P equipment PE equipment CE Equipment

PDevice,PEDevice,CEDevice

Mpls vpn has three types of routers: CE router, PE router, and P router.

(1) The CE router is a client router that provides you with a connection to the PE router. The PE router is the operator's edge router, that is, the Label Edge Router (LER) in the MPLS network ), it processes the VPN data from the CE router or the label exchange path (LSP) based on the stored route information and forwards the data. It is also responsible for exchanging route information with other PE routers;

(2) The P router is the main router of the carrier network, that is, the label exchange router (LSR) in the MPLS network. It transparently forwards the VPN data according to the outer labels of the group, the P router only maintains the route information to the PE router, rather than the VPN-related route information.

This is a concept in the ip man. It is explained in the MPLS protocol that the P device is a supplier device (Provider), a core layer device, and a PE is a Provider Edge device, that is, an operator Edge device, it is generally BRAS, and CE is the user's edge device.

Concepts in MPLS VPN
1. P (Provider) is a core layer device, a Provider router, and a service Provider is a backbone network router that does not connect to any CE router. It is equivalent to a label exchange router (LSR ).
2. PE (Provider Edge) is the Edge router of Provide, which is equivalent to the tag Edge router (LER ). The PE router connects CE routers and P routers, which are the most important network nodes. User traffic flows into the user network through the PE router or to the MPLS backbone network through the PE router.
3. CE (Customer Edge), the user Edge device, and the client router connected by the service provider. The CE router connects one or more PE routers to provide service access for users. The CE router is usually an IP router, which establishes an adjacent relationship with the connected PE router.
User site: a user site can connect to the backbone network of a service provider through one or more links.

The existing China Telecom CN2 China Netcom's broadband bearer network adopts the mpls vpn technology.

Mpls vpn working process
Use the tag protocol stack to connect to the same VPNPEBuild a tunnel between routes. The label protocol stack uses two-layer labels,PELabels between routers are located at the underlying layer, whilePELabels between routers, P routers, and two P routers are located at the upper layer of the protocol stack. The lower layer protocol is transparent to the upper layer protocol.
When user data belonging to a VPN enters the MPLS backbone networkCEVro andPEThe router connection interface can identify thisCEThe router belongs to that VPN, and then reads the next hop label from the VRF corresponding to the VPN, and adds the label as the internal label to the label protocol stack.PEAfter the router continues to find its own global route table and obtains the next hop interface and label, add the label as an external label to the label protocol stack and send the packet with two-layer labels from the corresponding interface to the P router. Inside the MPLS backbone network, the P router forwards data packets based on the outer label until the egressPEVro. At exitPERouter,PEThe router removes the packet label and forwards it as a general IP packet toCEVro. Because each packet contains two labels, the last-to-last hop label of the MPLS domain must be used to exit the stack.