evpn隧道建立不起来

两台68做m-lag组网使用evpn与友商交换机对接，现出现隧道无法建立，对端建立正常本端无法建立

1． 邻居建立正常：

[B21/32U]display bgp peer l2vpn evpn

 BGP local router ID: 2.1.1.1

Local AS number: 1

Total number of peers: 1         Peers in established state: 1

  * - Dynamically created peer

  ^ - Peer created through link-local address

  Peer                    AS  MsgRcvd  MsgSent OutQ PrefRcv Up/Down  State

  1.1.1.1               11    34854     2804    0       1 0001d19h Established

2、隧道无回显：

[B21/32U]display vxlan tunnel

Total number of VXLANs: 1

VXLAN ID: 253, VSI name: 253

3、有收到三类路由：

[B21/32U]display bgp l2vpn evpn route-type imet

 BGP local router ID is 2.1.1.1

 Status codes: * - valid, > - best, d - dampened, h - history

               s - suppressed, S - stale, i - internal, e - external

               a - additional-path

       Origin: i - IGP, e - EGP, ? - incomplete

 Total number of routes from all PEs: 1

 Route distinguisher: 253:100

Total number of routes: 3

    e Network : [3][0][32][10.10.1.1]/80

     NextHop : 10.10.1.1                                LocPrf    :         

     PrefVal : 0                                        OutLabel  : NULL     

     MED     :                                         

     Path/Ogn: 1?

 * >  Network : [3][0][32][38.1.1.2]/80

     NextHop : 1.1.1.2                                 LocPrf    : 100      

     PrefVal : 32768                                    OutLabel  : NULL     

     MED     : 0                                       

     Path/Ogn: i           

* >  Network : [3][0][32][39.1.1.1]/80

     NextHop : 2.1.1.1                                 LocPrf    : 100      

     PrefVal : 32768                                    OutLabel  : NULL     

     MED     : 0                                        

     Path/Ogn: i

4、没有五类：

5、RT RD配置无一致：

#

vsi 253

arp suppression enable

vxlan 253

evpn encapsulation vxlan

  route-distinguisher 253:100

  vpn-target 253:100 export-extcommunity

  vpn-target 253:100 import-extcommunity

#

对端：

#

evpn vpn-instance evpn253 bd-mode

route-distinguisher 253:100

vpn-target 253:100 export-extcommunity

vpn-target 253:100 import-extcommunity

#

路由学习正常：

[B21/32U]display bgp l2vpn evpn peer 1.1.1.1 received-routes

Total number of routes: 1

BGP local router ID is 2.1.1.1

 Status codes: * - valid, > - best, d - dampened, h - history

               s - suppressed, S - stale, i - internal, e - external

               a - additional-path

       Origin: i - IGP, e - EGP, ? - incomplete

Route distinguisher: 253:100

Total number of routes: 1

   e Network : [3][0][32][10.10.1.1]/80

     NextHop : 10.10.1.1                                LocPrf    :         

     PrefVal : 0                                        OutLabel  : NULL     

     MED     :                                         

     Path/Ogn: 1?

查看路由明细：

[B20/32U-probe]dis bgp l2vpn evpn route-type imet [3][0][32][10.10.1.1]/80

BGP local router ID: 2.1.1.1

Local AS number: 11

 Route distinguisher: 253:100

Total number of routes: 1

Paths:   1 available, 0 best

 BGP routing table information of [3][0][32][10.10.1.1]/80:

From            : 1.2.2.1  (10.10.1.1)

Rely nexthop    : not resolved

Original nexthop: 10.10.1.1

OutLabel        : NULL

Ext-Community   : <RT: 253:100>, <Encapsulation Type: VXLAN>

RxPathID        : 0x0 

 TxPathID        : 0xffffffff 

 PMSI tunnel     : Flag 0, TunnelType 6, Label 253, EndPointAddress 10.10.1.1

AS-path         : 1

Origin          : incomplete

Attribute value : pref-val 0

State           : external

 IP precedence   : N/A

QoS local ID    : N/A

Traffic index   : N/A

EVPN route type : Inclusive multicast Ethernet tag route

Ethernet tag ID : 0

Origin address  : 10.10.1.1/32

Re-orignination : Disabled

查看本端收到的三类路由信息明细，看Rely nexthop记录为not resolved，即没有迭代出下一跳地址；

1.1.1.1是个直连ebgp邻居，由于直连ebgp只能迭代直连，路由的原始下一跳10.10.1.1没有对应的直连路由，迭代失败了；

本端可以配置peer  ebgp-max-hop，改成非直连邻居，则迭代不再限制直连协议；