Figure 28 Network Of Vpls - Zte ZXR10 8900 Series User Manual

Chapter 4 MPLS L2VPN Configuration
Service providers which provide two-layer VPN of MPLS are only in
charge of the connectivity of layer two, and they do not take part in
routing computation of VPN subscription. All-connected two-layer
VPN has a problem that it needs to assign a connection between
CE and PE for every CE to others.
For example, if there are four CEs in one VPN, it needs to establish
six connections for all CEs. The extension of two-layer VPN of
MPLS is not good.
Two-layer VPN can be built through MP-BGP extension or LDP ex-
tension, and drafts of these two are respectively draft-ietf-l2vpn-
vpls-bgp-xx and draft-ietf-l2vpn-vpls-ldp-xx.
In VPLS LDP plan, it emphasizes in solving the problem of how
to establish Virtual Circuit (VC) between two CEs. Martini L2 VPN
uses VC-TYPE+VC-ID to distinguish VC. VC-TYPE indicates type of
VC is ATM, VLAN or PPP and VC-ID is used to identity a VC solitarily.
In all VCs of one VC-TYPE, VC-ID has uniqueness in the entire SP
network. PE which connects to two CEs switches VC-ID through
LDP and binds CE with its VC-ID.
After LSP has been established successfully between two PEs and
VC-IDs of two sides have been switched and bound, a VC is estab-
lished successfully. Two CEs can transmit two-layer data through
this VC.
For switching VC-ID between PEs, Martini draft extended LDP and
added FEC type (128 types and 129 types) of VC FEC. Moreover,
two PEs which switches VC-ID may be not connected directly, LDP
must use Remote peer to establish session and switch VC FEC and
VC-ID in this session.
CE1, CE2 and CE3 are connected through core network of MPLS.
In the view of subscribers, they are connected through a LAN net-
work. This is shown in Figure 28.
F 28 N VPLS
IGURE ETWORK OF
VPLS instances of PE1, PE2 and PE3 are connected to others and
build an all-connected of PW. All VPLS instances in one VPLS do-
main use the same VC-ID.
It is assumed that PE1 distributes a VC label of 102 to PE2 and a
VC label of 103 to PE3. PE2 distributes a VC label of 201 to PE1
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