A little over a week ago I took and passed the 640-911: Introducing Cisco Data Center Networking DCICN by Cisco. I had a month to study and achieve this as my CCNA Routing and Switching was set to expire.
After much discussion and thought, I felt the CCNA Data Center was more relevant to the job I currently do. I can confirm once passed the 640-911 does extend the life of the CCNA Routing and Switching by a further 3 years.
This morning I took and passed the Cisco ICND2 on the second attempt. I felt it was a little harder than ICND1 and in some ways I was a little unprepared the first time due to changing jobs / Open University commitments. Having previously done the course via the Open University a few years ago and got a little complacent, despite the blog posts.
Any tips for taking the exam? read the question and re-read. I think i made this mistake on the first attempt, though I doubt that would’ve made much of a difference, however it could make the difference between a pass and a fail.
DCLI’s are local – layer 2 addressing. Not advertised to other routers
Permanent virtual circuit (PVC) – Dedicated circuit always up
Switched virtual circuit (SVC) – Temporary circuit that is only up for example during a data transfer session
Three LMI types cisoc, ansi and q933a
Local Management Interface (LMI) – passes information about the status of the circuit. Must match on the DCE (Provider) and DTE end
non-broadcast multi-access (NBMA) – broadcasts are not sent over frame-relay by default
inverse ARP – Used to allow dynamic mapping. On by default can be turned off using no frame-relay inverse-arp
Split horizon – Stops rouging updates such as RIP from being sent out of the same interface it was received on. Turning off split horizon may cause routing loops
Sub-interfaces can overcome the split horizon by creating sub interfaces out of a serial interface. This gets around the problem of a routing update being sent and received out of the same interface. Sub-interfaces can either be point-to-point or multipoint
show frame-relay map – Table of frame maps, shows dlci and lmi information
show frame-relay lmi – Shows configured LMI type, if timeouts occur and increase could indiciate a lmi mis-match
show frame-relay pvc – Shows BECN and FECN information