H3C Technologies H3C S5820V2 Series Switches - Manual (Page 10)

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• 16-bit AS number:32-bit user-defined number. For example, 100:1.
• 32-bit IPv4 address:16-bit user-defined number. For example, 172.1.1.1:1.
• 32-bit AS number:16-bit user-defined number, where the minimum value of the AS number is 65536.
For example, 65536:1.
MCE
BGP/MPLS VPN transmits private network data through MPLS tunnels over the public network. However,
the traditional MPLS L3VPN architecture requires each VPN instance use an exclusive CE to connect to a
PE, as shown in
Figure 1 .
For better services and higher security, a private network is usually divided into multiple VPNs to isolate
services. To meet these requirements, you can configure a CE for each VPN, which increases device
expenses and maintenance costs. Or, you can configure multiple VPNs to use the same CE and the same
routing table, which sacrifices data security.
Using the Multi-VPN-Instance CE (MCE) function, you can remove the contradiction of low cost and high
security in multi-VPN networks. MCE allows you to bind each VPN with a VLAN interface. The MCE
creates and maintains a separate routing table for each VPN. This separates the forwarding paths for
packets of different VPNs and, in conjunction with the PE, can correctly advertise the routes of each VPN
to the peer PE, ensuring the normal transmission of VPN packets over the public network.
How MCE works
The following uses Figure 3 to describe how an MCE maintains the routing tables for multiple VPNs and
exchanges VPN routes with PEs.
Figure 3 Network diagram for the MCE function
On the left-side network, there are two VPN sites, both of which are connected to the MPLS backbone
through the MCE device. VPN 1 and VPN 2 on the left-side network must establish a tunnel with VPN 1
and VPN 2 on the right-side network, respectively.
The MCE creates a routing table for VPN 1 and VPN 2 respectively. VLAN-interface 2 is bound to VPN
1 and VLAN-interface 3 is bound to VPN 2. Upon receiving a route, the MCE determines the source of
the route according to the number of the receiving interface, and adds it to the corresponding routing
table.