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Merge branch '17-l3-eigrp'

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@ -31,6 +31,7 @@
\newacronym{dns}{DNS}{Domain Name System}
\newacronym{dns6}{DNSv6}{Domain Name System version 6}
\newacronym{dr}{DR}{Danmarks Radio}
\newacronym{dual}{DUAL}{Diffusing Update Algorithm}
\newacronym{dsl}{DSL}{Digital Subscriber Line}
\newacronym{dst}{dst}{destination}
\newacronym{dwdm}{DWDM}{}
@ -46,6 +47,7 @@
\newacronym{fhrp}{FHRP}{First Hop Redundancy Protocol}
\newacronym{fib}{FIB}{Forward Information Base}
\newacronym{fix}{FIX}{Federal Internet Exchange}
\newacronym{frr}{FRR}{Free Range Routing daemon}
\newacronym{fsm}{FSM}{Finite State Machine}
\newacronym{ftp}{FTP}{File Transfer Protocol}
\newacronym{ftps}{FTPS}{File Transfer Protocol Secure}
@ -78,6 +80,7 @@
\newacronym{ip6}{IPv6}{Internet Protocol version 6}
\newacronym{ipv4}{IPv4}{Internet Protocol version 4}
\newacronym{ipv6}{IPv6}{Internet Protocol version 6}
\newacronym{ipx}{IPX}{Internetwork Packet Exchange}
\newacronym{irc}{IRC}{Internet Relay Chat}
\newacronym{irtf}{IRTF}{Internet Research Task Force}
\newacronym{isis}{IS-IS}{Intermediate System to Intermediate System}
@ -115,6 +118,7 @@
\newacronym{ospf}{OSPF}{Open Shortest Path First}
\newacronym{ospf3}{OSPFv3}{Open Shortest Path First v3}
\newacronym{ospfv3}{OSPFv3}{Open Shortest Path First v3}
\newacronym{p2p}{P-2-P}{Point-to-Point}
\newacronym{pagp}{PAgP}{Port Aggregation Protocol}
\newacronym{poe}{PoE}{Power over Ethernet}
\newacronym{poe+}{PoE+}{Power over Ethernet Plus}
@ -140,9 +144,11 @@
\newacronym{rpvst}{RPVST}{Per Vlan Rapid Spanning Tree}
\newacronym{rpvst+}{RPVST+}{Per Vlan Rapid Spanning Tree Plus}
\newacronym{rsvp}{RSVP}{Resource Reservation Protocol}
\newacronym{rtp}{RTP}{Reliable Transport Protocol}
\newacronym{sdm}{SDM}{Security Device Manager}
\newacronym{sdsl}{SDSL}{Symmetric Digital Subscriber Line}
\newacronym{sftp}{SFTP}{Secure Shell File Transfer Protocol}
\newacronym{sia}{SIA}{Stuck in Active}
\newacronym{sla}{SLA}{Service Level Agreement}
\newacronym{slaac}{SLAAC}{Stateless Address Autoconfiguration}
\newacronym{smtp}{SMTP}{Simpe Mail Transfer Protocol}
@ -170,6 +176,7 @@
\newacronym{ula}{ULA}{Unique Local Address}
\newacronym{utc}{UTC}{Coordinated Universal Time}
\newacronym{vlan}{VLAN}{Virtual Local Area Network}
\newacronym{vlsm}{VLSM}{Variable-Length Subnet Masking}
\newacronym{vpn}{VPN}{Virtual Private Network}
\newacronym{vrf}{VRF}{Virtual Routing and Forwarding}
\newacronym{vrrp}{VRRP}{Virtual Router Redundancy Protocol}

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@ -2,9 +2,194 @@
\section{Routed Network}
\subsection{Administrative Distance}
\begin{table}[]
\centering
\resizebox{\columnwidth}{!}{%
\begin{tabular}{|l|l|}
\hline
\textbf{Routing Protocol} & \textbf{Administrative distance} \\ \hline
Directly connected interface & 0 \\ \hline
Static route out an interface & 1 \\ \hline
Static route to next-hop address & 1 \\ \hline
DMNR - Dynamic Mobile Network Routing & 3 \\ \hline
EIGRP summary route & 5 \\ \hline
External BGP & 20 \\ \hline
Internal EIGRP & 90 \\ \hline
IGRP & 100 \\ \hline
OSPF & 110 \\ \hline
IS-IS & 115 \\ \hline
Routing Information Protocol (RIP) & 120 \\ \hline
Exterior Gateway Protocol (EGP) & 140 \\ \hline
On Demand Routing (ODR) & 160 \\ \hline
External EIGRP & 170 \\ \hline
Internal BGP & 200 \\ \hline
Next Hop Resolution Protocol (NHRP) & 250 \\ \hline
Floating Static Route (ex. DHCP-learned) & 254 \\ \hline
Unknown (Others) & 255 \\ \hline
\end{tabular}%
}
\caption{Cisco default administrative distances}
\label{cisco-default-administrative-distances}
\end{table}
Always remember the following points for Cisco devices:\cite{wiki:Administrative_distance}
\begin{itemize}
\item An administrative distance of 255 will cause the router to remove the route from the routing table and not use it.
\item Since IOS 12.2, the administrative distance of a static route with an exit interface is 1. Prior to the release of 12.2 it was in fact 0.
\item Only the interface itself has an administrative distance of 0, since a route cannot have a distance of less than 1.
\item Directly connected routes have an administrative distance of 0.
\end{itemize}
\newpage
\section{OSPF}
\newpage
\section{IS-IS}
\newpage
\section{EIGRP}
\gls{eigrp} is Cisco's enhanced edition if \gls{igrp}. Dating back to 1993 and a leg for Cisco over other vendors back in the early days of the Internet. (.. hmm. And remember Cisco's implementation of \gls{ospf} was known to be unstable until the early 2000's.)
The change to \gls{eigrp} from \gls{igrp} was due to the support of classless routing. (\gls{igrp} only supported classful routing of class A (/8), B (/16), and C (/24) networks.)
Cisco converted \gls{eigrp} to an open standard back in 2013 with \rfc{7868}.\cite{wiki:Enhanced_Interior_Gateway_Routing_Protocol}
\gls{eigrp} adds support for \gls{vlsm} and the \gls{dual} with improved routing capabilities in comparison to \gls{igrp}. Overall \gls{eigrp} provides better capabilities compared to it's predecessor.
\subsection[Math]{The Math behind}
\fig{math/eigrp-dual-long}{eigrp-dual-long}{\glspl{eigrp} \gls{dual} full formula}
By default $K_2$, and $K_4$ is set to zero. (The are user customizable!) And $K_5$ is set to 0.
In effect the resulting shorter formula is this:
\fig{math/eigrp-dual-short}{eigrp-dual-short}{\glspl{eigrp} \gls{dual} short formula}
\subsection{How it actually works}
\gls{eigrp} does it routing on a \texttt{next-hop} basis. Meaning it only stores information about a given routes next turn. And \textbf{not} about the destination itself. (Like \gls{ospf} does)
\subsubsection{Defaults}
\gls{eigrp} runs on Cisco equipment with values of:
\begin{itemize}
\item \itemhead[]{Administrative Distance (Defaults)}
\begin{itemize}
\item Internal: 90
\item External: 180
\item Summary: 5
\end{itemize}
\item \itemhead[]{Timers}
\begin{itemize}
\item Hello: 5s / 60s \footnote{The larger timer value applies at speeds <= T1 circuit bandwidth (a.k.a. lower-than-equal-to 1.544 Mbps)}
\item Hold: 15s / 180s
\end{itemize}
\item \itemhead[]{Supported Protocols}
\begin{itemize}
\item \gls{ip}
\item \gls{ipx}
\item AppleTalk
\end{itemize}
\item \itemhead[]{Other}
\begin{itemize}
\item Type: Distance Vector
\item Algorithm: \gls{dual}
\item Transport: \gls{ip}/88
\item Authentication: MD5
\item Multicast \gls{ipv4}: 224.0.0.10
\item Multicast \gls{ipv6}: <!-- some number -->
\end{itemize}
\end{itemize}
\subsubsection{Tables}
\gls{eigrp} contains three tables for storing route information.
\begin{enumerate}
\item \itemhead[]{Neighbor Table}
\begin{itemize}
\item \textit{Lists \textbf{all} directly connected neighbors}
\item Next-Hop Router(s)
\item Interface(s)
\end{itemize}
\item \itemhead[]{Topology Table}
\begin{itemize}
\item \textit{Lists \textbf{all} learned from \textbf{all} \gls{eigrp} neighbors}
\item Destination
\item Metric
\end{itemize}
\item \itemhead[]{Global Routing Table}
\begin{itemize}
\item \textit{Best routes from \gls{eigrp} topology tabel will be copied to the routing table}
\end{itemize}
\end{enumerate}
\subsection{Stub Routing}
\gls{eigrp} features some different ways to configure routers for specific routing scenarios. \texttt{Stub} routing is one of them.
Stub routing effectively prevents the given stub site/router to be used for transit traffic.
If a router is configured as a \texttt{Stud Router}. It only carries information about \tsq{it}s locally connected routes and a default route back to the transit routers. \tsq{It}s also omitted from being queried about networks is does not advertise. {\small (I.e. The Routes Query Process)}s
\subsection{Updates Exchange}
\begin{enumerate}
\item Routers always exchange full topology table information when neighbor-ship is established.
\item Now refresh of data will be done. Unless topology updates occur.
\item If the topology changes. A partial update about the specific prefix is sent to neighbors.\footnote{Changes includes metric components, link statuses, change in announced topology information.}
\item If a neighbor-ship fail. Then a new adjacency is formed with a full topology exchange is done.
\end{enumerate}
Always remember \gls{eigrp} does split-horizon by default on all active links when exchanging topology updates.
Split-horizon is the \textit{famous} rule about not sending topology updates back to the router who sent the topology update in the first place.
\gls{eigrp} uses \gls{rtp} to send topology updates and confirmation receipts.
On \gls{p2p} interfaces. \gls{eigrp} simply send and ACK back to the sender.
On multi-access interface/segments. \gls{eigrp} sends updates to 224.0.0.10 and receivers reply with a unicast ACK message to the sender.
\subsection[SIA]{Stuck-in-Active}
\gls{eigrp} is known and feared for it being \texttt{Stuck-in-Active} mode when exchanging route updates between routers. The Stuck-in-Active state could cause problems on low end network gear with a low amount of resources available for the routing process. Which in cases could cause the network device to use all available resources when querying neighbor devices for updates.
\fig{eigrp/stuck-in-active}{stuck-in-active}{EIGRP Stuck in Active}
End result is neighbor ships between \gls{eigrp} routers is terminated and re-established again with a fresh set of route updates going out.
Imagine a large \gls{eigrp} topology (3-digit number of routers) in a single domain and beginning with 1 neighbor-ship gets re-established. And then again and again and again. Can result in quickly several routers going Stuck-in-Active because \gls{eigrp} queries are not getting answered within a short time-frame when all routers needs to query \tsq{it}s own neighbors and their neighbors and their neighbors and so forth. Until their are no more neighbors to be queried up and down the hierarchical network topology.
\fig{network/routing}{network-topology}{Medium sized network topology}
\subsection{Non-Cisco Implementations}
This is always a particular point of discussion around \gls{eigrp}. Cisco has released \textit{some} information on how \gls{eigrp} works.
Not \textit{all} information.
And only as \textit{informational} RFCs.
This ensures Cisco \textit{still} has control of the development of the protocol.
Because they have retained ownership by only publishing informational RFCs.
This has been a hindrance for the adoption of \gls{eigrp} in other vendors than Cisco them-self.
Known adoptions of EIGRP includes:
\begin{itemize}
\item \gls{frr} targeted release 4\cite{Frr30-4047:online}
\item Quagga has known works for trying to implement \gls{eigrp}. Still not officially implemented, thou.
\end{itemize}
\subsection{Filtering}
\gls{eigrp} routing updates can of course be filtered in- and outgoing direction on Cisco boxes by using prefix-lists and applying the prefix lists under the \texttt{router eigrp x} process.
\newpage
\section{RIP}
rip is the old routing protocol still existing using nukber-of-hops as the metric to calculate which route to take to the intended destination. This approach can work fine but has a nukber of weaknesses.
@ -13,10 +198,14 @@ rip is the old routing protocol still existing using nukber-of-hops as the metri
3. Has no concept of load sharing traffic between links if the same amount of hops is present amongst the best paths available.
4. Limited to a miximum of 16 hops between source and destination.
\newpage
\subsection{RIPng}
The version of rip supporting ipv6. different to the standard rip in the ng version is using different multicast addresses to communicate on.
\newpage
\section{Static}
\newpage

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month = "September",
year = "2011",
note = "[Online; accessed on 24-June-2017]"
}
@misc{Frr30-4047:online,
author = {Donald Sharp},
title = {Frr 3.0 → 4.0 · FRRouting/frr Wiki},
howpublished = {\url{https://github.com/FRRouting/frr/wiki/Frr-3.0-%E2%86%92-4.0}},
month = {February},
year = {2018},
note = {(Accessed on 02/18/2018)}
}

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year = "2017",
howpublished = {\url{http://en.wikipedia.org/w/index.php?title=Solicited-node\%20multicast\%20address&oldid=787116453}},
note = "[Online; accessed 19-July-2017]"
}
@misc{ wiki:Administrative_distance,
author = "Wikipedia",
title = "{Administrative distance} --- {W}ikipedia{,} The Free Encyclopedia",
year = "2017",
howpublished = {\url{http://en.wikipedia.org/w/index.php?title=Administrative\%20distance&oldid=799742717}},
note = "[Online; accessed 18-September-2017]"
}
@misc{ wiki:Enhanced_Interior_Gateway_Routing_Protocol,
author = "Wikipedia",
title = "{Enhanced Interior Gateway Routing Protocol} --- {W}ikipedia{,} The Free Encyclopedia",
year = "2017",
howpublished = {\url{http://en.wikipedia.org/w/index.php?title=Enhanced\%20Interior\%20Gateway\%20Routing\%20Protocol&oldid=800921738}},
note = "[Online; accessed 18-September-2017]"
}

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\usepackage{lmodern}
\usepackage{geometry}
\usepackage{listings}
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\usepackage[usenames,dvipsnames,svgnames]{xcolor}
\usepackage{color} % makes custom color codes available.
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\usepackage{graphicx}
\usepackage[numbers,square,sectionbib,comma,nonamebreak,elide]{natbib}
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\usepackage{titlepic}
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\usepackage{url}
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\usepackage{url} % cmd \url.
\usepackage[showisoZ]{datetime2} % more options for time formatting.
\usepackage{transparent}
\usepackage{soul}
\usepackage{caption}
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\usepackage{tikzsymbols} % http://ctan.math.utah.edu/ctan/tex-archive/graphics/pgf/contrib/tikzsymbols/tikzsymbols.pdf
\usepackage{textcomp}
\usepackage{parskip}
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\usepackage{makecell}
\usepackage{inconsolata}
\usepackage{blindtext}
\usepackage{expdlist}
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\usepackage{epigraph} % used to style quotes
\usepackage{titling} % makes available \thetitle \theauthor \thedate
\usepackage[toc,acronym,footnote,nomain]{glossaries} % Load the package with the acronym option
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citecolor=darkgray,
filecolor=darkgray,
urlcolor=darkgray]{hyperref} % https://en.wikibooks.org/wiki/LaTeX/Hyperlinks
\usepackage{amsmath,amssymb} % math things.
\usepackage{lipsum}
\renewcommand*{\multicolumntoc}{3} % https://tex.stackexchange.com/a/6455