05-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 [ recursive-lookup host-route ] | vpn-instance d-vpn-instance-name next-hop-address [ recursive-lookup host-route ] } [ permanent | track track-entry-number ] [ 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 [ recursive-lookup host-route ] [ public ] | vpn-instance d-vpn-instance-name next-hop-address [ recursive-lookup host-route ] } [ permanent | track track-entry-number ] [ 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.) Enable periodic sending of ARP requests to the next hops of static routes.

ip route-static arp-request interval interval

By default, the device does not send ARP requests to the next hops of static routes.

4.        (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 static route groups

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

By default, no static route is configured.

Deleting static routes

About deleting static routes

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.

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

Configuring bidirectional control mode

About bidirectional control mode

To use BFD bidirectional control detection between two devices, enable BFD control mode for each device's static route destined to the peer.

To configure a static route and enable BFD control mode, use one of the following methods:

·          Specify an output interface and a direct next hop.

·          Specify an indirect next hop and a specific BFD packet source address for the static route.

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

1.        Enter system view.

system-view

2.        Configure BFD control 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 [ 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 [ preference preference ] [ tag tag-value ] [ description text ]

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

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

1.        Enter system view.

system-view

2.        Configure BFD control 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 | vpn-instance d-vpn-instance-name next-hop-address bfd control-packet bfd-source ip-address } [ 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 | vpn-instance d-vpn-instance-name next-hop-address bfd control-packet bfd-source ip-address } [ preference preference ] [ tag tag-value ] [ description text ]

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

Configuring single-hop echo mode

About single-hop echo mode

With BFD echo 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.

 

IMPORTANT

IMPORTANT:

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

 

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 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 [ 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 [ preference preference ] [ tag tag-value ] [ description text ]

Configuring static route FRR

About static route FRR

A link or router failure on a path can cause packet loss and even routing loop. 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 BFD echo packet mode

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 mode for static route FRR is disabled.

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 [ 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 switches 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 Switch A.

<SwitchA> system-view

[SwitchA] ip route-static 0.0.0.0 0.0.0.0 1.1.4.2

# Configure two static routes on Switch B.

<SwitchB> system-view

[SwitchB] ip route-static 1.1.2.0 255.255.255.0 1.1.4.1

[SwitchB] ip route-static 1.1.3.0 255.255.255.0 1.1.5.6

# Configure a default route on Switch C.

<SwitchC> system-view

[SwitchC] 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 static routes on Switch A.

[SwitchA] 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         Vlan500

 

Static Routing table Status : <Inactive>

Summary Count : 0

# Display static routes on Switch B.

[SwitchB] 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         Vlan500

 

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 Switch A.

·          Configure a static route to subnet 121.1.1.0/24 on Switch 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 Switch C.

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

Figure 3 Network diagram

 

Table 1 Interface and IP address assignment

Device

Interface

IP address

Switch A

VLAN-interface 10

12.1.1.1/24

Switch A

VLAN-interface 11

10.1.1.102/24

Switch B

VLAN-interface 10

12.1.1.2/24

Switch B

VLAN-interface 13

13.1.1.1/24

Switch C

VLAN-interface 11

10.1.1.100/24

Switch C

VLAN-interface 13

13.1.1.2/24

 

Procedure

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

2.        Configure static routes and BFD:

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

<SwitchA> system-view

[SwitchA] interface vlan-interface 10

[SwitchA-vlan-interface10] bfd min-transmit-interval 500

[SwitchA-vlan-interface10] bfd min-receive-interval 500

[SwitchA-vlan-interface10] bfd detect-multiplier 9

[SwitchA-vlan-interface10] quit

[SwitchA] ip route-static 120.1.1.0 24 vlan-interface 10 12.1.1.2 bfd control-packet

[SwitchA] ip route-static 120.1.1.0 24 vlan-interface 11 10.1.1.100 preference 65

[SwitchA] quit

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

<SwitchB> system-view

[SwitchB] interface vlan-interface 10

[SwitchB-vlan-interface10] bfd min-transmit-interval 500

[SwitchB-vlan-interface10] bfd min-receive-interval 500

[SwitchB-vlan-interface10] bfd detect-multiplier 9

[SwitchB-vlan-interface10] quit

[SwitchB] ip route-static 121.1.1.0 24 vlan-interface 10 12.1.1.1 bfd control-packet

[SwitchB] ip route-static 121.1.1.0 24 vlan-interface 13 13.1.1.2 preference 65

[SwitchB] quit

# Configure static routes on Switch C.

<SwitchC> system-view

[SwitchC] ip route-static 120.1.1.0 24 13.1.1.1

[SwitchC] ip route-static 121.1.1.0 24 10.1.1.102

Verifying the configuration

# Display BFD sessions on Switch A.

<SwitchA> display bfd session

 

 Total Session Num: 1     Up Session Num: 1     Init Mode: Active

 

 IPv4 Session Working Under Ctrl Mode:

 

 LD/RD          SourceAddr      DestAddr        State    Holdtime    Interface

 4/7            12.1.1.1        12.1.1.2        Up       2000ms      Vlan10

The output shows that the BFD session has been created.

# Display the static routes on Switch A.

<SwitchA> 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        Vlan10

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 10. Then the link over VLAN-interface 10 fails.

# Display static routes on Switch A.

<SwitchA> 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      Vlan11

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 11.

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

Network configuration

Figure 4 shows the network topology as follows:

·          Switch A has a route to interface Loopback 1 (2.2.2.9/32) on Switch B, with the output interface VLAN-interface 10.

·          Switch B has a route to interface Loopback 1 (1.1.1.9/32) on Switch A, with the output interface VLAN-interface 12.

·          Switch D has a route to 1.1.1.9/32, with the output interface VLAN-interface 10, and a route to 2.2.2.9/32, with the output interface VLAN-interface 12.

Configure the following:

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

·          Configure a static route to subnet 121.1.1.0/24 on Switch 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 Switch C and Switch D.

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

Figure 4 Network diagram

 

Table 2 Interface and IP address assignment

Device

Interface

IP address

Switch A

VLAN-interface 10

12.1.1.1/24

Switch A

VLAN-interface 11

10.1.1.102/24

Switch A

Loopback 1

1.1.1.9/32

Switch B

VLAN-interface 12

11.1.1.1/24

Switch B

VLAN-interface 13

13.1.1.1/24

Switch B

Loopback 1

2.2.2.9/32

Switch C

VLAN-interface 11

10.1.1.100/24

Switch C

VLAN-interface 13

13.1.1.2/24

Switch D

VLAN-interface 10

12.1.1.2/24

Switch D

VLAN-interface 12

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 Switch A and enable BFD control mode for the static route that traverses Switch D.

<SwitchA> system-view

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

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

[SwitchA] bfd multi-hop detect-multiplier 9

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

[SwitchA] ip route-static 120.1.1.0 24 vlan-interface 11 10.1.1.100 preference 65

[SwitchA] quit

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

<SwitchB> system-view

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

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

[SwitchB] bfd multi-hop detect-multiplier 9

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

[SwitchB] ip route-static 121.1.1.0 24 vlan-interface 13 13.1.1.2 preference 65

[SwitchB] quit

# Configure static routes on Switch C.

<SwitchC> system-view

[SwitchC] ip route-static 120.1.1.0 24 13.1.1.1

[SwitchC] ip route-static 121.1.1.0 24 10.1.1.102

# Configure static routes on Switch D.

<SwitchD> system-view

[SwitchD] ip route-static 120.1.1.0 24 11.1.1.1

[SwitchD] ip route-static 121.1.1.0 24 12.1.1.1

Verifying the configuration

# Display BFD sessions on Switch A.

<SwitchA> display bfd session

 

 Total Session Num: 1     Up Session Num: 1     Init Mode: Active

 

 IPv4 Session Working Under Ctrl 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 the static routes on Switch A.

<SwitchA> 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        Vlan10

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 10. Then the link over VLAN-interface 10 fails.

# Display static routes on Switch A.

<SwitchA> 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      Vlan11

 

Static Routing table Status : <Inactive>

Summary Count : 0

The output shows that Switch A communicates with Switch B through VLAN-interface 11.

Example: Configuring static route FRR

Network configuration

As shown in Figure 5, configure static routes on Switch A, Switch B, and Switch 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

Switch A

VLAN-interface 100

12.12.12.1/24

Switch A

VLAN-interface 200

13.13.13.1/24

Switch A

Loopback 0

1.1.1.1/32

Switch B

VLAN-interface 101

24.24.24.4/24

Switch B

VLAN-interface 200

13.13.13.2/24

Switch B

Loopback 0

4.4.4.4/32

Switch C

VLAN-interface 100

12.12.12.2/24

Switch C

VLAN-interface 101

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 Switch A, and specify VLAN-interface 100 as the backup output interface and 12.12.12.2 as the backup next hop.

<SwitchA> system-view

[SwitchA] ip route-static 4.4.4.4 32 vlan-interface 200 13.13.13.2 backup-interface vlan-interface 100 backup-nexthop 12.12.12.2

# Configure a static route on Switch A to reach the same destination.

[SwitchA] ip route-static 4.4.4.4 32 vlan-interface 100 12.12.12.2 preference 70

# Configure a static route on Switch B, and specify VLAN-interface 101 as the backup output interface and 24.24.24.2 as the backup next hop.

<SwitchB> system-view

[SwitchB] ip route-static 1.1.1.1 32 vlan-interface 200 13.13.13.1 backup-interface vlan-interface 101 backup-nexthop 24.24.24.2

# Configure a static route on Switch B to reach the same destination.

[SwitchB] ip route-static 1.1.1.1 32 vlan-interface 101 24.24.24.2 preference 70

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

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

<SwitchA> system-view

[SwitchA] ip route-static 4.4.4.4 32 vlan-interface 200 13.13.13.2

[SwitchA] ip route-static 4.4.4.4 32 vlan-interface 100 12.12.12.2 preference 70

[SwitchA] ip route-static fast-reroute auto

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

<SwitchB> system-view

[SwitchB] ip route-static 1.1.1.1 32 vlan-interface 200 13.13.13.1

[SwitchB] ip route-static 1.1.1.1 32 vlan-interface 101 24.24.24.2 preference 70

[SwitchB] ip route-static fast-reroute auto

3.        Configure static routes on Switch C.

<SwitchC> system-view

[SwitchC] ip route-static 4.4.4.4 32 vlan-interface 101 24.24.24.4

[SwitchC] ip route-static 1.1.1.1 32 vlan-interface 100 12.12.12.1

Verifying the configuration

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

[SwitchA] 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

  Tunnel ID: Invalid           Interface: Vlan-interface200

BkTunnel ID: Invalid         BkInterface: Vlan-interface100

   FtnIndex: 0x0            TrafficIndex: N/A

  Connector: N/A

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

[SwitchB] 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: 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: 13.13.13.1

      Label: NULL            RealNextHop: 13.13.13.1

    BkLabel: NULL              BkNextHop: 24.24.24.2

  Tunnel ID: Invalid           Interface: Vlan-interface200

BkTunnel ID: Invalid         BkInterface: Vlan-interface101

   FtnIndex: 0x0            TrafficIndex: N/A

  Connector: N/A


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 (such as OSPF, IS-IS, and RIP) 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.