[j-nsp] LACP hashing algorithm

[Pavel Lunin]

To troubleshoot this kind of condition, you need to understand 1) the
complete structure of the headers (is there any tunneling, MPLS,
pseudowires etc) 2) what kind of forwarding decision your MX performs for
those packets: IP LPM only, Ethernet switching, IP + Ethernet (irb-based
L3), MPLS, MPLS+IP ect.

If you have Ethernet bridging towards this interface, it might be a result
of unknown unicast or some other sort of flooding (e. g. multicast dst MAC).

Also cheek the [edit forwarding-options enhanced-hash-key] configuration.
People often tend to put nonsense there.

If it resembles a bug, there is a uKernel command to check the "really"
(from the MPC's point of view) applied hash-key config. Being far from my
PC I don't remember the exact syntax, you can find it at least in David
Roy's brochure "an expert packet walkthrough on the mx series 3d" or
someone here might remind us.

--
Pavel

пт, 10 авг. 2018 г., 20:43 junos fordummies via juniper-nsp <
juniper-nsp at puck.nether.net>:

> Guys thanks for all the replies, when I took an sflow sample, I oculd see
> at least 100+ flows with varying src/dst tuple and flow sizes, so cant
> understand why flows are stuck on one link. I can understand if tuples were
> hashing to one link, but these are varies sources/destinations... makes no
> sense.
>
> I will have to raise a JTAC as I cant for the life of riley figure out
> whats happening. I have double checked the config, will also look at what
> Niall posted.
>
> I will come back to you once JTAC have a look.
>
> Thanks
>
> JFD
>
> On 9 August 2018 at 12:17, Luis Balbinot <luis at luisbalbinot.com> wrote:
>
> > How many flows are there in total? Is there a test appliance involved? We
> > had many issues with those in the past during service delivery tests.
> >
> > Also I assume you are using MPCs and not DPCs and also that you are
> > talking about IP traffic. Please correct me if not.
> >
> > Luis
> >
> > On Wed, 8 Aug 2018 at 20:32 junos fordummies via juniper-nsp <
> > juniper-nsp at puck.nether.net> wrote:
> >
> >> Hi all,
> >>
> >> This will sound like a very weird question, but has anyone seen a
> scenario
> >> whereby an MX960 with 4 x 10G links always hashes (uses) a single link
> out
> >> of the 40G bundle ? We have restarted the device, traffic flows in one
> >> direction only use a single link, the reverse path is all 4 links in the
> >> bundle. Both ends of the AE is MX960 running 16.1r2
> >>
> >> Just wondering if anyone has seen anything similar ?
> >>
> >> Many thanks
> >>
> >> JfD.
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> >
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