Hello,

I need two responses of at least 150 words each for the below students discussions for this week. Also in the bold below are the questions the students at answering.

Questions:

Routing protocols use metrics to decide on the best path on the network. Name two different metrics and explain how routing protocols use these metrics to decide on the best path.

Student one:

Hello and good Morning Class,

For this week’s forum I have chosen to discus OSPF (Open Shortest Path Frist) and EIGRP (Enhanced Interior Gateway Routing Protocol). Starting with OSPF first it is most commonly used in large enterprise network and is a link state routing protocol. OSPF uses the Dijkstra algorithm and sends update out on the network to look for network changes to automatically update the routing table. OSPF areas are a group of router on the network and when one area gets to large you simply would just add a new area to the current and area Zero is the backbone area that all other area must use to send data to other areas within the network. Another aspect of OSPF is the dead time when a router dead time gets to zero it is presumed dead and the link will be removed from the SPF calculations.

The next routing protocol would like to discuss is EIGRP, which uses every little network resources during normal operation only sending hello packets out on a stable network hello packet are sent to check status of the other connect routers and the timers or interval can be adjust to meet your given requirements. This helps when you have a link go down the redundant link will failover almost instantaneously and service interruption should not be noticeable. EIRGP will chose its path to another location on the network by counting the number of hops it take to get to the other router if one path as 3 and the other 2 it will choose the path that only has two. Within a cisco router you can use command like show ip eirgp neighbors to see what other routers are connect to interface within the router you are currently log in to. Both of these protocols are good and are in common use today. I hope you all have a great week.

https://www.cisco.com/c/en/us/support/docs/ip/enha…

https://www.auvik.com/franklymsp/blog/ospf-protoco…

-Randy

Student two:

Routing protocols use metrics to decide on the best path on the network. Name two different metrics and explain how routing protocols use these metrics to decide on the best path.

Before looking at the two routing protocol metrics I wanted to quickly touch on the administrative distance (AD) for routing information which I thought was interesting. AD distinguishes the trustworthiness received on one router from its neighboring router. It is illustrated using a number range from 0 to 255, where 0 is the “most trusted” and 255 is the “least”. The AD is one of the first things the router checks and whichever path has the lower value is included on the routing table. Each routing protocol has a default AD value and the router will automatically trust a connected interface, known as a static route (Lammle, 2012).

The two protocols I chose to further discuss are Routing Information Protocol (RIP (AD-120)) and Enhanced Interior Gateway Routing Protocol (EIGRP (AD-90)). Note that the highest default AD is 255 which our texts says will never be used (Lammle, 2012). RIP works by sending its complete routing table to all active interfaces every 30-seconds and makes the best route determination through use of what is called the “hop count” only. RIPs maximum hop count is 15, meaning a hop count of anything higher would be unreachable. A hop count is the number of additional devices the information has to travel though before reaching its destination.

With EIGRP, it uses an autonomous system concept to share routing information and also includes subnet mask information in its routing updates, unlike its predecessor IGRP. EIGRP is considered a hybrid protocol because it shares similarities of distance vector and link state based protocols in how it functions. EIGRP, being a hybrid holds several advantages over some of the other protocols such as IP/IPv6 support, more efficient neighbor discovery, and best path selection thru use of Diffusing Update Algorithm (DUAL). Through use of DUAL, EIGRP prevents data looping by calculating the both the best and alternate [best] path for travel.

Josh

Works Cited

Lammle, T. (2012). CompTIA Network+ Study Guide, Second Edition (Exam N10-005). Indianapolis, IN: Wiley & Sons, Inc.