[159314] in North American Network Operators' Group
Re: [j-nsp] Krt queue issues
daemon@ATHENA.MIT.EDU (Tim Vollebregt)
Tue Jan 8 09:45:24 2013
From: Tim Vollebregt <tim@interworx.nl>
In-Reply-To: <2A76E400AC84B845AAC35AA19F8E7A5D0C996C97@MUNEXBE1.medline.com>
Date: Tue, 8 Jan 2013 15:45:10 +0100
To: nanog list <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hi,
What we do nowadays as some workaround, is configuring a default route =
towards a core router on 8 x 10G before maintaining an MX box. Which =
will be installed before BGP sessions come up, this will cause some =
packet loss during burst hour outages but is fine during maintenance =
hours.=20
I've seen cases where it took up to 30 minutes before the full table was =
installed correctly in the PFE's.
Currently this issue/bug is holding back our Juniper deployments. As far =
as I know Juniper created a project group for this bug, and so far they =
were able to reproduce the issue. Looks like the issue is being taken =
serious from now.
Tim
On Oct 3, 2012, at 11:50 PM, Naslund, Steve wrote:
> I think route retention might help in the event the table was cleared =
or
> routing process restarted but I don't that it will help with a boot
> because the table structures are being built as part of the system
> initialization. In reality, I would expect the static routes to get
> installed very early as soon as the routing process comes up. Since =
you
> will need a route to your BGP neighbor (even though it may be directly
> connected, it is still a route), routing has to be up BEFORE BGP
> establishes and by definition your static routes will have to be up
> before your BGP routes are ready. How well your router responds to
> traffic during an initial boot and during a 300,000 route update is
> another story. My experience with very large routers and tables is =
that
> you will have a hard time guaranteeing user traffic will pass with =
very
> much performance during an event like a full table rebuild. Luckily
> with the bandwidth we have these days and the CPU power on the =
routers,
> it does not take that long to pull in a full internet table and begin
> handling traffic.
>=20
> Steven Naslund
>=20
> -----Original Message-----
> From: Jensen Tyler [mailto:JTyler@fiberutilities.com]=20
> Sent: Wednesday, October 03, 2012 9:45 AM
> To: nanog@nanog.org
> Subject: RE: [j-nsp] Krt queue issues
>=20
> Look into Static route retain. Should keep the route in the forwarding
> table.
>=20
> =46rom Jniper site
> <<<
> Route Retention
>=20
> By default, static routes are not retained in the forwarding table =
when
> the routing process shuts down. When the routing process starts up
> again, any routes configured as static routes must be added to the
> forwarding table again. To avoid this latency, routes can be flagged =
as
> retain, so that they are kept in the forwarding table even after the
> routing process shuts down. Retention ensures that the routes are =
always
> in the forwarding table, even immediately after a system reboot.
>>>>=20
>=20
> Thanks,
>=20
> Jensen Tyler
> Sr Engineering Manager
> Fiberutilities Group, LLC
>=20
>=20
> -----Original Message-----
> From: juniper-nsp-bounces@puck.nether.net
> [mailto:juniper-nsp-bounces@puck.nether.net] On Behalf Of Benny =
Amorsen
> Sent: Wednesday, October 03, 2012 8:32 AM
> To: Jared Mauch
> Cc: Saku Ytti; juniper-nsp@puck.nether.net
> Subject: Re: [j-nsp] Krt queue issues
>=20
> Jared Mauch <jared@puck.nether.net> writes:
>=20
>> As far as the fallback 'default' route, if you are purchasing transit=20=
>> from someone, you could consider a last-resort default pointed at=20
>> them. You can exclude routes like 10/8 etc by routing these to =
discard
>> + install on your devices.
>=20
> That only helps if the default gets installed first, though. If the
> default has to wait at boot in the krt-queue behind the 300k+
> Internet-routes, I have not really gained anything...
>=20
> I suppose it is likely that a static default would be installed before
> the BGP sessions even come up.
>=20
>=20
> /Benny
> _______________________________________________
> juniper-nsp mailing list juniper-nsp@puck.nether.net
> https://puck.nether.net/mailman/listinfo/juniper-nsp
>=20
>=20
