Routing protocols Routing protocols are the set of rules used by the routers to communicate between source & destination. they do not move the information to source to destination only update the routing table(contains the information Each protocol has its own algorithm to choose the best path. The metrics by routing protocols , *Number of network layer devices along with the path (hop count) *Bandwidth *Delay *Load *MTU *Cost Routing protocols store the result of these metrics in routing table.
TYPES OF ROUTING PROTOCOL DYNAMICSTATIC ROUTING ROUTING PROTOCOL PROTOCOLS DISTANCE LINK STATE VECTOR RIP IGRP EIGRP RIPv1 OSPF RIPv2
Static routing protocols Static routing ,when an administrator manually assigns the path from source to destination network. It provides more security to network. The main drawback of static routing is that when a link fail in the internetwork all the network goes down. This is feasible in small networks, but not in large networks.Advantages No overhead on router CPU. No bandwidth usage between links. Security (only administrator add routes.)Disadvantages Administrator must really understand internetwork & how each router is connected. Not practical on large networks as it is time intensive. Administrator must update all routers.
Dynamic routing protocols Dynamic routing is the process in which routing tables are automatically updates by routing table *Dynamically discover & maintains routes. *Calculate routes *Distributing routing updates to other routers in the network Advantages -less work in maintaining the configuration when adding & deleting networks. -protocols automatically react to the topology changes. -configuration is less-prone. -More scalable. Disadvantages -Routers resource are used. -More administrator knowledge is required for configuration
Types of dynamic routingprotocols The dynamic routing protocols can be categorized on the basis of various parameters .Dynamic routing protocols are classified into two protocols: 1. Distance Vector Routing Protocols: - It uses simple algorithms that calculate cumulative distance value between routers based on hop count.Example: Routing Information Protocol(RIP) Interior Gateway Routing Protocols (IGRP 2. Link State Routing Protocols: - It uses sophisticated algorithms that maintain a complex database of internetwork topology. Example: Enhanced Interior Gateway Routing Protocol(EIGRP) Open Shortest Path First (OSPF)
Routing Information Protocol (RIP) RIP allows routers to exchange their routing tables at a predefined interval RIP is a distance-vector routing protocol which employs the hop count as a routing metric. RIP router transmitted full updates in every 30 seconds. Characteristics of RIP include: Uses hop count metric Supports 15 hop-count limit Supports six equal-cost paths AD value is 120. Broadcasting done in RIP & RIPv1. Supports classful networks.
RIPv2 It is a distance vector protocol. AD value is 120. Metric is hop count. Supports classless network. Supports VLSM/CIDR. Maximum hop count is 15. Route updates after 30 sec. Uses multicast ip for convergence. It supports authentication.
Configuring RIP se 0/1/0 192.168.2.0 192.168.2.1 se 0/1/0 192.168.2.2 fa 0/0 fa 0/0 192.168.1.0 192.168.3.0 192.168.3.2 192.168.3.31188.8.131.52 192.168.1.3
Configure RIPConfiguration for RIPv1Router>enableRouter# configure terminalRouter(config)#router ripRouter(config)#serial 0/1/0Router(config-router)#network _network address of own router(e.g.192.168.1.0)Router(config-router)#version 1Router(config)save & exitConfiguration for RIPv2Router>enableRouter# configure terminalRouter(config)#router ripRouter(config)#serial 0/1/0Router(config-router)#network _network address of own router(e.g.192.168.1.0)Router(config-router)#version 2Router(config)save & exit
INTERIOR GATEWAY ROUTING PROTOCOL (IGRP) IGRP is a distance vector protocol. To overcome RIP limitations IGRP introduced. The metrics used are bandwidth, load, delay, MTU AND reliability. Routing updates are broadcast every 90 seconds (by default).It is used by routers to exchange routing data within an autonomous system.The following are the characteristics of IGRP: - Uses composite metrics - Uses multipath routing - Supports unequal-cost load balancing - Supports hold-downs - Supprts spilt horizons
Configuring IGRP se 0/1/1 se 0/1/0 184.108.40.206 10.0.0.0 220.127.116.11 10.0.0.1 se 0/1/0 se 0/1/0 10.0.0.2 18.104.22.168 fa 0/0 fa 0/0 fa 0/0 192.168.3.0 192.168.1.0 192.168.2.01922.214.171.124 192.168.1.3 192.168.2.2 192.168.2.3 192.168.3.2 192.168.3.3
Configure igRPThe syntax for configuring IGRP is : -Router igrp AS_number (1 to 65535) -Network IP_networksConfigure IGRP,Router>enableRouter#configure terminalRouter#(config)#router igrp 100 (AS Number)Router#(config-router)# network _ network address of own routerRouter#(config-router)#exitRouter#(config)#Verifying IGRP configurations, Show ip route (I indicates that IGRP was added as the routing protocol.) Show ip protocols Show ip igrp events
Enhanced INTERIOR GATEWAYROUTING PROTOCOL (eIGRP) Works on any condition. It’s supports the features both distance vector & link state protocol. It is a cisco proprietary protocol. EIGRP is an ideal protocol in the large networks. The AD value of EIGRP is 90. By default, bandwidth & delay are the activated metrics. EIGRP uses the following tables for route discovery i.e. Neighbor Table, Topology Table, Route Table. The following are the characteristics of EIGRP: - communication done via RTP (capable of transmitting both multicast & unicast ) - uses DUAL algorithm - supports classless network - supports VLSM/CIDR, - supports Discontiguous network. - supports all layer 3 protocols (IPv4, IPX, and IPv6)
Configuring EIGRP R1 se 0/1/0 R2 192.168.2.1 192.168.2.0/30 se 0/1/0 192.168.2.2 fa 0/0 fa 0/0 192.168.1.0/25 192.168.1.128/25192.168.1.2 192.168.1.3 192.168.1.129 192.168.1.130
Configure EIGRPR1>enableR1#configure terminalR1#(config)#router eigrp 100(AS Number)R1#(config-router)#network _ network address of own routerR1#(config-router)#exitR1#(config)#Verifying EIGRP configurations, Show ip route (D indicates that EIGRP was added as the routing protocol.) Show ip eigerp neighbors Show ip eigrp topology
OPEN SHORTEST PATH FIRST (OSPF) The large network can be broken into the small areas so the router in one area know less topology and they don’t have information about other areas routers. Creating OSPF areas result in smaller database which reduce the memory consumption and processing.OSPF maintains a two layer hierarchy consisting of: -Backbone area (area 0) -Off backbone area (areas1-65,535)The following are the characteristics of OSPF: -AD value is 110. -supports classless network -supports VLSM/CIDR & has unlimited hop counts -Supports hierarchical network. -Route propagation using multicasting.
Configuring OSPFR1 R2 126.96.36.199/8 fa 0/0 172.16.0.0/16 fa 0/0 192.168.1.0/24 AREA 0
Configuring OSPFThe syntax for configuring OSPF is :-process ID-Network IP_networks-Wildcard mask-areaconfiguration R1#configure terminalR1#(config)#router ospf 1R2#(config-router)#network _ network address of own router_wild card mask_areae.g. (R2#(config-router)#network _192.168.1.0_0.0.0.255_area 0)R1#(config-router)#exitR1#(config)#Verifying OSPF configurations,-Show ip route(O indicates that OSPF was added as the routing protocol.)-Show ip ospf database-Show ip ospf interface
. Routing Protocols Comparison Name Class Type Administ Metric Classful/ Algorith Transport rative less m Type Distance RIP v1 Distance IGP 120 Hop Count Classful Bellman- UDP/520 Vector Ford RIP v2 Distance IGP 120 Hop Count Classless Bellman- UDP/520 Vector Ford OSPF Link State IGP 110 Cost Classless Dijkstra (SP OSPF F) Protocol 89 IGRP Distance IGP 100 Composite Classful Dijkstra (SP IP Protocol Vector (BW + DLY) F) 9 Hybrid EIGRP (Advanced IGP 90 Composite Classless DUAL EIGRP Distance (internal) (BW + DLY) Protocol 88 Vector) 170 (external)