Enterprise Networking

ISIS NET Statements

When configuring ISIS, under the router process, it mandatory to have a NET statement, for example: router (config) # router isis 1 router (config-isis) # net 49.0002.3131.3131.3131.00 So what is the NET statement and what do it’s segments mean? The Network Entity Title (NET) is an Network Service Acces Point (NSAP) address whose trailing byte…

BGP prefix suppression

BGP Prefix Suppression can relate to suppresion of routers learnt from a BGP neighbor, or routes adertised to a neighbor. For the latter, there is Selective Prefix Suppression, which explicitly lists the networks which should not be advertised along with a summary route to a neighbor. On IOS, you would use a suppress-map keyword with…

Ultimate Hop Popping & QoS

The default behaviour for MPLS routers is Penultimate Hop Popping.  The last hop router generates the implicit null to indicate that the penultimate router should pop the label.   However, if the network is configured for QoS based on MPLS EXP bits, then QoS is lost between penultimate router and last hop router. Therefore, in this…

DSCP Tunnelling Methods over MPLS

There are commonly defined 3 types of DiffServ tunnelling methods over MPLS:  the Pipe Model, Short Pipe Model and Uniform Model (QoS for IP MPLS Networks, Santiago Alvarez 2006). The Pipe model ensure that there are no changes to the DSCP marking through the Label Switched Path (LSP) – even if a Provider router remarks…

Dockerfiles

Docker, the container software, requires images to specify how a container is created. Dockerfiles are text documents named simply ‘dockerfile’, which when docker is run (with the ‘docker run’ or ‘docker build’ command) from within the directory which contains the file, creates the image the container is based upon. Every Docker image is made up…


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