Merge branch '17-l3-eigrp'

acronyms.tex

@@ -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}

chapter/layer3.tex

@@ -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

references-websites.bib

@@ -40,3 +40,12 @@
     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)}
+}

references-wikipedia.bib

@@ -97,3 +97,19 @@
     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]"
+}

structure.tex

@@ -4,28 +4,25 @@
 \usepackage{lmodern}
 \usepackage{geometry}
 \usepackage{listings}
-\usepackage{color}
+\usepackage{color} % makes custom color codes available.
-\usepackage[usenames,dvipsnames,svgnames]{xcolor}
+\usepackage[usenames,dvipsnames,svgnames]{xcolor} % makes custom color codes available.
 \usepackage{graphicx}
-\usepackage[numbers,square,sectionbib,comma,nonamebreak,elide]{natbib}
+\usepackage[numbers,square,sectionbib,comma,nonamebreak,elide]{natbib} % used with layout for bibliography section.
 \usepackage{float}
 \usepackage[english]{babel}
 \usepackage{fancyhdr}
 \usepackage{wrapfig}
 \usepackage{array}
-\usepackage{lipsum}
+\usepackage{fancybox} % styling of boxes.
-\usepackage{fancybox}
 \usepackage{varwidth}
-\usepackage{enumitem}
+\usepackage{enumitem} % makes available changes to lists.
 \usepackage{titlepic}
 \usepackage[nottoc]{tocbibind}
-\usepackage{url}
+\usepackage{url} % cmd \url.
-\usepackage[showisoZ]{datetime2}
+\usepackage[showisoZ]{datetime2} % more options for time formatting.
 \usepackage{transparent}
 \usepackage{soul}
 \usepackage{caption}
-\usepackage{enumitem}
-\usepackage{amssymb}
 \usepackage{tikzsymbols} % http://ctan.math.utah.edu/ctan/tex-archive/graphics/pgf/contrib/tikzsymbols/tikzsymbols.pdf
 \usepackage{textcomp}
 \usepackage{parskip}
@@ -47,6 +44,8 @@
     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