目录
实验 6-2 BFD与OSPF联动配置实验
实验目标
·掌握BFD在OSPF环境下的快速配置
拓扑图
场景
两台路由器R1和R2经过S1彼此互连，并将各自的接口运行于OSPF区域0，由于不是接口直接相连，若其中一台的接口Down，另一台不会立即感知，需要等待4倍的Hello时间来删除邻居，在这段时间内，数据转发都会处于非正常状态。在这种场景下，可以通过BFD检测来加快OSPF的收敛速度。
学习任务
步骤一.IP编址与基本配置
给所有路由器配置IP地址信息。
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R1
[R1]interface GigabitEthernet 0/0/1
[R1-GigabitEthernet0/0/1]ip address 10.0.12.1 24
[R1-GigabitEthernet0/0/1]quit
[R1]interface loopback 0
[R1-LoopBack0]ip address 10.0.1.1 32
[R1-LoopBack0]quit
配置好地址立即在每台路由器进行检查。
[R1]display ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
(E): E-Trunk down
The number of interface that is UP in Physical is 3
The number of interface that is DOWN in Physical is 9
The number of interface that is UP in Protocol is 3
The number of interface that is DOWN in Protocol is 9
Interface IP Address/Mask Physical Protocol
Cellular0/0/0 unassigned down down
Cellular0/0/1 unassigned down down
GigabitEthernet0/0/0 unassigned *down down
GigabitEthernet0/0/1 10.0.12.1/24 up up
GigabitEthernet0/0/2 unassigned *down down
GigabitEthernet0/0/3 unassigned *down down
LoopBack0 10.0.1.1/32 up up(s)
NULL0 unassigned up up(s)
Serial1/0/0 unassigned *down down
Serial2/0/0 unassigned *down down
Serial3/0/0 unassigned *down down
Serial4/0/0 unassigned *down down
<Huawei>system-view
Enter system view, return user view with Ctrl+Z.
[Huawei]sysname R2
[R2]interface GigabitEthernet 0/0/1
[R2-GigabitEthernet0/0/1]ip address 10.0.12.2 24
[R2-GigabitEthernet0/0/1]quit
[R2]interface loopback 0
[R2-LoopBack0]ip address 10.0.2.2 32
[R2-LoopBack0]quit
[R2]display ip interface brief
*down: administratively down
^down: standby
(l): loopback
(s): spoofing
(E): E-Trunk down
The number of interface that is UP in Physical is 3
The number of interface that is DOWN in Physical is 10
The number of interface that is UP in Protocol is 3
The number of interface that is DOWN in Protocol is 10
Interface IP Address/Mask Physical Protocol
Cellular0/0/0 unassigned down down
Cellular0/0/1 unassigned down down
Ethernet4/0/0 unassigned *down down
Ethernet4/0/1 unassigned *down down
GigabitEthernet0/0/0 unassigned *down down
GigabitEthernet0/0/1 10.0.12.2/24 up up
GigabitEthernet0/0/2 unassigned *down down
GigabitEthernet0/0/3 unassigned *down down
LoopBack0 10.0.2.2/32 up up(s)
NULL0 unassigned up up(s)
Serial1/0/0 unassigned *down down
Serial2/0/0 unassigned *down down
Serial3/0/0 unassigned *down down
检查R1到R2的连通性：
[R1]ping 10.0.12.2
PING 10.0.12.2: 56 data bytes, press CTRL_C to break
Request time out
Reply from 10.0.12.2: bytes=56 Sequence=2 ttl=255 time=1 ms
Reply from 10.0.12.2: bytes=56 Sequence=3 ttl=255 time=1 ms
Reply from 10.0.12.2: bytes=56 Sequence=4 ttl=255 time=1 ms
Reply from 10.0.12.2: bytes=56 Sequence=5 ttl=255 time=1 ms
--- 10.0.12.2 ping statistics ---
5 packet(s) transmitted
4 packet(s) received
20.00% packet loss
round-trip min/avg/max = 1/1/1 ms
步骤二.OSPF配置
按照拓扑将R1和R2路由器的接口包括环回口0划入OSPF区域0：
[R1]ospf 1
[R1-ospf-1]area 0
[R1-ospf-1-area-0.0.0.0]network 10.0.12.0 0.0.0.255
[R1-ospf-1-area-0.0.0.0]network 10.0.1.1 0.0.0.0
[R1-ospf-1-area-0.0.0.0]quit
[R1-ospf-1]quit
[R2]ospf 1
[R2-ospf-1]area 0
[R2-ospf-1-area-0.0.0.0]network 10.0.12.0 0.0.0.255
[R2-ospf-1-area-0.0.0.0]network 10.0.2.2 0.0.0.0
[R2-ospf-1-area-0.0.0.0]quit
[R2-ospf-1]quit
检查OSPF接口状态和邻居状态：
[R1]display ospf interface
OSPF Process 1 with Router ID 10.0.12.1
Interfaces
Area: 0.0.0.0 (MPLS TE not enabled)
IP Address Type State Cost Pri DR BDR
10.0.12.1 Broadcast BDR 1 1 10.0.12.2 10.0.12.1
10.0.1.1 P2P P-2-P 0 1 0.0.0.0 0.0.0.0
[R2]display ospf interface
OSPF Process 1 with Router ID 10.0.12.2
Interfaces
Area: 0.0.0.0 (MPLS TE not enabled)
IP Address Type State Cost Pri DR BDR
10.0.12.2 Broadcast DR 1 1 10.0.12.2 10.0.12.1
10.0.2.2 P2P P-2-P 0 1 0.0.0.0 0.0.0.0
检查OSPF邻居状态：
[R1]display ospf peer brief
OSPF Process 1 with Router ID 10.0.12.1
Peer Statistic Information
----------------------------------------------------------------------------
Area Id Interface Neighbor id State
0.0.0.0 GigabitEthernet0/0/1 10.0.12.2 Full
----------------------------------------------------------------------------
Total Peer(s): 1
[R2]display ospf peer brief
OSPF Process 1 with Router ID 10.0.12.2
Peer Statistic Information
----------------------------------------------------------------------------
Area Id Interface Neighbor id State
0.0.0.0 GigabitEthernet0/0/1 10.0.12.1 Full
----------------------------------------------------------------------------
Total Peer(s): 1
邻居已经是Full的状态，OSPF配置完毕。
步骤三.配置BFD session
需要在系统全局下开启BFD，并且在OSPF视图下启用联动BFD。
[R1]bfd
[R1-bfd]quit
[R1]ospf 1
[R1-ospf-1]bfd all-interfaces enable
[R1-ospf-1]quit
[R2]bfd
[R2-bfd]quit
[R2]ospf 1
[R2-ospf-1]bfd all-interfaces enable
[R2-ospf-1]quit
在两端都配置完毕后检查BFD session状态：
[R1]display bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
8192 8192 10.0.12.2 Up D_IP_IF GigabitEthernet0/0/1
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 1/0
[R2]display bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
8192 8192 10.0.12.1 Up D_IP_IF GigabitEthernet0/0/1
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 1/0
[R1]display ospf bfd session all
OSPF Process 1 with Router ID 10.0.12.1
Area 0.0.0.0 interface 10.0.12.1(GigabitEthernet0/0/1)'s BFD Sessions
NeighborId:10.0.12.2 AreaId:0.0.0.0 Interface:GigabitEthernet0/0/1
BFDState:up rx :1000 tx :1000
Multiplier:3 BFD Local Dis:8192 LocalIpAdd:10.0.12.1
RemoteIpAdd:10.0.12.2 Diagnostic Info:No diagnostic information
测试BFD效果，在R2接口上shutdown：
[R2]interface GigabitEthernet 0/0/1
[R2-GigabitEthernet0/0/1]shutdown
如果在R1上开启了debug功能，在R1上若观察debug日志，会出现如下内容：
<R1>debug ospf bfd
Sep 23 2016 03:39:25+00:00 R1 %%01BFD/4/STACHG_TODWN(l)[23]:BFD session changed to Down. (SlotNumber=0, Discriminator=8192, Diagnostic=DetectDown, Applications=OSPF, ProcessPST=False, BindInterfaceName=GigabitEthernet0/0/1, InterfacePhysicalState=Up, InterfaceProtocolState=Up)
<R1>
Sep 23 2016 03:39:25+00:00 R1 %%01OSPF/3/NBR_CHG_DOWN(l)[24]:Neighbor event:neighbor state changed to Down. (ProcessId=1, NeighborAddress=10.0.12.2, NeighborEvent=KillNbr, NeighborPreviousState=Full, NeighborCurrentState=Down)
<R1>
Sep 23 2016 03:39:25+00:00 R1 %%01OSPF/3/NBR_DOWN_REASON(l)[25]:Neighbor state leaves full or changed to Down. (ProcessId=1, NeighborRouterId=10.0.12.2, NeighborAreaId=0, NeighborInterface=GigabitEthernet0/0/1,NeighborDownImmediate reason=Neighbor Down Due to Kill Neighbor, NeighborDownPrimeReason=BFD Session Down, NeighborChangeTime=2016-09-23 03:39:25)
还有其他关联性日志，此处略，重点是以上的第三条日志。
重新开启接口：
[R2-GigabitEthernet0/0/1]undo shutdown
再次查看BFD会话和OSPF邻居关系：
[R1]display bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
8193 8193 10.0.12.2 Up D_IP_IF GigabitEthernet0/0/1
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 1/0
[R1]display ospf bfd session all
OSPF Process 1 with Router ID 10.0.12.1
Area 0.0.0.0 interface 10.0.12.1(GigabitEthernet0/0/1)'s BFD Sessions
NeighborId:10.0.12.2 AreaId:0.0.0.0 Interface:GigabitEthernet0/0/1
BFDState:up rx :1000 tx :1000
Multiplier:3 BFD Local Dis:8193 LocalIpAdd:10.0.12.1
RemoteIpAdd:10.0.12.2 Diagnostic Info:No diagnostic information
[R2]display bfd session all
--------------------------------------------------------------------------------
Local Remote PeerIpAddr State Type InterfaceName
--------------------------------------------------------------------------------
8193 8193 10.0.12.1 Up D_IP_IF GigabitEthernet0/0/1
--------------------------------------------------------------------------------
Total UP/DOWN Session Number : 1/0
[R2]display ospf bfd session all
OSPF Process 1 with Router ID 10.0.12.2
Area 0.0.0.0 interface 10.0.12.2(GigabitEthernet0/0/1)'s BFD Sessions
NeighborId:10.0.12.1 AreaId:0.0.0.0 Interface:GigabitEthernet0/0/1
BFDState:up rx :1000 tx :1000
Multiplier:3 BFD Local Dis:8193 LocalIpAdd:10.0.12.2
RemoteIpAdd:10.0.12.1 Diagnostic Info:No diagnostic information
BFD重新建立。
配置文件参考
<R1>display current-configuration
[V200R007C00SPC600]
#
sysname R1
#
bfd
#
interface GigabitEthernet0/0/1
ip address 10.0.12.1 255.255.255.0
#
interface LoopBack0
ip address 10.0.1.1 255.255.255.255
#
ospf 1
bfd all-interfaces enable
area 0.0.0.0
network 10.0.1.1 0.0.0.0
network 10.0.12.0 0.0.0.255
#
return
<R2>display current-configuration
[V200R007C00SPC600]
#
sysname R2
#
bfd
#
interface GigabitEthernet0/0/1
ip address 10.0.12.2 255.255.255.0
#
interface LoopBack0
ip address 10.0.2.2 255.255.255.255
#
ospf 1
bfd all-interfaces enable
area 0.0.0.0
network 10.0.2.2 0.0.0.0
network 10.0.12.0 0.0.0.255
#
return