CMIT 456 at the University of Maryland Global Campus is an in-depth study of advanced routing technologies and services in enterprise networks, with a strong focus on troubleshooting.
UMGC designed it to help prepare for the Cisco CCNP Implementing Cisco Enterprise Advanced Routing and Services (ENARSI) exam. The aim is to implement and troubleshoot Layer 3, VPN services, infrastructure security, infrastructure services and infrastructure automation.
The prerequisite is CMIT 455. Where that course surveys the enterprise network, CMIT 456 goes deep into routing behavior: why a route was chosen, why it was not advertised, and how to prove the fix.
Course at a Glance
| Item | Details |
|---|---|
| University | University of Maryland Global Campus (UMGC) |
| Course code | CMIT 456 (3 credits) |
| Level | Undergraduate, upper level |
| Prerequisite | CMIT 455 |
| Certification alignment | Cisco CCNP ENARSI |
| Credit note | Credit for only one of CMIT 452 or CMIT 456 |
| Typical work | Routing and troubleshooting labs, VPN configuration, documented reports |
What CMIT 456 Covers
| Area (UMGC) | Typical content |
|---|---|
| Layer 3 | EIGRP, OSPF and BGP in depth, redistribution, route filtering, policy-based routing |
| VPN services | Site-to-site VPN designs such as DMVPN, and MPLS VPN concepts |
| Infrastructure security | Access control lists, control plane protection, device access |
| Infrastructure services | DHCP, SNMP, logging, NetFlow and similar supporting services |
| Infrastructure automation | Templates, scripts and APIs to configure and check devices |
Key Concepts Explained
Route Redistribution
Redistribution shares routes between protocols. It is powerful and risky: done in two places without care, it can create routing loops or suboptimal paths.
Example: OSPF and EIGRP are redistributed into each other on two border routers. A route learned from OSPF goes into EIGRP on router A and back into OSPF on router B, now looking like a better path. Tagging routes on the way in and filtering tagged routes on the way back stops the loop.
BGP Path Selection
BGP chooses routes by a sequence of attributes, not just shortest distance. Local preference and AS path length are common levers in assignments.
Example: A company has two internet links and wants outbound traffic to prefer ISP 1. Setting a higher local preference on routes received from ISP 1 makes every internal router choose that exit.
Structured Troubleshooting
Define the problem, gather facts, form a hypothesis, test it and document the result. ENARSI-style labs reward this discipline more than lucky guesses.
Typical Assignments and How to Approach Them
| Assignment type | What it tests | How to approach it |
|---|---|---|
| Routing labs | Advanced protocol configuration | Show configs and routing tables before and after |
| Troubleshooting tickets | Finding faults in a broken network | Record symptom, tests, root cause and fix |
| VPN tasks | Secure site-to-site connectivity | Verify tunnels and show traffic passing |
| Services and automation | Supporting infrastructure | Explain each service's purpose and show it working |
Writing up a Troubleshooting Ticket
A clear structure keeps troubleshooting write-ups short and convincing:
- Symptom: what the user or monitor reported.
- Scope: which devices, networks or users are affected.
- Tests: each command and what it showed.
- Root cause: the one setting or event that explains every symptom.
- Fix and verification: the change and the output proving it worked.
If your root cause does not explain every symptom, keep looking: there may be a second fault.
DMVPN in Plain Terms
Dynamic Multipoint VPN (DMVPN) connects many branch sites to a hub over the internet, and lets branches build direct tunnels to each other when needed, without configuring every tunnel by hand.
It combines multipoint GRE tunnels, the Next Hop Resolution Protocol to discover peers, and usually IPsec for encryption. When troubleshooting, check each layer in turn: underlay reachability, tunnel registration with the hub, routing over the tunnel, then encryption.
Where Students Get Stuck
- Redistribution loops. Plan tags and filters before redistributing in more than one place.
- BGP attributes. Learn the path selection order rather than guessing.
- Fixing symptoms. A static route may restore traffic but hide the real problem.
- Thin documentation. Show the evidence behind each conclusion.
Study Tips for CMIT 456
- Practice breaking your own lab and fixing it; troubleshooting is a skill built by repetition.
- Memorize the main BGP path selection steps with a short mnemonic.
- Keep one-page summaries for each routing protocol's neighbor requirements.
- Compare your notes with Cisco's current ENARSI exam topics.
How We Help with CMIT 456
Send the lab or ticket instructions, the topology, your configurations and outputs, and the rubric. A writer with advanced routing knowledge can explain a protocol behavior, review your troubleshooting write-up, or prepare a custom report to learn from. See our lab report guide for general structure.
GradeEssays is independent of the University of Maryland Global Campus and of Cisco. We never access your lab or classroom; our work is a study aid within UMGC's academic integrity policy, with free revisions within the scope of your original request.
Make Your CMIT 456 Troubleshooting Write-Ups Clear
Share the lab and your outputs. A networking writer shows you how to document diagnosis and verification.
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Frequently Asked Questions
UMGC lists CMIT 455 as the prerequisite.
UMGC designed it to help prepare for the Cisco CCNP ENARSI exam, a concentration exam in the CCNP Enterprise track.
No. UMGC states that students may receive credit for only one of CMIT 452 or CMIT 456.
Routing: how routers learn, choose and share paths, including EIGRP, OSPF, BGP and redistribution between them.
UMGC's description says to implement and troubleshoot, and ENARSI is known for troubleshooting scenarios, so diagnosis is a core skill.
No. We do not access your lab. We explain, review and provide model write-ups for study.