Why should a Network Engineer move into an App Space
If you are a “pure” network engineer and still have a mortgage to pay, this post is probably for you!. Those who are preparing for CCIE voice or application firewall or F5 load balancer are on the right track. In short, SDN (Software defined network, aka SDN cat) products are already out of the bag […]
BIGDATA BUBBLE – Infinite Possibilities
If you live in Australia you probably have heard about the Mining Boom, so was the famous “DotCOM bubble” in way back in 199x . Recently, this new buzzword “BigData” in IT data mining space seems to be a new technology trend for many enterprises and Telco’s. They need bigdata to be implemented to solve […]
Five Features of Brocade VCS
Virtual Cluster Switching (VCS) is Brocade's brand of datacenter ethernet switching. VCS allows for the creation of a network fabric that's capable of converging storage and data traffic via standards-based datacenter bridging. It also solves the “Spanning Tree Protocol (STP) problem” by implementing a standards-based TRILL data plane paired with their own control plane in the form of Fabric Shortest Path First (FSPF). This data + control plane enable the “routing” of MAC addresses through the fabric, negates the need for STP, enables the use of all cabled links, and prevents traffic loops. VCS is only (currently) available on the VDX line of switches from Brocade.
In this post I'm going to outline five aspects of VCS that I found particularly interesting or unique. This is a companion article to an earlier one titled Five Functional Facts about FabricPath where I broke down five features of Cisco's fabric technology.
A Milestone Reached: CoDel is in Linux!
The CoDel AQM algorithm by Kathie Nichols and Van Jacobson provides us with an essential missing tool to control queues properly. This work is the culmination of their at three major attempts to solve the problems with AQM algorithms over the last 14 years.
Eric Dumazet wrote the codel queuing discipline (based on a quick prototype by Dave Täht, who spent the last year working 60 hour weeks on bufferbloat) which landed in net-next a week or two ago; yesterday, net-next was merged into the Linux mainline for inclusion in the next Linux release. Eric also implemented a fq_codel queuing discipline, combining fair queuing and CoDel (pronounced “coddle”), and it works very well. The CoDel implementation was dual licensed BSD/GPL to help the *BSD community. Eric and others have tested CoDel on 10G Ethernet interfaces; as expected, CoDel performance is good in what’s been tested to date.
Linux 3.5 will likely release in August. So it was less than a month from first access to the algorithm (which was formally published in the AQM Queue May 6) to Linux mainline; it should be about four total from availability of the algorithm to Linux release. Not bad at all :-).
Felix Fietkau Continue reading
Cisco CUBE v8.5 vs. v8.6 Features
Surprisingly, there is a lot of difference between these 2 CUBE versions. If you are an ITSP and providing SIP trunks to your customer. Make sure you choose the right IOS!! SR# FEATURE CUBE 8.5 CUBE 8.6 1. Support for Updating codecs dynamically X YES 2. Media DO-EO flow around X YES 3. High […]
CUCM and H323 GW: Inbound Calls OK but no Outbound Calls
Is there out anybody who doesn’t like playing with ‘BREAK-FIX” ? I have ran into this issue before but, it was a few year ago! I forgot what I did (I should have boggled it out) and it took me solid 5 hours to troubleshoot one this real world break fix! SCENARIO: PSTN—H323GW—CUCM—PHONESInbound call works […]
Double CCIE Now!
It was way back in 2008 when I passed My Voice LAB In 2011 , I passed my CCIE Security. More on voiceIE.com and SecurityIE.com ! Cheers, Push
Zone-Based Firewall-Part 1 of 2-Basic Configuration
Great 60 minute video on zone-based firewalls by Solarwinds. Instructor Anthony Sequeira walks us through a couple of constructs and demonstrates the configuration.
SDN for Internet Providers Use Case
In the bag of magic tricks that SDN has the potential to add as our networks get decomposed over the next few years is self provisioned provider edge nodes. Forget OpenFlow in this, as that is a wire protocol that is vital, but a small and important component of the bigger picture. OF is extremely […]...
What is a Fabric Extender
In this post I would like to cover the base of what is needed to know about the Cisco Fabric Extender that ships today as the Nexus 2000 series hardware. The Modular Switch The concept is easy to understand referencing existing knowledge. Everybody is familiar with the distributed switch architecture commonly called a modular switch: […]
OpenStack Essex and Quantum Installation using OpenvSwitch from Scratch
Here is a walkthrough for the Quantum Network Manager Plugin for OpenStack. It is still in dev so expect weird things and stability issues. For a guy with a networking bread and butter this is the extremely exciting piece of OpenStack for me. I will do a followup and try and breakdown the OpenvSwitch components […]...
The Next Nightmare is Coming
BitTorrent was NEVER the Performance Nightmare
BitTorrent is a lightning rod on two fronts: it is used to download large files, which the MPAA sees as a nightmare to their business model, and BitTorrent has been a performance nightmare to ISP’s and some users. Bram Cohen has taken infinite grief for BitTorrent over the years, when the end user performance problems are not his fault.
Nor is TCP the performance problem, as Bram Cohen recently flamed about TCP on his blog.
I blogged about this before but several key points seem to have been missed by most: BitTorrent was never the root cause of most of the network speed problems BitTorrent triggered when BitTorrent deployed. The broadband edge of the Internet was already broken when BitTorrent deployed, with vastly too much uncontrolled buffering, which we now call bufferbloat. As my demonstration video shows, even a single simple TCP file copy can cause horrifying speed loss in an overbuffered network. Speed != bandwidth, despite what the ISP’s marketing departments tell you.
But almost anything can induce bufferbloat suffering (filling bloated buffers) too: I can just as easily fill the buffers with UDP or other protocols as with TCP. So long as uncontrolled, single queue Continue reading
Troubleshooting Common OpenStack Errors
##############General Tips############## /*Check all services $nova-manage service list (check for XXX or smiley face) Binary Host Zone Status State Updated_At nova-scheduler openstack1 nova enabled :-) 2012-05-12 22:42:14 nova-compute openstack1 nova enabled :-) 2012-05-12 22:42:12 nova-network openstack1 nova enabled :-) 2012-05-12 22:42:14 $ ps -ea | grep nova 11448 ? 00:02:54 nova-cert 12072 ? 00:02:57 nova-network […]...
Cisco UCS B440 Blade Replacement
Cisco announced recently a replacement program for their B440 blades (M1 and M2) http://www.cisco.com/en/US/ts/fn/634/fn63430.html Something I noticed on the front of each blade, where the model is shown, the new generation blades (replacements) have the black background with the silver text, shown as the top blade on the picture below: However, the old blades still have the black text with no background. An interesting way to identify the newer generation of hardware.Cisco UCS B440 Blade Replacement
Cisco announced recently a replacement program for their B440 blades (M1 and M2) http://www.cisco.com/en/US/ts/fn/634/fn63430.html Something I noticed on the front of each blade, where the model is shown, the new generation blades (replacements) have the black background with the silver text, shown as the top blade on the picture below: However, the old blades still have the black text with no background. An interesting way to identify the newer generation of hardware.N5K Stuck in Boot Mode
Another trivial post. The upcoming posts following this one will take a more in-depth look at the Nexus technologies. So you do an non-ISSU NX-OS upgrade on a Nexus 5000 switch and something goes wrong. After reload you get the following prompt: The switch did not successfully boot from the images it was suppose to. […]
OpenBSD 5.1 SNMP MIBs
It's May and that means a new version of OpenBSD is out. My SNMP MIBs have been updated for 5.1 and are available for download on the OpenBSD SNMP MIBs page. THIS WILL BE ONE OF THE LAST RELEASES OF THE MIBS FOR NET-SNMP During the OpenBSD 5.1 development cycle, I committed the CARP MIB to the base OpenBSD snmpd. The kernel sensor MIB has been in the base snmpd for a few releases now.Management VLAN Best Practices in ESXi and Cisco UCS
If you’ve set up an ESXi host, you’ve likely seen this screen: This allows you to configure which VLAN is used for management. But what does this really do? Time after time I run into very smart engineers that primarily work on virtualization and not as much on the physical networking side - and they miss a few of the networking fundamentals that those of us that were brought up in ROUTE/SWITCH know and love.Management VLAN Best Practices in ESXi and Cisco UCS
If you’ve set up an ESXi host, you’ve likely seen this screen: This allows you to configure which VLAN is used for management. But what does this really do? Time after time I run into very smart engineers that primarily work on virtualization and not as much on the physical networking side - and they miss a few of the networking fundamentals that those of us that were brought up in ROUTE/SWITCH know and love.Who? What? When? Wired? Wireless? With Cisco ISE
Cisco's Identity Services Engine (ISE) is a powerful rule-based engine for enabling policy-based network access to users and devices. ISE allows policy enforcement around the Who?, What?, and When? of network access.
- Who is this user? A guest? An internal user? A member of the Finance department?
- What device is the user bringing onto the network? A corporate PC? A Mac? A mobile device?
- When are they connecting? Are they connecting to the secure network during regular business hours or at 02:00 in the morning?
These questions can all be answered easily within ISE and are all standard policy conditions that are relatively easy to implement. In the post below I'm going to focus on the How? — How is the user or device connecting to the network? Asked another way, the question is Wired? or Wireless?