Above is the IP Packet Switching architecture, with the IP Route / ARP Table at the "Control Plane" at the Top, which then feeds the FIB (Forward Information Base) aka IP CEF and Adjacency Table to perform Hardware Packet Switching. Packet Switching is covered extremely in depth in this article, however it will be briefly … Continue reading TSHOOT – IPv4 Route Selection / Packet Switching process, Static Routing for IPv4 and IPv6 with troubleshooting!
It's easy to assume that an Access-List may be blocking traffic to a Destination IP in a TSHOOT Topology / Trouble ticket, so it is important to know exactly how to read them, and to assess if it applies to your trouble ticket! IPv4 Standard / Extended / Time-Based ACL review / troubleshooting I will … Continue reading TSHOOT – Standard / Extended / Time-Based ACLs, Prefix-List review and troubleshooting!
Above is the IPv6 TSHOOT Topology, and though I will not go into RIPng or OSPFv3 in this article, I want to begin identifying IPv6 subnetworks without hesitation! The full article to understand IPv6 / Subnetting can be found here. A quick review of IPv6 Addressing concepts An IPv6 Address is 128 bits / 64 … Continue reading TSHOOT – IPv6 EUI-64, SLAAC, Auto-Configuration, DHCPv6 Stateful and Stateless review and troubleshooting!
Total credit to Wikipedia for the above graphic, it perfectly describes how Hex breaks down to binary, as I've heard so many complicated explanations of Hex that are just unnecessary when Hex is just representations of 4-bit groupings (1 byte). Hex has way too many complex explanations! Generally Hex is represented 2 characters at a … Continue reading TSHOOT – Hex Conversion and IPv6 Addressing simplified for IPv6 TSHOOT Topology, multiple subnetting examples, some real world talk mixed in!
Will cover the three FHRP's for the CCNP R/S in the article, review some very basics of each protocol, and jump into commands to troubleshoot them on TSHOOT day! HSRP (Hot Standby Router Protocol) Review and Troubleshooting Review HSRP is Cisco Propriety HSRP works on both Layer 3 switches and Cisco Routers Hello 3 sec … Continue reading TSHOOT – HSRP, VRRP, and GLBP First Hop Redundancy Protocol review and troubleshooting!
Above is a visual of Private VLANs and how they can communicate with each other, however this is going to be a lot of Switch security, so lets get to it. Port Security troubleshooting Some common issues that can cause Port Security not to work: Port Security is configured but not enabled - This is … Continue reading TSHOOT – Port Security, DHCP Snooping, IP Source Guard, DAI, Protected Ports, Private VLANs, and VACL Troubleshooting!
Though router on a stick is not on current TSHOOT Topologies that I see, and will more likely be SVI's that you are troubleshooting, I wanted to add some notes on here pertaining to that subject as well for possible dated real life scenarios of dated networks. Quick review of Router on a Stick Troubleshooting … Continue reading TSHOOT – Router On A Stick, Switched Virtual Interface (SVI), Routed Ports, and Layer 3 EtherChannel troubleshooting!
Above is a simple STP topology from earlier SWITCH labbing, however this will cover all STP flavors (PVST+ / RSTP / MSTP), features that go with them, and EtherChannels. STP issues, how to identify and resolve them, and feature behaviors In relation to the TSHOOT exam, the most important thing to note is that the … Continue reading TSHOOT – Troubleshooting Spanning-Tree and Layer 2 EtherChannel issues!
The troubleshooting of Layer 2 issues seems like it may be the easiest, as the information is really taught quite thorough at the CCNA level, however there are some caveats that are potential exam landmines for TSHOOT to avoid on exam day! First I want to start with some verification commands that are critical for … Continue reading TSHOOT – Layer 2 troubleshooting of Trunks, VTP, and VLANs!
Multi-Layer Switch architecture, and how SDM can play a role in relieving the issue, and as this will only be a reference to commands to use / method of using them the following articles will need to be read or understood for the commands to make sense: Detailed review of MLS Architecture SDM templates reviewed … Continue reading TSHOOT – Troubleshooting Memory / CPU issues, and how to apply it to “follow the path” troubleshooting method!
I left myself with one device to assist in getting my network back up and running, and that is the Frame-Relay Switch running configuration, which I can look at the above 3 interfaces and do the "Stare and Compare" with R1 / R2 / R3 to get them reconfigured for labbing TSHOOT concepts going forward … Continue reading TSHOOT – Using CLI tools Part 1 – Network information access, Show / Logging / NTP / Debugging concepts reviewed!
Network Admins hard at work maintaining and fine tuning the network proactively, to make reactive troubleshooting easier when a network problem is reported! Overview of Proactive Network Maintenance and what it might involve Network maintenance is part of any network administrators set of duties in maintaining a healthy network, which often maintenance items are uncovered … Continue reading TSHOOT – Network Maintenance, Documentation, and Change Management discussed in detail!
Above is the flow chart of the "Structured Troubleshooting" method, which takes into consideration who is authorized to implement network changes and fixes, and also focuses on documenting those steps to ensure the fix is implemented correctly and documentation exists that can be referenced at a later time when needed. There are several different methods … Continue reading TSHOOT – Simplified, Structured, and other Troubleshooting Methods described in detail for exam day success!