Mpls-Te Forwarding Adjacency Benefits - Cisco ASR 9000 Series Configuration Manual

Path Computation Element

MPLS-TE Forwarding Adjacency Benefits

TE tunnel interfaces are advertised in the IGP network just like any other links. Routers can then use these
advertisements in their IGPs to compute the SPF even if they are not the head end of any TE tunnels.
Related Topics
Configuring MPLS-TE Forwarding Adjacency, on page 192
Configure Forwarding Adjacency: Example, on page 257
MPLS-TE Forwarding Adjacency Restrictions
The MPLS-TE Forwarding Adjacency feature has these restrictions:
• Using the MPLS-TE Forwarding Adjacency increases the size of the IGP database by advertising a TE
• The MPLS-TE Forwarding Adjacency is supported by Intermediate System-to-Intermediate System
• When the MPLS-TE Forwarding Adjacency is enabled on a TE tunnel, the link is advertised in the IGP
• MPLS-TE forwarding adjacency tunnels must be configured bidirectionally.
• Multicast intact is not supported with MPLS-TE Forwarding Adjacency.
MPLS-TE Forwarding Adjacency Prerequisites
Your network must support the following features before enabling the MPLS -TE Forwarding Adjacency
feature:
• MPLS
• IP Cisco Express Forwarding
• Intermediate System-to-Intermediate System (IS-IS)
• OSPF
Path Computation Element
Path Computation Element (PCE) solves the specific issue of inter-domain path computation for MPLS-TE
label switched path (LSPs), when the head-end router does not possess full network topology information
(for example, when the head-end and tail-end routers of an LSP reside in different IGP areas).
PCE uses area border routers (ABRs) to compute a TE LSP spanning multiple IGP areas as well as computation
of Inter-AS TE LSP.
PCE is usually used to define an overall architecture, which is made of several components, as follows:
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
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tunnel as a link.
(IS-IS).
network as a Type-Length-Value (TLV) 22 without any TE sub-TLV.
Implementing MPLS Traffic Engineering
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