Is MPLS mandatory for Traffic Engineering? Read more
If I input MPLS traffic engineering on any search engines, I will find about 100 articles on the internet providing the same explanations about MPLS traffic engineering.
But unfortunately, nobody ask these questions: do I really need it? What are the reasons behind the implementation of MPLS Traffic Engineering?
Would it worth the time and energy to deploy and learn such a complex technology if there are many easier, resource-friendly alternatives.
In this article, I will explain all the answers to these questions. Undoubtedly, MPLS traffic engineering has many used cases and it helps to solve numerous problems in an MPLS enabled networks.
Segment Routing Fast Reroute – Traffic Engineering with Segment Routing uses LFA mechanism to provide 50 msec fast reroute capability. Current Segment Routing implementation for the OSPF uses regular LFA (Loop Free Alternate) for fast reroute in Cisco devices.
Because LFA (Loop Free Alternate) has topology limitations, it does not include many faulty scenarios.
On the other hand, the IS-IS supports topology independent LFA and TI-LFA covers every faulty scenario.
As of today, Segment Routing is enabled on ASR9000 and CRS1/3. Cisco NXOS software supports Segment Routing.
Indeed, you do not need to configure tunnels, complex link, or node protection configuration to use LFA to provide fast reroute capability.
First, you need to remember MPLS-Traffic engineering operation.
MPLS-traffic engineering requires four steps, as shown below, for its operation.
- Link information such as bandwidth, IGP metric, TE metric, and SRLG is flooded throughout the IGP domain by the link state protocols.
- The path is calculated either with CSPF in a distributed manner or with offline tools as a centralized fashion.
- If a suitable path is found, it is signalled via RSVP-TE and the RSVP assigns the label for the tunnels.
- The traffic is placed in the tunnels.