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DES-7200 Configuration Guide Chapter 8 VRF
Configuration
8-2
VRF-lite Typical Application Model
The packet-forwarding process in a VRF-lite enabled network is shown below:
When the CE receives a packet from a VPN, it looks up the relevant VRF
routing table based on the input interface. When a route is found, the CE
forwards the packet to the PE.
When the ingress PE receives a packet from the CE, it performs a VRF
lookup. When a route is found, the router adds a corresponding MPLS label
to the packet and sends it to the MPLS network.
When an egress PE receives a MPLS packet from the MPLS network, it
strips the MPLS label and uses the label to identify the correct VPN routing
table. Then the egress PE performs the normal route lookup. When a route is
found, it forwards the packet to the correct adjacency.
When a CE receives a packet from an egress PE, it uses the input interface
to look up the correct VPN routing table. If a route is found, the CE forwards
the packet within the VPN.
8.3 VRF Configuration Task
VRF-Lite usage guidance:
CE supports multiple users using VRF-lite. Each user owns its routing table;
Users may use the same IP address (which is not supported at present);
Many users share the physical lines between CE and PE in many ways via
multiple logic interfaces;
VRF-Lite does not support MPLS-VRF function, which mainly plays a role in
CE end;
On the PE, connections of multiple CEs is similar to using VRF-lite;
It is recommended to use EBGP for the route interaction between PE and CE.
It will be more complicated if use OSPF, RIP, static routing to achieve the
route interaction. If you are using OSPF routing interactions, need to be
carefully configured, It is recommended to use the capability vrf-lite function
when using the OSPF for the route interaction.
8.3.1 Creating VRF
Command Function
DES-7200(config)# ip vrf vrf-name
Create VRF.
vrf-name shall not exceed 31 characters.