master-thesis/doc/Conclusion.tex

\chapter{\label{summary}Conclusion}
%** Summary.tex: What have you achieved, what have you presented in this
%                document.  What are the highlights of your work.
%                It should conclude by a conclusion.

Sum up what you have done and recapitulate your key findings.

%\section{\label{conclusion:overall}Overall}

\section{\label{conclusion:softwarenat64}Software based NAT64}

\section{\label{conclusion:general}General}
Many misleading


\section{\label{conclusion:bmv2}BMV2}


\section{\label{conclusion:P4}P4}

checksumming a frequent problem and helper

Many possibilities
Protocol independent
Easy architecture

Limitations in

if in action limitations

Limits if in actions

python2 only - unicode errors

IPv6: NDP: not easy to parse, as unknown number of following fields

No support for multiple LPM keys in a table, can be solved with
ternary matching.

switch cannot be used in actions

if things don't work, often a checksum problem.

if frame checksum, then length of packet is broken

\begin{verbatim}
p4c --target bmv2 --arch v1model --std p4-16 "../p4src/static-mapping.p4" -o "/home/p4/master-thesis/p4src"
../p4src/static-mapping.p4(366): error: Program is not supported by this target, because table MyIngress.v6_networks has multiple successors
    table v6_networks {
          ^^^^^^^^^^^

\end{verbatim}

\begin{verbatim}
ipaddress.ip_network("2001:db8:61::/64")
IPv6Network(u'3230:3031:3a64:6238:3a36:313a:3a2f:3634/128')

Fix:
from __future__ import unicode_literals

\end{verbatim}

The tooling around P4 is still fragile, encountered many bugs
in the development.\cite{schottelius:github1675}

or missing features (\cite{schottelius:github745},
\cite{theojepsen:_get})

Hitting expression bug

\section{\label{conclusion:netpfga}NetFGPA - all HERE}
personal note here

MTU limitations: 1500 according to a private mail from Salvator Galea
cambridge / uk

long compile process
error prone compile process
many dependencies
lpm not supported!
Netpfga live,
Vivado
SDNET
xx k lines of supporting code

Vivado installation: silent errors, infinite loop, missing libncurses5

82k lines of code that are interdependent
Many non critical error messages on the way
Zero exit fatal errors

missing / spreaded documentation

tcpdump on local nfX doesn't work -> can only debug on other endpoint


First card: Writing tables fails
hardware debug shows some errors
but hardware debug on correct card also shows some error
Debug ioctl errors when writing table entries


Output all ports -> port mapping documented only in a testdata script


hwtest: Execution fails due to missing djtgcfg


no payload accessq

Many workarounds

Table size 63, table size 64,

Table entries require arguments of all possible actions, not only used
one.

Compile time hours

Silent errors

Unclear errors: broken board

Due to the very fragile nature of the build framework from the
NetFPGA-Live repository,

Renaming VARIABLES in the definition of

Reproducibility:

hours for finding right output ports

packet size / annotation



\section{\label{conclusion:realworld}Real world applications}
Can be deployed using the netpfga. Or Barefoot or Arista.

\section{\label{conclusion:outlook}Outlook}

%** Outlook.tex: What needs to be done further, what is planed
%
What are the consequences of your work for future work?

Different HW

Speed only limited to line speed. Could be running at 100 Gbit/s
without modifications.

PMTU
handling error cases

Our algorithm uses the IPv4-Compatible IPv6 Address\cite{rfc4291} to
embed IPv4 addresses. However RFC6052\cite{rfc6052} defines different
embeddings depending on the prefix size. A future version should
support these schemes to be compatible to other implementations.

No fragmentation
No address / mac learning

\section{\label{conclusion:closing}Closing words (NAME?)}
While the port to NetPFGA was significantly more effort then expected,
the learnings of the different layers were very much appreciated / liked

It was a

\section{todo - FIXME: remove}
\begin{verbatim}
***** Summary eher kurz
***** Outlook als subsection!
\end{verbatim}