Respond

Respond 3 of your colleagues' postings in one or more of the following ways:

· Ask a probing question.

· Share an insight from having read your colleague’s posting.

· Offer and support an opinion.

· Validate an idea with your own experience.

· Make a suggestion.

· Expand on your colleague’s posting.

Student #1

Routing protocols can be the Interior Gateway Protocol (IGP), which is for you internal networks and the exterior routing protocol is Exterior Gateway Protocol (EGP).  This protocol maintains the routing information for networks (external) to your network.   It only knows how to deliver data outside your network.   EGP does not know how to deliver data within your network.  Border Gateway Protocol (BGP) is the only EGP in use today.  BGP is the routing protocol for the Internet. 

          Open Shortest Path First (OSPF) is starting to become the popular interior routing protocol (Tiso, 2011).  If designing a new network, I would recommend OSPF or EIGRP because of the popularity, flexibility, and fast convergence.   Reason I say OSPF is because there is not limitation on the hop count like there is with RIP (15).  OSPF uses IP multicast to send link-state updates ("Cisco," 2014).  Updates sent when routing changes occur instead of periodically. Better convergence since routing changes is instantaneously and not periodically.

           My experience with OSPF occurred back in 2003 when a team I was working with was task to put in a new video teleconference network for an intelligence agency that consisted of over 250 rooms moving from H.320 to H.323.  The network would consist of CONUS and OCONUS.  Fourteen years later, equipment has been upgraded routers, switches, endpoints, etc. but the same routing protocol still used. 

References

Cisco Networking Academy's Introduction to Routing Dynamically. (2014). Retrieved from http://www.ciscopress.com/articles/article.asp?p=2180210&seqNum=7

Tiso, J. (2011). Designing Cisco Network Service Architectures (ARCH): Developing an Optimum Design for Layer 3 (CCDP). Retrieved from http://www.ciscopress.com/articles/article.asp?p=1763921&seqNum=6

Student #2

Enhanced Interior Gateway Routing Protocol (EIGRP) is Cisco's proprietary routing protocol, based on IGRP. EIGRP is a distance-vector routing protocol, with optimizations to minimize routing instability incurred after topology changes, and the use of bandwidth and processing power in the router. Routers that support EIGRP will automatically redistribute route information to IGRP neighbours by converting the 32-bit EIGRP metric to the 24-bit IGRP metric. Most of the routing optimizations are based on the Diffusing Update Algorithm (DUAL), which guarantees loop-free operation and provides fast router convergence. Origin: Based only on Cisco’s implementation, not an Internet RFC Type of protocol: Hybrid distance vector Metric: Delay, bandwidth, reliability, and load, using the Diffusing Update Algorithm (DUAL) Methodology: Sends hello packets every five seconds to neighbours (can interoperate with IGRP) to see if the neighbours are still available; updates other routers by notifying them only when routes change Ideal topology: Any network, small to very large; all routers must be Cisco Strengths

· Uses DUAL to provide very quick convergence and a loop-free network

· Supports IP and IPX

· Requires less CPU than OSPF (see next section)

· Requires little bandwidth for routing updates

· Supports VLSM or CIDR

· Uses the delay, bandwidth, reliability, and load of a link as its metric; this makes it very accurate in selecting the proper route

· Offers backward compatibility with IGRP

Weaknesses:

-  Not an Internet standard; all routers must be from Cisco Systems

 Broadcast networks and Open Shortest Path First (OSPF)

Broadcast networks such as Ethernet have a designated router (DR) and a backup designated router (BDR) that are elected ideal for their routing solutions. Designated routers establish adjacencies with all routers on that network segment. This is to reduce broadcasts from all routers sending regular hello packets to its neighbors. The DR sends multicast packets to all routers that it has established adjacencies with. If the DR fails, it is the BDR that sends multicasts to specific routers. Each router is assigned a router ID, which is the highest assigned IP address on a working interface. OSPF uses the router ID (RID) for all routing processes. my recommendation for OSPF routing for broadcast networks is justified by the its characteristics below: Link State Routes IP Routing Advertisements: Partial When Route Changes Occur Metric: Composite Cost of each router to Destination (100,000,000/interface speed) Hop Count: None (Limited by Network) Variable Length Subnet Masks Summarization on Network Class Address or Subnet Boundary Load Balancing Across 4 Equal Cost Paths Router Types: Internal, Backbone, ABR, ASBR Area Types: Backbone, Stubby, Not-So-Stubby, Totally Stubby LSA Types: Intra-Area (1,2) Inter-Area (3,4), External (5,7) Fast Hello Timer Interval: 250 msec. for Ethernet, 30 seconds for Non-Broadcast Dead Timer Interval: 1 second for Ethernet, 120 seconds for Non-Broadcast Bidirectional Forwarding Detection (BFD) Support LSA Multicast Address: 224.0.0.5 and 224.0.0.6 (DR/BDR) Don't Filter! Interface Types: Point to Point, Broadcast, Non-Broadcast, Point to Multipoint, Loopback

References

Black, U. D. (Ed.). (2000). IP routing protocols: RIP, OSPF, BGP, PNNI, and Cisco routing protocols. Upper Saddle River, NJ: Prentice Hall.

Cisco Networking Academy Program (Ed.). (2014). Routing protocols.

Retana, A, Slice, D, & White, R (2005).  Which Routing Protocol Should My Network Use?

Graziani, R., & Johnson, A. (Eds.). (2008). Routing protocols and concepts: CCNA exploration companion guide

References

Cisco Networking Academy's Introduction to Routing Dynamically. (2014). Retrieved from http://www.ciscopress.com/articles/article.asp?p=2180210&seqNum=7

Tiso, J. (2011). Designing Cisco Network Service Architectures (ARCH): Developing an Optimum Design for Layer 3 (CCDP). Retrieved from http://www.ciscopress.com/articles/article.asp?p=1763921&seqNum=6

Student #3

You provided a very comprehensive and informative post on Enhanced Interior Gateway Routing Protocol (EIGRP) with a side by side comparison of EIGRP and Open Shortest Path First (OSPF). In today's technological world, communication is incredibly important, and much of these communication happens through a very complex web of networks throughout the world. Networking professionals must, therefore, understand it's importance and have the knowledge of routing processes and the types of routing particles we need to use on a particular project. EIGRP, an advanced distance vector routing particle, and OSPF, a more complex protocol that brings many more features and greater flexibility to the network are suitable for enterprise networks. As you already know, the EIGRP is limited to only Cisco routers while the biggest particle of all; the OSPF is open to both Cisco and non-Cisco routers. Do you think that Cisco should ‘completely’ open EIRGP to enable it to enhance its security capabilities in future? I say “completely” because according to the announcement made by Cisco (2013), they were only releasing the basic EIGRP to the IETF as an Informational RFC. These basic features include all the information needed to implement EIGRP, and its associated features, including High Availability (HA). Cisco (2013), further explained that the EIGRP was being released as an "Informational RFC" to allow Cisco to retain control of the EIGRP protocol so as to preserve the customer experience and deployment investments.

Reference

Cisco (2013). Enhanced Interior Gateway Routing Protocol (EIGRP) Informational RFC Frequently Asked Questions Retrieved April 17, 2017, from

http://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/enhanced-interior-gateway-routing-protocol-eigrp/qa_C67-726299.html