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I came across the OSPF subcommand 'Sham-link' when studying for my CCNP Route exam, and was curious as to what it was. The OSPF sham link provides a logical link between two VRFs. It creates a link that makes the MPLS PE’s participating in the sham link appear as a point to point link within OSPF. These links are able…

NOC to Network Engineering Working in a NOC styled position is what I was used to for the previous 2 years, as well as 2 years on a help desk. A Network call/ticket comes in, I solve said issue either on the phone or shortly after, and it's done. Quick and simple. This is not the case with Engineering. I…

Layer 2 Etherchannels, like any protocol, have their pro's and con's. Using layer 2 extends Spanning Tree Protocol (STP) over the Etherchannel, which can have adverse effects if you're not careful. Take for example the following topology crudely drawn in paint. SW1 is the STP  root bridge because it has the lowest bridge ID priority, so ports fa0/1 - 3 are designated…

Whilst the CCNA Security exam recommends disabling CDP in the production environment, I felt it didn't really explain in depth why it's a good idea. I mean sure, they mention that information about the device is leaked, but what information exactly is leaked? I ran a wireshark capture to find out!     I think the above screenshot of the CDP message explains it…