In this video tutorial, prepared for my UMGC CMIT-456 (Cisco Networking Academy ENARSI v8 curriculum) course, we take our first look, at our first overlay technology: Generic Routing Encapsulation (GRE). We discuss the original GRE use cases, take a peek at the RFCs, and then configure a GRE tunnel between Site A and Site B. I go over the keepalive setting, the MTU setting, and why the command ‘tunnel mode gre ip’ is not a command needed if you are using IPv4 on hour point-to-point GRE tunnel. We then spice things up a bit by removing the static routes and configuring BOTH OSPF and EIGRP as our dynamic routing protocols!
Here are the additional GRE/IPSec/SVTI videos I mentioned:
Supplemental Video Tutorial: GRE over IPsec w/IKEv1 and OSPF (47:57) – https://youtu.be/tF8fItQHJNY
Supplemental Video Tutorial: Static Tunnel Virtual Interface (SVTI) w/IKEv1 and Default ISAKMP/IPsec (26:40) – https://youtu.be/5g3qrKq8d6s
Supplemental Video Tutorial: Static Tunnel Virtual Interface (SVTI) w/IKEv1 w/Custom ISAKMP/IPsec (27:10) – https://youtu.be/kRyaOGaHJso
Supplemental Video Tutorial: Static Tunnel Virtual Interface (SVTI) w/IKEv2 (37:47) – https://youtu.be/RMXukF7uS_w Enjoy!
***This video is an in-depth tutorial and is far more than simply an answer key to the aforementioned Packet Tracer activity. This tutorial is being made to assist my UMGC CMIT-456 learners in their journey through the ENARSI v8 material so, if you are just looking for a shortcut or easy answers for the activity, this is not the video you should watch. However, if you are looking to gain a deeper understanding of GRE tunnels/overlays, my hope is that this will increase your comprehension and help you to become a better and more effective network engineer. Enjoy!
*This techtorial/Packet Tracer activity is all done running Cisco Modeling Labs (CML) v2.1.1-b19, some physical routers in my Evil Command Center Lab and/or Packet Tracer version 8.1.0 (for the Mac) which was just recently released! The MINIMUM version you can use for any of the new CCNAv8 curriculum activities is Packet Tracer v7.3.0! Be sure to leave your feedback and questions below and I hope I have earned the privilege of your time!