[j-nsp] Bypass LSP functionality question

[Harry Reynolds]

Do you have a per-packet lb policy applied to the forwarding table at the point of local repair?

AFAIK, any fast reroute/bypass needs this for optimal switchover as it allows the detour/bypass to be preinstalled in the pfe waiting for its day in the sun.

As I recollect, the ingress will continue to use the bypass until it can signal a new path (MBB). You may want to set the ingress lsp to adaptive to better chances of the new path being established so the lsp can get of the bypass.



Regards


 

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of David Ball
Sent: Thursday, July 07, 2011 8:41 AM
To: Phil Bedard
Cc: Juniper-Nsp
Subject: Re: [j-nsp] Bypass LSP functionality question

  ...and this is what I had originally hoped....but isn't what I'm seeing in the lab.  Unless I pre-signal a secondary path with standby, I lose ~300,000 frames (sending ~56000fps) when I fail a link in the active path.  When staring at the test set and/or a 'monitor interface traffic' when this failure occurs, things appear to switch instantly, but after about 1-3secs there's a second hit where the frame lost jumps.....hence my concern about how long the bypass was actually being used.  If I pre-signal the secondary path, on the other hand, I only lose ~1000 frames.

  It may be code level related, as things are failing differently (ie.
worse) under 10.4R5.5 then they were under 10.3R2.11 with identical configs.

  Continuing to dig.  Thanks for the replies.

David



On 6 July 2011 22:29, Phil Bedard <philxor at gmail.com> wrote:
> That's not correct.  You should take a look at RFC4090.  A Patherr 
> message is sent to the head-end node with a flag set to notify it 
> local protection is in use.  There are also flags in the RESV RRO to 
> notify the head-end local protection is in use.  The head-end node is 
> smart enough to keep using the path until it can reserve a new path and do a MBB operation.
>
> Facility bypass wouldn't be very useful if it only protected traffic 
> for a few ms...:)
>
> Phil
>
> On 7/6/11 11:50 AM, "David Ball" <davidtball at gmail.com> wrote:
>
>>  Just looking for confirmation of a suspicion here.
>>
>>  If I have an LSP configured with link-protection on every interface 
>>along the way (creating many-to-one Bypass LSPs, as opposed to 1:1 
>>detours), no secondary standby path defined, and a protected interface 
>>fails, the ingress node will have no ability to perform a 
>>make-before-break, right?  Because the Path Tear messages will be sent 
>>both upstream and downstream from the failed interface?  The bypass 
>>will only help me up until the upstream nodes process the Path Tears 
>>and a new LSP is signalled from the ingress node....or am I missing 
>>something?
>>
>>  More familiar with detours, so just checking myself wrt bypasses....
>>
>>Cheers,
>>
>>David
>>_______________________________________________
>>juniper-nsp mailing list juniper-nsp at puck.nether.net 
>>https://puck.nether.net/mailman/listinfo/juniper-nsp
>
>
>

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