Brocade Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide (Supporting R05.6.00) - Manual (Page 149)

Multi-Service IronWare Multiprotocol Label Switch (MPLS) Configuration Guide 125
53-1003031-02
Setting up signaled LSPs
1
• Specifying which packets are to be forwarded along the LSP (optional)
Setting up paths
A path is a list of router hops that specifies a route across an MPLS domain. Once the user creates
a path, the user can create signaled LSPs that see the path. Paths are configured separately from
LSPs so that a path may be specified once and then used by several LSPs that see the path by
name. An LSP may specify a primary and one or more redundant paths.
A path is always configured at the ingress LER and assumes that the ingress LER is the beginning
of the path. A path can contain any number of nodes, which correspond to MPLS-enabled routers in
the network. Each node has one attribute: whether it is strict or loose. A strict node means that the
router must be directly connected to the preceding node. A loose node means that there can be
other routers in between.
Creating a path is not absolutely necessary when configuring an LSP. When the user configures a
signaled LSP without naming a path, CSPF uses only information in the Traffic Engineering
Database (TED), as well as the user-configured attributes and requirements of the LSP to calculate
the path. Refer to
“How CSPF calculates a traffic-engineered path” for more information. When the
LSP has been configured not to use CSPF, the path between the ingress and egress LERs is
determined using standard hop-by-hop routing methods, as if the path consisted of a single loose
node.
The following commands set up a path called sf_to_sj that has four nodes.
Brocade(config-mpls)# path sf_to_sj
Brocade(config-mpls-path)# strict 10.150.1.1
Brocade(config-mpls-path)# insert strict 10.150.1.1 strict 10.150.1.2
Brocade(config-mpls-path)# loose 10.1.1.1
Brocade(config-mpls-path)# strict 10.100.1.1
Brocade(config-mpls-path)# exit
Syntax: [no] path path name
Syntax: [no] strict | loose ip address
The path is assumed to start from the local node. The user specifies the nodes in order from
ingress to egress. Specifying the local node itself as the first node in the path is optional. Further,
the final node does not necessarily have to be the egress LER in the LSP. (The egress LER is
specified at the LSP configuration level with the to command.) When the final node in the path
differs from the egress LER, the hop between the final node in the path and the egress LER is
treated as a hop to a loose node; that is, standard IP routing is used to determine the path between
the final node and the egress LER.
The IP address defines an LSR and can be any interface address or a loopback interface address
on the LSR.
The strict and loose parameters are relative to the preceding node. In the sf_to_sj path defined
above, LSR 10.150.1.2 is a strict node; it must be directly connected to LSR 10.150.1.1. LSR
10.1.1.1 is a loose node; this means there can be other routers between LSR 10.150.1.2 and
10.1.1.1. When specifying a strict node, the user must make sure that the LSR is actually directly
connected to the preceding node.