| posted in Cisco Networking | |
| by killabee on May 14th, 2012 | tags: cisco 4500, ios, issu, upgrade |
I recently had to upgrade the IOS on a Cisco 4500. I figured it was the perfect opportunity to try out ISSU and to blog about it.
ISSU (In-Service Software Upgrade) is a feature that allows the operator to upgrade (or downgrade) the IOS on device without having to take the entire device down and potentially impact service. This is partly accomplished with the SSO supervisor redundancy mode that performs the subsecond supervisor switchovers while each supervisor is restarted and loaded with the new (or old) IOS.
In brief, the process works as follows: Both supervisors are running the old image. The standby supervisor is restarted and loaded with the new image. The operator switches over to the standby supervisor to ‘test drive’ the new image. The switchover automatically restarts the active supervisor, bringing it up as the standby and making the current standby supervisor the active. Finally, the standby supervisor, which started as the active, is restarted and loaded with the new image. In the end, both supervisors have the new image.
| posted in Interviews | |
| by Steve on February 20th, 2012 | tags: Cisco, Cisco Press, interview, Wendell Odom |
In December, I posted a thread in the Announcement forum asking for you guys to submit any questions you may have for distinguished author and CCIE #1624, Wendell Odom. I sent your questions to Wendell in January and got a quick response but have been a bit slow getting this blog post together. Well, here it is. Enjoy!
Wendell, first off, thanks so very much for sitting down and taking time out of your busy schedule to answer our questions!
How do you feel about Cisco fragmenting their certification paths and seemingly making a certification discipline out of anything they can? Do you feel they’re playing a sort of “catch up” to quickly ratify the newest industry buzzwords in a certification?
Thank you!
| posted in Education, Training | |
| by Reggle on January 5th, 2012 | tags: beginner, CCENT, Tutorial |
If you’re new in the networking field and are faced with a complex network design, or are asked to design one, it can be a difficult task understanding what everything does. The certifications don’t cover it all: there’s so much more to networking than just routers and switches.
Therefor: an explanation about various appliances you’ll likely meet or need in a company. An appliance is a device that performs a specific purpose. Most simple example is a router: it’s actually a computer, but it can only provide routing. Here’s a list of other common devices:
| posted in Cisco Networking | |
| by Reggle on December 1st, 2011 | tags: Cisco, GNS3, OSPF |
The topology above is an example network, consisting of four OSPF areas (one backbone, area 0) and one external EIGRP area. I’ve set up an IP addressing scheme using 10.0.0.0/8 for OSPF and 172.16.0.0/12 for EIGRP. In case you didn’t notice, the second part of the IP address is the same as the area number (10.x.0.0 for area x).
| posted in General, Technical | |
| by ittech2010 on September 9th, 2011 | tags: Backup, CentOS, linux, RHEL, Rsync, Tutorial |
Just a quick blog about Rsync on A CentOS 5.6 box. I’m currently using Rsync to backup our Samba Server – all 500 Gigs of it!!
It’s going to take a few days but it will have an exact replica of the Samba server on the Rsync server and you don’t have to have any clients installed on other machines for Rsync to work. All you need is administrative credentials on the machine you are going to Rsync with.
Once I’ve figured all of this out, I will be setting my Rsync box to start backing up automatically every night (full backup) and also, when a file is changed on the Samba Server. I’m going to try and figure out the latter as I haven’t figured out how Rsync will be able to detect that a file has changed or been removed, etc. Once I have done so though I’m sure it’s going to be very handy, also I’ll be setting the Rsync box to backup all of the the user areas and profiles held on the DCs and also the users folder on the PCs.
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