Cisco customers can update their licenses using this handy portal. Sounds good ? Exciting ? No, not the person who bought the software license, the partner that sold you the license can update the licenses. You might have forgotten who is Cisco’s real customer, and it’s not the person who paid for products. Partners, the [...]
Martin sent me an email about packet capture tool for IOU that he wrote. I haven’t tested it because I’m short on time right now so let me know what your experiences are: Some of you might already know IOU, it’s Cisco IOS compiled on Unix. It allows emulating routers and switches. One IOU process [...]
I was going to call this article “Ethernet Switches for Virtualisation Engineers” but, really, everyone should have some understanding of the internals of an Ethernet switch. But particularly I want to focus on how multicast and broadcasts are handled in a high speed, low latency environment like a Data Centre Network.
It’s vital to understand that latency is critical to your application performance. It is common for a single transaction to take hundreds of round trips so a small increase in latency on each round trip has a large impact on the perceived performance. The client will send a chunk of data and wait for acknowledgement. Even setting up the TCP connection takes a few round trip – remember that TCP sessions are setup, and each data transfer is confirmed.
A modern network switch will have latency around 10 microseconds. The Cisco Nexus 7000 is about 8 microseconds & Brocade VDX 8770 claims less than 4 microseconds. There are many reasons why a switch can be faster or slower but I’ll look at a specific example
Remember, the latency interval is the time taken to receive a packet, decode the address, lookup the forwarding table, switch the packet (and copy it if needed) and transmit out of an Ethernet interface. That’s really fast processing. How does an Ethernet switch do this ?
I’m regularly asked the question: What privileges or special access does Cisco give to people when they pass the CCIE™exam ?
Short answer: None. Nada. Nothing. Zip. Zero.
Read on for the “Longer Answer”
I’ve been thinking about the security issues of working with Huawei equipment and Huawei the company. I’ve spoken with a number of people who, off the record, talk of working with Huawei as customers and their experiences of the product have been less than excellent but the price is low. What I’ve realised is concerning. [...]
Was reading through some documentation as noticed that the Nexus 5500 series has some unusual behaviours for Store and Forward. I made myself notes about the functional modes. Cut-Through vs Store and Forward In cut-through mode of operation a switch will start transmitting a frame before the frame has been completely received and this is the [...]
Cisco recently bought vCider. vCider gives Cisco tools for cloud bursting and a proven network driver to deliver overlay networks. It’s a significant boost to their Programmable Networks strategy and definitely an SDN play.
The vCider technology was architecturally similar to Nicira by building tunnels overlays in a network and, in my view, many people are incorrectly misinterpreting this as the core value on the acquisition.
I would posit that there are two aspects to vCider that Cisco is likely to extract value from. 1 – Network driver in Linux. 2 – Cloud burst networking
Check this out. An entire webinar devoted to licensing of just a single product from Cisco. Obviously, Cisco licensing of UCM is now so complicated and involved that there “Subject Matter Experts” dedicated to handling your queries about licensing upgrades. Not the product itself mind you, or the great new features, or planning your migration process. [...]
One thing that Cisco doesn’t do well is close down products that are close to the core of the business. If you are going to quit making a product then simply say that. “Go big or go home” is a popular American saying. These partial death notices are bad for my business and I’m losing [...]
Cisco Nexus 1000 has been a platform since it was launched, at least, that’s what I’ve always thought. Lately, Cisco has talked extensively about vPath 2.0 offering a multiservice data plane (great podcast with Cisco on vPath 2.0 at Packet Pushers) for service delivery on VMware hypervisors. And sometime NX1K will likely be on Openvswitch [...]