How are you configuring BFD timers?

Måns Nilsson mansaxel at besserwisser.org
Fri Mar 23 05:10:22 UTC 2018


--On 22 mars 2018 23:45:16 +0200 Saku Ytti <saku at ytti.fi> wrote:

> On 22 March 2018 at 22:41, Måns Nilsson <mansaxel at besserwisser.org>
> wrote:
> 
>> Subject: Re: How are you configuring BFD timers? Date: Wed, Mar 21, 2018
>> at 04:24:47PM +0000 Quoting Job Snijders (job at instituut.net):
>>> Silly question perhaps, but why would you do BFD on dark fiber?
>> 
>> Because Ethernet lacks the PRDI that real WAN protocols have.
> 
> Indeed, RFI on ethernet is rather modern addition, turning 20 this year.

(You just reminded me I've been doing some sort of WAN network ops for
about 20 years.)

That does indeed solve the problem for dark fibre, and those lucky WDM
systems that actually reflect input status to output. Not always true, I'm
afraid (just look at the Ethernet switch mid-span that Thomas Bellman wrote
about; a fitting metaphor for all "ethernet-over-other.." models..).
Ethernet still regards "no frames seen on the yellow coax" as an
opportunity to send traffic rather than an error, if we're talking old
things ;-).  BFD solves that, and it is worthwhile to have one setup
regardless of technology, if possible. 

-- 
Måns Nilsson     primary/secondary/besserwisser/machina
MN-1334-RIPE           SA0XLR            +46 705 989668
CHUBBY CHECKER just had a CHICKEN SANDWICH in downtown DULUTH!
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