Configuring static routing· 1

Configuring a static route· 1

Configuring BFD for static routes 2

Bidirectional control mode· 2

Single-hop echo mode· 3

Configuring static route FRR· 4

Configuration guidelines 4

Configuration procedure· 4

Displaying and maintaining static routes 5

Static route configuration examples 5

Basic static route configuration example· 5

BFD for static routes configuration example (direct next hop) 7

BFD for static routes configuration example (indirect next hop) 9

Static route FRR configuration example· 12

Configuring a default route· 1

 

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

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

Before you configure a static route, complete the following tasks:

·           Configure the physical parameters for related interfaces.

·           Configure the link-layer attributes for related interfaces.

·           Configure the IP addresses for related interfaces.

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.

To configure a static route:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Configure a static route.	·       Approach 1: ip route-static dest-address { mask | mask-length } { next-hop-address [ track track-entry-number ] | interface-type interface-number [ next-hop-address ] | vpn-instance d-vpn-instance-name next-hop-address [ track track-entry-number ] } [ permanent ] [ preference preference-value ] [ tag tag-value ] [ description description-text ] ·       Approach 2: ip route-static vpn-instance s-vpn-instance-name dest-address { mask | mask-length } { next-hop-address [ public ] [ track track-entry-number ] | interface-type interface-number [ next-hop-address ] | vpn-instance d-vpn-instance-name next-hop-address [ track track-entry-number ] } [ permanent ] [ preference preference-value ] [ tag tag-value ] [ description description-text ]	Use either approach. By default, no static route is configured.
3.     (Optional.) Configure the default preference for static routes.	ip route-static default-preference default-preference-value	The default setting is 60.
4.     (Optional.) Delete all static routes, including the default route.	delete [ vpn-instance vpn-instance-name ] static-routes all	To delete one static route, use the undo ip route-static command.

 

Configuring BFD for static routes

 

IMPORTANT: Enabling BFD for a flapping route could worsen the situation.

 

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.

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 for it, specify an output interface and a direct next hop, or specify an indirect next hop and a specific BFD packet source address for the static route.

To configure BFD control mode for a static route (direct next hop):

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
1.     Configure BFD control mode for a static route.	·       Approach 1: ip route-static dest-address { mask | mask-length } interface-type interface-number next-hop-address bfd control-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] ·       Approach 2: ip route-static vpn-instance s-vpn-instance-name dest-address { mask | mask-length } interface-type interface-number next-hop-address bfd control-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ]	Use either approach. By default, BFD control mode for a static route is not configured.

 

To configure BFD control mode for a static route (indirect next hop):

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Configure BFD control mode for a static route.	·       Approach 1: ip route-static dest-address { mask | mask-length } { 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-value ] [ tag tag-value ] [ description description-text ] ·       Approach 2: ip route-static vpn-instance s-vpn-instance-name dest-address { mask | mask-length } { 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-value ] [ tag tag-value ] [ description description-text ]	Use either approach. By default, BFD control mode for a static route is not configured.

 

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

 

To configure BFD echo mode for a static route:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
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.	·       Approach 1: ip route-static dest-address { mask | mask-length } interface-type interface-number next-hop-address bfd echo-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ] ·       Approach 2: ip route-static vpn-instance s-vpn-instance-name dest-address { mask | mask-length } interface-type interface-number next-hop-address bfd echo-packet [ preference preference-value ] [ tag tag-value ] [ description description-text ]	Use either approach. By default, BFD echo mode for a static route is not configured.

 

Configuring 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, FRR specifies a backup next hop by using a routing policy for routes matching the specified criteria. Packets are directed to the backup next hop to avoid traffic interruption.

Configuration guidelines

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

·           Static route does not take effect when the backup output interface is unavailable.

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

·           The backup output interface and next hop cannot be modified directly or the same as the primary output interface and next hop.

Configuration procedure

To configure static route FRR:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Configure the source address of BFD echo packets.	bfd echo-source-ip ip-address	By default, the source address of BFD echo packets is not configured. For more information about this command, see High Availability Command Reference.
3.     Configure static route FRR.	·       Approach 1: ip route-static dest-address { mask | mask-length } interface-type interface-number [ next-hop-address [ backup-interface interface-type interface-number [ backup-nexthop backup-nexthop-address ] ] ] [ permanent ] ·       Approach 2: ip route-static vpn-instance s-vpn-instance-name dest-address { mask | mask-length } interface-type interface-number [ next-hop-address [ backup-interface interface-type interface-number [ backup-nexthop backup-nexthop-address ] ] ] [ permanent ]	Use either approach. By default, static route FRR is not configured.

 

Displaying and maintaining static routes

Execute the display command in any view.

 

Task	Command
Display static route information.	display ip routing-table protocol static [ inactive | verbose ]

 

Static route configuration examples

By default, Ethernet, VLAN, and aggregate interfaces are down. To configure such an interface, bring the interface up by executing the undo shutdown command.

Basic static route configuration example

Network requirements

Configure static routes on the switches in Figure 2 for interconnections between any two hosts.

Figure 2 Network diagram

 

Configuration 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.

BFD for static routes configuration example (direct next hop)

Network requirements

In Figure 3, configure a static route to subnet 120.1.1.0/24 on Switch A, and 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 and inform Switch A and Switch B to communicate through Switch C.

Figure 3 Network diagram

 

Device	Interface	IP address	Device	Interface	IP address
Switch A	Vlan-int10	12.1.1.1/24	Switch B	Vlan-int10	12.1.1.2/24
	Vlan-int11	10.1.1.102/24		Vlan-int13	13.1.1.1/24
Switch C	Vlan-int11	10.1.1.100/24
	Vlan-int13	13.1.1.2/24

 

Configuration 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.

BFD for static routes configuration example (indirect next hop)

Network requirements

In Figure 4, 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 a static route to subnet 120.1.1.0/24 on Switch A, and 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 and inform Switch A and Switch B to communicate through Switch C.

Figure 4 Network diagram

 

 

Configuration 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      Loop1

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.

Static route FRR configuration example

Network requirements

As shown in Figure 5, configure static routes on Switch S, Switch A, and Switch D, and configure static route FRR so when Link A fails, traffic can be switched to Link B immediately.

Figure 5 Network diagram

 

Configuration procedure

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

2.      Configure static routes FRR on link A:

# Configure a static route on Switch S, and specify VLAN-inteface 100 as the backup output interface and 12.12.12.2 as the backup next hop.

<SwitchS> system-view

[SwitchS] bfd echo-source-ip 4.4.4.4

[SwitchS] 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 D, and specify VLAN-interface 101 as the backup output interface and 24.24.24.2 as the backup next hop.

<SwitchD> system-view

[SwitchD] bfd echo-source-ip 1.1.1.1

[SwitchD] 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

3.      Configure static routes on Switch A.

<SwitchA> system-view

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

[SwitchA] 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 S to view the backup next hop information.

[SwitchS] 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

        Tag: 0                    State: Active Adv

  OrigTblID: 0x0                OrigVrf: default-vrf

    TableID: 0x2                 OrigAs: 0

      NBRID: 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

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

[SwitchD] 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

        Tag: 0                    State: Active Adv

  OrigTblID: 0x0                OrigVrf: default-vrf

    TableID: 0x2                 OrigAs: 0

      NBRID: 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

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 a static route."

·           Some dynamic routing protocols, such as OSPF, RIP, and IS-IS, can generate a default route. For example, an upstream router running OSPF can generate a default route and advertise it to other routers, which 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.