[j-nsp] Segment Routing Real World Deployment (was: VPC mc-lag)

[adamv0025 at netconsultings.com]

> From: Alexandre Guimaraes [mailto:alexandre.guimaraes at ascenty.com]
> Sent: Sunday, July 08, 2018 11:16 PM
> 
> Adam,
> 
> Important observation, I prefer keep my pw working even a lot of segments
> of the network are affected by fiber cut and so on...
> 
> When I migrate my BGP VPLS services to l2circuits, my problems today is
> almost Zero.
> 
I don't think this was down to BGP/tLDP cause both of these are TCP sessions carrying PW VC label and in both cases underlying LDP is used to carry information about transport labels.
It was probably down to the inadequate use of bridge domains on PEs. 
Or do you see this as an overall trend in your network please? That is faulty fibre causes BGP session problems but not targeted-LDP session problems?   

> No matter what happens, business order for everyone is to keep everything
> running 24/7/365 with zero downtime no matter what.... planned
> maintenance doesn’t count, since is planned.
> 
> VPLS services, as I said before, cause two outages in one year due l2 loop
> caused by operation team, after hours with no progress to find the loop
> origin, I was called (escalated) to solve the problem.
> 
This one I'd blame on bridge-domains.
Yes L2 is tricky and dumb -that's why I hate it, but if configured correctly you should not run into L2 loops.
Maybe the STP BPDUs where not making it through the PEs for some reason -resulting in inability of the L2 network to block the loop?
Also each bridge-domain should be configured with tight "storm-control" i.e. rate-limiting BUM traffic.       

adam

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