Re: [Tsv-art] ECMP [Tsvart last call review of draft-ietf-opsec-ipv6-eh-filtering-06]

[Fernando Gont <[e-mail]>]

On 6/12/18 10:36, Stewart Bryant wrote:
> 
> 
> On 06/12/2018 11:42, Ole Troan wrote:
>> Stewart,
>>
>>>>> If it has to look at any it has a much more complex set of tests, or a
>>>>> large vector table  given the way the EH space is fragmented.
>>>> Frankly doing it without a network processor seems wrong. You can't
>>>> expect
>>>> an ASIC or FPGA based device to handle the EH structures.
>>> Something that has served the IETF well over the years is not to
>>> constrain the forwarding
>>> implementation, and I think we would be wise to continue in that
>>> mould. Also we need
>>> to remember that an NP is an application specific processor, and thus
>>> has various
>>> hardware assists.
>>>
>>> No one talks about the internals of an NP, and I am not current on
>>> any vendor's design,
>>> but it is reasonable to suggest that in addition to the s/w parser
>>> there might
>>> be a h/w parser that does the heavy lifting, i.e. if IPv6 packet of
>>> expected type, dec
>>> TTL and do what the TCAM say picking this ECMP option else parse it
>>> the hard way.
>>>
>>> Then there is something that we do not talk at all about in such
>>> designs: electrical power.
>>> There is no question that it takes more power to s/w parse a packet,
>>> and sooner of later
>>> the power burn of the Internet is going to come under scrutiny, and
>>> we will be asked
>>> to reduce its carbon footprint.
>> So you are arguing that we need to define ULPs that are easy for
>> routers to parse?
> I don't see how you would conclude that from the above. What is needed
> is that whatever the parser needs to parse needs to be easy and cheap to
> parse.

At the end of the day, it ends up being the call of the folks running
the net. -- see RFC7872.

"I'm gonna make it hard for your to parse the packets"
"OK, good. I'll just drop them. Good luck. Bye".

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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