Friday, May 15, 2015

Australia-US project achieves SDN routing breakthrough

Image result for sdn 
Software-defined networking reaches internet scale.

The Australian Academic Research Network (AARNet) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) have demonstrated internet-scale software-defined network routing to the United States, using open source components.

Using a high throughput programmable Corsa OpenFlow DP6410 data plane, the Australian institutions set up a production SDN-based peering router with a switch deployed in AARNet's data centre in Haymarket, Sydney, and an Open Network Operating System (ONOS) application 15km away in Marsfield.

The Australian side has been peering for a month with the Vandervecken SDN router at the US Department of Energy's research Energy Sciences Network (ESnet) situated at the University of California, Berkeley, over a trans-pacific connection.


Read more: http://www.itnews.com.au/News/403686,australia-us-project-achieves-sdn-routing-breakthrough.aspx#ixzz3ZhWwzMUN



Tuesday, May 12, 2015

Random Cisco based networking questions - CCNA - Part 6

 Here's another half a dozen random networking questions to get the grey matter ticking :-)



1. Which switching mode is the most likely to forward frames containing errors?

A) FIFO
B) Modified Cut-Through
C) Store-and-Forward
D) Cut-Through
E) Fragment-Free


2. Where would you place standard access lists?

A) As close to the destination as possible
B) As close to the source as possible


3. Frame tagging is used to identify...

A) The intended recipient of a frame
B) The IP address of the frame
C) The source of the frame
D) The VLAN ID of the frame
E) The trunking method


4. When each network segment uses a different subnet mask this is referred to as...

A) Classful routing
B) Classless routing


5. A CIDR value of /12 equates to what subnet mask?

A) 255.0.0.0
B) 255.128.0.0
C) 255.192.0.0
D) 255.224.0.0
E) 255.240.0.0


6. How would you copy the IOS to a TFTP server?

A) Router(config)#copy ram tftp
B) Router(config)#copy tftp flash
C) Router#copy flash tftp
D) Router#copy tftp flash
E) None of the above





1.  Answer D 

Cut-Through switching is also referred to as Fast Forward.

When in cut-through mode the switch waits for the destination MAC Address to be received. Once the MAC Address is known the switch refers to its MAC filter table to determine which port the frame should be forwarded out. The switch forwards the frame even before the entire frame has arrived.

Frames with and without errors are forwarded in cut-through switching, leaving the error detection of the frame to the intended recipient.


2. Answer A

Standard access lists only filter based on source address so they have to be placed as close to the destination as possible.


3. Answer D

Frame tagging is used to tags frames on trunked links to identify what VLAN they belong to.

http://en.wikipedia.org/wiki/Virtual_LAN#Protocols_and_design


4. Answer B

http://en.wikipedia.org/wiki/Classful_network

5. Answer E

http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#Assignment_of_CIDR_blocks

6. Answer C

It is a good practice to backup your existing system image to the TFTP server using the copy flash tftp command.  I personally use Pumpkin or Solarwinds TFTP servers, but there are may other types around.




 Stay tuned for more updates, and let me know if you find these useful or any errors 

Please share around if you find these questions of value.

   “Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for.”
? Socrates