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Title | Size | Download |
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02-Static routing configuration | 193.98 KB |
Configuring BFD for static routes
Displaying and maintaining static routes
Static route configuration examples
Basic static route configuration example
BFD for static routes configuration example (direct next hop)
BFD for static routes configuration example (indirect next hop)
Static route FRR configuration example
Configuring static routing
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
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. (Optional.) Create a static route group and enter its view. |
ip route-static-group group-name |
By default, no static route group is configured. |
3. (Optional.) Configure a static route prefix. |
prefix dest-address { mask-length | mask } |
By default, no static route prefix is configured. |
4. (Optional.) Return to system view. |
quit |
N/A |
5. Configure a static route. |
· Method 1: · Method 2: · Method 3: |
By default, no static route is configured. |
6. (Optional.) Configure the default preference for static routes. |
ip route-static default-preference default-preference |
The default setting is 60. |
7. (Optional.) Delete all static routes, including the default route. |
delete [ topology topo-name | 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, 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.
To configure BFD control mode for a static route (direct next hop):
Step |
Command |
Remarks |
1. Enter system view. |
system-view |
N/A |
2. Configure BFD control mode for a static route. |
· Method 1: · Method 2: |
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. |
· Method 1: · Method 2: |
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. |
· Method 1: · Method 2: |
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.
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).
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, and cannot be the same as the primary output interface and next hop.
· Static route FRR is available only when the state of primary link (with Layer 3 interfaces staying up) changes from bidirectional to unidirectional or down.
Configuration procedure
Configuring static route FRR by specifying a backup next hop
Step |
Command |
Remarks |
1. Enter system view. |
system-view |
N/A |
2. Configure static route FRR. |
· Method 1: · Method 2: · Method 3: |
By default, static route FRR is disabled. |
Configuring static route FRR to automatically select a backup next hop
Step |
Command |
Remarks |
1. Enter system view. |
system-view |
N/A |
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
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.
To enable BFD echo packet mode for static route FRR:
Step |
Command |
Remarks |
1. Enter system view. |
system-view |
N/A |
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. |
Displaying and maintaining static routes
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 [ topology topo-name | vpn-instance vpn-instance-name ] [ ip-address { mask-length | mask } ] |
Static route configuration examples
Basic static route configuration example
Network requirements
As shown in Figure 2, configure static routes on the routers for interconnections between any two hosts.
Configuration 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 GE1/1/2
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 GE1/1/1
1.1.3.0/24 Static 60 0 1.1.5.6 GE1/1/2
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.
BFD for static routes configuration example (direct next hop)
Network requirements
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 |
GigabitEthernet 1/1/1 |
12.1.1.1/24 |
Router A |
GigabitEthernet 1/1/2 |
10.1.1.102/24 |
Router B |
GigabitEthernet 1/1/1 |
12.1.1.2/24 |
Router B |
GigabitEthernet 1/1/2 |
13.1.1.1/24 |
Router C |
GigabitEthernet 1/1/1 |
10.1.1.100/24 |
Router C |
GigabitEthernet 1/1/2 |
13.1.1.2/24 |
Configuration 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 mode for the static route that traverses the Layer 2 switch.
[RouterA] interface gigabitethernet 1/1/1
[RouterA-GigabitEthernet1/1/1] bfd min-transmit-interval 500
[RouterA-GigabitEthernet1/1/1] bfd min-receive-interval 500
[RouterA-GigabitEthernet1/1/1] bfd detect-multiplier 9
[RouterA-GigabitEthernet1/1/1] quit
[RouterA] ip route-static 120.1.1.0 24 gigabitethernet 1/1/1 12.1.1.2 bfd control-packet
[RouterA] ip route-static 120.1.1.0 24 gigabitethernet 1/1/2 10.1.1.100 preference 65
[RouterA] quit
# Configure static routes on Router B and enable BFD control mode for the static route that traverses the Layer 2 switch.
[RouterB] interface gigabitethernet 1/1/1
[RouterB-GigabitEthernet1/1/1] bfd min-transmit-interval 500
[RouterB-GigabitEthernet1/1/1] bfd min-receive-interval 500
[RouterB-GigabitEthernet1/1/1] bfd detect-multiplier 9
[RouterB-GigabitEthernet1/1/1] quit
[RouterB] ip route-static 121.1.1.0 24 gigabitethernet 1/1/1 12.1.1.1 bfd control-packet
[RouterB] ip route-static 121.1.1.0 24 gigabitethernet 1/1/2 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 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 GE1/1/1
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 GE1/1/1
Static Routing table Status : <Inactive>
Summary Count : 0
The output shows that Router A communicates with Router B through GigabitEthernet 1/1/1. Then the link over GigabitEthernet 1/1/1 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 GE1/1/2
Static Routing table Status : <Inactive>
Summary Count : 0
The output shows that Router A communicates with Router B through GigabitEthernet 1/1/2.
BFD for static routes configuration example (indirect next hop)
Network requirements
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 GigabitEthernet 1/1/1.
· Router B has a route to interface Loopback 1 (1.1.1.9/32) on Router A, with the output interface GigabitEthernet 1/1/1.
· Router D has a route to 1.1.1.9/32, with the output interface GigabitEthernet 1/1/1, and a route to 2.2.2.9/32, with the output interface GigabitEthernet 1/1/2.
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.
Table 2 Interface and IP address assignment
Device |
Interface |
IP address |
Router A |
GigabitEthernet 1/1/1 |
12.1.1.1/24 |
Router A |
GigabitEthernet 1/1/2 |
10.1.1.102/24 |
Router A |
Loopback 1 |
1.1.1.9/32 |
Router B |
GigabitEthernet 1/1/1 |
11.1.1.2/24 |
Router B |
GigabitEthernet 1/1/2 |
13.1.1.1/24 |
Router B |
Loopback 1 |
2.2.2.9/32 |
Router C |
GigabitEthernet 1/1/1 |
10.1.1.100/24 |
Router C |
GigabitEthernet 1/1/2 |
13.1.1.2/24 |
Router D |
GigabitEthernet 1/1/1 |
12.1.1.2/24 |
Router D |
GigabitEthernet 1/1/2 |
11.1.1.2/24 |
Configuration 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 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 gigabitethernet 1/1/2 10.1.1.100 preference 65
[RouterA] quit
# Configure static routes on Router B and enable BFD control 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 gigabitethernet 1/1/2 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 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 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 GE1/1/1
Static Routing table Status : <Inactive>
Summary Count : 0
The output shows that Router A communicates with Router B through GigabitEthernet 1/1/1. Then the link over GigabitEthernet 1/1/1 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 GE1/1/2
Static Routing table Status : <Inactive>
Summary Count : 0
The output shows that Router A communicates with Router B through GigabitEthernet 1/1/2.
Static route FRR configuration example
Network requirements
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.
Table 3 Interface and IP address assignment
Device |
Interface |
IP address |
Router A |
GigabitEthernet 1/1/1 |
12.12.12.1/24 |
Router A |
GigabitEthernet 1/1/2 |
13.13.13.1/24 |
Router A |
Loopback 0 |
1.1.1.1/32 |
Router B |
GigabitEthernet 1/1/1 |
24.24.24.4/24 |
Router B |
GigabitEthernet 1/1/2 |
13.13.13.2/24 |
Router B |
Loopback 0 |
4.4.4.4/32 |
Router C |
GigabitEthernet 1/1/1 |
12.12.12.2/24 |
Router C |
GigabitEthernet 1/1/2 |
24.24.24.2/24 |
Configuration 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 GigabitEthernet 1/1/1 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 gigabitethernet 1/1/2 13.13.13.2 backup-interface gigabitethernet 1/1/1 backup-nexthop 12.12.12.2
# Configure a static route on Router B, and specify GigabitEthernet 1/1/1 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 gigabitethernet 1/1/2 13.13.13.1 backup-interface gigabitethernet 1/1/1 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 gigabitethernet 1/1/2 13.13.13.2
[RouterA] ip route-static 4.4.4.4 32 gigabitethernet 1/1/1 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 gigabitethernet 1/1/2 13.13.13.1
[RouterB] ip route-static 1.1.1.1 32 gigabitethernet 1/1/1 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 gigabitethernet 1/1/2 24.24.24.4
[RouterC] ip route-static 1.1.1.1 32 gigabitethernet 1/1/1 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
Tunnel ID: Invalid Interface: GigabitEthernet1/1/2
BkTunnel ID: Invalid BkInterface: GigabitEthernet1/1/1
FtnIndex: 0x0 TrafficIndex: N/A
Connector: N/A
# 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
Tunnel ID: Invalid Interface: GigabitEthernet1/1/2
BkTunnel ID: Invalid BkInterface: GigabitEthernet1/1/1
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 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. 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.