Archive

Category Archives for "Networking"

Review: Remote Desktop Connection Manager

It’s been a while since I’ve done a review of anything on the site and since I’d rather continue to make use of the category than delete it, I decided to share a piece of software I recently discovered that’s helping make my life easier. Remote Desktop Connection Manager is essentially just that - it manages remote desktop connections. However, it does it in a way that I find appealing and EASIER to use than the native client or other organizational methods out there.

Load-Sharing across ASICs

Port-channels have become an acceptable solution in data centers to both mitigate STP footprints and extend physical interface limits. One of the biggest drawbacks with port-channels is the single point of failure. Scenario 1- Failure of an ASIC on one switch, which could potentially bring the port-channel down, if all member interfaces were connected on […]

My Cisco Live 2012 program

My Cisco Live 2012 program is below. I was able to select most of the sessions although there were some overlap with one session (something ARC overlapping with another ARC). You might note that the closing keynote is by the guys who play Mythbusters on TV - that'll most likely be a fun filled event! I'll blog about my pre-event feelings if I have the time and interest ;-)



Windows Server 2008 R2 Boot From SAN on Cisco UCS

For those that have worked with any type of blade server system, you know that boot from SAN is just about the coolest thing since sliced bread. Cisco UCS makes this even cooler by integrating with the service profile concept, allowing for stateless compute provisioning across the board. I’ve done boot from SAN many times, but never with Windows. I’ve primarily used ESXi4.1 or ESXi5.0 stored on a Fibre Channel LUN, then the VMs are stored in either a FC or NFS datastore.

Windows Server 2008 R2 Boot From SAN on Cisco UCS

For those that have worked with any type of blade server system, you know that boot from SAN is just about the coolest thing since sliced bread. Cisco UCS makes this even cooler by integrating with the service profile concept, allowing for stateless compute provisioning across the board. I’ve done boot from SAN many times, but never with Windows. I’ve primarily used ESXi4.1 or ESXi5.0 stored on a Fibre Channel LUN, then the VMs are stored in either a FC or NFS datastore.

A Quick and Dirty Netapp SnapMirror

Snapmirror is a Netapp feature that’s pretty commonly used to copy data from one system to another. You can copy volumes, or qtrees. It’s also very useful in Disaster Recovery plans, since volumes can be incrementally backed up to an offsite location. I have a VMWare vCenter instance running on Cisco UCS that utilizes a Fibre Channel LUN to store VM templates. It’s pretty large, since it holds templates for a variety of operating systems.

A Quick and Dirty Netapp SnapMirror

Snapmirror is a Netapp feature that’s pretty commonly used to copy data from one system to another. You can copy volumes, or qtrees. It’s also very useful in Disaster Recovery plans, since volumes can be incrementally backed up to an offsite location. I have a VMWare vCenter instance running on Cisco UCS that utilizes a Fibre Channel LUN to store VM templates. It’s pretty large, since it holds templates for a variety of operating systems.

Cisco UCS Firmware Upgrade Explorations

I’m currently working with a relatively large Cisco UCS installation. Initially, the system was installed and brought up to relatively recent levels of firmware, but a mismatch in the way that the firmware packages were set up in various sub-organizations on some of the UCS systems caused some of the blades to retain the old version of firmware on the M81KR adapters and the CIMC controllers. Due to the scope of the installation, I wanted to ensure that the blades were able to continue operating while I made my changes.

KICLet: Cisco UCS Socket Connect Error

I recently observed some strange behavior with Cisco UCS Manager. When I visited the web page that allows me to download the .jnlp file that launches UCSM, it came up just fine. But when I clicked on “Launch UCS Manager” to actually launch this applet, the splash screen showed briefly, but disappeared after a few seconds, never to be seen again. Eventually, you might also see some java error messages that say something like

KICLet: Cisco UCS Socket Connect Error

I recently observed some strange behavior with Cisco UCS Manager. When I visited the web page that allows me to download the .jnlp file that launches UCSM, it came up just fine. But when I clicked on “Launch UCS Manager” to actually launch this applet, the splash screen showed briefly, but disappeared after a few seconds, never to be seen again. Eventually, you might also see some java error messages that say something like

Cisco UCS Firmware Upgrade Explorations

I’m currently working with a relatively large Cisco UCS installation. Initially, the system was installed and brought up to relatively recent levels of firmware, but a mismatch in the way that the firmware packages were set up in various sub-organizations on some of the UCS systems caused some of the blades to retain the old version of firmware on the M81KR adapters and the CIMC controllers. Due to the scope of the installation, I wanted to ensure that the blades were able to continue operating while I made my changes.

Fabric stats: OP script for Mx platform

My previous post has presented an hidden command for analysing in real time fabric statistics. I've developed a small op script, for the MX platform, that provides in one command the PFE/Fabric IN/OUT statistics for all the Fabric Planes (0 to 5) for...

Fabric stats: OP script for Mx platform

My previous post has presented an hidden command for analysing in real time fabric statistics. I've developed a small op script, for the MX platform, that provides in one command the PFE/Fabric IN/OUT statistics for all the Fabric Planes (0 to 5) for...

Five Functional Facts about FabricPath

FabricPath is Cisco's proprietary, TRILL-based technology for encapsulating Ethernet frames across a routed network. Its goal is to combine the best aspects of a Layer 2 network with the best aspects of a Layer 3 network.

  • Layer 2 plug and play characteristics
  • Layer 2 adjacency between devices
  • Layer 3 routing and path selection
  • Layer 3 scalability
  • Layer 3 fast convergence
  • Layer 3 Time To Live field to drop looping packets
  • Layer 3 failure domain isolation

An article on FabricPath could go into a lot of detail and be many pages long but I'm going to concentrate on five facts that I found particularly interesting as I've learned more about FabricPath.

How does Openflow, SDN help Virtualization/Cloud (Part 2 of 3)

Using Openflow – state of the ART

In my last article I discussed the components of Openflow and building blocks of a Software Defined Network. In this part, let me discuss some of the things people are doing to make it all work. One of the pieces that needs to be discussed beforehand is the various ways in which a packet can be matched against a flow and what kind of actions can be taken.

Flow Classification and the split between Hardware and Software

A flow is a simple mechanism to identify a group of packets on the wire. So a packets coming from a particular machine can be identified by the machines MAC or IP addresses which appears as source MAC in L2 header or source IP in L3 header. By putting a flow rule around either of those fields and just counting the packets going through the switch that hit that rule, we can determine the number of packets being sent by the machine. Its useful information. To make it more useful, one could add another flow to measure the packets going to our target machine. Adding a destination MAC or destination IP rule based on the machines Continue reading

BRAS on Juniper MX

One of the latest features on the Juniper MX-series devices is the BRAS functionality. The first functionality (automatically configuring interfaces) has been available since a long time, but most BRAS features have been introduced last year in JUNOS 11.x releases. With JUNOS 11.4 (also a Long-Term-Support release) the features matured as all major components are now available and (fingers crossed) stable.

This functionality can be named in different ways. BRAS or Broadband Remote Access Server is the most common name. Other names are Broadband Network Gateway (BNG) or Broadband Service Router (BSR).

This functionality is used in Internet Service Provider environments usually where DSL or Cable is used as the last mile access.

The following drawing demonstrates how the end-to-end path looks and where a BRAS/BSR is placed.

The CPE (DSL/Cable modem) is connected to the Multi-Service Access Node (MSAN), this MSAN is either a DSLAM in case of DSL networks or a CMTS in case of Cable networks. The DSLAM and CMTS devices convert the signal to Ethernet (or any other transport) and forward it to the rest of the network. This connection is then terminated on a BRAS device before it enters the rest of the Continue reading

Vital Gadgets for a Datacenter Network Engineer

I would like to share some tips regarding gadgets that I believe every Datacenter Network Engineer should have with them. There are several, but I want to bring up my top two.ß Travel Router I am often in situations where it is either difficult or impossible to manage Nexus switches and/or UCS remotely. Pick your reasons - sometimes the management network doesn’t exist (yet) or there are heavy security measures in place that restrict wired management, whatever.

Vital Gadgets for a Datacenter Network Engineer

I would like to share some tips regarding gadgets that I believe every Datacenter Network Engineer should have with them. There are several, but I want to bring up my top two.ß Travel Router I am often in situations where it is either difficult or impossible to manage Nexus switches and/or UCS remotely. Pick your reasons - sometimes the management network doesn’t exist (yet) or there are heavy security measures in place that restrict wired management, whatever.

Fabric Stats

Small tips for analyse the fabric stats. I mean packets stats (IN/OUT/Drops) between each PFE and the Fabric. Usually fabric stats can be observe by using the following cli command. Remember, that there are only 2 streams at fabric level: High and Low...