Cisco Nexus 7K – Secret decoder ring
Back when I first starting using the 7K’s I thought the naming of the line cards followed the same logical naming scheme of all other Cisco equipment (by that I mean there is no logic to it at all!). It was when I was watching one of this years Cisco Live presentations on the 7K architecture that it all became a lot clearer. So without further ado here is how to use the magical Nexus 7K linecard decoder ring: N7K-M224XP-23L N7K – Signifies that the card is for a Nexus…
CCIE Update and plaque
So this week my CCIE package arrived along with this little beauty. I had no idea these things weighed so much, mind you I suppose for $1500 its what you should expect I’m currently on with studying for the SP, all good so far as a lot of it is very familiar due to my day job but there are still a fair few new things to learn before I make an attempt. Perhaps try and make a lab attempt by the end of the year? I guess we will…
Service Provider – Half-Duplex VPN’s
The other day whilst reading up on some SP topics I came across a rarely used function available on some higher end Cisco models called half duplex VRF’s (or HD VRF’s in some places).
I know it is quite a common thing to see in service provider topologies where you have a radius / virtual-template driven platform such as a DSL LNS etc but up until now I wasn’t aware that it can also be used on other platforms on regular (non virtual) interfaces.
For the demo topology I am going to use a faily simple network of three 7200′s in GNS3. According to the Cisco documentation here this feature has been around since 12.4(20)T or 12.2(33)SRC for the SR train.
In the topolgy I am using R1 and R2 to emulate customer sites which will be a member of the same VRF on R3 which will play the role of our PE.
Cisco kills of first gen ASA’s
So yesterday Cisco announced that it has EoL’d some (most) of the first generation ASA series of firewall.
It’s not really a surprise given that last year they released what I will call the second generation of ASA’s and pretty much all aspects they wiped the floor with the first generation.
Cisco RIB operations – AD comparisons
A post over at the IEOC forums got me thinking to something I picked up a long time ago but I can’t really remember where…
When a prefix arrives at a device from two different sources the AD is compared and the lower AD wins out, simple CCNA level stuff right? Well what if the AD is the same due to AD manipulation?
DHCP and conflict logging
DHCP is something that is kind of overlooked sometimes and is treat as a given. There was a recent DHCP issue at a customer site and I wanted to clarify my thoughts on what happened behind the scenes but I can’t say I have ever actually checked and proved that the conflict process works in the way I expected. When a fresh DHCP client first goes live on the network it carries out a pretty standard ‘handshake’ of: DHCPDISCOVER – This is broadcasted on the local LAN with a request…
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