Virtual Private Wire Service (VPWS)
VPWS (Virtual Private Wire Service) is Point-to-Point Layer 2 MPLS VPN Service of Nokia Service Routers. The other Layer 2 VPN Service is VPLS that will be explaine in the following articles. Here, we will focus on VPWS (Virtual Private Wire Service) . In another lesson, we will learn How to Configure VPWS on Nokia Service Routers.
Below, a logical picture is given for VPWS Service and shows this structure better.
This general structure shows, VPWS logical structure independant from the used L2 technology and VPWS type.
VPWS (Virtual Private Wire Service) is also called as Virtual Leased Line. It provides Point-to-Point VPN service and from the point of Customer it is like a Leased Line. With VPWS two sites of customer are like directly connected as Point-to-Point.
As you can see, it is like a connection that connects customer’s different branches.
VPWS service encapsulates the customer data and transports over the service provider’s IP or MPLS network in a GRE or MPLS tunnel.
Above we said that VPWS is a Layer 2 VPN Service. But sometimes VPWS can be defined Layer 1 VPN Service, because there is no MAC learning in this service.
VPWS service offers service for interworking for Ethernet, ATM, Frame-Relay and TDM across a common IP/MPLS network. According to used L2 technology, there are five types of Nokia VPWS Services.
These are :
– Epipe : Epipe is Ethernet Pipe. It is a simple Point-to-Point L2 VPN Ethernet Service between two Ethernet SAPs.
– Fpipe : Fpipe is Frame-Relay Pipe. It is a simple Point-to-Point L2 VPN Frame-Relay Service between two Frame-Relay SAPs.
– Apipe : Apipe is ATM Pipe. It is a simple Point-to-Point L2 VPN ATM Service between two ATM SAPs.
– Cpipe : Cpipe is TDM Pipe. It is a simple Point-to-Point L2 VPN TDM Service between two TDM SAPs.
– Ipipe : Ipipe is Interworking VPWS. It is a simple Point-to-Point L2 VPN Service between two nodethat has different technologies.
Epipe is the VPWS VPN Service of Nokia that is for Ethernet Services. Epipe uses Ethernet SAPs. Epipe Servie is also called “Virtual Leased Line (VLL)”. This is like a Virtual Leased Line for customers.
By the way, for Epipe service, there is no need for MAC Learning.
Fpipe is the VPWS VPN Service of Nokia for Frame-Relay. Fpipe uses Frame-Relay SAPs. Here, Frame-Relay PVCs are used between routers.
Apipe is the VPWS VPN Service of Nokia for ATM. Apipe uses ATM SAPs. Here, ATM PVCs are used between routers.
Cpipe is the VPWS VPN Service of Nokia for TDM. Cpipe uses TDM SAPs. It is a TDM Leased Line.
Ipipe is Interworking VPWS. It is a simple Point-to-Point L2 VPN Service between two node that has different technologies. For example, this can be connect an Ethernet technology to an ATM technology, or a Frame-Relay technology to Ethernet technology etc..
VPWS SAP Encapsulations
SAP encapsulation is used for some important roles. According to Layer 2 technology, there are some different encapsulations types. Let’s talk about these encapsulations.
There are some SAPs encapsulations used in Epipe and Ethernet. These encapsulations and their roles are given below:
Null Encapsulation means that this interface can be used for “Single Service” for “Single Customer”.
Dot1q Encapsulation means that this interface can be used for “Multiple Services”for “Multiple Customers”.
Q-in-Q Encapsulation means that this interface can be used to expand VLAN space by tagging tagged packets.
There are also other encapsulation types for SONET. These are :
• SONET/SDH (IPCP)
• SONET/SDH TDM (BCP-null)
• SONET/SDH TDM (BCP-Dot1Q)
• SONET/SDH ATM (ATM)
• SONET/SDH Frame Relay (Frame Relay)
In the following parts, we will focus on VPWS Configurations on Nokia Service Routers.