[j-nsp] Limit on interfaces in bundle

Cydon Satyr cydonsatyr at gmail.com
Thu Oct 29 18:54:46 EDT 2015

Hey all,

Adam I believe that is correct. If I remember this, if it's something other
than 0x4/0x6 Trio chip looks at bits after first 12 bytes; if it's
0x0800/0x86dd it still load balances this packet based on IPv4/IPv6 rules,
and if it's 0x8100 it skips up to two vlan headers and again checks for
real ethertype.  If it's something other than this it stops and just load
balances used MPLS tags.
So if there's CW, it still check for three things above (since CW doesn't
start with 0x4/0x6), and then just fails. I think...

How would router be certain of packet type based on packet length?
Also since hashing is decided on ingress PFE if next-hop is aggregate/ecmp,
trio only looks at first 128bytes or so. So probably looking at 0x4/0x6 is
the cheapest/fastest way of guessing without performance penalty...

Somebody correct me if I'm wrong


On Thu, Oct 29, 2015 at 11:10 PM, Adam Vitkovsky <Adam.Vitkovsky at gamma.co.uk
> wrote:

> > Saku Ytti
> > Sent: Thursday, October 29, 2015 7:49 PM
> >
> > Now you can have MAC address
> > starting with 4, which would be incorrectly balanced as if it were IPv4,
> causing
> > reordering.
> >
> But shouldn’t the box check for packet length to avoid the "4" or "6" DMAC
> issue
> So it should revert back to ethernet parsing when DMAC starts with 4x: or
> 6x: and length does not match right?
> For ethernet pw it should be able to skip upto 2 vlans and still include
> its ipv4/v6 payload.
> But I haven't lab this yet so it's just a theory.
> adam
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