Routing Methods in Telecommunications: Complex Project Task Part ipv4 Network Addressing Map

RIP implements the split horizon, route poisoning and hold down mechanisms to prevent incorrect routing information from being propagated. These are some of the stability features of RIP. It is also possible to use the Routing Information Protocol with Metric-Based Topology (RMTI) algorithm to cope with the count-to-infinity problem. With RMTI, it is possible to detect every possible loop with a very small computation effort.

Originally, each RIP router transmitted full updates every 30 seconds. In the early deployments, routing tables were small enough that the traffic was not significant. As networks grew in size, however, it became evident there could be a massive traffic burst every 30 seconds, even if the routers had been initialized at random times. It was thought, as a result of random initialization, the routing updates would spread out in time, but this was not true in practice. Sally Floyd and Van Jacobson showed in 1994 that, without slight randomization of the update timer, the timers synchronized over time. In most current networking environments, RIP is not the preferred choice for routing as its time to converge and scalability are poor compared to EIGRP, OSPF, or IS-IS (the latter two being link-state routing protocols), and (without RMTI) a hop limit severely limits the size of network it can be used in. However, it is easy to configure, because RIP does not require any parameters on a router unlike other protocols.

RIP uses the User Datagram Protocol (UDP) as its transport protocol, and is assigned the reserved port number 520.

Router>enable

Router#configure terminal

Router(config)#router rip

Router(config-router)#network ……………

Router(config-router)#network ……………
Router(config-router)#version 2 (use RIP2)

Router(config-router)#exit (exit of the RIP configuring mode)

Router(config)#exit (exit of the configuring console)

Enter

Router#write memory (save settings in memory)

Building configuration...

[OK]
Open Shortest Path First routing protocol (OSPF)

OSPF is an interior gateway protocol that routes Internet Protocol (IP) packets solely within a single routing domain (autonomous system). It gathers link state information from available routers and constructs a topology map of the network. The topology determines the routing table presented to the Internet Layer which makes routing decisions based solely on the destination IP address found in IP packets. OSPF was designed to support variable-length subnet masking (VLSM) or Classless Inter-Domain Routing (CIDR) addressing models. OSPF detects changes in the topology, such as link failures, and converges on a new loop-free routing structure within seconds. It computes the shortest path tree for each route using a method based on Dijkstra's algorithm, as shortest path first algorithm. The OSPF routing policies to construct a route table are governed by link cost factors (external metrics) associated with each routing interface. Cost factors may be the distance of a router (round-trip time), network throughput of a link, or link availability and reliability, expressed as simple unit less numbers. This provides a dynamic process of traffic load balancing between routes of equal cost.

An OSPF network may be structured, or subdivided, into routing areas to simplify administration and optimize traffic and resource utilization. Areas are identified by 32-bit numbers, expressed either simply in decimal, or often in octet-based dot-decimal notation, familiar from IPv4 address notation.

By convention, area 0 (zero) or 0.0.0.0 represents the core or back bone region of an OSPF network. The identifications of other areas may be chosen at will; often, administrators select the IP address of a main router in an area as the area's identification. Each additional area must have a direct or virtual connection to the backbone OSPF area. Such connections are maintained by an interconnecting router, known as area border router (ABR). An ABR maintains separate link state databases for each area it serves and maintains summarized routes for all areas in the network.

OSPF does not use a TCP/IP transport protocol (UDP, TCP), but is encapsulated directly in IP datagram with protocol number 89. This is in contrast to other routing protocols, such as the Routing Information Protocol (RIP), or the Border Gateway Protocol (BGP). OSPF handles its own error detection and correction functions.

OSPF uses multicast addressing for route flooding on a broadcast domain. For non-broadcast networks special provisions for configuration facilitate neighbor discovery. OSPF multicast IP packets never traverse IP routers (never traverse Broadcast Domains), they never travel more than one hop. OSPF reserves the multicast addresses 224.0.0.5 for IPv4 (all SPF/link state routers, also known as AllSPFRouters) and 224.0.0.6 for IPv4 (all Designated Routers, AllDRouters), as specified in RFC 2328 and RFC 5340.

For routing multicast IP traffic, OSPF supports the Multicast Open Shortest Path First protocol (MOSPF) as defined in RFC 1584.  Cisco does not include MOSPF in their OSPF implementations. PIM (Protocol Independent Multicast) in conjunction with OSPF or other IGPs, (Interior Gateway Protocol), is widely deployed.

The OSPF protocol, when running on IPv4, can operate securely between routers, optionally using a variety of authentication methods to allow only trusted routers to participate in routing.

OSPF version 3 introduces modifications to the IPv4 implementation of the protocol. 
Configuring the network routers scenario (OSPF)

Router>enable

Router#configure terminal

Router(config)#router ospf 1

Router(config-router)#network ……………

Router(config-router)#network ……………
Router(config-router)#exit (exit of the OSPF configuring mode)

Router(config)#exit (exit of the configuring console)

Router#write memory (save settings in memory)

Building configuration...

[OK]
* router ospf <processID> defines a unique numeric value of routing process within a common OSPF routing area. This value must be taken in range from 1 to 65535.

2. Construct the 4-th octet of the Network Addresses (see Tab.6)

3. Create and complete all the network options (see Tab.7)

4. Using the Cisco PT make your network model with two hosts in any NW1−NW3 networks

5. Make sure your network is functioning correctly

6. Make your report (one for 3 students) in form PP presentation or printed copy.

7. Make a PP presentation (or printed material) for the part 4 of the complex project; be ready to present your project in PT (any students will present a part of a joint working team project).
Student 1: Explain the network addresses planning according to your variant.

Student 2: Explain the network options in table 7.

Student 3: Explain the main steps of Cisco router configuring.

Table 5 -Individual variants

Internet

NW0
NW1

R0

R1

R2

NW7

NW4

1

1

1

2

2

3

3

2

Fig 1- Network topology scheme: R0−R1−R2−R3−R0

Table 7− Network Design options

* Two addresses in accordance to individual task variant (here the two first minimal ones).

** Two addresses for adjacent router interfaces.
Part 5. IPv4 Static Router Configuration

5.1. Take the network framework according to your individual task variant, see Tab.5 and Fig.1. (One variant of the task is assigned to a joint working team of 3 students).

5.2. Build (manually) routing tables for all of the 4 network routers R0−R3.

5.3. Preinstall 4 routers of your network in static mode (manually) using the Cisco PT interface.

5.4. Make sure your network is designed correctly using the ping command.

5.5. Describe briefly the main steps of Cisco static routing.

5.6. Prepare a PP presentation for the part 5 of the complex project (in addition to the previously made part 4 PP presentation).

5.7. Present your complex project design in PPP (or printed form) to get a final credit of the Lab work.