Mpls L2Vpn Interworking; Pw Redundancy - HP MSR2000 Configuration Manual

MPLS L2VPN interworking

CEs might connect to PEs through various types of links, such as ATM, FR, HDLC, Ethernet, and PPP. MPLS
L2VPN interworking connects such CEs and allow them to communicate.
MPLS L2VPN supports Ethernet interworking and IP interworking modes. The device only supports IP
interworking. Only local MPLS L2VPN connections, static PWs, LDP PWs, and remote CCC connections
support the interworking feature.
Figure 92 Ethernet to PPP interworking
Eth header IP header
As shown in
1. CE 1 sends an Ethernet frame destined for CE 2 to PE 1.
2. PE 1 checks whether the packet encapsulated in the received Ethernet frame is an IP packet. If yes,
PE 1 removes the Ethernet header, adds PW label V and tunnel label T to the IP packet, and
forwards the packet to PE 2 through the tunnel. If not, PE 1 drops the frame.
3. PE 2 obtains the output interface information according to the PW label V in the received packet,
removes the PW label, adds an PPP header, and forwards the PPP frame to CE 2.
In an MPLS L2VPN interworking scenario, link layer negotiation packets cannot be delivered on the
network. Therefore, Layer 2 connections cannot be established between CEs. CEs must establish Layer 2
connections with the PEs. For example, CE 2 and PE 2 must perform PPP negotiation to establish a PPP
connection.

PW redundancy

PW redundancy provides redundant links between PEs so that the customer networks can communicate
when the path over one PW fails. As shown in
one backup). The CEs communicate through the primary PW. When the primary PW fails, PE 1 brings
up the backup PW and forwards packets from CE 1 to CE 2 through the backup PW. When CE 2
receives the packets, it updates its MAC address table, so that packets from CE 2 to CE 1 also travel
through the backup PW. Only static PWs and LDP PWs support PW redundancy.
T
PE 1
IP data
Ethernet link
CE 1
Figure 92, a packet is forwarded as follows:
MPLS or IP backbone
V IP header IP data
Figure 93, PE 1 establishes two PWs (one primary and
377
V: PW label
T: Tunnel identifier
PE 2
PPP header IP header
PPP link
CE 2
IP data