Several of my peers at PB NAP are reporting significant loss (>10%) over
the
PB NAP. All are OC3 connected, and it seems that PB doesn't have the ability to look too closely at OC3 connections.
Death of the 'net predicted: film at 11.
So, does this mean that ATM NAPs also have problems with high traffic load?
-- Dave Rand dlr@bungi.com http://www.bungi.com
I wouldn't jump to conclusions. Not likely that the ATM switches are backplane loaded like the MAEs. These are Stratacom BPXs that replaced the Newbridge 36150s over three years ago. High bandwidth-delay product paths on a heavily loaded OC-3 to OC-3 virtual circuit will strain the ATM switch buffers. If you can detect regularly recurring losses on a high BDP path across an all-OC3 virtual circuit, then look for buffer exhaustion on the OC3 interfaces. If no one at Pac Bell knows what to do, tell them to look in the files in Fred Chang's Network Engineering Group for Kent England's ATM NAP switch test plan and go out and get some test gear that will stress an OC3 link in the lab. Mike Rudik in the lab knows what to do to test for this. But my recollection was that the BPX had enough buffers to run UBR over a full OC3. If the loss is on DS3-OC3 virtual circuits then perhaps you are pushing more than 45 Mbps toward the DS3. There might be a Kentrox ADSU or two left on the NAP that could have trouble with the cisco OC3 interface at much less than 45 Mbps. If the cisco OC3 interfaces haven't been thoroughly shaken down, you might look there for things like buffer exhaustion. If the ciscos are losing, my test plan should show that effect if the ciscos are included in the test path. If no one at PacBell seems interested in the problem, you can talk to the Texans who run the place now. I can give you some names to call in Richardson, Texas but I wouldn't hold my breath. If you happen to be a Texan, then you can probably get something to happen, but if you are an avocado-sucking Hawaiian-shirt-wearing ears-pierced laid-back California dude, then you won't get far with the prime-rib-for-lunch crowd. ;-) --Kent