2.15 Examples for Configuring of ISIS
2.15.8 Example for Configuring Dynamic BFD for IS-IS
interface GigabitEthernet2/0/0 ip address 100.2.1.1 255.255.255.0 isis enable 1
#
bfd btoa bind peer-ip 100.1.1.1 interface GigabitEthernet1/0/0 discriminator local 2
discriminator remote 1 commit
# return
Configuration file of RouterC
#
sysname RouterC
# isis 1
is-level level-2
network-entity aa.3333.3333.3333.00
#
interface GigabitEthernet1/0/0 ip address 100.2.1.2 255.255.255.0 isis enable 1
# return
2.15.8 Example for Configuring Dynamic BFD for IS-IS
Networking Requirements
As shown in Figure 2-15-8, three routers are interconnected using IS-IS, and RouterA and RouterB communicate with each other through a Layer 2 switch. When the link that passes through the switch between RouterA and RouterB fails, the two routers need to rapidly respond to the fault, and traffic can be switched to the link that passes through RouterC for forwarding.
2016-1-11 Huawei Confidential Page 104 of 1210 Figure 2-15-8 Networking diagram of configuring dynamic BFD for IS-IS
Configuration Roadmap
The configuration roadmap is as follows:
1. Configure IP addresses for interfaces and enable IS-IS on each router to ensure reachable routes between the routers.
2. Set the IS-IS interface cost to control route selection of the routers to make the link that passes through the switch from RouterA to RouterB as the primary link and the link that passes through RouterC as the backup link.
3. Configure dynamic BFD for IS-IS on RouterA, RouterB, and RouterC so that link faults can be detected rapidly and traffic can be switched to the backup link for forwarding.
Procedure
1. Configure IP addresses for interfaces on each router.
# Configure RouterA.
[RouterA] interface gigabitethernet 1/0/0
[RouterA-GigabitEthernet1/0/0] ip address 1.1.1.1 24 [RouterA-isis-1] quit
[RouterA] interface gigabitethernet 2/0/0
[RouterA-GigabitEthernet1/0/0] ip address 3.3.3.1 24
The configurations of RouterB and RouterC are similar to the configuration of RouterA, and are not mentioned here.
2. Configure basic IS-IS functions.
# Configure RouterA.
[RouterA] isis
[RouterA-isis-1] is-level level-2
[RouterA-isis-1] network-entity 10.0000.0000.0001.00 [RouterA-isis-1] quit
[RouterA] interface gigabitethernet 1/0/0 [RouterA-GigabitEthernet1/0/0] isis enable 1 [RouterA-GigabitEthernet1/0/0] quit [RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] isis enable 1 [RouterA-GigabitEthernet2/0/0] quit
# Configure RouterB.
[RouterB] isis
[RouterB-isis-1] is-level level-2
[RouterB-isis-1] network-entity 10.0000.0000.0002.00 [RouterB-isis-1] quit
[RouterB] interface gigabitethernet 1/0/0 [RouterB-GigabitEthernet1/0/0] isis enable 1 [RouterB-GigabitEthernet1/0/0] quit
[RouterB] interface gigabitethernet 2/0/0 [RouterB-GigabitEthernet1/0/0] isis enable 1 [RouterB-GigabitEthernet1/0/0] quit
[RouterB] interface gigabitethernet 3/0/0 [RouterB-GigabitEthernet3/0/0] isis enable 1 [RouterB-GigabitEthernet3/0/0] quit
# Configure RouterC.
[RouterC] isis
[RouterC-isis-1] is-level level-2
[RouterC-isis-1] network-entity 10.0000.0000.0003.00 [RouterC-isis-1] quit
[RouterC] interface gigabitEthernet 1/0/0 [RouterC-GigabitEthernet1/0/0] isis enable 1 [RouterC-GigabitEthernet1/0/0] quit
[RouterC] interface gigabitethernet 2/0/0 [RouterC-GigabitEthernet2/0/0] isis enable 1 [RouterC-GigabitEthernet2/0/0] quit
# After the preceding configurations, run the display isis peer command. You can see that the neighbor relationships are established between RouterA and RouterB, and between RouterA and RouterC. The following uses the configuration of RouterA as an example.
[RouterA] display isis peer
Peer information for ISIS(1)
2016-1-11 Huawei Confidential Page 106 of 1210 ---
System Id Interface Circuit Id State HoldTime Type PRI 0000.0000.0002 GE2/0/0 0000.0000.0002.01 Up 9s L2 64 0000.0000.0003 GE1/0/0 0000.0000.0001.02 Up 21s L2 64 Total Peer(s): 2
# Routers have learned routes from each other. The following uses the routing table of RouterA as an example.
[RouterA] display ip routing-table Route Flags: R - relay, D - download to fib
--- Routing Tables: Public
Destinations : 8 Routes : 9
Destination/Mask Proto Pre Cost Flags NextHop Interface 1.1.1.0/24 Direct 0 0 D 1.1.1.1
GigabitEthernet1/0/0
1.1.1.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 1.1.1.1/32 Direct 0 0 D 127.0.0.1
GigabitEthernet1/0/0
2.2.2.0/24 ISIS-L2 15 20 D 1.1.1.2 GigabitEthernet1/0/0
3.3.3.0/24 Direct 0 0 D 3.3.3.1 GigabitEthernet2/0/0
3.3.3.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 3.3.3.1/32 Direct 0 0 D 127.0.0.1
GigabitEthernet2/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 172.16.1.0/24 ISIS-L2 15 20 D 3.3.3.2
GigabitEthernet2/0/0
As shown in the routing table, the next-hop address of the route to 172.16.1.0/24 is 3.3.3.2, and traffic is transmitted on the primary link RouterA→RouterB.
3. Set the interface cost.
# Configure RouterA.
[RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet1/0/0] isis cost 5 [RouterA-GigabitEthernet1/0/0] quit
# Configure RouterB.
[RouterB] interface gigabitethernet 2/0/0
[RouterB-GigabitEthernet1/0/0] isis cost 5 [RouterB-GigabitEthernet1/0/0] quit 4. Configure BFD for IS-IS processes.
# Enable BFD for IS-IS on RouterA.
[RouterA] bfd [RouterA-bfd] quit [RouterA] isis
[RouterA-isis-1] bfd all-interfaces enable [RouterA-isis-1] quit
# Enable BFD for IS-IS on RouterB.
[RouterB] bfd [RouterB-bfd] quit [RouterB] isis
[RouterB-isis-1] bfd all-interfaces enable [RouterB-isis-1] quit
# Enable BFD for IS-IS on RouterC.
[RouterC] bfd [RouterC-bfd] quit [RouterC] isis
[RouterC-isis-1] bfd all-interfaces enable [RouterC-isis-1] quit
# After the preceding configurations, run the display isis bfd session all command on RouterA, RouterB, and RouterC. You can see that the BFD session status is Up.
The following uses the display on RouterA as an example.
[RouterA] display isis bfd session all
BFD session information for ISIS(1) ---
Peer System ID : 0000.0000.0002 Interface : GE2/0/0
RX : 1000 LocDis : 8193 Local IP Address: 3.3.3.1 Multiplier : 3 RemDis : 8192 Type : L2
Diag : No diagnostic information
Peer System ID : 0000.0000.0003 Interface : GE1/0/0 Multiplier : 3 RemDis : 8192 Type : L2
Diag : No diagnostic information Total BFD session(s): 2
As shown in the preceding display, the status of the BFD session between RouterA and RouterB and that between RouterA and RouterC is Up.
2016-1-11 Huawei Confidential Page 108 of 1210 5. Configure BFD for IS-IS interfaces.
# Configure BFD on GE2/0/0 of RouterA, set the minimum interval for sending packets to 100 ms, the minimum interval for receiving packets to 100 ms, and the local detection multiplier to 4.
[RouterA] interface gigabitethernet 2/0/0 [RouterA-GigabitEthernet2/0/0] isis bfd enable
[RouterA-GigabitEthernet2/0/0] isis bfd min-tx-interval 100 min-rx-interval 100 detect-multiplier 4
[RouterA-GigabitEthernet2/0/0] quit
# Configure BFD on GE2/0/0 of RouterB, set the minimum interval for sending packets to 100 ms, the minimum interval for receiving packets to 100 ms, and the local detection multiplier to 4.
[RouterB] bfd [RouterB-bfd] quit
[RouterB] interface gigabitethernet 2/0/0 [RouterB-GigabitEthernet2/0/0] isis bfd enable
[RouterB-GigabitEthernet2/0/0] isis bfd min-tx-interval 100 min-rx-interval 100 detect-multiplier 4
[RouterB-GigabitEthernet2/0/0] quit
# After the preceding configurations, run the display isis bfd session all command on RouterA or RouterB. You can see that the BFD parameters have taken effect. The following uses the display on RouterB as an example.
[RouterB] display isis bfd session all
BFD session information for ISIS(1) --- Peer System ID : 0000.0000.0001 Interface : GE2/0/0 TX : 100 BFD State : up Peer IP Address : 3.3.3.1 RX : 100 LocDis : 8192 Local IP Address: 3.3.3.2 Multiplier : 4 RemDis : 8192 Type : L2
Diag : No diagnostic information
Peer System ID : 0000.0000.0003 Interface : GE1/0/0 TX : 100 BFD State : up Peer IP Address : 2.2.2.1 RX : 100 LocDis : 8192 Local IP Address: 2.2.2.2 Multiplier : 3 RemDis : 8193 Type : L2
Diag : No diagnostic information Total BFD session(s): 2
6. Verify the configuration.
# Run the shutdown command on GigabitEthernet2/0/0 of RouterB to simulate a primary link failure.
[RouterB] interface gigabitethernet 2/0/0 [RouterB-GigabitEthernet2/0/0] shutdown 7. # View the routing table of RouterA.
[RouterA] display ip routing-table Route Flags: R - relay, D - download to fib
--- Routing Tables: Public
Destinations : 8 Routes : 8
Destination/Mask Proto Pre Cost Flags NextHop Interface 1.1.1.0/24 Direct 0 0 D 1.1.1.1
GigabitEthernet1/0/0
1.1.1.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 1.1.1.1/32 Direct 0 0 D 127.0.0.1
GigabitEthernet1/0/0
2.2.2.0/24 ISIS-L2 15 20 D 1.1.1.2 GigabitEthernet1/0/0
3.3.3.0/24 Direct 0 0 D 3.3.3.1 GigabitEthernet1/0/0
3.3.3.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 3.3.3.1/32 Direct 0 0 D 127.0.0.1
GigabitEthernet1/0/0
127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 172.16.1.0/24 ISIS-L2 15 20 D 1.1.1.2 GigabitEthernet1/0/0 As shown in the routing table, the backup link RouterA→RouterC→RouterB takes effect after the primary link fails, and the next-hop address of the route to 172.16.1.0/24 becomes 1.1.1.2.
# Run the display isis bfd session all command on RouterA. You can see that the status of the BFD session between RouterA and RouterC is Up.
[RouterA] display isis bfd session all
BFD session information for ISIS(1) --- Peer System ID : 0000.0000.0003 Interface : GE1/0/0 TX : 100 BFD State : up Peer IP Address : 1.1.1.2 RX : 100 LocDis : 8192 Local IP Address: 1.1.1.1 Multiplier : 3 RemDis : 8192 Type : L2
Diag : No diagnostic information
2016-1-11 Huawei Confidential Page 110 of 1210 Total BFD session(s): 1
Configuration Files
Configuration file of RouterA
#
sysname RouterA
# bfd
# isis 1
is-level level-2
bfd all-interfaces enable
network-entity 10.0000.0000.0001.00
#
interface GigabitEthernet1/0/0 ip address 1.1.1.1 255.255.255.0 isis enable 1
#
interface GigabitEthernet2/0/0 ip address 3.3.3.1 255.255.255.0 isis enable 1
isis cost 5 isis bfd enable
isis bfd min-tx-interval 100 min-rx-interval 100 detect-multiplier 4
# return
Configuration file of RouterB
#
sysname RouterB
# bfd
# isis 1
is-level level-2
bfd all-interfaces enable
network-entity 10.0000.0000.0002.00
#
interface GigabitEthernet1/0/0
ip address 2.2.2.2 255.255.255.0 isis enable 1
#
interface GigabitEthernet2/0/0 ip address 3.3.3.2 255.255.255.0 isis enable 1
isis cost 5 isis bfd enable
isis bfd min-tx-interval 100 min-rx-interval 100 detect-multiplier 4
#
interface GigabitEthernet3/0/0 ip address 172.16.1.1 255.255.255.0 isis enable 1
# return
Configuration file of RouterC
#
sysname RouterC
# bfd
# isis 1
is-level level-2
bfd all-interfaces enable
network-entity 10.0000.0000.0003.00
#
interface GigabitEthernet1/0/0 ip address 1.1.1.2 255.255.255.0 isis enable 1
#
interface GigabitEthernet2/0/0 ip address 2.2.2.1 255.255.255.0 isis enable 1
# return
2016-1-11 Huawei Confidential Page 112 of 1210