Optimizing Network Systems with NAT and GRE

Introduction

The purpose of formulation of this Report is to study and analyse four different technologies which are implemented in Networking Environments, Point-to-point (PPP) Connections, Network Address Translation (NAT), Generic Routing Encapsulation (GRE) Tunnels and Frame Relay. From the academic perspective, implementation of these technologies could assist in the improvement or upgrading of any Network System as a way to replicate a business working environment. In this Report, I will also illustrate the main features of each technology, its benefits and challenges, the Researcher is going to demonstrate common issues related to the adoption of these technologies and the associated aspects of troubleshooting the same.

Point- to-Point (PPP) Connections

The Point-to-point (PPP) protocol is a non-proprietary protocol that offers an open standard for building point-to-point links amongst distinct supplier equipment. It utilizes a standardized Protocol Type field – Network Control Protocol (NCP) which is field in the header to recognize the encapsulated network layer packets. It handles authentication, multilink connections and is able to function over synchronous and asynchronous links. PPP uses HDLC to encapsulate and transfer packets over point to point links and PPP supports recovery from errors and glitches (Hoong, 2012).

It is considered that by implementing PPP connections on the Router in the customer´s Network would permit and facilitate the connection of LAN segments within the Network and it also enables the connection of the LANs to the Service provider WANs.

Benefits

The implementation of Point-to-point (PPP) Connections offers the following advantages:

Operates on Ethernet Networks.

Transports all the traffic between two devices via a single connection.

Provides multilink bundling.

Ability to be compressed.

Enables error detection.

Supports various routed protocols.

It can be authenticated.

Challenges

The main downside of the PPP connections is the complexity of the configuration.

Troubleshooting PPP Connections

Based on the PPP Connections which had been carried out by the Researcher in the class based researches, there are some issues when dealing with PPP Connections such as:

A Scenario where exists a Mismatched WAN Encapsulation method - as a solution , We reconfigure both end's interfaces with the same encapsulation method.

A scenario where there is a Mismatched IP configuration - as a solution, the necessary troubleshooting could involve the configuration of the IP addresses in both ends from same subnet.

A scenario where there is a problem with PPP authentication - as a solution, the debug ppp authentication command could be utilised.

Network Address Translation (NAT)

Network Address Translation (NAT) is a service that is incorporated on router devices. It translates a set of IP addresses to another set of IP addresses by using a NAT table in order to keep record of the translations, It can as well assist in preserving the restricted amount of public IPv4 addresses.

The Researcher is of the opinion that by implementing the Network Address Translation (NAT) particularly the Overloading NAT to the router in the customer's Network, the client computers could be assisted to connect to the Internet by having a single real IP Address. The implementation of static NAT would also be beneficial if there is a web server on the Network that requires a static IP Address.

Benefits

The Implementation of NAT provides the following advantages:

Sustaining officially registered IP addresses.

Resolving address overlap events.

Maximize flexibility when accessing to the Internet.

It does not require address renumbering as a network changes.

Challenges

Despite the implementation of NAT providing some advantages there are some drawbacks such as:

Translation results in switching path slowdowns.

Leads to loss of end-to-end IP traceability.

Some programs do not work with NAT enabled.

Troubleshooting NAT

Based on the NAT Labs the Researcher has performed the research in class and there are some issues when dealing with NAT such as:

- A Scenario where there is IPV4 connectivity issues in a NAT environment - as a solution, We can conduct the following actions:

First, rule out NAT as the reason for the problem.

Run the show IP NAT translations command to check if accurate translations exit in the translation table.

Run the clear IP NAT statistics and the debug IP NAT commands to find out if the NAT is working properly and to discover if dynamic entries are recreated once they are removed.

Check if the routers have accurate routing information and examine the packet's information.

Generic Routing Encapsulation (GRE) Tunnels

Generic Routing Encapsulation (GRE) is utilized to transfer Internet Protocol packets utilizing private IP addresses through the Web to a remote private Internet Protocol network. It offers a technique to encapsulate any Layer 3 protocol over other Layer 3 protocol as well as it enables router devices to function like they possess a virtual PPP-connection to one another (Adtran, 2005).

I believe that by implementing GRE tunnels to the Router in the customer's Network would be Beneficial due to the following factors:

The VPN by itself is not the best option for remote locations connection because some downsides such as It does not allow multicast traffic, the access lists have to be manually configured and managed which is time consuming when dealing with large Networks and susceptible to misconfigurations (Adtran, 2015).

GRE tunnels enable routing protocols to be forwarded between routers via the Internet (Adtran, 2015).

For Dynamic Routing Updates, routing protocols like RIP and OSPF are not solutions anymore. The Network Administration will be affected without having dynamic routing from one site to another (Adtran, 2015).

When Implemented , GRE Tunnels could be a method for the Internet Service Provider Company not being able to see the data which is traveling the throughout the Routers (Arora, 2010).

Benefits

The Implementation of Generic Routing Encapsulation (GRE) Tunnel offers the following advantages:

Ability to bundle other Network Protocols.

Network Systems with restricted hops are offered as workarounds.

Enabling of interrupted sub-networks to be connected.

Permits Virtual Private Networks across wide area networks.

When usedwith IPsec GRE tunnels become secure.

Multicast traffic forwarding capability.

Significantly less resource intensive than VPN and IPsec.

Challenges

The main downsides of the the Generic Routing Encapsulation (GRE) tunnels are the absence of flow-control and security elements.

Troubleshooting GRE Tunnels

Based on the GRE Tunnels Labs I have carried out in class and researching , there are some issues when dealing with GRE Tunnels such as:

A scenario where the Packet being transmitted is greater than what the Interface is able to allows - as a solution, the technicians configure IP TCP adjust-mss 1436 on Tunnel Interface (Davis, 2017).

A scenario where one side of the tunnel is down and the other side continues up - as a solution the technicians enable keepalive Packets on each side of the Tunnel (Davis, 2017).

Frame Relay

The Frame relay is a packet-switched, connection-oriented WAN technology that functions at the data link layer of the OSI reference model and this utilizes a subset of the high-level data link control (HDLC) protocol known as Link Access Procedure for Frame Relay (Hoong, 2012).

Through employing the Frame Relay to the Router in customer's Network, it would be beneficial to pretend to replicate a commercial working environment. The Frame relay would enable the interconnection of distributed LANs across other locations via the web if the company possesses facilities in other locations. It also would allow the encapsulation of other crucial Network protocols that are commonly implemented in Networks. In addition to this, the Network would be less susceptible to errors due the fact of the Frame Relay being one of the most reliable Internet Protocols.

Benefits

The implementation of Frame Relay provides the following advantages:

Reduced cost of ownership.

Minimized overhead and high reliability.

Flexible and scalable networks along with properly defined recovery processes.

Interoperability with many other protocols and programs, such as TCP/IP and ATM protocols.

A more cost effective service compared to other typical WAN solutions.

Higher data performance transmission.

Challenges

Despite the implementation of Frame Relay providing some advantages there are some drawbacks such as:

Dependency on reliable Network Structure as Frame Relay does not contend with the errors and flow control mechanisms throughout sending and receiving packets.

Frame Relay is a primitive protocol comparing with protocols that utilize link-state algorithm such as Netware, OSPF and IS-IS Stack OSI.

Troubleshooting Frame Relay

Based on the Frame Relay Labs which the Researcher has performed in class based researces, there are some issues with Frame Relay while this could be under utilisation such as :

A Scenario where a problem could exist with physical connection between the DSU/CSU and the Router - as solution, We run the show interface command to identify the status of the physical connection (Cisco, 2017).

A scenario where LMI is not correctly exchanged between the Router and the Frame Relay provider (the line protocol is down) - as a solution. The technicians could utilise the show frame-relay lmi command to diagnose the issue (Cisco, 2017).

A scenario where the PVC status could become inactive as a solution, the technicians then have to operate the show frame-relay pvc command to diagnose the issue (Cisco , 2017).

Conclusion

In the Report, the Researcher has examined and evaluated four distinct technologies such as the the Point-to-point (PPP) connections, Network Address Translation (NAT), Generic Routing Encapsulation (GRE) and Frame Relay.; It has been assumed that by using these the customer could be assisted in upgrading their Network System in order to replicate a business working environment. In the Report, the major functions of each technology have been demonstrated and common issues associated to the adoption of these technologies and how to troubleshoot them have been illustrated as well.