Wednesday, August 15, 2007

Does Qwest still do Cold-Potato Routing?

This is somewhat of a rhetorical question, but I do question it. Qwest has always (AFAIK) advertised and bragged about this feature with their DIA services.

First, some may be wondering, what the heck is Cold-Potato Routing? The best explanation may be that it is the opposite of Hot-Potato routing in which an ISP will hand off it packets to a peer or downstream ISP as soon as possible to get it off of their system. So, in Cold-Potato routing, the well intentioned ISP will hold onto the traffic and haul it across a geographic region as far as possible before handing it over to the downstream provider. This provides a best end-to-end quality of service for the ISP customers, assuming the ISP has the backbone to handle it.

The reason I question weather Qwest is still providing Cold-potato routing is that if I trace routes from my Los Angeles based POP (Qwest provided) to my co-lo in Chicago, IL the traffic gets handed off in Los Angeles to Level 3. net. Level3 then hauls it across the country to it's Chicago facility. Now, I know that Qwest has a big OC-192 backbone direct from their Burbank, CA TeraPOP direct to Chicago, IL TeraPOP. So, what the heck? Can anyone shine some light on this issue?

Firefox memory leak revisited

I recently wrote about Firefox 2 becoming a pig, meaning that it consumes huge amounts of memory and slows down. This of course is a memory leak as expected. During the course of research of the problem I have discovered a couple of things that are short term work arounds.
  1. Restart Firefox every day. It consumes memory over time (NSS!) so by restarting it, the memory will be released
  2. uninstall any add-ons (extensions) that you don't use.
  3. Uninstall extra themes
  4. Run Firefox in Safe Mode
  5. Keep unused browser tabs closed
I found this list of known problematic extensions that you should check out to make sure you are not running them:

There are claims that the extensions (especially the problematic ones) are causing the memory leaks. However, I only run about 4 lightweight extensions that I keep updated and only the default Firefox theme and I still have the memory leak problem. In fact, today Firefox on my desktop is comsuming over 163mb after restarting it about 18 hours ago. Guess it's about time for another restart.

Come On Mozilla Foundation! Get this fixed or I fear that many will resort back to IE. Oh the guilt...

Thursday, August 9, 2007

Check Your Network Switch Speed Negotiation

In dealing with a recent bandwidth issue, we discovered that it was a speed negotiation issue between a Cisco 3845 router and a Cisco PIX Firewall. You would think that these two interfaces would do a better job of speed negotiation. There were no errors recorded on either side but we experienced horrible throughput... like 500kpbs. The issue was resolved by setting both sides to AUTO and reset the interfaces.

I have had many issues in the past with Cisco interfaces to other manufacturer interfaces (Netgear and Linksys to name a couple). They don't do auto negotiate well, so I have learned to fix the Cisco interface to the max speed of the other side. But, in the case of Cisco to Cisco, it seems that AUTO is the best choice... at least in this case.

The moral to the story is that when troubleshooting bandwidth issues, alway check your speed setting settings on interfaces... even when no errors are recorded.