doc: document IS-IS three-way handshake config

[cfra]

No description provided.

[donaldsharp]

Once CI finishes I will push in.

[qlyoung]

If you want, Sphinx will automatically generate a link to the RFC if you use the following markup:

:rfc:`5303`

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

Congratulations, this patch passed basic tests

Tested-by: NetDEF / OpenSourceRouting.org CI System

CI System Testrun URL: https://ci1.netdef.org/browse/FRR-FRRPULLREQ-2894/

This is a comment from an EXPERIMENTAL automated CI system.
For questions and feedback in regards to this CI system, please feel free to email
Martin Winter - mwinter (at) opensourcerouting.org.

---

CLANG Static Analyzer Summary

• Github Pull Request 1893, comparing to Git base SHA 2f9fca6
• Base image data for Git 2f9fca6 does not exist - compare skipped

19 Static Analyzer issues remaining.

See details at
https://ci1.netdef.org/browse/FRR-FRRPULLREQ-2894/artifact/shared/static_analysis/index.html

[LabN-CI]

💚 Basic BGPD CI results: SUCCESS, 0 tests failed

Results table

_	_
Result	SUCCESS git merge/1893 51e01fe
Date	03/14/2018
Start	13:20:39
Finish	13:44:02
Run-Time	23:23
Total	1816
Pass	1816
Fail	0
Valgrind-Errors	0
Valgrind-Loss	0
Details	vncregress-2018-03-14-13:20:39.txt
Log	autoscript-2018-03-14-13:21:29.log.bz2

For details, please contact louberger

[NetDEF-CI]

Continuous Integration Result: SUCCESSFUL

Congratulations, this patch passed basic tests

Tested-by: NetDEF / OpenSourceRouting.org CI System

CI System Testrun URL: https://ci1.netdef.org/browse/FRR-FRRPULLREQ-2897/

This is a comment from an EXPERIMENTAL automated CI system.
For questions and feedback in regards to this CI system, please feel free to email
Martin Winter - mwinter (at) opensourcerouting.org.

---

CLANG Static Analyzer Summary

• Github Pull Request 1893, comparing to Git base SHA 2f9fca6

No Changes in Static Analysis warnings compared to base

19 Static Analyzer issues remaining.

See details at
https://ci1.netdef.org/browse/FRR-FRRPULLREQ-2897/artifact/shared/static_analysis/index.html