HP MSR2000 Configuration Manual page 384

Ethernet over MPLS
Ethernet over MPLS uses MPLS L2VPN to connect Ethernets, and delivers Ethernet packets through a PW
over the MPLS backbone.
The following PW types are available for Ethernet over MPLS:
Ethernet—P-tag is not transferred on a PW.
•
For a packet from a CE:
−
−
For a packet to a CE:
−
−
However, rewriting and removing existing tags are not allowed.
VLAN—Packets transmitted over a PW must carry a P-tag.
•
For a packet from a CE:
−
−
For a packet to a CE:
−
−
NOTE:
Access modes include Ethernet and VLAN. For more information about access modes, see the ac interface
command in
Ethernet over MPLS supports the following modes:
Port mode—A Layer 3 Ethernet interface is bound to a PW. Packets received from the Layer 3
•
Ethernet interface are forwarded through the bound PW. The default data encapsulation type for
port mode is Ethernet.
If the packet contains a P-tag, the PE removes the P-tag, and adds a PW label and an outer
tag into the packet before forwarding it.
If the packet contains no P-tag, the PE directly adds a PW label and an outer tag into the
packet before forwarding it.
If the access mode is configured as VLAN by using the ac interface command, the PE adds
a P-tag into the packet before sending it to the CE.
If the access mode is configured as Ethernet by using the ac interface command, the PE
directly sends the packet to the CE.
If the peer PE does not require the ingress to rewrite the P-tag, the PE keeps the P-tag
unchanged for the packet, and then encapsulates the packet. If the packet contains no P-tag,
the PE adds a null label (the label value is 0) into the packet, and then encapsulates the
packet.
If the peer PE requires the ingress to rewrite the P-tag, the PE changes the P-tag to the VLAN
tag (the tag might be a null tag) expected by the peer PE, and then adds a PW label and
an outer tag into the packet. If the packet contains no P-tag, the PE adds a VLAN tag
expected by the peer PE (the tag value might be 0), and then adds a PW label and an outer
tag into the packet.
If the access mode is configured as VLAN by using the ac interface command, the PE
rewrites or retains the P-tag before forwarding the packet.
If the access mode is configured as Ethernet by using the ac interface command, the PE
removes the P-tag before forwarding the packet.
MPLS Command Reference
.
375