玩转华为ENSP模拟器系列 | 配置多段拼接场景下的伪线BFD示例

Posted 2022-05-06 COCOgsta

素材来源：华为路由器配置指南

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附上汇总贴：玩转华为ENSP模拟器系列 | 合集_COCOgsta的博客-CSDN博客_ensp实验大全

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目标

验证在多段伪线拼接场景下，BFD for 主备伪线中BFD报文的收发情况

组网需求

配置思路

• 配置OSPF和LDP邻居。

• R1与R2/R3之间启用主备伪线，并启用BFD for 主备伪线。同理R8与R5/R6也启用主备伪线，并启用BFD for 主备伪线。

• R2/R3/R4/R5/R6/R7启用动动伪线拼接，将R1与R8之间的主备伪线形成端到端伪线。

操作步骤

1. 配置各设备接口地址、OSPF、MPLS、MPLS LDP以及Target LDP邻居。
2. R1配置主备2条伪线，分别指向R2和R3，并采用主从模式。

R1:
interface Ethernet1/0/2
 mpls l2vc 2.2.2.2 100 control-word
 mpls l2vc 3.3.3.3 1000 control-word secondary
 mpls l2vpn redundancy master

1. R8配置主备2条伪线，分别指向R6和R7，并采用主从模式。

R8:
interface Ethernet1/0/2
 mpls l2vc 6.6.6.6 100 control-word
 mpls l2vc 7.7.7.7 1000 control-word secondary
 mpls l2vpn redundancy master

1. R2配置伪线拼接，将R1-R2与R2-R4的伪线拼接起来。同理配置其他设备的伪线拼接。

R2:
mpls switch-l2vc 4.4.4.4 101 between 1.1.1.1 100 encapsulation ethernet control-
word-transparent

1. R1查看伪线状态

[~R1-Ethernet1/0/2]dis mpls l2vc
 Total LDP VC : 2     2 up       0 down
 *client interface       : Ethernet1/0/2 is up
  Administrator PW       : no 
  session state          : up
  AC status              : up
  Ignore AC state        : disable
  VC state               : up
  Label state            : 0
  Token state            : 0
  VC ID                  : 100
  VC type                : Ethernet
  destination            : 2.2.2.2
  local VC label         : 48090        remote VC label      : 48060
  control word           : enable
  remote control word    : enable
  forwarding entry       : exist
  local group ID         : 0
  remote group ID        : 0
  local AC OAM State     : up
  local PSN OAM State    : up
  local forwarding state : forwarding
  local status code      : 0x0 (forwarding)
  remote AC OAM state    : up
  remote PSN OAM state   : up
  remote forwarding state: forwarding
  remote status code     : 0x0 (forwarding)
  ignore standby state   : no
  BFD for PW             : available
    BFD sessionIndex     : 1            BFD state : up
  VCCV State             : up
  manual fault           : not set
  active state           : active
  OAM Protocol           : --
  OAM Status             : --
  OAM Fault Type         : --
  PW APS ID              : --
  PW APS Status          : --
  TTL Value              : 1
  link state             : up
  local VC MTU           : 1500         remote VC MTU        : 1500
  local VCCV             : cw alert ttl lsp-ping bfd 
  remote VCCV            : cw alert ttl lsp-ping bfd 
  tunnel policy name     : -- 
  PW template name       : --  
  primary or secondary   : primary
  load balance type      : flow
  Access-port            : false
  Switchover Flag        : false
  VC tunnel info         : 1 tunnels 
    NO.0  TNL type       : ldp            , TNL ID : 0x0000000001004c4b42
  create time            : 0 days, 0 hours, 9 minutes, 14 seconds  
  up time                : 0 days, 0 hours, 1 minutes, 58 seconds
  last change time       : 0 days, 0 hours, 1 minutes, 58 seconds
  VC last up time        : 2020/05/10 17:06:01
  VC total up time       : 0 days, 0 hours, 1 minutes, 58 seconds
  CKey                   : 1
  NKey                   : 16777301
  PW redundancy mode     : master
  AdminPw interface      : --
  AdminPw link state     : --
  Forward state          : send active, receive active
  Diffserv Mode          : uniform
  Service Class          : --
  Color                  : --
  DomainId               : --
  Domain Name            : --  
 *client interface       : Ethernet1/0/2 is up
  Administrator PW       : no 
  session state          : up
  AC status              : up
  Ignore AC state        : disable
  VC state               : up
  Label state            : 0
  Token state            : 0
  VC ID                  : 1000
  VC type                : Ethernet
  destination            : 3.3.3.3
  local VC label         : 48091        remote VC label      : 48060
  control word           : enable
  remote control word    : enable
  forwarding entry       : exist
  local group ID         : 0
  remote group ID        : 0
  local AC OAM State     : up
  local PSN OAM State    : up
  local forwarding state : forwarding
  local status code      : 0x20 (standby)
  remote AC OAM state    : up
  remote PSN OAM state   : up
  remote forwarding state: forwarding
  remote status code     : 0x20 (standby)
  ignore standby state   : no
  BFD for PW             : available
    BFD sessionIndex     : 2            BFD state : up
  VCCV State             : up
  manual fault           : not set
  active state           : inactive
  OAM Protocol           : --
  OAM Status             : --
  OAM Fault Type         : --
  PW APS ID              : --
  PW APS Status          : --
  TTL Value              : 1
  link state             : up
  local VC MTU           : 1500         remote VC MTU        : 1500
  local VCCV             : cw alert ttl lsp-ping bfd 
  remote VCCV            : cw alert ttl lsp-ping bfd 
  tunnel policy name     : -- 
  PW template name       : --  
  primary or secondary   : secondary
  load balance type      : flow
  Access-port            : false
  VC tunnel info         : 1 tunnels 
    NO.0  TNL type       : ldp            , TNL ID : 0x0000000001004c4b43
  create time            : 0 days, 0 hours, 9 minutes, 14 seconds  
  up time                : 0 days, 0 hours, 2 minutes, 1 seconds
  last change time       : 0 days, 0 hours, 2 minutes, 1 seconds
  VC last up time        : 2020/05/10 17:05:59
  VC total up time       : 0 days, 0 hours, 2 minutes, 1 seconds
  CKey                   : 2
  NKey                   : 16777302
  PW redundancy mode     : master
  AdminPw interface      : --
  AdminPw link state     : --
  Forward state          : send inactive, receive inactive
  Diffserv Mode          : uniform
  Service Class          : --
  Color                  : --
  DomainId               : --
  Domain Name            : --  
[~R1-Ethernet1/0/2] 

1. R2上抓取R2-R4链路的BFD报文

MPLS标签值为VC Label，可通过dis mpls l2vc或dis mpls switch-l2vc查看。PW Associated Channel Header用来传递PW的OAM报文

1. R2上抓取R2-R4链路的ICMP报文

对于IP报文，由于启用了控制字，所以会携带PW Ethernet Control Word，其中Sequence Number恒为0（TDM年代时需要携带多个sequence number来表示1个报文）

1. R2上抓到报文，说明BFD for PW的报文是端到端传递的，虽然PW至R1与R2之间建立，但BFD报文对R2来说，会当做正常的IP报文处理