华为实验 | ENSP模拟VXLAN EVPN分布式网关

网络技术联盟站

发布于 2023-03-13 09:28:44

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文章被收录于专栏：网络技术联盟站网络技术联盟站

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代码可运行

拓扑

一、Ping网关不通

首先确认网关有没有ARP，有不通的话，将pc重启，或者将物理接口重新undo shutdown。
PC写了网关，如果配置没问题的情况下，能到网关地址，就算不通，正常应该是TIMEOUT超时。如果Ping回应是destination host unreachable不可达，有可能是BUG，说明网关都找不到，重启PC，或者接入SW。

二、VXLAN隧道建立问题

EVPN建立不起来，通常Underlay网关能起来，EVPN基本没问题，有问题检查Underlay
EVPN建立起来学习不到IRB路由条目，查看Vbdif下是否开启arp collect host enable，这个命令作用是收集主机路由信息，EVPN会将这些信息以TYPE 2路由传递给对端。

三、CE L3GW学习到路由，跨子网能通，同子网不能通

这个问题我研究了很久，最终是在bd域下加了arp broadcast-suppress enable（ARP广播抑制）与arp l2-proxy gateway-mac （L2网关代答）功能才能通，因为配置手册是不用加的，然后我针对加与不加抓包进行对比发现：

不加：192.168.1.1Ping192.168.1.2同网段，默认CE1收到BUM报文会找到对应L2 VNI的头端复制隧道列表，将广播报文发送到CE2，CE2收到后发现VNI是发给自己的，解封装把BUM报文发个192.168.1.2，回报同理，后续发包就为单播了，但抓包一直发送是ARP广播包，DMAC：全FFFF，对面没回复，不明白是不是BUG。
加ARP抑制，L2网关代答，这2条命令缺一不可，少一条都不通。

因为启用L2网关代答，DMAC是CE1网关的MAC地址，这样才通的，但我认为不需要也能通。

原因有两种情况：

第一：ARP抑制，代答都不启用，正常第一个包全FFFF，对端回应单播包，后续有MAC地址表就能正常转发。
第二：仅开启ARP抑制，第一个包为全FFFF，发送至网关，网关上有type2路由主机信息（MAC/IP/VTEP IP/VNI ID），所以会将广播转单播，直接发送到对端VTEP节点上，对端VTEP解封装找到自己MAC地址打上VLAN ID送到主机上了。

配置信息：

sysname CE1
#
device board 17 board-type CE-MPUB
device board 1 board-type CE-LPUE
#
evpn-overlay enable
#
ip vpn-instance a
 ipv4-family
  route-distinguisher 1:1
  vpn-target 11:1 export-extcommunity evpn
  vpn-target 11:1 import-extcommunity evpn
 vxlan vni 10
#
bridge-domain 2
 vxlan vni 2
 evpn
  route-distinguisher 1:1
  vpn-target 10:1 export-extcommunity
  vpn-target 11:1 export-extcommunity
  vpn-target 10:1 import-extcommunity
 arp broadcast-suppress enable
#
aaa
 #
 authentication-scheme default
 #
 authorization-scheme default
 #
 accounting-scheme default
 #
 domain default
 #
 domain default_admin
#
interface Vbdif2
 ip binding vpn-instance a
 ip address 192.168.1.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface MEth0/0/0
 undo shutdown 
#
interface GE1/0/0
 undo shutdown
#
interface GE1/0/0.2 mode l2
 encapsulation dot1q vid 2
 bridge-domain 2
#
interface GE1/0/1
 undo portswitch
 undo shutdown
 ip address 12.1.1.1 255.255.255.0
#
interface GE1/0/2
 shutdown
#
interface GE1/0/3
 shutdown
#
interface GE1/0/4
 shutdown
#
interface GE1/0/5
 shutdown
#
interface GE1/0/6
 shutdown
#
interface GE1/0/7
 shutdown
#
interface GE1/0/8
 shutdown
#
interface GE1/0/9
 shutdown
#
interface LoopBack0
 ip address 1.1.1.1 255.255.255.255
#
interface Nve1
 source 1.1.1.1
 vni 2 head-end peer-list protocol bgp
#
interface NULL0
#              
bgp 100
 peer 2.2.2.2 as-number 100
 peer 2.2.2.2 connect-interface LoopBack0
 peer 12.1.1.2 as-number 100
 #
 ipv4-family unicast
  network 1.1.1.1 255.255.255.255
  peer 2.2.2.2 enable
  peer 12.1.1.2 enable
 #
 l2vpn-family evpn
  policy vpn-target
  peer 2.2.2.2 enable
  peer 2.2.2.2 advertise irb

sysname CE2
#
device board 17 board-type CE-MPUB
device board 1 board-type CE-LPUE
#
evpn-overlay enable
#
evpn
#
ip vpn-instance b
 ipv4-family
  route-distinguisher 2:2
  vpn-target 11:1 export-extcommunity evpn
  vpn-target 11:1 import-extcommunity evpn
 vxlan vni 10
#
bridge-domain 2
 vxlan vni 2
 evpn
  route-distinguisher 2:3
  vpn-target 10:1 export-extcommunity
  vpn-target 11:1 export-extcommunity
  vpn-target 10:1 import-extcommunity
#
bridge-domain 3
 vxlan vni 3
 evpn
  route-distinguisher 2:2
  vpn-target 20:1 export-extcommunity
  vpn-target 11:1 export-extcommunity
  vpn-target 20:1 import-extcommunity
#
aaa
 #
 authentication-scheme default
 #
 authorization-scheme default
 #
 accounting-scheme default
 #
 domain default
 #
 domain default_admin
#
interface Vbdif2
 ip binding vpn-instance b
 ip address 192.168.1.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface Vbdif3
 ip binding vpn-instance b
 ip address 192.168.2.254 255.255.255.0
 arp distribute-gateway enable
 arp collect host enable
#
interface MEth0/0/0
 undo shutdown
#
interface GE1/0/0
 undo shutdown
#
interface GE1/0/0.2 mode l2
 encapsulation dot1q vid 2
 bridge-domain 2
#              
interface GE1/0/0.3 mode l2
 encapsulation dot1q vid 3
 bridge-domain 3
#
interface GE1/0/1
 undo portswitch
 undo shutdown
 ip address 12.1.1.2 255.255.255.0
#
interface GE1/0/2
 shutdown
#
interface GE1/0/3
 shutdown
#
interface GE1/0/4
 shutdown
#
interface GE1/0/5
 shutdown
#
interface GE1/0/6
 shutdown      
#
interface GE1/0/7
 shutdown
#
interface GE1/0/8
 shutdown
#
interface GE1/0/9
 shutdown
#
interface LoopBack0
 ip address 2.2.2.2 255.255.255.255
#
interface Nve1
 source 2.2.2.2
 vni 2 head-end peer-list protocol bgp
 vni 3 head-end peer-list protocol bgp
#
interface NULL0
#
bgp 100
 peer 1.1.1.1 as-number 100
 peer 1.1.1.1 connect-interface LoopBack0
 peer 12.1.1.1 as-number 100
 #
 ipv4-family unicast
  network 2.2.2.2 255.255.255.255
  peer 1.1.1.1 enable
  peer 12.1.1.1 enable
 #
 l2vpn-family evpn
  policy vpn-target
  peer 1.1.1.1 enable
  peer 1.1.1.1 advertise irb
#
ssh authorization-type default aaa
#
ssh server cipher aes256_gcm aes128_gcm aes256_ctr aes192_ctr aes128_ctr aes256_cbc aes128_cbc 3des_cbc
#
ssh server dh-exchange min-len 1024
#
ssh client cipher aes256_gcm aes128_gcm aes256_ctr aes192_ctr aes128_ctr aes256_cbc aes128_cbc 3des_cbc
#
user-interface con 0

查看信息：

[~CE1-bd2]dis ip rou vpn a
Proto: Protocol        Pre: Preference
Route Flags: R - relay, D - download to fib, T - to vpn-instance, B - black hole route
------------------------------------------------------------------------------
Routing Table : a
         Destinations : 6        Routes : 6        
Destination/Mask    Proto   Pre  Cost        Flags NextHop         Interface
    192.168.1.0/24  Direct  0    0             D   192.168.1.254   Vbdif2
    192.168.1.2/32  IBGP    255  0             RD  2.2.2.2         VXLAN
  192.168.1.254/32  Direct  0    0             D   127.0.0.1       Vbdif2
  192.168.1.255/32  Direct  0    0             D   127.0.0.1       Vbdif2
    192.168.2.1/32  IBGP    255  0             RD  2.2.2.2         VXLAN
255.255.255.255/32  Direct  0    0             D   127.0.0.1       InLoopBack0
[~CE1-bd2]dis bgp evpn al rou ma
 Local AS number : 100
 BGP Local router ID is 12.1.1.1
 Status codes: * - valid, > - best, d - damped, x - best external, a - add path,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 
 EVPN address family:
  Number of Mac Routes: 6
 Route Distinguisher: 1:1
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>    0:48:5489-98fd-0378:32:192.168.1.1                     0.0.0.0
 *>    0:48:707b-e8ad-235d:0:0.0.0.0                          0.0.0.0
 Route Distinguisher: 2:2
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98bc-1b5e:32:192.168.2.1                     2.2.2.2
 *>i   0:48:707b-e837-2581:0:0.0.0.0                          2.2.2.2
 Route Distinguisher: 2:3
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98c4-6f7b:32:192.168.1.2                     2.2.2.2
 *>i   0:48:707b-e837-2581:0:0.0.0.0                          2.2.2.2
   EVPN-Instance 2:
 
 Number of Mac Routes: 4
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98c4-6f7b:32:192.168.1.2                     2.2.2.2
 *>    0:48:5489-98fd-0378:32:192.168.1.1                     0.0.0.0
 *>i   0:48:707b-e837-2581:0:0.0.0.0                          2.2.2.2
 *>    0:48:707b-e8ad-235d:0:0.0.0.0                          0.0.0.0
   EVPN-Instance __RD_1_1_1__:
 
 Number of Mac Routes: 2
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98bc-1b5e:32:192.168.2.1                     2.2.2.2
 *>i   0:48:5489-98c4-6f7b:32:192.168.1.2                     2.2.2.2
[~CE1-bd2] dis vx pe
Number of peers : 1
Vni ID    Source                  Destination            Type      Out Vni ID
-------------------------------------------------------------------------------
2         1.1.1.1                 2.2.2.2                dynamic   2         
[~CE1-bd2]dis vx tun
Number of vxlan tunnel : 1
Tunnel ID   Source                Destination           State  Type     Uptime
-----------------------------------------------------------------------------------
4026531841  1.1.1.1               2.2.2.2               up     dynamic  00:34:16 
[~CE1-bd2]dis vx vn
Number of vxlan vni : 1
VNI            BD-ID            State  
---------------------------------------
2              2                up         
[~CE1-bd2]

[~CE2]dis bgp evpn al routing-table mac-route
 Local AS number : 100
 BGP Local router ID is 12.1.1.2
 Status codes: * - valid, > - best, d - damped, x - best external, a - add path,
               h - history,  i - internal, s - suppressed, S - Stale
               Origin : i - IGP, e - EGP, ? - incomplete
 
 EVPN address family:
  Number of Mac Routes: 6
 Route Distinguisher: 1:1
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98fd-0378:32:192.168.1.1                     1.1.1.1
 *>i   0:48:707b-e8ad-235d:0:0.0.0.0                          1.1.1.1
 Route Distinguisher: 2:2
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>    0:48:5489-98bc-1b5e:32:192.168.2.1                     0.0.0.0
 *>    0:48:707b-e837-2581:0:0.0.0.0                          0.0.0.0
 Route Distinguisher: 2:3
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>    0:48:5489-98c4-6f7b:32:192.168.1.2                     0.0.0.0
 *>    0:48:707b-e837-2581:0:0.0.0.0                          0.0.0.0
   EVPN-Instance 2:
 
 Number of Mac Routes: 4
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>    0:48:5489-98c4-6f7b:32:192.168.1.2                     0.0.0.0
 *>i   0:48:5489-98fd-0378:32:192.168.1.1                     1.1.1.1
 *>    0:48:707b-e837-2581:0:0.0.0.0                          0.0.0.0
 *>i   0:48:707b-e8ad-235d:0:0.0.0.0                          1.1.1.1
   EVPN-Instance 3:
 
 Number of Mac Routes: 2
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>    0:48:5489-98bc-1b5e:32:192.168.2.1                     0.0.0.0
 *>    0:48:707b-e837-2581:0:0.0.0.0                          0.0.0.0
   EVPN-Instance __RD_1_2_2__:
 
 Number of Mac Routes: 1
       Network(EthTagId/MacAddrLen/MacAddr/IpAddrLen/IpAddr)  NextHop
 *>i   0:48:5489-98fd-0378:32:192.168.1.1                     1.1.1.1
[~CE2]dis vx pe                              
Number of peers : 1
Vni ID    Source                  Destination            Type      Out Vni ID
-------------------------------------------------------------------------------
2         2.2.2.2                 1.1.1.1                dynamic   2         
[~CE2]dis vx tu
Number of vxlan tunnel : 1
Tunnel ID   Source                Destination           State  Type     Uptime
-----------------------------------------------------------------------------------
4026531841  2.2.2.2               1.1.1.1               up     dynamic  00:34:52 
[~CE2]