The MPLS WG Archive

["Thomas D. Nadeau" <tnadeau@cisco.com>]

At 01:43 PM 11/19/2002 -0500, Alia Atlas wrote:
>The idea is not to mandate how traffic distribution is done.  It's to say 
>that the reserved labels should be excluded from consideration in 
>determining that.  I'm certainly against anything which increases the size 
>of the microflows which can be load-balanced - this doesn't do that, b/c 
>only the OAM packets would have those reserved labels.
>
>Which huge problems are you seeing with this?  I'm not saying that it 
>should be mandated in anyway, simply that it may be superior design, if 
>one chose to implement it thusly.

         I think it might be a great design if EVERYONE implemented it.
However, I think that is a not possible.

>Absolutely, this isn't something to be required and it is revolutionary in 
>that it requires hardware changes.  I don't see how it is a burden on 
>existing and future implementations; it is a suggestion for how to make 
>the ECMP friendlier.

         It is a burden because some hardware from vendors may not be able to
support the algorithm (i.e.: look at that many labels).  Also your point of
wanting to look at more labels than might be mandated would prohibit
better load sharing behavior.

         --Tom

>  Didn't we also have discussions about how routers should do microflow 
> classification for the load-balancing instead of doing round-robin to 
> avoid microflow reordering?  And that  is not what all routers do or, 
> probably, will ever do depending on where in the network they are...
>
>Alia
>
>At 01:27 PM 11/19/2002 -0500, Thomas D. Nadeau wrote:
>
>>>The concept of avoiding the reserved labels in an MPLS hash as a "best 
>>>way" makes some sense,
>>
>>
>>         Does this mean that we then have to mandate how IP (L2TPV3) does
>>traffic distribution too?  What is next?    I think that this solution looks
>>good in theory, but in practice there are huge problems with it.
>>
>>>though it would probably only be gradually available as hardware changes.
>>
>>         Kireeti or you made a good point that
>>this solution is not evolutionary; it is revolutionary as it will require
>>hardware changes.  On the surface it might sound reasonable to
>>say that well, hardware will evolve and as it does it must support
>>this sort of load-balancing. However, the fact of the matter is that
>>one size does not fit all in this case, and thus this will be a burden
>>on both existing and future implementations.
>>
>>         --Tom
>>
>>>Doing this would make OAM work for pseudo-wires, where there is no 
>>>underlying packet information which can be examined and where the TTL is fixed.
>>>
>>>But this does change fast-path hardware...
>>>
>>>Doing JUST that doesn't have bad impact on load-balancing of microflows 
>>>(or identifying as small a microflow as possible).
>>>
>>>Alia
>>>
>>>At 07:36 AM 11/19/2002 -0800, Shahram Davari wrote:
>>>>Hi,
>>>>
>>>>One of the criticism for this draft was that it is designed to overcome
>>>>Y.1711 limitation, in which a reserved label is used. As I mentioned
>>>>in the meeting the MPLS-Ping also requires usage of an extra reserved
>>>>label for non-IP carrying LSPs:
>>>>
>>>>   "To test an LSP that carries non-IP traffic, before injecting ICMP and
>>>>    MPLS ping messages into the LSP, the IPv4 Explicit NULL label should
>>>>    be prepended to such messages."
>>>>
>>>>So this draft is equally applicable to MPLS-ping.
>>>>
>>>>Yours,
>>>>Shahram
>>
>>Success is relative; the more success, the more relatives. -Anonymous
>>
>

Success is relative; the more success, the more relatives. -Anonymous