All-electric sedan in Tucson Jan. 4

The plug-in, all-electric Nissan Leaf will make its first public appearance in Tucson Jan. 4, said Colleen Crowninshield, Clean Cities program manager at Pima Association of Governments.

Tucson is one of several U.S. cities chosen for the test marketing of the joint Renault-Nissan all-electric vehicle. The car is expected to go into production later in 2010 and be available for sale in the test markets in 2011.

Tucson is also one of several cities on the Nissan Leaf national introduction tour. No specific Tucson site for the introduction has been chosen yet, she said.

Crowninshield said she saw the car coming to Tucson at its national rollout at Dodger Stadium in Los Angeles last week. She said it's a preproduction version of the Leaf and won't be available for test drives. For demonstration purposes Nissan has installed the all-electric drivetrain in a Nissan Versa, a comparable-sized model normally powered by a gas engine.

In a related development, Crowninshield said two Bookmans Entertainment Exchange stores — 1930 E. Grant Road and 3733 W. Ina Road — will install electric car-charging stations.

She said Bookmans management is supportive of electric vehicles — the Grant Road store had a charging station for the all-electric GM EV-1 in the 1990s — and decided to foot the entire bill for the charging stations rather than wait for the federal stimulus package's electric car charging infrastructure funding, which won't be available until early 2010.

Tucson qualified for a share of a $100 million charging infrastructure funding package that will be used to install public charging stations throughout the Tucson area. source

Comcast Internet throttling is up and running

COMCAST, the second-largest US cable television and Internet communications service provider, has a new broadband traffic throttling scheme installed and operating in all of its markets.

The ISP's new regime for restricting its customers' bandwidth utilisation replaces its former stealthy practice of arbitrarily blocking subscribers' peer-to-peer (P2P) upload traffic, which was criticised by the FCC last year after it was exposed by the Associated Press and others.

Comcast's filing with FCC (PDF) says it has put in new hardware and software technology at its Regional Network Routers locations to effect this cunning traffic management plan.

Its network throttling implements a two-tier packet queueing system at the routers, driven by two trigger conditions.

Comcast's first traffic throttling trigger is tripped by using more than 70 per cent of your maximum downstream or upstream bandwidth for more than 15 minutes.

Its second traffic throttling trigger is tripped when the Cable Modem Termination System you're hooked-up to – along with up to 15,000 other Comcast subscribers – gets congested, and your traffic is somehow identified as being responsible.

Tripping either of Comcast's high bandwidth usage rate triggers results in throttling for at least 15 minutes, or until your average bandwidth utilisation rate drops below 50 per cent for 15 minutes.

The Comcast two-tier traffic throttling system enforces different quality-of-service levels. Internet packets to and from a specific subscriber are assigned 'Priority Best Effort' (PBE) queueing by default, and the traffic rate is throttled by switching packets to lower priority 'Best Effort' (BE) queueing.

Comcast uses a bus analogy to explain how its two-tier traffic throttling system works:

"If there is no congestion, packets from a user in a BE state should have little trouble getting on the bus when they arrive at the bus stop. If, on the other hand, there is congestion in a particular instance, the bus may become filled by packets in a PBE state before any BE packets can get on. In that situation, the BE packets would have to wait for the next bus that is not filled by PBE packets."

According to the company, upstream and downstream traffic is managed separately, and its router packet queueing increments - the waiting time between each 'bus' in its analogy - are two milliseconds, or 1/500th of a second.

Comcast says that a throttled subscriber's connection that is forced into the lower BE quality of service queue "may or may not result in the user's traffic being delayed or, in extreme cases, dropped before PBE traffic is dropped."

Thus, Comcast's latest traffic throttling method can lead to transfers being blocked, too. But only in 'extreme cases' it says, so that's alright then.

Comcast has also imposed a monthly 250GB bandwidth usage cap on all of its customers, and it will, after one warning, terminate service for one year to those who exceed that cap twice within a six-month period.

So you punters who signed up with Comcast as your ISP can be assured that the company will deliver only about half of the maximum bandwidth it advertises, on a consistent basis. source