Choosing firmware for Draytek ADSL Routers

I recently stumbled upon the firmware page for the Draytek DV120 after having an issue with stable connectivity – http://www.draytek.com.au/downloads.php?type=Vigor120. The manufacturer makes available 10 varieties of the same version of firmware with no guidance as to how we should be choosing firmware for Draytek ADSL Routers.

After contacting various suppliers of Draytek worldwide and discussions with Telco’s in New Zealand I’ve found that two main chipset DSLAMs exist at the moment. Broadcomm chipset based DSLAMs are used in older installations and the Ikanos chipset isused in the dual personality A/VDSL DSLAMs within Chorus cabinets.

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Cisco CCIE Lab in Sydney

My first attempt at passing the Cisco CCIE Lab in Sydney (Routing and Switching) last week was unsuccessful. By the time I had completed the Troubleshooting section at the start of the exam I knew I hadn’t achieved the objectives of 3 of my troubleshooting questions, with the number of points I missed putting me below the 80% requred for that section. Nevertheless I persisted with the Configuration section and thought I’d share my experience of the exam and the format of the day. Knowing how the day is structured and what to expect will definetly help me in my next attempt.

I’m giving myself 6 months of revision and then I’ll hit the exam again.

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Extreme Switches and Microsoft Multicast NLB

Extreme Switches and Microsoft Multicast NLB

I’ve recently been troubleshooting an issue with Extreme Switches and Microsoft Multicast NLB. The Extreme switches (along with many other major Layer 3 switch vendors – Cisco, Juniper etc) have the issue that they break the NLB’s ability to mask the MAC address in use.

When you use Extreme Switches and Microsoft Multicast NLB, each cluster host retains the original MAC address of the adapter. In addition to the original MAC address of the adapter, the adapter is assigned a multicast MAC address, which is shared by all cluster hosts. The incoming client requests are sent to all cluster hosts by using the multicast MAC address. From what I could see on the Extreme switches the Multicast MAC never entered the FDB table.

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