[j-nsp] BFD advice

[Rafal Szarecki (WA/EPO)]

George,

If you connect routers over dark-fibers or SDH, and simulte failure by removing/cuting of fiber, then detection of fail can be quicker then with BFD. This is because Lost-of-Light, AIS, RDI are asynchounus, do not depend from interval, so can be faster.

I guess You connect routers over fiber back-to-back. Then observed 200ms or more is rather effect of spf-delay then BFD.

BFD is usefull if:
 - routers are connected via Eth. Switch
 - L2 protocols or handling hardware fail, while L1(lasers, SDH driver) handling HW works fine. ( There is light on fiber, no AIS, no RDI...)

Rafa³ Jan Szarecki JNCIE
Senior Consultant - Datacom Networks
Ericsson Poland EPO/S/D
Office: +48 22 6916635
ECN:    837 6635
Mobile: +48 602418971
Skype: callto://Rafal_Szarecki <callto://Rafal_Szarecki/> 




> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net 
> [mailto:juniper-nsp-bounces at puck.nether.net]On Behalf Of 
> Rafal Szarecki (WA/EPO)
> Sent: Thursday, August 04, 2005 11:16 AM
> To: George Yalamov; juniper-nsp at puck.nether.net
> Subject: RE: [j-nsp] BFD advice
> 
> 
> 
> 
> I was paly with BFD in _lab env._ only, but I have no 
> problems with interval at few ms level. I do this year ago in 
> lab test in Bulgaris togheder with BTC. As fare as I remember 
> we was observe low the 30ms restoration in our lab network.
> 
> Person responsible from BTC for this tests was Nedialko 
> Dimitrov (from BTC - your colegue). Test cases e.g. 
> 001.001.001 , 001.001.003.
> 
> If you look for fast convergency BFD helps to detect link 
> failure, but then normal IS-IS/OSPF process start. To squize 
> time I suggest to tune also SFP-delay parameter under [edit 
> protocols isis]. (JUNOS 7.3 default 200ms, RFC standart 1s, 
> minimum 50ms)
> 
> If you need experts support you can contact with local 
> Ericsson office.
> 
> Rafa³ Jan Szarecki JNCIE
> Senior Consultant - Datacom Networks
> Ericsson Poland EPO/S/D
> Office: +48 22 6916635
> ECN:    837 6635
> Mobile: +48 602418971
> Skype: callto://Rafal_Szarecki <callto://Rafal_Szarecki/> 
> 
> 
> 
> 
> > -----Original Message-----
> > From: juniper-nsp-bounces at puck.nether.net 
> > [mailto:juniper-nsp-bounces at puck.nether.net]On Behalf Of 
> > George Yalamov
> > Sent: Wednesday, August 03, 2005 5:45 PM
> > To: juniper-nsp at puck.nether.net
> > Subject: [j-nsp] BFD advice
> > 
> > 
> > 
> > Hi all,
> > 
> > 	Does any one have real life experance with BFD, tunning timers, 
> > measurement of traffic disruption between 2 end points, 
> > convergance time 
> > in IGP (ISIS for example).
> > 
> > I've tested this feature in lab environment with some M 
> > boxes, and the 
> > minimum time of traffic interruption was 200 - 400ms measured 
> > with iperf.
> > 
> > Any ideas?
> > 
> > 
> > regards
> > George
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > http://puck.nether.net/mailman/listinfo/juniper-nsp
> > 
> 
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