Below is a short overview of STP and how to navigate it in the CISCO IOS enjoy.
[youtube=http://www.youtube.com/watch?v=zapAZRP7mEk&w=560&h=315]
STP Overview Video
December 12, 2013
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IOS Commands, Networking, Protocols, Switches, Videos | Tagged: 802.1w, blocking port, ccent, ccent exam, ccent study, ccna, cisco icnd2, cisco packet tracer, designated port, fast ethernet, GNS3, icnd1 study, icnd2, icnd2 exam, interface cost, Microsegmentation, packet racer, root bridge, stp, stp overview, stp port roles, testking | 
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Posted by Josh Gahan
Open Shortest Path First (OSPF)
December 12, 2013Moving forwards the next bunch of topics on the list look like so:
Configure and Verify OSPF
- Neighbour Adjacencies
- OSPF States
- Discuss Multi-area
- Configure OSPFv2 and v3
- Router ID
- LSA Types
So lets first get a little background on OSPF before moving any further.
OSPF or Open Shortest Path First is, as the name suggest, an open standard link state routing protocol. The AD of OSPF is 110 and OSPF uses a metric of the outgoing interface Cost to determine the best route. It’s a fast converging and flexible routing protocol which also enables us to separate the topology into areas.
The Topology data for the OSPF network is contained within Link State Advertisements and all routers in the same area share the exact same topology information.
I won’t delve any further into OSPF at this point, i just simply want to introduce the upcoming topics and as you can see there are a few things to get through. So in the upcoming days i will describe the purpose of the LSA’s the RID , configuration and some helpful troubleshooting commands.
Don’t stress too hard this stuff is pretty easy.
Leave a Comment » | ICND2 Topics, Networking, Protocols, Routers | Tagged: ccent, ccna, cisco, Cisco routing, GNS3, icnd1, icnd2, Link State Advertisement, Link State Advertisements, LSA, LSA1, LSA2, LSA3, LSA4, Open Standards, ospf, OSPF network, OSPFv2, OSPFv3, RID, Router ID, routing protocols, test king | Permalink
Posted by Josh Gahan
Routing Metrics
December 10, 2013On our journey through the Cisco ICND2 objectives, we are expected to know a thing or two about “Metrics”
So what is a metric you ask ?
Well a routing metric is used by all routing protocols to decide on the best path to any given network. Not to be confused with Administrative Distance (AD). Which tell the router which path to believe when a router learns a route from more then one routing protocol.
Below is an example of what a metric is, with the use of RIPv2. As you can see R1 has two paths to reach R2. One is out FA0/1 directly to R2 (Which in the real world would be a connected route with a lower AD then RIP) and out FA0/2 through R3.
The metric with RIP is calculated using hop count, so the path with the least hops is the best path. The path highlighted in red would be used in this example.
Leave a Comment » | ICND2 Topics, Networking, Protocols, Routers | Tagged: AD, administrative distance, ccent, ccna exam, cisco ccna, cisco exam, cisco icnd1, cisco icnd2, eigrp, GNS3, hop count, icnd1, icnd2, igp, ripng, ripv2, routing, routing path, routing protocol, test king | Permalink
Posted by Josh Gahan
Split Horizon
December 9, 2013The next routing protocol feature to talk about is Split Horizon.
A feature of Distance Vector that prevents routing loops from forming. Split horizon rules stop a router from sending routing updates back out the interface from which it learnt them from.
Split horizon is used with RIPv2 and EIGRP and yup you guessed it they are Distance Vector routing protocols.
The example below gives you some understanding of what Split Horizon is actually doing. The RIP update going out R1’s FA0/1 interface only includes the subnet 192.168.0.0/24 (Route highlighted in red). As you can see from the routing table below, R1 learnt this network from an update off FA0/3, so Split Horizon Rules allow this network to be sent in an update out FA0/1.
The routes highlighted in black, are learnt from FA0/1 so Split horizon rules will not allow these routes to be sent in an update, over FA0/1
Leave a Comment » | ICND2 Topics, Networking, Protocols, Routers | Tagged: ccent, ccna, eigrp, fa0/1, GNS3, horizon, icnd2, poison reverse, ripv, routers, routing protocol, split, split horizon, test king | Permalink
Posted by Josh Gahan
Study Update
November 13, 2013Hi all, just a quick update to let you know what’s happening.
Well i’ve almost almost completed reading the ICND2 book , the new 200-101 exam and it is quite different to it’s predecessor so i highly recommend you purchase the new one if you haven’t already. The next thing i have to do is also finish up my notes and get those ios commands stuck in my head. I had initially planned to obtain the CCNA by the end of November but due to some hurdles in the last couple of weeks i will be happy with finishing up all the notes before then.
Also the networkdictionary.wikispaces.com wiki which i have created is coming along nicely. Plenty of Cisco related acronyms in there now, so don’t forget it’s free for anyone and to join also, add whatever is missing (that’s alot)
So keep at it and when the times right i will be covering the rest of the ICND2 exam soon. I’m thinking Identifying WAN technologies next, it’s my favourite.
Leave a Comment » | Networking, Uncategorized | Tagged: 200-101, ccent, ccna, ccna exam, cisco, icnd2, study ccna, study cisco | Permalink
Posted by Josh Gahan
VLAN Trunking Protocol (VTP) – Synchronisation
August 24, 2013Synchronisation occurs when all switches learn of a new VLAN configuration and they all learn the same VLAN ID and name.
Leave a Comment » | Networking, Protocols, Switches, VLANs, VTP | Tagged: ccent, ccna, ccna exam, icnd2, server mode, synchronisation, transparent mode, vlan, VLAN domain name, vlan id, VLAN name, VLAN Trunking Protocol, VTP server | Permalink
Posted by Josh Gahan
Switch IP & Default Gateway Checklist
June 7, 2013- Enter VLAN1 configuration mode using the Interface VLAN 1 global configuration command
- Assign an IP address and mask using the IP address ip address mask interface sub-command
- Enable the VLAN1 interface using No shutdown interface subcommand
- Add the IP default-gateway ip address global command to configure the default gateway
Leave a Comment » | IOS Commands, Networking, Security, Switches | Tagged: can exam, ccent, ccent exam, ccna, cisco checklist, cisco cli, cisco routers, cisco switches, command line interface, default gateway, icnd1, icnd2, ios commands, ip address, mask, subnet | Permalink
Posted by Josh Gahan
Switch Memory Types and Files
June 5, 2013Types Of Memory In A Switch
| -RAM-
–Working Memory -Running Config |
-FLASH-
-CISCO IOS Software |
-ROM-
-Bootstrap programme |
-NVRAM-
Startup Config |
Two Main CISCO IOS Files
| Configuration File name | Purpose | Where is it stored ? |
| Startup-config | Stores the initial config used anytime the switch reloads CISCO IOS | NVRAM |
| Running-Config | Stores the currently used configuration commands. This file changes dynamically when someone enters commands in configuration mode. | RAM |
Leave a Comment » | Networking, Switches | Tagged: bootstrap, ccent, ccent study, ccna, ccna exam, cisco ios, flash, icnd1, icnd2, iOS, nvram, ram, rom, running-config, startup-config | Permalink
Posted by Josh Gahan
Benefits of Switching
May 31, 2013- Switch ports connected to a single device and microsegment the LAN, providing dedicated bandwidth to that single device.
- Switches allow multiple simultaneous conversations between devices on different ports
- Switch ports connected to a single device support full duplex, in effect doubling the amount of bandwidth available to the device.
- Switches support rate adaptation, which means that devices that use different ethernet speeds can communicate through the switch (HUBS CANNOT)
Leave a Comment » | Networking, Switches | Tagged: adaptation, benefits of switching, ccent, ccna exam, cisco, cisco networking, cisco switches, full duplex, icnd1, microsegment, Microsegmentation, segment, switch ports, switches, switching | Permalink
Posted by Josh Gahan
CDP Video Tutorial
May 31, 2013A quick run through the CDP commands to help you map a network, HD is available for this video guys.
[youtube=http://youtu.be/nzGconvPllo]
Leave a Comment » | Networking, Protocols, Videos | Tagged: ccent, ccna, cdp, cisco, cisco discovery protocol, cisco ios, cisco networking, cli, icnd1, iOS, networking, nvram, router, show cdp, switch | Permalink
Posted by Josh Gahan