[j-nsp] improving global unicast convergence (with or without BGP-PIC)

[adamv0025 at netconsultings.com]

> Dragan Jovicic [mailto:draganj84 at gmail.com]
> Sent: Wednesday, April 19, 2017 5:20 PM
> 
> What Juniper calls "BGP Edge Link Protection" is something different. It
> allows Edge ASBR router to reroute/tunnel traffic from failed CE link over
> core to another ASBR. 
Yup same as Cisco's PIC Edge (or former feature called local-reroute/protection or something along those lines). 
 
> For this to work the router must not look at IP packet
> (still pointing to failed PE-CE links), hence per-prefix labels are used. 
Although more convenient it's not a hard requirement, router can forward using IP header you just need to make sure the backup router prefers locally introduced eBGP routes before iBGP routes advertised by primary router. 
Also I don't ever see a need for per-prefix labels -certainly doing that for the Internet VRF would be madness. 
Using per next-hop labels is sufficient to avoid lookup in this case -but then things like IP FW filters are bypassed.   
    
adam


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