A label is removed on the router before the last hop within an MPLS domain. PHP optimises MPLS performance (one less LFIB lookup) PHP does not work on ATM (Virtual Path Identifiers/virtual channel identifies cannot be removed) The pop or implicit null label uses a reserved value when being …

OK, so having known about MPLS for a few years and actually get a provided service in my work environment as well as the fact it is on the CCIE R&S blueprint I thought I should get a much better understanding of how it works and the various terminology’s. My notes so far; The benifits of MPLS; …

Root Guard is a mechanism that allows the administrator to control where candidate root bridges can be connected to the network, it will basically prevent the wrong switch (say a random one just added) from becoming the root bridge. If a Rood guard port receives a BPDU that might cause the sender to …

The following tables is the CCIE R&S Blueprint, it is a combination of DOC-4375 and DOC-6864. [table id=15 /]

Unidirectional Link Detection (UDLD) is a Cisco proprietary extension that lives to detect miss-configured and broken links between Cisco switches. It verifies that they can both send and receive data on a point-to-point link. This can be used to assist spanning-tree and compliments things like …

So I have started looking at CCIE study and have been looking around to see what books and useful material exists out there. To begin with this list may be a little messy.I look to have been very lucky in that a number of these books (and more) my Dad actually got for me while he was working for …

To prevent loops that might develop if a port that should be blocking transitions to the forwarding state we have loop guard. This could happen if a port stops receiving BPDUs, maybe due to a unidirectional (on point-to-point) link or software/configuration problem on the neighbour. The following …

The IEEE (Institute of Electrical and Electronics Engineers) is a group that produced standards in many fields and industries. The mission statement; IEEE’s core purpose is to foster technological innovation and excellence for the benefit of humanity. The vision statement; IEEE will be essential to …

I have been using IOS for years but it would appear that a number of useful shortcuts fail to stick in my mind or did not know. As a result I thought I would note some of them so I have a quick lookup page. I am sure that this list will grow over time as I lab more and more and therefore am more …

As people have become more security concious with the transfer of data, in particular on the Enterprise/Corporate environments security teams are tightening down more and more on the use of insecure protocols. As a result the old favourites of TFTP/FTP etc are being removed. A number of replacements …