< Home

Example for Configuring Ethernet over GRE to Build a Virtual Layer 2 Network

Networking Requirements

In Figure 1, SwitchA, SwitchB, and SwitchC use the Open Shortest Path First (OSPF) protocol to communicate with each other over the Internet. A GRE tunnel is established between SwitchA and SwitchC. The customer wants to construct a virtual Layer 2 network over the Internet between SwitchA and SwitchC to allow PC1 and PC2 to communicate at Layer 2.

Figure 1 Ethernet over GRE tunnel

Configuration Roadmap

To meet the preceding requirements, an Ethernet over GRE tunnel needs to be deployed between SwitchA and SwitchC. A VE interface forwards Ethernet packets over the GRE tunnel, enabling Layer 2 communication between PC1 and PC2.

The configuration roadmap is as follows:

  1. Run OSPF on all the switches to implement communication over the Internet.

  2. Create tunnel interfaces on SwitchA and SwitchC to establish a GRE tunnel between them.

  3. Create VE interfaces on SwitchA and SwitchC and add them to a VLAN.

  4. Bind VE interfaces to the GRE tunnel on SwitchA and SwitchC to forward Ethernet packets over the GRE tunnel.

Procedure

  1. Configure an IP address for each physical interface.

    # Configure SwitchA. 

    <HUAWEI> system-view
[HUAWEI] sysname SwitchA
[SwitchA] vlan batch 10 30
[SwitchA] interface gigabitethernet 0/0/1
[SwitchA-GigabitEthernet0/0/1] port link-type trunk
[SwitchA-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[SwitchA-GigabitEthernet0/0/1] quit
[SwitchA] interface gigabitethernet 0/0/2
[SwitchA-GigabitEthernet0/0/2] port link-type access
[SwitchA-GigabitEthernet0/0/2] port default vlan 30
[SwitchA-GigabitEthernet0/0/2] quit
[SwitchA] interface vlanif 10
[SwitchA-Vlanif10] ip address 20.1.1.1 24
[SwitchA-Vlanif10] quit

    # Configure SwitchB.

    <HUAWEI> system-view
[HUAWEI] sysname SwitchB
[SwitchB] vlan batch 10 20
[SwitchB] interface gigabitethernet 0/0/1
[SwitchB-GigabitEthernet0/0/1] port link-type trunk
[SwitchB-GigabitEthernet0/0/1] port trunk allow-pass vlan 10
[SwitchB-GigabitEthernet0/0/1] quit
[SwitchB] interface gigabitethernet 0/0/2
[SwitchB-GigabitEthernet0/0/2] port link-type trunk
[SwitchB-GigabitEthernet0/0/2] port trunk allow-pass vlan 20
[SwitchB-GigabitEthernet0/0/2] quit
[SwitchB] interface vlanif 10
[SwitchB-Vlanif10] ip address 20.1.1.2 24
[SwitchB-Vlanif10] quit
[SwitchB] interface vlanif 20
[SwitchB-Vlanif20] ip address 30.1.1.1 24
[SwitchB-Vlanif20] quit

    # Configure SwitchC.

    <HUAWEI> system-view
[HUAWEI] sysname SwitchC
[SwitchC] vlan batch 20 30
[SwitchC] interface gigabitethernet 0/0/1
[SwitchC-GigabitEthernet0/0/1] port link-type trunk
[SwitchC-GigabitEthernet0/0/1] port trunk allow-pass vlan 20
[SwitchC-GigabitEthernet0/0/1] quit
[SwitchC] interface gigabitethernet 0/0/2
[SwitchC-GigabitEthernet0/0/2] port link-type access
[SwitchC-GigabitEthernet0/0/2] port default vlan 30 
[SwitchC-GigabitEthernet0/0/2] quit
[SwitchC] interface vlanif 20
[SwitchC-Vlanif20] ip address 30.1.1.2 24
[SwitchC-Vlanif20] quit

  2. Run OSPF on the switches to implement communication over the Internet.

    # Configure SwitchA. 

    [SwitchA] ospf 1
[SwitchA-ospf-1] area 0
[SwitchA-ospf-1-area-0.0.0.0] network 20.1.1.0 0.0.0.255
[SwitchA-ospf-1-area-0.0.0.0] quit
[SwitchA-ospf-1] quit

    # Configure SwitchB.

    [SwitchB] ospf 1
[SwitchB-ospf-1] area 0
[SwitchB-ospf-1-area-0.0.0.0] network 20.1.1.0 0.0.0.255
[SwitchB-ospf-1-area-0.0.0.0] network 30.1.1.0 0.0.0.255
[SwitchB-ospf-1-area-0.0.0.0] quit
[SwitchB-ospf-1] quit

    # Configure SwitchC.

    [SwitchC] ospf 1
[SwitchC-ospf-1] area 0
[SwitchC-ospf-1-area-0.0.0.0] network 30.1.1.0 0.0.0.255
[SwitchC-ospf-1-area-0.0.0.0] quit
[SwitchC-ospf-1] quit

    # After the configuration is complete, run the display ip routing-table command on SwitchA and SwitchC. You can find that they have learned the OSPF routes destined for the network segment of the peer.

  3. Configure tunnel interfaces and create a GRE tunnel.

    # Configure SwitchA. 

    [SwitchA] interface tunnel 1
[SwitchA-Tunnel1] tunnel-protocol gre
[SwitchA-Tunnel1] ip address 40.1.1.1 255.255.255.0
[SwitchA-Tunnel1] source 20.1.1.1
[SwitchA-Tunnel1] destination 30.1.1.2
[SwitchA-Tunnel1] quit

    # Configure SwitchC.

    [SwitchC] interface tunnel 1
[SwitchC-Tunnel1] tunnel-protocol gre
[SwitchC-Tunnel1] ip address 40.1.1.2 255.255.255.0
[SwitchC-Tunnel1] source 30.1.1.2
[SwitchC-Tunnel1] destination 20.1.1.1
[SwitchC-Tunnel1] quit

    # After the configuration is complete, the tunnel interfaces turn Up and can ping each other. A GRE tunnel has been set up between them.

    The display on SwitchA is used as an example.

    [SwitchA] ping -a 40.1.1.1 40.1.1.2
  PING 40.1.1.2: 56  data bytes, press CTRL_C to break
    Reply from 40.1.1.2: bytes=56 Sequence=1 ttl=255 time=1 ms
    Reply from 40.1.1.2: bytes=56 Sequence=2 ttl=255 time=1 ms
    Reply from 40.1.1.2: bytes=56 Sequence=3 ttl=255 time=1 ms
    Reply from 40.1.1.2: bytes=56 Sequence=4 ttl=255 time=1 ms
    Reply from 40.1.1.2: bytes=56 Sequence=5 ttl=255 time=1 ms

  --- 40.1.1.2 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 1/1/1 ms

  4. Add VE interfaces to a VLAN. Note that the VE interface and inbound interface for user-side packets must be added to the same VLAN.

    # Configure SwitchA. 

    [SwitchA] interface Virtual-Ethernet0/0/1
[SwitchA-Virtual-Ethernet0/0/1] portswitch
[SwitchA-Virtual-Ethernet0/0/1] port link-type trunk
[SwitchA-Virtual-Ethernet0/0/1] undo port trunk allow-pass vlan 1
[SwitchA-Virtual-Ethernet0/0/1] port trunk allow-pass vlan 30
[SwitchA-Virtual-Ethernet0/0/1] quit

    # Configure SwitchC.

    [SwitchC] interface Virtual-Ethernet0/0/1
[SwitchC-Virtual-Ethernet0/0/1] portswitch
[SwitchC-Virtual-Ethernet0/0/1] port link-type trunk
[SwitchC-Virtual-Ethernet0/0/1] undo port trunk allow-pass vlan 1
[SwitchC-Virtual-Ethernet0/0/1] port trunk allow-pass vlan 30
[SwitchC-Virtual-Ethernet0/0/1] quit

  5. Bind VE interfaces to the GRE tunnel to forward Ethernet packets over the GRE tunnel.

    # Configure SwitchA. 

    [SwitchA] interface tunnel 1
[SwitchA-Tunnel1] map interface virtual-ethernet 0/0/1
[SwitchA-Tunnel1] quit

    # Configure SwitchC.

    [SwitchC] interface tunnel 1
[SwitchC-Tunnel1] map interface virtual-ethernet 0/0/1
[SwitchC-Tunnel1] quit

  6. Verify the configuration.

    After the configurations are complete, PC1 and PC2 can ping each other successfully.

    The ping result from PC1 to PC2 is used as an example.

    C:\Users\pc1> ping 10.1.1.2
  PING 10.1.1.2: 56  data bytes, press CTRL_C to break
    Reply from 10.1.1.2: bytes=56 Sequence=1 ttl=253 time=72 ms
    Reply from 10.1.1.2: bytes=56 Sequence=2 ttl=253 time=34 ms
    Reply from 10.1.1.2: bytes=56 Sequence=3 ttl=253 time=50 ms
    Reply from 10.1.1.2: bytes=56 Sequence=4 ttl=253 time=50 ms
    Reply from 10.1.1.2: bytes=56 Sequence=5 ttl=253 time=34 ms
  --- 10.1.1.2 ping statistics ---
    5 packet(s) transmitted
    5 packet(s) received
    0.00% packet loss
    round-trip min/avg/max = 34/48/72 ms

Configuration Files

  • SwitchA configuration file

    #
sysname SwitchA
#
vlan batch 10 30
#
interface Vlanif10
 ip address 20.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
 port link-type access
 port default vlan 30
#
interface Virtual-Ethernet0/0/1
 portswitch
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 30
#
interface Tunnel1
 ip address 40.1.1.1 255.255.255.0
 tunnel-protocol gre
 source 20.1.1.1
 destination 30.1.1.2
 map interface Virtual-Ethernet0/0/1
#
ospf 1
 area 0.0.0.0
  network 20.1.1.0 0.0.0.255
#
return

  • SwitchB configuration file

    #
sysname SwitchB
#
vlan batch 10 20
#
interface Vlanif10
 ip address 20.1.1.2 255.255.255.0
#
interface Vlanif20
 ip address 30.1.1.1 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 10
#
interface GigabitEthernet0/0/2
 port link-type trunk
 port trunk allow-pass vlan 20
#
ospf 1
 area 0.0.0.0
  network 20.1.1.0 0.0.0.255
  network 30.1.1.0 0.0.0.255
#
return

  • SwitchC configuration file

    #
sysname SwitchC
#
vlan batch 20 30
#
interface Vlanif20
 ip address 30.1.1.2 255.255.255.0
#
interface GigabitEthernet0/0/1
 port link-type trunk
 port trunk allow-pass vlan 20
#
interface GigabitEthernet0/0/2
 port link-type access
 port default vlan 30
#
interface Virtual-Ethernet0/0/1
 portswitch
 port link-type trunk
 undo port trunk allow-pass vlan 1
 port trunk allow-pass vlan 30
#
interface Tunnel1
 ip address 40.1.1.2 255.255.255.0
 tunnel-protocol gre
 source 30.1.1.2
 destination 20.1.1.1
 map interface Virtual-Ethernet0/0/1
#
ospf 1
 area 0.0.0.0
  network 30.1.1.0 0.0.0.255
#
return
Parent Topic: Configuration Examples for GRE
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
< Previous topic Next topic >