04-Layer 3-IP Routing Configuration Guide

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02-Static routing configuration
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Configuring static routing

About static routes

Static routes are manually configured. If a network's topology is simple, you only need to configure static routes for the network to work correctly.

Static routes cannot adapt to network topology changes. If a fault or a topological change occurs in the network, the network administrator must modify the static routes manually.

Configuring a static route

1.     Enter system view.

system-view

2.     Configure a static route.

Public network:

ip route-static dest-address { mask-length | mask } { interface-type interface-number [ next-hop-address ] | next-hop-address [ nexthop-index index-string ] [ recursive-lookup host-route ] | vpn-instance d-vpn-instance-name next-hop-address [ nexthop-index index-string ] [ recursive-lookup host-route ] } [ permanent | track track-entry-number ] [ preference preference ] [ tag tag-value ] [ description text ]

ip route-static dest-address { mask-length | mask } vpn-instance d-vpn-instance-name [ preference preference ] [ tag tag-value ] [ description text ]

By default, no static route is configured.

You can associate Track with a static route to monitor the reachability of the next hops. For more information about Track, see High Availability Configuration Guide.

VPN:

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } { interface-type interface-number [ next-hop-address ] | next-hop-address [ nexthop-index index-string ] [ recursive-lookup host-route ] [ public ] | vpn-instance d-vpn-instance-name next-hop-address [ nexthop-index index-string ] [ recursive-lookup host-route ] } [ permanent | track track-entry-number ] [ preference preference ] [ tag tag-value ] [ description text ]

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } { public | vpn-instance d-vpn-instance-name } [ preference preference ] [ tag tag-value ] [ description text ]

By default, no static route is configured.

You can associate Track with a static route to monitor the reachability of the next hops. For more information about Track, see High Availability Configuration Guide.

3.     (Optional.) Configure the default preference for static routes.

ip route-static default-preference default-preference

The default setting is 60.

Configuring a static route group

About this task

This task allows you to batch create static routes with different prefixes but the same output interface and next hop.

You can create a static route group, and specify the static group in the ip route-static command. All prefixes in the static route group will be assigned the next hop and output interface specified in the ip route-static command.

Procedure

1.     Enter system view.

system-view

2.     Create a static route group and enter its view.

ip route-static-group group-name

By default, no static route group is configured.

3.     Add a static route prefix to the static route group.

prefix dest-address { mask-length | mask }

By default, no static route prefix is added to the static route group.

4.     Return to system view.

quit

5.     Configure a static route.

Public network:

ip route-static group group-name { interface-type interface-number [ next-hop-address ] | next-hop-address [ recursive-lookup host-route ] [ track track-entry-number ] | vpn-instance d-vpn-instance-name next-hop-address [ recursive-lookup host-route ] [ track track-entry-number ] } [ permanent ] [ preference preference ] [ tag tag-value ] [ description text ]

ip route-static group group-name vpn-instance d-vpn-instance-name [ preference preference ] [ tag tag-value ] [ description text ]

VPN:

ip route-static vpn-instance s-vpn-instance-name group group-name { interface-type interface-number [ next-hop-address ] | next-hop-address [ recursive-lookup host-route ] [ public ] [ track track-entry-number ] | vpn-instance d-vpn-instance-name next-hop-address [ recursive-lookup host-route ] [ track track-entry-number ] } [ permanent ] [ preference preference ] [ tag tag-value ] [ description text ]

ip route-static vpn-instance s-vpn-instance-name group group-name { public | vpn-instance d-vpn-instance-name } [ preference preference ] [ tag tag-value ] [ description text ]

By default, no static route is configured.

Deleting static routes

About this task

To delete a static route, use the undo ip route-static command. To delete all static routes including the default route, use the delete static-routes all command.

Procedure

1.     Enter system view.

system-view

2.     Delete all static routes.

Public network:

delete static-routes all

VPN:

delete vpn-instance vpn-instance-name static-routes all

Configuring BFD for static routes

IMPORTANT

IMPORTANT:

Enabling BFD for a flapping route could worsen the situation.

 

About BFD

BFD provides a general-purpose, standard, medium-, and protocol-independent fast failure detection mechanism. It can uniformly and quickly detect the failures of the bidirectional forwarding paths between two routers for protocols, such as routing protocols and MPLS.

For more information about BFD, see High Availability Configuration Guide.

Configuring BFD control packet mode

About this task

This mode uses BFD control packets to detect the status of a link bidirectionally at a millisecond level.

BFD control packet mode can be applied to static routes with a direct next hop or with an indirect next hop.

Restrictions and guidelines for BFD control packet mode

If you use BFD control packet mode at the local end, you must use this mode also at the peer end.

Configuring BFD control packet mode for a static route (direct next hop)

1.     Enter system view.

system-view

2.     Configure BFD control packet mode for a static route.

Public network:

ip route-static dest-address { mask-length | mask } interface-type interface-number next-hop-address bfd { control-packet | static session-name } [ preference preference ] [ tag tag-value ] [ description text ]

VPN:

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } interface-type interface-number next-hop-address bfd { control-packet | static session-name } [ preference preference ] [ tag tag-value ] [ description text ]

By default, BFD control packet mode for a static route is not configured.

3.     (Optional.) Configure BFD session parameters for the static route.

ip route-static bfd interface-type interface-number next-hop-address { detect-multiplier detect-multiplier | min-receive-interval min-receive-interval | min-transmit-interval min-transmit-interval } *

By default, no BFD session parameters are specifically configured for a static route. The static route uses the session parameters configured for the BFD module (common BFD session parameters).

Configuring BFD control packet mode for a static route (indirect next hop)

1.     Enter system view.

system-view

2.     Configure BFD control packet mode for a static route.

Public network:

ip route-static dest-address { mask-length | mask } { next-hop-address bfd { control-packet bfd-source ip-address | static session-name } | vpn-instance d-vpn-instance-name next-hop-address bfd { control-packet bfd-source ip-address | static session-name } } [ preference preference ] [ tag tag-value ] [ description text ]

VPN:

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } { next-hop-address bfd { control-packet bfd-source ip-address | static session-name } | vpn-instance d-vpn-instance-name next-hop-address bfd { control-packet bfd-source ip-address | static session-name } } [ preference preference ] [ tag tag-value ] [ description text ]

By default, BFD control packet mode for a static route is not configured.

3.     (Optional.) Configure BFD session parameters for the static route.

ip route-static bfd [ vpn-instance d-vpn-instance-name ] next-hop-address source-ip ip-address { detect-multiplier detect-multiplier | min-receive-interval min-receive-interval | min-transmit-interval min-transmit-interval } *

By default, no BFD session parameters are specifically configured for a static route. The static route uses the session parameters configured for the BFD module (common BFD session parameters).

Configuring BFD echo packet mode

About this task

With BFD echo packet mode enabled for a static route, the output interface sends BFD echo packets to the destination device, which loops the packets back to test the link reachability.

Restrictions and guidelines

IMPORTANT

IMPORTANT:

Do not use BFD for a static route with the output interface in spoofing state.

 

You do not need to configure BFD echo packet mode at the peer end.

Procedure

1.     Enter system view.

system-view

2.     Configure the source address of echo packets.

bfd echo-source-ip ip-address

By default, the source address of echo packets is not configured.

For more information about this command, see High Availability Command Reference.

3.     Configure BFD echo packet mode for a static route.

Public network:

ip route-static dest-address { mask-length | mask } interface-type interface-number next-hop-address bfd { echo-packet | static session-name } [ preference preference ] [ tag tag-value ] [ description text ]

VPN:

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } interface-type interface-number next-hop-address bfd { echo-packet | static session-name } [ preference preference ] [ tag tag-value ] [ description text ]

By default, BFD echo packet mode for a static route is not configured.

4.     (Optional.) Configure BFD session parameters for the static route.

ip route-static bfd interface-type interface-number next-hop-address { detect-multiplier detect-multiplier | min-echo-receive-interval min-echo-receive-interval } *

By default, no BFD session parameters are specifically configured for a static route. The static route uses the session parameters configured for the BFD module (common BFD session parameters).

Configuring static route FRR

 

About static route FRR

A link or router failure on a path can cause packet loss. Static route fast reroute (FRR) enables fast rerouting to minimize the impact of link or node failures.

Figure 1 Network diagram

 

As shown in Figure 1, upon a link failure, packets are directed to the backup next hop to avoid traffic interruption. You can either specify a backup next hop for FRR or enable FRR to automatically select a backup next hop (which must be configured in advance).

Restrictions and guidelines for static route FRR

·     Do not use static route FRR and BFD (for a static route) at the same time.

·     Equal-cost routes do not support static route FRR.

·     Besides the configured static route for FRR, the device must have another route to reach the destination.

When the state of the primary link (with Layer 3 interfaces staying up) changes from bidirectional to unidirectional or down, static route FRR quickly redirects traffic to the backup next hop. When the Layer 3 interfaces of the primary link are down, static route FRR temporarily redirects traffic to the backup next hop. In addition, the device searches for another route to reach the destination and redirects traffic to the new path if a route is found. If no route is found, traffic interruption occurs.

Configuring static route FRR by specifying a backup next hop

Restrictions and guidelines

A static route does not take effect when the backup output interface is unavailable.

To change the backup output interface or next hop, you must first remove the current setting. The backup output interface and next hop must be different from the primary output interface and next hop.

Procedure

1.     Enter system view.

system-view

2.     Configure static route FRR.

Public network:

ip route-static dest-address { mask-length | mask } interface-type interface-number [ next-hop-address [ backup-interface interface-type interface-number [ backup-nexthop backup-nexthop-address ] ] ] [ permanent ] [ preference preference ] [ tag tag-value ] [ description text ]

VPN:

ip route-static vpn-instance s-vpn-instance-name dest-address { mask-length | mask } interface-type interface-number [ next-hop-address [ backup-interface interface-type interface-number [ backup-nexthop backup-nexthop-address ] ] ] [ permanent ] [ preference preference ] [ tag tag-value ] [ description text ]

By default, static route FRR is disabled.

Configuring static route FRR to automatically select a backup next hop

1.     Enter system view.

system-view

2.     Configure static route FRR to automatically select a backup next hop.

ip route-static fast-reroute auto

By default, static route FRR is disabled from automatically selecting a backup next hop.

Enabling BFD echo packet mode for static route FRR

About this task

By default, static route FRR uses ARP to detect primary link failures. Perform this task to enable static route FRR to use BFD echo packet mode for fast failure detection on the primary link.

Procedure

1.     Enter system view.

system-view

2.     Configure the source IP address of BFD echo packets.

bfd echo-source-ip ip-address

By default, the source IP address of BFD echo packets is not configured.

The source IP address cannot be on the same network segment as any local interface's IP address.

For more information about this command, see High Availability Command Reference.

3.     Enable BFD echo packet mode for static route FRR.

ip route-static primary-path-detect bfd echo

By default, BFD echo packet mode for static route FRR is disabled.

Allowing static routes to recurse to LSP tunnels

About this task

Devices in the service provider network will learn a large number of routes if they perform IP forwarding for all customer network packets. To conserve resources on the devices, use this feature on the device through which customer network users access the service provider network. This feature allows static routes to recurse to LSP tunnels. As a result, devices in the provider network will forward customer network IP packets based on labels, without the need to learn customer network routes.

This feature allows a device to preferentially recurse static routes to LSP tunnels. If a static route cannot recurse to an LSP tunnel, the device recurses the static route to an output interface and next hop.

Procedure

1.     Enter system view.

system-view

2.     Enable the device to recurse static routes to LSP tunnels.

ip route-static recursive-lookup tunnel [ prefix-list ipv4-prefix-list-name ] [ tunnel-policy tunnel-policy-name ]

By default, static routes cannot recurse to LSP tunnels.

Display and maintenance commands for static routing

Execute display commands in any view.

 

Task

Command

Display static route information.

display ip routing-table protocol static [ inactive | verbose ]

Display static route next hop information.

display route-static nib [ nib-id ] [ verbose ]

Display static routing table information.

display route-static routing-table [ ip-address { mask-length | mask } ]

display route-static routing-table [ vpn-instance vpn-instance-name ] [ ip-address { mask-length | mask } ]

Static route configuration examples

Example: Configuring basic static routes

Network configuration

As shown in Figure 2, configure static routes on the routers for interconnections between any two hosts.

Figure 2 Network diagram

Procedure

1.     Configure IP addresses for interfaces. (Details not shown.)

2.     Configure static routes:

# Configure a default route on Router A.

<RouterA> system-view

[RouterA] ip route-static 0.0.0.0 0.0.0.0 1.1.4.2

# Configure two static routes on Router B.

<RouterB> system-view

[RouterB] ip route-static 1.1.2.0 255.255.255.0 1.1.4.1

[RouterB] ip route-static 1.1.3.0 255.255.255.0 1.1.5.6

# Configure a default route on Router C.

<RouterC> system-view

[RouterC] ip route-static 0.0.0.0 0.0.0.0 1.1.5.5

3.     Configure the default gateways of Host A, Host B, and Host C as 1.1.2.3, 1.1.6.1, and 1.1.3.1. (Details not shown.)

Verifying the configuration

# Display the static route information on Router A.

[RouterA] display ip routing-table protocol static

 

Summary Count : 1

 

Static Routing table Status : <Active>

Summary Count : 1

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

0.0.0.0/0           Static 60   0            1.1.4.2         HGE1/0/2

 

Static Routing table Status : <Inactive>

Summary Count : 0

# Display the static route information on Router B.

[RouterB] display ip routing-table protocol static

 

Summary Count : 2

 

Static Routing table Status : <Active>

Summary Count : 2

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

1.1.2.0/24          Static 60   0            1.1.4.1         HGE1/0/1

1.1.3.0/24          Static 60   0            1.1.5.6         HGE1/0/2

 

Static Routing table Status : <Inactive>

Summary Count : 0

# Use the ping command on Host B to test the reachability of Host A (Windows XP runs on the two hosts).

C:\Documents and Settings\Administrator>ping 1.1.2.2

 

Pinging 1.1.2.2 with 32 bytes of data:

 

Reply from 1.1.2.2: bytes=32 time=1ms TTL=126

Reply from 1.1.2.2: bytes=32 time=1ms TTL=126

Reply from 1.1.2.2: bytes=32 time=1ms TTL=126

Reply from 1.1.2.2: bytes=32 time=1ms TTL=126

 

Ping statistics for 1.1.2.2:

    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),

Approximate round trip times in milli-seconds:

    Minimum = 1ms, Maximum = 1ms, Average = 1ms

# Use the tracert command on Host B to test the reachability of Host A.

C:\Documents and Settings\Administrator>tracert 1.1.2.2

 

Tracing route to 1.1.2.2 over a maximum of 30 hops

 

  1    <1 ms    <1 ms    <1 ms  1.1.6.1

  2    <1 ms    <1 ms    <1 ms  1.1.4.1

  3     1 ms    <1 ms    <1 ms  1.1.2.2

 

Trace complete.

Example: Configuring BFD for static routes (direct next hop)

Network configuration

Configure the following, as shown in Figure 3:

·     Configure a static route to subnet 120.1.1.0/24 on Router A.

·     Configure a static route to subnet 121.1.1.0/24 on Router B.

·     Enable BFD for both routes.

·     Configure a static route to subnet 120.1.1.0/24 and a static route to subnet 121.1.1.0/24 on Router C.

When the link between Router A and Router B through the Layer 2 switch fails, BFD can detect the failure immediately. Router A then communicates with Router B through Router C.

Figure 3 Network diagram

Table 1 Interface and IP address assignment

Device

Interface

IP address

Router A

HundredGigE 1/0/1

12.1.1.1/24

Router A

HundredGigE 1/0/2

10.1.1.102/24

Router B

HundredGigE 1/0/1

12.1.1.2/24

Router B

HundredGigE 1/0/2

13.1.1.1/24

Router C

HundredGigE 1/0/1

10.1.1.100/24

Router C

HundredGigE 1/0/2

13.1.1.2/24

 

Procedure

1.     Configure IP addresses for interfaces. (Details not shown.)

2.     Configure static routes and BFD:

# Configure static routes on Route A and enable BFD control packet mode for the static route that traverses the Layer 2 switch.

<RouterA> system-view

[RouterA] interface hundredgige 1/0/1

[RouterA-HundredGigE1/0/1] bfd min-transmit-interval 500

[RouterA-HundredGigE1/0/1] bfd min-receive-interval 500

[RouterA-HundredGigE1/0/1] bfd detect-multiplier 9

[RouterA-HundredGigE1/0/1] quit

[RouterA] ip route-static 120.1.1.0 24 hundredgige 1/0/1 12.1.1.2 bfd control-packet

[RouterA] ip route-static 120.1.1.0 24 hundredgige 1/0/2 10.1.1.100 preference 65

[RouterA] quit

# Configure static routes on Router B and enable BFD control packet mode for the static route that traverses the Layer 2 switch.

<RouterB> system-view

[RouterB] interface hundredgige 1/0/1

[RouterB-HundredGigE1/0/1] bfd min-transmit-interval 500

[RouterB-HundredGigE1/0/1] bfd min-receive-interval 500

[RouterB-HundredGigE1/0/1] bfd detect-multiplier 9

[RouterB-HundredGigE1/0/1] quit

[RouterB] ip route-static 121.1.1.0 24 hundredgige 1/0/1 12.1.1.1 bfd control-packet

[RouterB] ip route-static 121.1.1.0 24 hundredgige 1/0/2 13.1.1.2 preference 65

[RouterB] quit

# Configure static routes on Router C.

<RouterC> system-view

[RouterC] ip route-static 120.1.1.0 24 13.1.1.1

[RouterC] ip route-static 121.1.1.0 24 10.1.1.102

Verifying the configuration

# Display BFD sessions on Router A.

<RouterA> display bfd session

 Total sessions: 1        Up sessions: 1        Init mode: Active

 

 IPv4 session working in control packet mode:

 

 LD/RD          SourceAddr      DestAddr        State    Holdtime    Interface

 4/7            12.1.1.1        12.1.1.2        Up       2000ms      HGE1/0/1

The output shows that the BFD session has been created.

# Display static routes on Router A.

<RouterA> display ip routing-table protocol static

 

Summary Count : 1

 

Static Routing table Status : <Active>

Summary Count : 1

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

120.1.1.0/24        Static 60   0            12.1.1.2        HGE1/0/1

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Router A communicates with Router B through HundredGigE 1/0/1. Then the link over HundredGigE 1/0/1 fails.

# Display static routes on Router A.

<RouterA> display ip routing-table protocol static

 

Summary Count : 1

 

Static Routing table Status : <Active>

Summary Count : 1

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

120.1.1.0/24        Static 65   0            10.1.1.100      HGE1/0/2

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Router A communicates with Router B through HundredGigE 1/0/2.

Example: Configuring BFD for static routes (indirect next hop)

Network configuration

Figure 4 shows the network topology as follows:

·     Router A has a route to interface Loopback 1 (2.2.2.9/32) on Router B, with the output interface HundredGigE 1/0/1.

·     Router B has a route to interface Loopback 1 (1.1.1.9/32) on Router A, with the output interface HundredGigE 1/0/1.

·     Router D has a route to 1.1.1.9/32, with the output interface HundredGigE 1/0/1, and a route to 2.2.2.9/32, with the output interface HundredGigE 1/0/2.

Configure the following:

·     Configure a static route to subnet 120.1.1.0/24 on Router A.

·     Configure a static route to subnet 121.1.1.0/24 on Router B.

·     Enable BFD for both routes.

·     Configure a static route to subnet 120.1.1.0/24 and a static route to subnet 121.1.1.0/24 on both Router C and Router D.

When the link between Router A and Router B through Router D fails, BFD can detect the failure immediately. Router A then communicates with Router B through Router C.

Figure 4 Network diagram

Table 2 Interface and IP address assignment

Device

Interface

IP address

Router A

HundredGigE 1/0/1

12.1.1.1/24

Router A

HundredGigE 1/0/2

10.1.1.102/24

Router A

Loopback 1

1.1.1.9/32

Router B

HundredGigE 1/0/1

11.1.1.2/24

Router B

HundredGigE 1/0/2

13.1.1.1/24

Router B

Loopback 1

2.2.2.9/32

Router C

HundredGigE 1/0/1

10.1.1.100/24

Router C

HundredGigE 1/0/2

13.1.1.2/24

Router D

HundredGigE 1/0/1

12.1.1.2/24

Router D

HundredGigE 1/0/2

11.1.1.2/24

 

Procedure

1.     Configure IP addresses for interfaces. (Details not shown.)

2.     Configure static routes and BFD:

# Configure static routes on Router A and enable BFD control packet mode for the static route that traverses Router D.

<RouterA> system-view

[RouterA] bfd multi-hop min-transmit-interval 500

[RouterA] bfd multi-hop min-receive-interval 500

[RouterA] bfd multi-hop detect-multiplier 9

[RouterA] ip route-static 120.1.1.0 24 2.2.2.9 bfd control-packet bfd-source 1.1.1.9

[RouterA] ip route-static 120.1.1.0 24 hundredgige 1/0/2 10.1.1.100 preference 65

[RouterA] quit

# Configure static routes on Router B and enable BFD control packet mode for the static route that traverses Router D.

<RouterB> system-view

[RouterB] bfd multi-hop min-transmit-interval 500

[RouterB] bfd multi-hop min-receive-interval 500

[RouterB] bfd multi-hop detect-multiplier 9

[RouterB] ip route-static 121.1.1.0 24 1.1.1.9 bfd control-packet bfd-source 2.2.2.9

[RouterB] ip route-static 121.1.1.0 24 hundredgige 1/0/2 13.1.1.2 preference 65

[RouterB] quit

# Configure static routes on Router C.

<RouterC> system-view

[RouterC] ip route-static 120.1.1.0 24 13.1.1.1

[RouterC] ip route-static 121.1.1.0 24 10.1.1.102

# Configure static routes on Router D.

<RouterD> system-view

[RouterD] ip route-static 120.1.1.0 24 11.1.1.2

[RouterD] ip route-static 121.1.1.0 24 12.1.1.1

Verifying the configuration

# Display the BFD session information on Router A.

<RouterA> display bfd session

 Total sessions: 1        Up sessions: 1        Init mode: Active

 

 IPv4 session working in control packet mode:

 

 LD/RD          SourceAddr      DestAddr        State    Holdtime    Interface

 4/7            1.1.1.9         2.2.2.9         Up       2000ms      N/A

The output shows that the BFD session has been created.

# Display static routes on Router A.

<RouterA> display ip routing-table protocol static

 

Summary Count : 1

 

Static Routing table Status : <Active>

Summary Count : 1

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

120.1.1.0/24        Static 60   0            12.1.1.2        HGE1/0/1

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Router A communicates with Router B through HundredGigE 1/0/1. Then the link over HundredGigE 1/0/1 fails.

# Display static routes on Router A.

<RouterA> display ip routing-table protocol static

 

Summary Count : 1

 

Static Routing table Status : <Active>

Summary Count : 1

 

Destination/Mask    Proto  Pre  Cost         NextHop         Interface

120.1.1.0/24        Static 65   0            10.1.1.100      HGE1/0/2

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Router A communicates with Router B through HundredGigE 1/0/2.

Example: Configuring static route FRR

Network configuration

As shown in Figure 5, configure static routes on Router A, Router B, and Router C, and configure static route FRR. When Link A becomes unidirectional, traffic can be switched to Link B immediately.

Figure 5 Network diagram

Table 3 Interface and IP address assignment

Device

Interface

IP address

Router A

HundredGigE 1/0/1

12.12.12.1/24

Router A

HundredGigE 1/0/2

13.13.13.1/24

Router A

Loopback 0

1.1.1.1/32

Router B

HundredGigE 1/0/1

24.24.24.4/24

Router B

HundredGigE 1/0/2

13.13.13.2/24

Router B

Loopback 0

4.4.4.4/32

Router C

HundredGigE 1/0/1

12.12.12.2/24

Router C

HundredGigE 1/0/2

24.24.24.2/24

 

Procedure

1.     Configure IP addresses for interfaces. (Details not shown.)

2.     Configure static route FRR on link A by using one of the following methods:

¡     (Method 1.) Specify a backup next hop for static route FRR:

# Configure a static route on Router A, and specify HundredGigE 1/0/1 as the backup output interface and 12.12.12.2 as the backup next hop.

<RouterA> system-view

[RouterA] ip route-static 4.4.4.4 32 hundredgige 1/0/2 13.13.13.2 backup-interface hundredgige 1/0/1 backup-nexthop 12.12.12.2

# Configure a static route on Router B, and specify HundredGigE 1/0/1 as the backup output interface and 24.24.24.2 as the backup next hop.

<RouterB> system-view

[RouterB] ip route-static 1.1.1.1 32 hundredgige 1/0/2 13.13.13.1 backup-interface hundredgige 1/0/1 backup-nexthop 24.24.24.2

¡     (Method 2.) Configure static route FRR to automatically select a backup next hop:

# Configure static routes on Router A, and enable static route FRR.

<RouterA> system-view

[RouterA] ip route-static 4.4.4.4 32 hundredgige 1/0/2 13.13.13.2

[RouterA] ip route-static 4.4.4.4 32 hundredgige 1/0/1 12.12.12.2 preference 70

[RouterA] ip route-static fast-reroute auto

# Configure static routes on Router B, and enable static route FRR.

<RouterB> system-view

[RouterB] ip route-static 1.1.1.1 32 hundredgige 1/0/2 13.13.13.1

[RouterB] ip route-static 1.1.1.1 32 hundredgige 1/0/1 24.24.24.2 preference 70

[RouterB] ip route-static fast-reroute auto

3.     Configure static routes on Router C.

<RouterC> system-view

[RouterC] ip route-static 4.4.4.4 32 hundredgige 1/0/2 24.24.24.4

[RouterC] ip route-static 1.1.1.1 32 hundredgige 1/0/1 12.12.12.1

Verifying the configuration

# Display route 4.4.4.4/32 on Router A to view the backup next hop information.

[RouterA] display ip routing-table 4.4.4.4 verbose

 

Summary Count : 1

 

 Destination: 4.4.4.4/32

    Protocol: Static

  Process ID: 0

   SubProtID: 0x0                       Age: 04h20m37s

        Cost: 0                  Preference: 60

       IpPre: N/A                QosLocalID: N/A

         Tag: 0                       State: Active Adv

   OrigTblID: 0x0                   OrigVrf: default-vrf

     TableID: 0x2                    OrigAs: 0

       NibID: 0x26000002             LastAs: 0

      AttrID: 0xffffffff           Neighbor: 0.0.0.0

       Flags: 0x1008c           OrigNextHop: 13.13.13.2

       Label: NULL              RealNextHop: 13.13.13.2

     BkLabel: NULL                BkNextHop: 12.12.12.2

     SRLabel: NULL                Interface: HundredGigE1/0/2

   BkSRLabel: NULL              BkInterface: HundredGigE1/0/1

   Tunnel ID: Invalid           IPInterface: HundredGigE1/0/2

 BkTunnel ID: Invalid         BkIPInterface: HundredGigE1/0/1

     InLabel: NULL           ColorInterface: N/A

    SIDIndex: NULL         BkColorInterface: N/A

    FtnIndex: 0x0              TrafficIndex: N/A

   Connector: N/A                    PathID: 0x0

      UserID: 0x0                SRTunnelID: Invalid

    SID Type: N/A                       NID: Invalid

    FlushNID: Invalid                 BkNID: Invalid

  BkFlushNID: Invalid

# Display route 1.1.1.1/32 on Router B to view the backup next hop information.

[RouterB] display ip routing-table 1.1.1.1 verbose

 

Summary Count : 1

 

 Destination: 1.1.1.1/32

    Protocol: Static

  Process ID: 0

   SubProtID: 0x0                       Age: 04h20m37s

        Cost: 0                  Preference: 10

       IpPre: N/A                QosLocalID: N/A

         Tag: 0                       State: Active Adv

   OrigTblID: 0x0                   OrigVrf: default-vrf

     TableID: 0x2                    OrigAs: 0

       NibID: 0x26000002             LastAs: 0

      AttrID: 0xffffffff           Neighbor: 0.0.0.0

       Flags: 0x1008c           OrigNextHop: 13.13.13.1

       Label: NULL              RealNextHop: 13.13.13.1

     BkLabel: NULL                BkNextHop: 24.24.24.2

     SRLabel: NULL                Interface: HundredGigE1/0/2

   BkSRLabel: NULL              BkInterface: HundredGigE1/0/1

   Tunnel ID: Invalid           IPInterface: HundredGigE1/0/2

 BkTunnel ID: Invalid         BkIPInterface: HundredGigE1/0/1

     InLabel: NULL           ColorInterface: N/A

    SIDIndex: NULL         BkColorInterface: N/A

    FtnIndex: 0x0              TrafficIndex: N/A

   Connector: N/A                    PathID: 0x0

      UserID: 0x0                SRTunnelID: Invalid

    SID Type: N/A                       NID: Invalid

    FlushNID: Invalid                 BkNID: Invalid

  BkFlushNID: Invalid


Configuring a default route

A default route is used to forward packets that do not match any specific routing entry in the routing table. Without a default route, packets that do not match any routing entries are discarded and an ICMP destination-unreachable packet is sent to the source.

A default route can be configured in either of the following ways:

·     The network administrator can configure a default route with both destination and mask being 0.0.0.0. For more information, see "Configuring static routing."

·     Some dynamic routing protocols can generate a default route. For example, an upstream router running OSPF can generate a default route and advertise it to other routers. These routers install the default route with the next hop being the upstream router. For more information, see the respective chapters on these routing protocols in this configuration guide.

 

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