Brocade Communications Systems IP250 user manual Mpls Virtual Leased Line VLL overview

MPLS Virtual Leased Line (VLL) overview 28

•Select Drill-down to LSP Hops Topology to display LSPs and hops as a line from the ingress router with an arrow to indicate direction. Operationally enabled LSPs are shown with a solid line. Operationally disabled LSPs are shown with a dotted line.

•Select LSP Ping to launch the LSP Ping dialog box.

•Select LSP Traceroute to launch the LSP Trace Route dialog box.

MPLS Virtual Leased Line (VLL) overview

MPLS VLL provides point-to-point Ethernet or VLAN connectivity over an MPLS domain. VLL is also known as Pseudo-Wire emulation. Figure 348 illustrates a basic VLL configuration.

MPLS Domain

Ingress Penultimate Egress

CE Device CE Device

PE Router Tunnel LSP PE Router

FIGURE 348 Basic VLL configuration

Packets are forwarded over an MPLS VLL as described below.

1.A Customer Edge (CE) product forwards a packet to an LER serving as a Provider Edge (PE) router at the edge of the MPLS domain.

2.The PE router assigns the packet to an RSVP-signalled LSP whose destination is an LER (also serving as a PE router) that is connected to a CE product at the far end of the MPLS domain. The PE router at the other end of the MPLS domain is known as this PE router’s VLL peer. The RSVP-signalled LSP used to reach the VLL peer is known as the tunnel LSP. Alternatively, an LDP-signalled, tunneled LSP can be used.

If a Class of Service (COS) value is set for the VLL, the product selects a tunnel LSP that also has this COS value, if one is available. If no tunnel LSP with this COS value is available, the product selects a tunnel LSP with the highest configured COS value (although never higher than the COS setting for the VLL).

If there are multiple tunnel LSPs that can be used to reach the VLL peer, the PE router selects one of the tunnel LSPs by using a round-robin method.

Brocade Network Advisor IP User Manual	867
53-1003056-01