View
233
Download
2
Tags:
Embed Size (px)
Citation preview
SYPCNSA Department 2007
Summer Youth Program: Summer Youth Program: Internal Protocols: Internal Protocols:
RIP & IGRPRIP & IGRP
SYPCNSA Department 2007
To route a router need to know:– Remote Networks
– Neighbor Routers
– All Possible routes to remote network
– The absolute best route to all remote networks
– Maintain and verify the routing information
What is Routing?
C B AD
SYPCNSA Department 2007
Basic Path Selection
What interface will the router send out a packet if it has destination address of 10.10.10.18?
SYPCNSA Department 2007
Basic IP Routing
172.16.1.0
BA
172.16.2.0
172.16.2.2
172.16.1.2172.16.2.1 172.16.1.1
e0 e0
>ping 172.16.1.2>ping 172.16.1.2
B
172.16.3.1 172.16.3.2
s0s0
Host A
Host B
SYPCNSA Department 2007
Routing/PDU Example:Host A Web browses to the HTTP
Server….
3. The destination port number in a segment header will have a value of __
1. The destination address of a frame will be the _______________________
2. The destination IP address of a packet will be the IP address of the ________________________________
SYPCNSA Department 2007
Routing/PDU Example:Host A Web browses to the HTTP
Server….
3. The destination port number in a segment header will have a value of 80
1. The destination address of a frame will be the Ethernet 0 on Lab A
2. The destination IP address of a packet will be the IP address of the NIC of the HTTP server
SYPCNSA Department 2007
172.16.3.2
SO
Static Routes
172.16.1.0
B172.16.3.1
A B
Stub Network
172.16.2.0
SOA
Routes must be unidirectional
SYPCNSA Department 2007
ip route remote network
[mask]
{address|interface}
[distance]
[permanent]
Router(config)#ip route remote_network mask next_hop
Static Route Configuration
SYPCNSA Department 2007
ip route 172.16.1.0 255.255.255.0 172.16.3.2orip route 172.16.1.0 255.255.255.0 s0
Static Route Example
172.16.3.2
SO
172.16.1.0
B172.16.3.1
A B
Stub Network
172.16.2.0
SO
SYPCNSA Department 2007
Default Routes
172.16.3.2
SO
172.16.1.0
B172.16.3.1
A B
Stub Network
172.16.2.0
SO
ip route 0.0.0.0 0.0.0.0 172.16.3.1 ip classless
SYPCNSA Department 2007
• Routing protocols are used between routers to: – Determine the path of a packet through a network– Maintain routing tables– Examples?
• Routed protocols are:– Assigned to an interface– Once the path is determined by the Routing protocol, determines
method of delivery– Examples?
Routing vs. Routed
SYPCNSA Department 2007
Autonomous System 1 Autonomous System 2
IGPs: RIP, IGRP EGPs: BGP
Routing Protocols
•An autonomous system is a collection of networks under a common administrative domain.
•IGPs operate within an autonomous system.
•EGPs connect different autonomous systems.
SYPCNSA Department 2007
Classful Routing Overview
Classful routing protocols do not include the subnet mask with the route advertisement.
– Within the same network, consistency of the subnet masks is assumed.
– Summary routes are exchanged between foreign networks.
– Examples of classful routing protocols:• RIP Version 1 (RIPv1)• IGRP
SYPCNSA Department 2007
Classless Routing Overview
Classless routing protocols include the subnet mask with the route advertisement.
– Classless routing protocols support variable-length subnet masking (VLSM).
– Summary routes can be manually controlled within the network.
– Examples of classless routing protocols:
• RIP Version 2 (RIPv2)
• EIGRP
• OSPF
• IS-IS
SYPCNSA Department 2007
IGRPAdministrative Distance=100
Router D
Router BRouter A
Router C
RIPAdministrative Distance=120
Default Administrative DistanceDirectly Connected: 0Static Route: 1RIP: 120IGRP: 100EIGRP: 90OSPF: 110
Administrative Distance
SYPCNSA Department 2007
C B AD
RoutingTable
RoutingTable
RoutingTable
RoutingTable
RoutingTable
RoutingTable
RoutingTable
RoutingTable
Distance—How farVector—In which direction
Distance—How farVector—In which direction
Distance vector algorithms do not allow a router to know the exact topology of an internetwork.
All routers just broadcast their entire routing table out all active interfaces on periodic time intervals
Distance Vector
SYPCNSA Department 2007
Discovering RoutesDiscovering Routes
SYPCNSA Department 2007
Routing Tables PopulatedRouting Tables Populated
SYPCNSA Department 2007
Routing Loops
SYPCNSA Department 2007
Router Loops
SYPCNSA Department 2007
64kbps
T1
T1 T1
– Hop count metric selects the path, 16 is unreachable– Full route table broadcast every 30 seconds– Load balance maximum of 6 equal cost paths (default = 4)– RIPv2 supports VLSM and Discontiguous networks
RIP Overview
SYPCNSA Department 2007
Router(config)#router rip
Router(config-router)#network network-number*
network 172.16.0.0network 192.168.10.0
router RIPnetwork 172.16.0.0network 10.0.0.0
router RIP
*Network is a classful network address.
Every device on network uses the same subnet mask
172.16.10.0 192.168.10.010.3.5.0
RIP Routing Configuration
SYPCNSA Department 2007
RIP Version 2
• Allows the use of variable length subnet masks (VLSM) by sending subnet mask information with each route update
• Distance Vector – same AD, and timers.• Easy configuration, just add the command
“version 2” under the router rip configuration
router ripnetwork 10.0.0.0version 2
SYPCNSA Department 2007
Discontiguous Addressing
• Two networks of the same classful networks are separated by a different network address
192.168.10.0/24
10.1.1.0/24192.168.10.0/24
– RIPv1 and IGRP do not advertise subnet masks, and therefore cannot support discontiguous subnets.
– OSPF, EIGRP, and RIPv2 can advertise subnet masks, and therefore can support discontiguous subnets.
SYPCNSA Department 2007
Passive Interface
Maybe you don’t want to send RIP updates out your router interface connected to the Internet. Use the passive-interface command:Router(config)#router rip
Router(config-router)#passive-interface serial0
This allows a router to receive route updates on an interface, but not send updates via that interface
S0 GatewayInternet
Updates
XX
SYPCNSA Department 2007
Verifying RIP
Router#show ip protocols
Router#show protocols
Router#show ip route
Router#debug ip rip
Router#undebug all (un all)
SYPCNSA Department 2007
IGRP• Interior Gateway Routing Protocol - Cisco Proprietary• Uses bandwidth and delay of the line by default to select best path
AutonomousSystem
Router D
Router BRouter A
Router C
Requires Autonomous System number for activation
SYPCNSA Department 2007
IGRP vs. RIP
• The important IGRP characteristics are as follows:– More scalability than RIP
– Fast response to network changes
– Sophisticated metric
– Multiple-path support
SYPCNSA Department 2007
Router(config)#router igrp autonomous-system
Router(config-router)#network network-number*
*Network is a classful network address.
Every device on network uses the same subnet mask
network 172.16.0.0
network 192.168.10.0
router IGRP 10network 172.16.0.0
network 10.0.0.0
router IGRP 10
172.16.10.0 192.168.10.010.3.5.0
Configuring IGRP
SYPCNSA Department 2007
Verifying IGRP
Router# show ip route
Router# show ip protocols
Router# debug ip igrp transaction
Router# debug ip igrp events
Router# undebug all (un all)