Code: Rich | [This space left intentionally blank.]

Dec/16

17

Hacked By By XwoLfTn

Hacked By XwoLfTn

Long life for Tunisia 
long life to Palestine

./Exit

 

No tags

Hello world!

No tags

Sep/16

14

ISP Traffic Prioritization

This was originally posted as a Slashdot comment. It discusses the idea of prioritizing traffic in an ISP environment, ideally using markings generated by the customers.

I do network engineering at an ISP. We are small, though I have discussed these things with my peers at larger networks. cialis pills 10 mg

Once you scale above a very small network (like your home connection), allowing congestion isn’t really okay in practice, even with QoS. When I say it’s not “okay” here, I’m speaking purely technically. cialis 5 generico

It might be possible to let networks congest somewhat if you had a large amount of elastic traffic that you could reliably identify. Netflix, for example, could meet these criteria. But that’s not okay politically; that’s an example of why net neutrality is good!

QoS in carrier networks is only useful for priority (de-)queuing of traffic to reduce latency and jitter. For example, real-time voice or video traffic could benefit. This is where it’d be nice to actually be able to honor user traffic markings. prices on viagra

It’s not (currently at least) practical to make the decisions on a flow-by-flow basis in the core of the network (which is what your proposal would require). This is a hardware scaling issue. To be clear, tracking flows statistically is okay at scale. ISPs do plenty with NetFlow/sFlow. But taking an incoming packet, assigning it to a flow, and marking it appropriately, for every packet, in real time is the scaling challenge.

The following approach would scale perfectly in trusted CPE (ONT/cable modem) or reasonably well in a DSLAM (for DSL). Give each user (for example) two queues. Honor the incoming DSCP markings. Put a small, but reasonable, limit on the size of the priority queue; overflowing traffic gets remarked and placed into the non-priority queue. Then, honor markings through the rest of the network.

There are a few problems with even this approach. First off, there are going to be users who legitimately create more high priority traffic than any limit that’s acceptable across the board. Is it okay to charge them for a higher limit? If not, how do you avoid gaming the system? If yes, won’t that incentivize ISPs to set the limit to zero and charging for all priority? Is that okay? If so, what fraction of people will request and pay for priority in that world? Will that be enough to encourage application developers to mark traffic appropriately? Or does this just degrade into our current zero-priority Internet?

Second, this only gets you one direction (upload). To handle the download direction, you’d need to honor priority bits on your upstream and peering links. But there, you can’t trust the markings (unless it’s a 1:1 peering link and you are guaranteed your peer implements a compatible policy at their incoming edge), at least without policing. Policing the queues there is easy, but gives you terrible results in real life viagra online prescription free. If the limit is exceeded with traffic that “should not have been” marked priority, it will destroy the prioritization of “legitimate” priority flows by forcing some fraction of their packets into the non-priority queue. If you accept all (or just a high enough fraction of) incoming traffic as priority traffic, then you have destroyed the prioritization yourself. If you try to mark flows per IP/customer, we’re back to that scaling problem.

It might be possible to do something that involves tracking flows at the customer edge and using the incoming markings for the downstream direction. But this is only prioritizing in the last mile. At best, this is a lot of work for very little benefit. how to get cialis in canada

No tags

I’m documenting this mainly for myself, but if you’re ending up here based on a Google query, I hope it helps! generic levitra fda

I tried to upgrade our Nexenta storage system (currently running 4.0.3FP3). After apt-get downloaded packages, I received this error:
Download complete and in download only mode
Upgrade is in progress. Please DO NOT interrupt...
Creating Upgrade Checkpoint...
Feb 03 19:13:23 EXCEPTION: FormatError: Failed to parse menu.lst: section content not complete
Uncaught exception from user code:
com.nexenta.nmu.FormatError: Failed to parse menu.lst: section content not complete
at /usr/perl5/5.12/lib/NZA/NMUUtil.pm line 731
NZA::NMUUtil::_mark_rootfs('syspool/rootfs-nmu-008', 0, '') called at /usr/perl5/5.12/lib/NZA/NMUUtil.pm line 817
NZA::NMUUtil::clone_rootfs() called at /usr/bin/nmu line 526

Nexenta tech support found that the issue was empty BOOTADM blocks in /syspool/boot/grub/menu.lst:
#---------- ADDED BY BOOTADM - DO NOT EDIT ----------
#---------------------END BOOTADM--------------------

The fix is to remove those and run bootadm update-archive -v.

If I understood correctly, the cause may have been using beadm destroy in the shell instead of setup appliance checkpoint ... in nmc.

No tags

This is another Facebook comment being kept here for posterity:

Regarding H.R. 1076…. I just read the text of the law and one source for the NRA’s position on it: http://www.americas1stfreedom.org/articles/2015/11/20/using-the-terrorist-watchlist-against-gun-owners/

The NRA seems to make some points worth considering:

1) Are terrorists (as defined in this law, and known to be such at the time of the purchase) actually buying guns from legal sellers?

I share their skepticism. If this isn’t a realistic problem, then there’s no point for the law and everything else is moot. So supporters need to prove that point first.

2) The NRA is saying this is based on the terrorist watch list, which is a mess: “Consider, for example, that even three federal legislators, including Sen. Ted Kennedy, found themselves on the list. As Charles C.W. Cooke pointed out on nationalreview.com, some 280,000 people on the list have ‘no affiliation with known terrorist groups’ but simply fall under ‘reasonable suspicion.'”

I didn’t parse the text of the law enough to know if using the terrorist watch list is what would actually be happening here. The text talks a lot about the attorney general denying a transfer, but would that be implemented in practice by blanket denying based on the watch list? It certainly could be. And it sure seems like that’d be a lot easier than trying to create a separate subset list of “terrorists to not allow to buy guns”. Plus, if they did create a separate list, there’s a potential for backlash if they miss someone who is on the bigger list, so that factor will encourage the use of just one list.

I think it’s widely agreed that the watch list is problematic in many ways. That’s why certain people have to deal with TSA redress numbers, etc.

3) There are essentially no consequences for listing someone.

As far as I know, this is generally the case with a lot of laws, so I’m not sure whether that’s creating a new or bigger problem here specifically.

Overall, I don’t see a lot of point for the bill. If this actually is a problem, the bill doesn’t seem too terrible to me. Ideally, I’d like to see the government be required to pay your court and attorney costs if you prevail on a challenge to your being listed.

No tags

Older posts >>

Theme Design by devolux.nh2.me

Ads