Extract from lectures on routing CCNA level.
Dynamic Routing
#WILDCARD MASK
#EX1: 10.0.12.0/30, then do 32-30=2, count two bits (2+1=3)
# The network mask will be: 255.255.255.(255-3=252)
# The wildcard mask will be: 0.0.0.3
#EX2: 10.0.12.0/28, then do 32-28=4, count four bits (8+4+2+1=15)
# The network mask will be: 255.255.255.(255-15=240)
# The wildcard mask will be: 0.0.0.15
#Default route
#Network route
#HOST route
#Floating static
#adjacencies = neighbor relationships
#lower Metric = superior
#DYNAMIC ROUTING PROTOCOLS
# IGP - Interior Gateway Protocol
# Works in a single AS
# Distance Vector Protocol = ie RIP, EIGRP
# Link State Protocol = ie OSPF, Is-Is
# EGP - Exterior Gateway Protocol
# Works between different AS
Path vector Protocol =ie BGP
###ECMP = Equal Cost Multi Path (balancing)####
#network [XXX/Y]
# | |
# | metric of the route
# Administative Distance (AD)
#---------------------------------------------------------------------------------------|
#Route protocol | AD | Metric based on # |
#---------------------------------------------------------------------------------------|
#Directly connected | 0 | Total cost (1+1+.) |
#---------------------------------------------------------------------------------------|
#Static | 1 | Always 0 |
#---------------------------------------------------------------------------------------|
#External BGP | 20 | Path attributes, ie AS_PATH |
#---------------------------------------------------------------------------------------|
#EIGRP | 90 | Based on bandwidth, delay (and + 3 unused metrics) |
#---------------------------------------------------------------------------------------|
#IGRP | 100 | Based on bandwidth, delay (and + 3 unused metrics) |
#---------------------------------------------------------------------------------------|
#OSPF | 110 | Cost based on bandwidth |
#---------------------------------------------------------------------------------------|
#IS-IS | 115 | Cost total metric each link |
#---------------------------------------------------------------------------------------|
#RIP | 120 | Hop count |
#---------------------------------------------------------------------------------------|
#EIGRP (external) | 170 | Based on bandwidth, delay (and + 3 unused metrics)
#---------------------------------------------------------------------------------------|
#Internal BGP | 200 | Path attributes, ie AS_PATH |
#---------------------------------------------------------------------------------------|
#Unusable route | 253 | |
#---------------------------------------------------------------------------------------|
#RIP
#Max hop count = 15. One router = 1 hop.
#RIP v1, v2 used for IP v4,
#RIP(ng) - next generation used for IP v6
#Two message types: REQUEST=RESPONSE / 30 seconds
#v1 - advertises classful addresses (Classs A,B,C)
# - doesn`t support VLSM, CIDR
# - doesn`t include subnet mask information
# Ex: 10.1.1.0/24 -->10.0.0.0 Class A, so assumed to be /8
# Ex: 172.16.192.0/18 will become 172.16.0.0, Class B, so assumed to be /16
#Messages are broadcast to 255.255.255.255
#v2 - supports CIDR, VLSM
# - includes subnet mask information in advertisement
# - messages are multicast 224.0.0.9
enable
configure terminal
router rip #to activate RIP protocol
version 2 #to set OSPF version
no auto summary #to disable auto summary (shows all route entries)
network 10.0.12.0 #to advertise all interfaces covered by 10.0.0.0/8
passive interface <interface name> #to deny get advertisements from other routers behind this interface
default-information originate #to share default route to other routers
distance <0-255> #to change the Administative Distance
maximum-paths <1-16> #route entries with equal AD will show in routes list (balancing)
ip route 0.0.0.0 0.0.0.0 192.168.1.1 #to set default route
show ip protocols
#EIGRP - Enhanced Interior Gateway Routing Protocol
#works faster than RIP
#doesn`t have limit of hops
#by default EIGPR metric uses bandwidth + delay
#bandwidth ot the slowest link + the delay of all links
#sends messages using muticast address 224.0.0.10
#can performs unequal-cost load-balancing (by default ECMP load-balancing over 4 paths like RIP)
#[XXX/YYY]
#XXX = Feasible Distance - router`s metric value to the route`s destination. (full distance)
#YYY = Reported Distance from neighbor router to the last touter (aka Advertized Distance)
#Successor - the router with the lowest metric ti the destination (the best route)
#Feasible Successor - an alternative route to the destination (not the best route) which meeets the feasiblity condition
#Feasibility condition - a route is considered a feasible successor it it`s reported distance (RD or AD) is lower than the
#the successor route`s feasible distance (FD)
#Ex: FD
# [28672 / 28416 ]
# [30976 / 28416 ]
# RD / AD
#Balancing / variance <number>
#Ex for variance 2
# [28672 / 28416 ] - FD=28672, 28672*2=57344 / if variance=3, then 28672*3 etc
# [30976 / 28416 ] - compare 57344 with 30976, so 30976 is less than 57344, so the route via 30976 can now be used for LB
#1. Write the ip address in binary format
#2. Write the network address in binary format
#3. Compare bitwise. If equal then 0, if not then 1
#Ex: Interface IP address 172.16.1.14, Advertisement network 172.16.1.0 - the IP interface address will be add to EIGPR
# 172.16.1.15, Advertisement network 172.16.1.0 - the IP interface address will be add to EIGPR
# 172.16.1.7, Advertisement network 172.16.1.0 - the IP interface address will be NOT add to EIGPR
#
#
route eigrp <number> #to activate EIGRP protocol. Number must be the same on all routers
no auto summary #to disable auto summary (shows all route entries)
network <network> <wildcard mask> #to advertise the network
network 10.0.0.0 #can be advertise this way too
passive-interface #to deny get advertisements from other routers behind this interface
variance 2 #Feasible Successor routes with an FD up to 2x successor route`s FD
show ip eigrp topology #to show everything about eigrp on the router
show ip route eigrp #to show only eigrp enteries on the route table
show ip protocols
#OSPF - Open Short Path First
#Stands for:
#v1 - not in use anymore
#v2 - used for IP v4
#v3 - used for IP v6
#LSA - Link State Advertisement
#LSDB - Link State Database
#Every router builds a map
#Routers will flood LSAs until all routers in the OSPF Area develop the same map of the network (LSDB)
#LSA`s age time is 30 minutes
#Backbone = Area 0
#OSPF areas should be contiguous
#Router ID order of priority
#1-Manual Configuration
#2-Highest IP address on a loopback interface
#3-Highest IP address on a physical interface
#ASBR - Autonomous System Boundary Router (on the edge between AS) - goes outside ie Internet
#Max path by default is 4
#ABR - between Areas
#COST - default reference bandwidth is 100 mbit/s
# reference cost for 10 mbit/s interface is: 100mbit/s:10mbit/s=10
# for 100 mbit/s interface is: 100mbit/s:100mbit/s=1
# but!
# for 1000 mbit/s interface is: 100mbit/s:1000mbit/s=1 too, not good! Then do ...
# auto-cost reference-bandwidth 100000 - it must be applied on all routers
# reference cost for 10 mbit/s interface is: 100000mbit/s:10mbit/s=10000
# for 100 mbit/s interface is:100000mbit/s:100mbit/s=1000
# for 1 Gbit/s interface is: 100000mbit/s:1000mbit/s=100
# for 10Gbit/s interface is: 100000mbit/s:100000mbit/s=10
#
router ospf 1
network <network> wildcard mask area <area number> #add the network to the OSPF
passive interface <interface name> #to deny get advertisements from other routers behind this interface
default-information originate #to share default route to other routers
router-ID <ID> #to set router ID
maximum-paths <1-32> #
distance <number> #to change distance
auto-cost reference-bandwidth 100000 #must be applied on all routers
ip route 0.0.0.0 0.0.0.0 <IP add> #to set default route. The router becomes ASBR
interface <interface>
ip ospf cost <1-65535> #to set cost manually on the interface
bandwidth <kbit/s> #to set bandwidth on the interface
show ip protocols
clear ip ospf proccess #ie restart OSPF proccess
show ip ospf interface brief #
show ip ospf neighbor #
show ip ospf interface <interface> #
show ip ospf database
#There is another way to change cost. Use Bandwidth on the interface. This bandwidth is not the same as D-Link.
#Cisco uses bandwidth to set counting for OSPF cost, EIGPR metric etc
#OSPF Neighbors
#Hello timers by default is 10 seconds, sends by routers to 224.0.0.5 - Multicast IP Addr for OSPF routers
#Dead Timer by default is 40 seconds and its counts down. Then 0 and no Hello packets, the neighbor will removed
#Dead Timer by default For Non Broadcast network is 120 seconds, Hello - 30 seconds
#IP header in the protocol`s header is 89
#Stages of the port on the router. There are 7 stages
# Down
# Init - sends the Hello packet
# 2-way - it means that router recieved the Hello packet from other router. Now they know each other
#===now routers become to DR (Designated Router) or BDR (Backup Designated Router)
# Exstart - the router with higher RID become Master and initiate the exchange
# - the router with the lower RID will become Slave
# - they will exchange DBD (Database Description) packets
# Exchange - compare its DBD and request only new LSA, than it hasn`t
# Loadind - loading proccess
# =loading states=
# LSR - Link State Request
# LSU - Link State Update
# LSAck - Link State Acknoledge
# Share LSAs to synchronize LSDB
# Full - All done.
#The other way to add the interface to the OSPF proccess
interface <interface>
ip ospf <proccess number> area <aren number>
#It is possible to make all interfaces passive and then add the interface manually
router ospf <ospf number>
passive-interface default
no passive-interface <interface>
#OSPF Network Types
# Broadcast - Ethernet and FDDI (DR+BDR)
# Point to Point - PPP and HDLC (no DR and no BDR)
# Non-Broadcast - Frame Relay and X.25
#DR and BDR must be elected on each subnet (Only DR if there is no OSPF neighbors)
#Routers are not the DR or BDR become a DROther
#DR and BDR election ordered of priority
# Highest OSPF interface priority (by default they are the same = 1)
# Highest OSPF Router ID/ First place becomes DR for the subnet, second place becomes BDR
# If OSPF interface priority set to 0, then it will not become DR or BDR for the interface subnet
# If OSPF interface priority set to 255 it makes this router DR
# To apply changes use command clear ip ospf proccess
# Each router can exchange LSA only with DR or BDR. DRother routers don`t exchange LSA at all.
#PPP Network Type
#The default encapsulation is HDLC
int S1 #Serial
encapsulation ppp
clock rate <bits per second>
show controllers <interface ID>
#To change P2P to Broadcast
interface <interface>
no ip ospf network point-to-point
#OSPF Neighbor Requirements
# 1.Area number must match
# 2.Interfaces must be in the same subnet
# 3.OSPF proccess must not be shutdown
# 4.OSPF routers ID must be unique
# 5.Hello and Dead timers must match (no ip ospf hello-interval , no ip ospf dead-interval)
# 6.Authentication settings must match (to enable use ip ospf authentication)
# 7.IP MTU settings must match. If not you can`t reach Full State. (ip mtu <bits>)
# 8. OSPF network type must match. (You can see Full State, check the routing table)
#LSA TYPES
#The OSPF LSDB is mase up of LSAs. There are 11 types of LSA, but only 3 should be aware of the CCNA
# Type 1 - Router LSA
# Type 2 - Network LSA
# Type 5 - AS External LSA
#Type 1
#Every OSPF router generates this type of LSA
#It identifies the router using its router-ID
#It also lists networks attached ti the router`s OSPF activated interfaces
#Type 2
#Generated by the DR of each "multi-access" network (ie the broadcast network type)
#List all routers which are attached to the "multi-access" network
#Type 5
#Generated by ASBR to describe routes to destination outside the AS (OSPF Domain)