Riverstone Networks WICT1-12 - Manual (Page 370)

17-62 Riverstone Networks RS Switch Router User Guide Release 8.0
Configuring L2 Tunnels MPLS Configuration
Transit LSR Configuration
In a static L2 LSP, transit LSRs can change (swap) the label value at the top of the label stack. Use the
mpls set
portlist
command to configure the static L2 LSP on the RS. When configuring the static L2 LSP on the transit LSR,
you specify:
• the incoming port(s)
• the outgoing port(s)
• the next-hop MAC address
• the incoming label value and one of the following actions to be taken on the label (the label map):
- swap the incoming label with a specified outgoing label value
- pop the top value on the label stack
- push a new label value on the top of the label stack
For example, the following command on a transit LSR looks at packets arriving on the port gi.4.1. Packets that have a
label value of 100 have their labels replaced by the value 200 before they are sent to the next-hop MAC address
00e063:3738ce.
Egress LSR Configuration
In a static L2 LSP, the egress LSR removes (pops) the label value at the top of the label stack and then forwards the
packet to its final destination. Use the
mpls set portlist
command to configure the static L2 LSP on the RS. When
configuring the static L2 LSP on the egress LSR, you specify:
• the incoming port(s)
• the incoming label value to be popped from the label stack (normally, this would be the only label in
the stack, as this is the egress router)
For example, the following command on an egress LSR looks at packets arriving on port gi.6.1. Packets that have a
label value of 200 have their label popped before they are sent to the destination VLAN (as determined by the 802.1q
header or the VLAN ID associated with the incoming port):
As mentioned previously, you need to configure an L2 LSP in each direction to allow for bi-directional traffic flow.
Thus, the static LSPs will logically appear as shown in
Figure 17-14 . The configurations of routers R1, R2, and R3 for
both paths are shown below.
mpls set portlist label-map 100 swap 200 next-hop-mac 00e063:3738ce in-port-list gi.4.1
out-port gi.5.1
mpls set portlist in-port-list gi.6.1 end-of-l2-tunnel-label 200