Orhan Ergun No Comments

Packet loss with Fast Reroute

Packet loss with Fast Reroute

Do we still lose packet with fast reroute? One of my students asked me this question. And I would like to share the answer with everyone.

Before we discuss whether or not we lose packet with fast reroute mechanisms, let’s remember what fast reroute is. Read more

Orhan Ergun 1 Comment

Segment Routing Fast Reroute

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.

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