency.
Remote LFA must allow asymmetric remote neighbor discovery—that is, it must send periodic targeted hello messages to the router that initiated the remote neighbor for LDP auto targeted adjacency.
Link protection or node-link protection must be configured on the point of local repair (PLR).

Overview

The example includes one ACX5000 router and eight other routers in a ring topology. Configure the OSPF protocol on the directly connected interfaces. Device R0 is the ACX5000 router and Device R6 is the PLR. This example verifies that Junos OS updates the routing table of Device R6 with LDP next-hop routes as the backup route.

Topology

In the topology Figure 1 shows the remote LFA over LDP tunnels in OSPF networks is configured on Device R6.

Figure 1: Example Remote LFA over LDP Tunnels

Configuration

CLI Quick Configuration

To quickly configure this example, copy the following commands, paste them into a text file, remove any line breaks, change any details necessary to match your network configuration, copy and paste the commands into the CLI at the [edit] hierarchy level, and then enter commit from configuration mode.

set interfaces ge-0/0/0 unit 0 family inet address 10.1.1.1/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 90.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces ge-0/0/2 unit 0 family inet address 110.1.1.1/24

set interfaces ge-0/0/2 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 1.1.1.1/32

set interfaces lo0 unit 0 family mpls

set routing-options static route 88.88.88.88/32 discard

set routing-options router-id 1.1.1.1

set routing-options forwarding-table export per-packet

set protocols mpls interface ge-0/0/0.0

set protocols mpls interface ge-0/0/1.0

set protocols mpls interface ge-0/0/2.0

set protocols mpls interface lo0.0

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf export static

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

set protocols ospf area 0.0.0.0 interface ge-0/0/2.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp egress-policy static

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface ge-0/0/2.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set policy-options policy-statement static from protocol static

set policy-options policy-statement static then accept

set interfaces ge-0/0/0 unit 0 family inet address 10.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 20.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces ge-0/0/2 unit 0 family inet address 80.1.1.1/24

set interfaces ge-0/0/2 unit 0 family mpls

set interfaces ge-0/0/3 unit 0 family inet address 100.1.1.1/24

set interfaces ge-0/0/3 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 2.2.2.2/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 2.2.2.2

set routing-options forwarding-table export per-packet

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf traffic-engineering

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/2.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0 link-protection

set protocols ospf area 0.0.0.0 interface ge-0/0/3.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface ge-0/0/2.0

set protocols ldp interface ge-0/0/3.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 20.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 30.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces ge-0/0/2 unit 0 family inet address 110.1.1.1/24

set interfaces ge-0/0/2 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 3.3.3.3/32

set interfaces lo0 unit 0 family mpls

set protocols ospf area 0.0.0.0 interface all

set protocols ospf area 0.0.0.0 interface fxp0.0 disable

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 30.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 40.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 4.4.4.4/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 4.4.4.4

set routing-options forwarding-table export per-packet

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf traffic-engineering

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 40.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 50.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 5.5.5.5/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 5.5.5.5

set routing-options forwarding-table export per-packet

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf traffic-engineering

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 60

set protocols ldp auto-targeted-session maximum-sessions 20

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 50.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 60.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 6.6.6.6/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 6.6.6.6

set routing-options forwarding-table export per-packet

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf traffic-engineering

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 60.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 70.1.1.1/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces ge-0/0/2 unit 0 family inet address 80.1.1.2/24

set interfaces ge-0/0/2 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 7.7.7.7/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 7.7.7.7

set routing-options forwarding-table export per-packet

set protocols ospf topology default backup-spf-options remote-backup-calculation

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf traffic-engineering

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0 link-protection

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0 link-protection

set protocols ospf area 0.0.0.0 interface ge-0/0/2.0 link-protection

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface ge-0/0/2.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 70.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 8.8.8.8/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 8.8.8.8

set routing-options forwarding-table export per-packet

set protocols mpls interface ge-0/0/0.0

set protocols mpls interface lo0.0

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

set interfaces ge-0/0/0 unit 0 family inet address 90.1.1.2/24

set interfaces ge-0/0/0 unit 0 family mpls

set interfaces ge-0/0/1 unit 0 family inet address 100.1.1.2/24

set interfaces ge-0/0/1 unit 0 family mpls

set interfaces lo0 unit 0 family inet address 9.9.9.9/32

set interfaces lo0 unit 0 family mpls

set routing-options router-id 9.9.9.9

set routing-options forwarding-table export per-packet

set protocols mpls interface ge-0/0/0.0

set protocols mpls interface ge-0/0/1.0

set protocols mpls interface lo0.0

set protocols ospf backup-spf-options remote-backup-calculation

set protocols ospf area 0.0.0.0 interface ge-0/0/0.0

set protocols ospf area 0.0.0.0 interface ge-0/0/1.0

set protocols ospf area 0.0.0.0 interface lo0.0

set protocols ldp auto-targeted-session teardown-delay 20

set protocols ldp auto-targeted-session maximum-sessions 60

set protocols ldp interface ge-0/0/0.0

set protocols ldp interface ge-0/0/1.0

set protocols ldp interface lo0.0

set policy-options policy-statement per-packet then load-balance per-packet

set policy-options policy-statement per-packet then accept

Configuring Device R6

Step-by-Step Procedure

The following example requires that you navigate various levels in the configuration hierarchy. For information about navigating the CLI, see Using the CLI Editor in Configuration Mode in the CLI User Guide.

To configure Device R6:

Configure the interfaces.
[edit interfaces]
user@R6# set ge-0/0/0 unit 0 family inet address 60.1.1.2/24
user@R6# set ge-0/0/0 unit 0 family mpls
user@R6# set ge-0/0/1 unit 0 family inet address 70.1.1.1/24
user@R6# set ge-0/0/1 unit 0 family mpls
user@R6# set ge-0/0/2 unit 0 family inet address 80.1.1.2/24
user@R6# set ge-0/0/2 unit 0 family mpls
Assign the loopback addresses to the device.
[edit lo0 unit 0 family]
user@R6# set address 7.7.7.7/32
user@R6# set mpls
Configure the router ID. Apply the policy to the forwarding table of the local router with the export statement.
[edit routing-options]
user@R6# set router-id 7.7.7.7
user@R6# set forwarding-table export per-packet
Enable remote LFA backup, which calculates the backup next hop using dynamic LDP label-switched path.
[edit protocols ospf]
user@R6# set topology default backup-spf-options remote-backup-calculation
user@R6# set backup-spf-options remote-backup-calculation
Configure the traffic engineering and the link protection for the interfaces in the OSPF area.
[edit protocols ospf]
user@R6# set traffic-engineering
user@R6# set area 0.0.0.0 interface ge-0/0/0.0 link-protection
user@R6# set area 0.0.0.0 interface ge-0/0/1.0 link-protection
user@R6# set area 0.0.0.0 interface ge-0/0/2.0 link-protection
user@R6# set area 0.0.0.0 interface lo0.0
Specify a time interval for which the targeted LDP sessions are kept up when the remote LFA goes down, and specify a maximum number of automatically, targeted LDP sessions to optimize the use of memory.
[edit protocols ldp]
user@R6# set auto-targeted-session teardown-delay 20
user@R6# set auto-targeted-session maximum-sessions 60
Configure the LDP protocols on the interfaces.
[edit protocols ldp]
user@R6# set interface ge-0/0/0.0
user@R6# set interface ge-0/0/1.0
user@R6# set interface ge-0/0/2.0
user@R6# set interface lo0.0
Configure the policy options to load-balance the per-packet of the policy-statement routing policy.
[edit policy-options policy-statement]
user@R6# set per-packet then load-balance per-packet
user@R6# set per-packet then accept

Results

From configuration mode, confirm your configuration by entering the show interfaces, show protocols, show policy-options, and show routing-options commands. If the output does not display the intended configuration, repeat the instructions in this example to correct the configuration.

user@R6# show interfaces

ge-0/0/0 {

unit 0 {

family inet {

address 60.1.1.2/24;

}

family mpls;

}

ge-0/0/1 {

unit 0 {

family inet {

address 70.1.1.1/24;

}

family mpls;

}

ge-0/0/2 {

unit 0 {

family inet {

address 80.1.1.2/24;

}

family mpls;

}

lo0 {

unit 0 {

family inet {

address 7.7.7.7/32;

}

family mpls;

}

user@R6# show protocols

ospf {

topology default {

backup-spf-options {

remote-backup-calculation;

}

backup-spf-options {

remote-backup-calculation;

inactive: per-prefix-calculation all;

}

traffic-engineering;

area 0.0.0.0 {

interface ge-0/0/0.0 {

link-protection;

}

interface ge-0/0/1.0 {

link-protection;

}

interface ge-0/0/2.0 {

link-protection;

}

interface lo0.0;

}

ldp {

auto-targeted-session {

teardown-delay 20;

maximum-sessions 60;

}

interface ge-0/0/0.0;

interface ge-0/0/1.0;

interface ge-0/0/2.0;

interface lo0.0;

}

user@R6# show policy-options

policy-statement per-packet {

then {

load-balance per-packet;

accept;

}

user@R6# show routing-options

router-id 7.7.7.7;

forwarding-table {

export per-packet;

}

If you are done configuring the device, enter commit from the configuration mode.

Verification

Confirm that the configuration is working properly.

Verifying the Routes

Purpose

Verify that the expected routes are learned.

Action

On Device R6, from operational mode, run the show route 6.6.6.6/24 command to display the routes in the routing table.

user@R6> show route 6.6.6.6/24

inet.0: 75 destinations, 75 routes (75 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

6.6.6.6/32         *[OSPF/10] 02:21:07, metric 1
                    > to 60.1.1.1 via ge-0/0/0.0
                      to 80.1.1.1 via ge-0/0/2.0, Push 299872

inet.3: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

6.6.6.6/32         *[LDP/9] 02:21:07, metric 1
                    > to 60.1.1.1 via ge-0/0/0.0
                      to 80.1.1.1 via ge-0/0/2.0, Push 299792, Push 299872(top)

inet.0: 75 destinations, 75 routes (75 active, 0 holddown, 0 hidden)
6.6.6.6/32 (1 entry, 1 announced)
        State: <FlashAll>
        *OSPF   Preference: 10
                Next hop type: Router, Next hop index: 1048585
                Address: 0x9df2690
                Next-hop reference count: 10
                Next hop: 60.1.1.1 via ge-0/0/0.0 weight 0x1, selected
                Session Id: 0x141
                Next hop: 80.1.1.1 via ge-0/0/2.0 weight 0x101 uflags Remote neighbor path
                Label operation: Push 299872
                Label TTL action: prop-ttl
                Load balance label: Label 299872: None; 
                Label element ptr: 0x9dc27a0
                Label parent element ptr: 0x0
                Label element references: 6
                Label element child references: 4
                Label element lsp id: 0
                Session Id: 0x142
                State: <Active Int>
                Age: 2:22:40    Metric: 1 
                Validation State: unverified 
                Area: 0.0.0.0
                Task: OSPF
                Announcement bits (2): 0-KRT 4-LDP 
                AS path: I

inet.3: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)

6.6.6.6/32 (1 entry, 1 announced)
State: <FlashAll>
        *LDP    Preference: 9
                Next hop type: Router, Next hop index: 0
                Address: 0x9df2a90
                Next-hop reference count: 1
                Next hop: 60.1.1.1 via ge-0/0/0.0 weight 0x1, selected
                Label element ptr: 0x9dc0dc0
                Label parent element ptr: 0x0
                Label element references: 1
                Label element child references: 0
                Label element lsp id: 0
                Session Id: 0x0
                Next hop: 80.1.1.1 via ge-0/0/2.0 weight 0x101 uflags Remote neighbor path
                Label operation: Push 299792, Push 299872(top)
                Label TTL action: prop-ttl, prop-ttl(top)
                Load balance label: Label 299792: None; Label 299872: None; 
                Label element ptr: 0x9dc1ba0
                Label parent element ptr: 0x9dc27a0
                Label element references: 1
                Label element child references: 0
                Label element lsp id: 0
                Session Id: 0x0
                State: <Active Int>
                Age: 2:22:40    Metric: 1 
                Validation State: unverified 
                Task: LDP               
                Announcement bits (1): 0-Resolve tree 1 
                AS path: I

Meaning

The output shows all the routes in the routing table of Device R6.

Verifying the LDP Routes

Purpose

Verify the automatically targeted LDP routes.

Action

From operational mode, enter the show ldp session auto-targeted detail command.

user@R6> show ldp session auto-targeted detail

  Address: 4.4.4.4, State: Operational, Connection: Open, Hold time: 28
  Session ID: 7.7.7.7:0--4.4.4.4:0
  Next keepalive in 8 seconds
  Active, Maximum PDU: 4096, Hold time: 30, Neighbor count: 1
  Neighbor types: auto-targeted
  Keepalive interval: 10, Connect retry interval: 1
  Local address: 7.7.7.7, Remote address: 4.4.4.4
  Up for 02:28:28
  Capabilities advertised: none
  Capabilities received: none
  Protection: disabled
  Session flags: none
  Local - Restart: disabled, Helper mode: enabled
  Remote - Restart: disabled, Helper mode: enabled
  Local maximum neighbor reconnect time: 120000 msec
  Local maximum neighbor recovery time: 240000 msec
  Local Label Advertisement mode: Downstream unsolicited
  Remote Label Advertisement mode: Downstream unsolicited
  Negotiated Label Advertisement mode: Downstream unsolicited
  MTU discovery: disabled
  Nonstop routing state: Not in sync
  Next-hop addresses received:
    4.4.4.4
    30.1.1.2
    40.1.1.1
    128.92.25.37

Verifying the OSPF Routes

Purpose

Display all the LDP backup routes in the OSPF routing table of Device R6.

Action

On Device R6, from operational mode, run the show ospf route command to display the routes in the OSPF routing table.

user@R6> show ospf route

Topology default Route Table:

Prefix             Path  Route      NH       Metric NextHop       Nexthop      
                   Type  Type       Type            Interface     Address/LSP
1.1.1.1            Intra AS BR      IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
2.2.2.2            Intra Router     IP            1 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
4.4.4.4            Intra Router     IP            3 ge-0/0/0.0    60.1.1.1
                                                    ge-0/0/2.0    80.1.1.1
5.5.5.5            Intra Router     IP            2 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
6.6.6.6            Intra Router     IP            1 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
8.8.8.8            Intra Router     IP            1 ge-0/0/1.0    70.1.1.2
9.9.9.9            Intra Router     IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.21.22       Intra Router     IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
1.1.1.1/32         Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
2.2.2.2/32         Intra Network    IP            1 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
3.3.3.3/32         Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
4.4.4.4/32         Intra Network    IP            3 ge-0/0/0.0    60.1.1.1
                                                    ge-0/0/2.0    80.1.1.1
5.5.5.5/32         Intra Network    IP            2 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
6.6.6.6/32         Intra Network    IP            1 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
7.7.7.7/32         Intra Network    IP            0 lo0.0
8.8.8.8/32         Intra Network    IP            1 ge-0/0/1.0    70.1.1.2
9.9.9.9/32         Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
10.1.1.0/24        Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
20.1.1.0/24        Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
30.1.1.0/24        Intra Network    IP            3 ge-0/0/2.0    80.1.1.1
                                    Bkup IP         ge-0/0/0.0    60.1.1.1
40.1.1.0/24        Intra Network    IP            3 ge-0/0/0.0    60.1.1.1
                                    Bkup IP         ge-0/0/2.0    80.1.1.1
50.1.1.0/24        Intra Network    IP            2 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
60.1.1.0/24        Intra Network    IP            1 ge-0/0/0.0
70.1.1.0/24        Intra Network    IP            1 ge-0/0/1.0
80.1.1.0/24        Intra Network    IP            1 ge-0/0/2.0
88.88.88.88/32     Ext2  Network    IP            0 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
90.1.1.0/24        Intra Network    IP            3 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
100.1.1.0/24       Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
110.1.1.0/24       Intra Network    IP            3 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.19.153/32   Intra Network    IP            1 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.19.176/32   Intra Network    IP            0 lo0.0
128.92.21.13/32    Intra Network    IP            1 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.21.22/32    Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.23.228/32   Intra Network    IP            1 ge-0/0/1.0    70.1.1.2
128.92.25.37/32    Intra Network    IP            3 ge-0/0/0.0    60.1.1.1
                                                    ge-0/0/2.0    80.1.1.1
128.92.25.196/32   Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.26.29/32    Intra Network    IP            2 ge-0/0/2.0    80.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4
128.92.29.156/32   Intra Network    IP            2 ge-0/0/0.0    60.1.1.1
                                    Bkup LSP                      LDP->4.4.4.4

Meaning

The output shows all the LDP backup routes in the OSPF routing table of Device R6.

Verifying the Designated Backup Path Node

Purpose

Display the remote LFA next hop determined for a given destination.

Action

From operational mode, enter the show ospf backup spf results command.

user@R6> show ospf backup spf results

Topology default results:

Area 0.0.0.0 results:

6.6.6.6
  Self to Destination Metric: 1
  Parent Node: 60.1.1.2
  Primary next-hop: ge-0/0/0.0 via 60.1.1.1
  Backup next-hop: LDP->4.4.4.4 via ge-0/0/2.0
  Backup Neighbor: 6.6.6.6 via: Direct
    Neighbor to Destination Metric: 0, Neighbor to Self Metric: 1
    Self to Neighbor Metric: 1, Backup preference: 0x0
    Not eligible, Reason: Primary next-hop link fate sharing
  Backup Neighbor: 2.2.2.2 via: Direct
    Neighbor to Destination Metric: 2, Neighbor to Self Metric: 1
    Self to Neighbor Metric: 1, Backup preference: 0x0
    Not eligible, Reason: Path loops
  Backup Neighbor: 8.8.8.8 via: Direct
    Neighbor to Destination Metric: 2, Neighbor to Self Metric: 1
    Self to Neighbor Metric: 1, Backup preference: 0x0
    Not eligible, Reason: Path loops
  Backup Neighbor: 4.4.4.4 via: LDP (LSP endpoint)
    Neighbor to Destination Metric: 2, Neighbor to Self Metric: 3
    Self to Neighbor Metric: 3, Backup preference: 0x0
    Eligible, Reason: Contributes backup next-hop

Meaning

The output indicates whether a specific interface or node has been designated as a remote backup path and why.

Verifying the Backup Neighbors

Purpose

Display the backup neighbors for the Device R6

Action

From operational mode, enter the show ospf backup neighbor command.

user@R6>show ospf backup neighbor

Topology default backup neighbors:

Area 0.0.0.0 backup neighbors:

6.6.6.6 via: Direct
  Neighbor to Self Metric: 1
  Self to Neighbor Metric: 1
  Direct next-hop: ge-0/0/0.0 via 60.1.1.1

8.8.8.8 via: Direct
  Neighbor to Self Metric: 1
  Self to Neighbor Metric: 1
  Direct next-hop: ge-0/0/1.0 via 70.1.1.2

2.2.2.2 via: Direct
  Neighbor to Self Metric: 1
  Self to Neighbor Metric: 1
  Direct next-hop: ge-0/0/2.0 via 80.1.1.1

4.4.4.4 via: LDP (LSP endpoint)
  Neighbor to Self Metric: 3
  Self to Neighbor Metric: 3
  Direct next-hop: LDP->4.4.4.4 via ge-0/0/2.0
  Direct next-hop: LDP->4.4.4.4 via ge-0/0/0.0
  Neighbors Protected: 2

Meaning

The output displays the backup neighbors available for area 0.0.0.0.

TechLibrary

Related Documentation

Example: Configuring Remote LFA over LDP Tunnels in OSPF Networks

Requirements

Overview

Topology

Configuration

CLI Quick Configuration

Configuring Device R6

Step-by-Step Procedure

Results

Verification

Verifying the Routes

Purpose

Action

Meaning

Verifying the LDP Routes

Purpose

Action

Verifying the OSPF Routes

Purpose

Action

Meaning

Verifying the Designated Backup Path Node

Purpose

Action

Meaning

Verifying the Backup Neighbors

Purpose

Action

Meaning

Related Documentation

Modified: 2017-03-08