Static
Routing
Separate Unsolicited Message form IOS:
(config)# line console 0
(config-line)# logging synchronous
Identify DCE/DTE devide:
# show controller S0/0/0
Gather Info
# show cdp neighbors [detail]
Distance
Vector Routing Protocols
Periodic Update
-
RIP = 30 seconds
-
IGRP = 90 seconds
Algorithm
-
Mechanism for sending and receiving routing information
-
Mechanism for calculating the best paths and installing routes
in the routing table
-
Mechanism for detecting and reacting to topology changes
Routing Protocols Characteristics
-
Time to convergence
-
Scalability
-
Classless (Use of VLSM) or classfull
-
Resource usage – hardware capacity
-
Implementation and Maintenance – administrator knowledge
Advantage and Disadvantage
of Distance Vector Routing protocols
Simple implement and maintenance
|
Slow convergence
|
Low resource requirements
|
Limited scalability
|
Routing loops
|
RIP Timers
-
Invalid – 180 seconds, 16 hopes count
-
Flush Timer – 240 seconds (180 + 60)
-
Holddown Timer – prevent loops, 180 seconds
Verifying Timers
# show ip route
# show ip protocols
EIGRP – Bounded Updates
-
Non-periodic – not regularly send
-
Partial update – sent only when topology change
-
Bounded – only send to routers that need the info are updated
Trigger Update – is used by RIP to send update info
to the others routers whenever the topology changed.
RIP_JITTER – is used to random variable update for
each routers.
Mechanisms to ease loops:
-
Defining a maximum metric to prevent count to infinity
-
Holddown timers
-
Split horizon
-
Route poisoning or poison reverse
-
Triggered updates
RIP
RIP Characteristic
-
Distance vector routing protocol
-
Hop count as metric
-
Advertise greater than 15 are unreachable
-
Broadcast message every 30 seconds
Check administrative distance (AD)
# show ip route
# show ip protocols
Configuring RIP
(config)#
router RIP
(config-router)#
network directly-connected-classful-network-address
Ex:
R(config)#router rip
R(config-router)#network 192.168.4.0
R(config-router)#network 192.168.5.1
Verify and troubleshooting
# show ip route
# show ip protocols
# debug ip rip
# undebug all //end
debug
Passive-interface - prevents the transmission of
routing updates through a router interface but still allows that network to be
advertised to other routers.
(config-router)#
passive-interface interface-type interface-number
Propagating the Default Route in RIPv1
(config-router)#
default-information originate
RIPv2
RFC 1918 Private Address
Class
|
Prefix/Mask
|
Address Range
|
A
|
10.0.0.0/8
|
10.0.0.0 – 10.255.255.255
|
B
|
172.16.0.0/12
|
172.16.0.0 – 172.31.255.255
|
C
|
192.168.0.0/16
|
192.168.0.0 – 192.168.255.255
|
Cisco Example IP Address (public IP for example purpose)
Prefix/Mask
|
Address Range
|
209.165.200.224/27
|
209.165.200.224 – 209.165.200.255
|
209.165.201.0/27
|
209.165.201.0 – 209.165.201.31
|
209.165.202.128/27
|
209.165.202.128 – 209.165.202.159
|
Static Routes and Null Interface
-
Supernet route 192.168.0.0/24 to 192.168.255.0/24
(config)#
ip route 192.168.0.0 255.255.0.0 Null0
Route Redistribution
-
Redistribute static route and route to other dynamic routing protocols
(config-route)#
redistribute static
Ex:
(config)#
ip route 192.168.0.0 255.255.0.0 null0
(config)#
router rip
(config-router)#
redistribute static //static route configured and redistributed
Enable RIP v2
(config-router)# version 2
Disable Auto-Summary
(config-router)# no auto-summary //enable
classless
EIGRP
IGRP and EIGRP: use metrics of bandwidth, delay,
reliablility, and load. By default Bandwidth and delay.
Configure EIGRP
(config)# router eigrp {autonomous-system} //[1
– 65535]
(config-router)# network network-address //classful
network address
(config-router)# network network-address
[wildcard-mask] //In case, don’t use classful
# show ip eigrp neighbors //View
neighbor table and verify
EIGRP update:
-
Partial – update only includes info about route changes
-
Bounded – only those routers affected by the change will receive
the update.
Diffusing Update Algorithm (DUAL)
-
Loop-free paths
-
Loop-free backup
-
Fast convergence
-
Minimum bandwidth usage with bounded udpates
DUAL use several terms:
-
Successor: neighbor router with least-cost route to destination
network.
-
Feasible distance (FD): the lowest calculated metric to reach the
destination network.
-
Feasible Successor (FS)
-
Report Distance (RD) or Advertised Distance (AD)
-
Feasible Condition or Feasibility Condition (FC)
One of the reasons DUAL can converge
quickly after a change in the topology is because it can use backup paths to
other routers known as feasible successors without having to recompute DUAL.
# show ip eigrp topology //verify
DUAL terms
# debug eigpr fsm //debug
DUAL
Configuring Bandwidth
(config-if)# bandwidth kilobits
(config-if)# no bandwidth //restore
the default value
# show interface //verify
bandwidth
EIGRP Composite Metric:
-
Default Composite Formula:
Metric = [K1*bandwidth +
K3*delay]
-
Complete Composite Formular:
Metric = [K1*bandwidth + (K2*bandwidth)/(256 – load) + K3*delay] * [K5/(reliability + K4)]
K1 (bandwidth) = 1
K2 (load) = 0
K3 (delay) = 1
K4 (reliability) = 0
K5 (reliability) = 0
-
Change “K” value:
(config-router)# metric weights tos k1 k2
k3 k4 k5 //tos = Type of service
-
Verify K values
# show ip protocols
Calculating the EIGRP Metric
Slowest bandwidth: (10,000,000/bandwidth
kbps) * 256
Plus the sum of
the delays: + (sum of delay / 10)
* 256
=
EIGRP metric
The Null0 Summary Route
-
Not allow EIGRP to look for a Supernet or Default route when an IEGRP
child route does not match a destination packet
-
Remove Null0
(config-router)# no auto-summary //by
default Enabled
Manual Summarization
(config-if)#
ip summary-address eigrp [AS-ID] Ip-address subnet-mask
Ex:
192.168.1.0/24
192.168.2.0/24
192.168.3.0/24
(config-if)# ip summary-address eigrp 1
192.168.0.0 255.255.252.0
Default Route
(config)# ip route 0.0.0.0 0.0.0.0
loopback 1
(config)# router eigrp 1
(config-router)# redistribute
static
EIGRP Bandwidth Utilization
(config-if)# ip bandwidth-percent
eigrp {as-num} percent //default 50
Ex:
(config)# int S0/0/0
(config-if)# bandwidth 64
(config-if)# ip bandwidth-percent
eigrp 1 50
Configuring Hello Intervals and Hold Times
(config-if)# ip hello-interval
eigrp {as-num} seconds //second [1-65535]
(config-if)# ip hold-time eigrp
{as-num} seconds
NOTE: Hold-Time >=
Hello-Interval, “no” to restore default
Ex:
(config)# int s0/0/0
(config-if)# ip hello-interval
eigrp 1 60
(config-if)# ip hold-time eigrp 1
180
10.
Link-State Routing Protocols
Link-State Packet (LSP) does not need to be sent
periodically, it only need to be sent :
-
During initial startup routing protocol on the router
-
Whenever there is a change in the topology
OSPF
Router Source
|
Administrative Distance
|
Connected
|
0
|
Static
|
1
|
EIGRP summary route
|
5
|
External BGP
|
20
|
Internal EIGRP
|
90
|
IGRP
|
100
|
OSPF
|
110
|
IS-IS
|
115
|
RIP
|
120
|
External EIGRP
|
170
|
Internal BGP
|
200
|
Configuring OSPF
(config)# router ospf {process-id}
(config-router)# network {IP
address} (wildcard mask} area {area-id}
(config-router)# router-id {ip
–address} //set router ID
# show ip protocols //verify
router ID
# show ip ospf
# show ip ospf interface
# clear ip ospf process //reloading
router after modify router ID
Configure Loop Address
(config)# interface loopback-number
(config-if)# ip address ip-address
subnet-mask
Verify OSPF
# show ip ospf neighbor
# show ip protocols
# show ip ospf
# show ip ospf interface
Reference Bandwidth
# auto-cost reference-bandwidth //modify
reference bandwidth
NOTE: if this command is set, it’s
recommended to use all routers
Accumulates Costs = sum of all costs to reach the
destination.
Check Default Bandwidth Value
# show interface
Set Bandwidth Manullay
(config-if)# bandwidth bandwidth-kbps
Ex:
(config)# inter S0/0/0
(config-if)# bandwidth 64
ð Cost : 1568
= (10^8 / 64000 bps = 1562)
Or (config-if)# ip ospf cost 1562 //no
calculation needed
Calculate
Number of Adjacencies = n(n-1)/2
n =
number of routers
Ex: 5
routers (5-1) / 2 = 10 adjacencies
-
Designated Router (DR): is elected by OSPF to solve the number of
adjuscencies and the flooding of LSAs on a multi-access.
-
Backup Designated Router (BDR): is also elected by OSPF to backup DR
fails.
-
The remaining routers are called DROthers.
OSPF Interface Priority
(config-if)# ip ospf priority (0 –
255) //default = 1, 0 = ineligible to be DR or BDR
Advertise the 0.0.0.0/0 static default route to the other
routers in the area
(config-router)# default-information
originate
Modifying OSPF Intervals
(config-if)# ip ospf hello-interval
seconds //default = 10
(config-if)# ip ospf dead-interval seconds //default
= 40
NOTE: OSPF requires the
Hellow and Dead intervals match between two routers for them to become
adjacent.
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