简介：
VPLS技术属于二层分组承载技术，本质上是一种基于IP/MPLS和以太网技术的L2VPN（二层虚拟专用网）技术。其核心思想是利用信令协议在VPLS实例中的PE（运营商边缘路由器）节点之间建立及维护PW（伪线），将二层协议帧封装后在PW上传输、交换，使广域范围内多个局域网在数据链路层面被整合为一张网络，向用户提供虚拟的以太网服务。VPLS技术有效地结合了IP/MPLS、L2VPN以太网交换等多种技术的特点，支持点到点、点到多点、多点到多点的业务类型，能够在较大网络规模下支持电信级以太网服务。
采用的技术：
网桥域接口(BDI) ；多协议BGP；集成ISIS；标签分发协议（LDP）
网络拓扑:
基本配置：
R4
interface Loopback0
ip address 192.168.255.4 255.255.255.255
ip router isis underlay
!
mpls label protocol ldp
mpls ldp router-id Loopback0 force
!
router isis underlay
net 49.0192.0000.0000.0004.00
is-type level-1
metric-style wide
log-adjacency-changes
mpls ldp autoconfig level-1
!
interface GigabitEthernet3
no shutdown
ip address 192.168.0.9 255.255.255.252
ip router isis underlay
!
检查RIB以及LFIB
LSR4#sh ip route isis
…
192.168.255.0/32 is subnetted, 4 subnets
i L1 192.168.255.1 [115/30] via 192.168.0.10, 18:55:47, GigabitEthernet3
i L1 192.168.255.2 [115/20] via 192.168.0.10, 18:55:51, GigabitEthernet3
i L1 192.168.255.3 [115/30] via 192.168.0.10, 18:55:51, GigabitEthernet3
======================================================
LSR4#sh mpls forwarding-table
Local Outgoing Prefix Bytes Label Outgoing Next Hop
Label Label or Tunnel Id Switched interface
…
26 Pop Label 192.168.0.0/30 0 Gi3 192.168.0.10
27 Pop Label 192.168.0.4/30 0 Gi3 192.168.0.10
28 16 192.168.255.1/32 0 Gi3 192.168.0.10
29 Pop Label 192.168.255.2/32 0 Gi3 192.168.0.10
30 17 192.168.255.3/32 0 Gi3 192.168.0.10
======================================================
L2VPN VPLS配置：
!
bridge irb————————————>集成路由交换
!
l2vpn vfi context vlan1
vpn id 1————————————->vpn id 需要一致
autodiscovery bgp signaling bgp—>自动发现与信令采用BGP
ve id 4————————————->ve id 必须唯一
!
interface GigabitEthernet4
no shutdown
service instance 1 ethernet—————>使用BDI
encapsulation untagged——————>封装无vlan tag
!
bridge-domain 1
member GigabitEthernet4 service-instance 1
member vfi vlan1
!
router bgp 65000
template peer-policy iBGP
route-reflector-client
send-community both //携带RT（自动）
suppress-signaling-protocol ldp //抑制LDP信令
exit-peer-policy
!
template peer-session iBGP
remote-as 65000
update-source Loopback0
exit-peer-session
!
bgp router-id 192.168.255.4
bgp cluster-id 192.168.255.4
bgp log-neighbor-changes
no bgp default ipv4-unicast
neighbor 192.168.255.1 inherit peer-session iBGP
neighbor 192.168.255.3 inherit peer-session iBGP
!
address-family l2vpn vpls
neighbor 192.168.255.1 activate
neighbor 192.168.255.1 inherit peer-policy iBGP
neighbor 192.168.255.3 activate
neighbor 192.168.255.3 inherit peer-policy iBGP
exit-address-family
检查：
LSR4#sh mpls l2transport vc
Local intf Local circuit Dest address VC ID Status
------------- -------------------------- --------------- ---------- ----------
VFI vlan1 vfi 192.168.255.1 1 UP
VFI vlan1 vfi 192.168.255.3 1 UP
LSR4#sh mpls l2transport vc detail | inc stack
Output interface: Gi3, imposed label stack {16 19}
Output interface: Gi3, imposed label stack {17 19}
LSR4#sh bgp l2vpn vpls all summary
…
Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd
192.168.255.1 4 65000 1269 1270 4 0 0 19:08:23 1
192.168.255.3 4 65000 1269 1273 4 0 0 19:08:25 1
抓包测试：
