S7700和S5700配置Eth-trunk,其中一个物理成员端口DOWN造成OSPF邻居收敛

发布时间:  2016-01-31 浏览次数:  506 下载次数:  0
问题描述

组网:S7700作为核心交换机,S5700作为汇聚交换机,S5700和S7700配置了eth-trunk。

问题:S7700和S5700之间的Eth-trunk其中一个物理成员端口DOWN造成OSPF邻居收敛。

S7700 eth-trunk接口:

===============display interface brief===============
Interface                   PHY   Protocol  InUti OutUti   inErrors  outErrors 
Eth-Trunk2                  up    up        0.01%  0.06%          0          0
  XGigabitEthernet1/3/0/3   up    up        0.02%  0.02%          0          0
  XGigabitEthernet2/3/0/3   up    up           0%  0.09%          0          0

S5700 eth-trunk接口:

===============display interface brief===============
Interface                   PHY   Protocol  InUti OutUti   inErrors  outErrors
Eth-Trunk1                  up    up        0.05%  0.01%          0          0
  XGigabitEthernet0/0/1     up    up        0.02%  0.02%          0          0
  XGigabitEthernet1/0/1     up    up        0.09%     0%          0          0

告警信息

S7700 logbuffer信息: XGigabitEthernet1/3/0/3down掉导致OSPF邻居down掉 
Dec 22 2015 08:46:01 SUz_2qi_CoreSW_S7706 %%01OSPF/3/NBR_DOWN_REASON(l)[7]:Neighbor state leaves full or changed to Down. (ProcessId=210, NeighborRouterId=10.132.1.1, NeighborAreaId=0, NeighborInterface=Vlanif3002,NeighborDownImmediate reason=Neighbor Down Due to 1-Wayhello Received, NeighborDownPrimeReason=1-Wayhello Received, NeighborChangeTime=2015-12-22 08:46:01+00:00)       //OSPF邻居关系down掉
Dec 22 2015 08:45:57 SUz_2qi_CoreSW_S7706 %%01IFPDT/4/IF_STATE(l)[8]:Interface XGigabitEthernet1/3/0/3 has turned into DOWN state.  //XGigabitEthernet1/3/0/3接口down掉

处理过程

1.查看S7700 trapbuffer信息:XGigabitEthernet1/3/0/3down掉导致STP收敛

#Dec 22 2015 08:46:35 SUz_2qi_CoreSW_S7706 MSTP/4/PDISC:OID 1.3.6.1.4.1.2011.5.25.42.4.2.2 The port has been set to discarding state. (InstanceID=0, PortInstanceID=0, PortID=3, IfIndex=31, PortName=Eth-Trunk3)
#Dec 22 2015 08:45:57 SUz_2qi_CoreSW_S7706 MSTP/4/PDISC:OID 1.3.6.1.4.1.2011.5.25.42.4.2.2 The port has been set to discarding state. (InstanceID=0, PortInstanceID=0, PortID=3, IfIndex=31, PortName=Eth-Trunk3)
#Dec 22 2015 08:45:57 SUz_2qi_CoreSW_S7706 MSTP/4/PDISC:OID 1.3.6.1.4.1.2011.5.25.42.4.2.2 The port has been set to discarding state. (InstanceID=0, PortInstanceID=0, PortID=1, IfIndex=32, PortName=Eth-Trunk1)
#Dec 22 2015 08:45:57 SUz_2qi_CoreSW_S7706 IFNET/1/IF_LINKDOWN:OID 1.3.6.1.6.3.1.1.5.3 Interface 13 turned into DOWN state.(AdminStatus=1,OperStatus=2,InterfaceName=XGigabitEthernet1/3/0/3)

2.查看S7700当前接口STP状态:

<SUz_2qi_CoreSW_S7706>display stp  bri     
MSTID   Port                        Role  STP State     Protection
    0    Eth-Trunk1                  DESI  FORWARDING      NONE
   0    Eth-Trunk2                  ROOT  FORWARDING      NONE      //当前角色是root
    0    Eth-Trunk3                  DESI  FORWARDING      NONE


3.查看S7700历史STP信息:

===============display stp history===============

---------------------------------
        Port Name: Eth-Trunk2                       
        Role Transition: Root->Desi       //物理成员接口down掉时,Eth-Trunk2由root角色变为desi角色
        IsAged: No            
        Time:  2015/12/22 08:46:35 UTC            

        RootPriority: 32768            
        RootMac: 3ce5-a6f8-73dd            
        PathExtCost: 20000            
        RegRootPriority: 32768            
        RegRootMac: e4c2-d1f6-65e0            
        PathInCost: 0            
        DesignatedPriority: 32768            
        DesignateMac: e4c2-d1f6-65e0            
        PortPriority: 128            
        PortId: 1            
---------------------------------

根因
S7700 Eth-trunk2的端口角色原来是Root端口,当其物理成员端口down后,该Eth-trunk端口的cost值会发生变化进而Eth-trunk端口的累计路径开销也会发生变化,这时设备会重新选择根端口,其他非边缘端口的状态也需要收敛。
解决方案

1.建议手动设置eth-trunk接口的cost值:

interface Eth-Trunk2
  stp instance 0 cost 1

2.网络中STP没有规划,导致核心交换机S7700的下行口成为根端口,可以规划S7700作为网络中STP的主根桥。

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