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Very Slow IRC

N/A

Very Slow IRC

With all the talk of 'Wireshark' I thought I'd give it a go and see what it had to say about the extremely slow IRC connections I experience on my PN Premier 1 plan.

Based on just 30 seconds of capture I found numerous 'errors' of the following form:

* Lots of "TCP DUP ACKs" - Duplicate ACKs

* Many "TCP Retransmissions"

* Many "TCP Previous segment lost"

Now, what is causing these? Is this a symptom of the Ellacoyas? It is easily replicated with other IRC users and so would not seem to be a specific problem with the specific server/user I am connected to.

By the way, with the above errors I am lucky to get 1 or 2 KB/sec with 0.47KB/sec a more typical speed. At other random times IRC will zip away at 200KB/sec+
4 REPLIES
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Very Slow IRC

I've never had any issues with IRC on Premier.

If you experiencing network related issue, that's right, raise a ticket and we'll pass it to Networks Wink
N/A

Very Slow IRC

Quote
I've never had any issues with IRC on Premier.


Do you use IRC on Premier?

Over a 5 minute period (of 1400 total packets) just now:

100 [TCP Retransmission] Packets
75 [TCP Previous segment lost] Packets
170 [TCP Dup ACK] Packets

So 345/1400 = 25% of the packets were 'errors'? Would this explain slow speeds?

EDIT: I will raise this as a ticket once I get a bit more feedback so that i have all the data they will need.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

Very Slow IRC

I do yes. We have our own "Comms" IRC channel which I use from home, and I know that Dave uses it extensively, because his ahift involves working from home for 3 hours a day.
N/A

Very Slow IRC

Having done a little digging I note that other users report a similar problem on Cogeco broadband in the USA (which also uses active traffic shaping).
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"If, like me, you've triggered Cogeco to employ whatever nasty tool (could it be P-cube? Ellacoya? other? ... The observed disruption is delayed ACK's coming from the receiving IP, causing repeated TCP data retransmission and resulting in severely decreased throughput."

Amusingly, Cogeco seem to take a similar stance to PN:
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"Cogeco denies responsibility. I would like to get to the bottom of it. ...The disruption is occurring somewhere between my cablemodem and the rest of the internet. I just want them to recognize it, and fix it."

Additionally, all this traffic shaping seems to contravene the generally-accepted notion of "net neutrality" as laid out in this JISC (Joint Information Systems Committee) report:
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2.3.3 Net Neutrality and packet shaping
At present, the Internet is an end-to-end network, over which, in theory, any traffic can flow freely, and no one application or use is prioritised over another. The network carriers and ISPs are, in effect, neutral as to the traffic they carry — known, unsurprisingly, as network neutrality.

Recently there has been considerable controversy, particularly in the US, over plans to alter this. Major US telecommunications carriers such as AT&T and Verizon want to prioritise some services and potentially charge different rates for premium services. At the moment there is nothing to stop them from doing this (other than the general ethos of the Internet) so objectors have called for regulation of the telecommunications carriers to ensure network neutrality (Stern, 2006). The key issue is whether prioritising ... will lead to a ‘two-tier’ Internet, with some services running more slowly, and less reliably, than others.



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There is concern that when such traffic-shaping policies are imposed by network operators or ISPs they could lead to packet discrimination, with content from some independent providers being discriminated against or excluded altogether, leading to the end of network neutrality. Interested readers should see Felten's (2006) excellent overview of the technical issues in relation to the policy and legal issues.

There have already been instances in which providers have expressed alarm over the potential impact of network discrimination. In 2005, US VoIP provider Vonage complained to the Federal Communications Commission that competitors were blocking the use of its service and as a consequence, one local US ISP was investigated by the FCC. Jeffrey Citron, CEO of Vonage, has expressed his concern that there is no protection for the Internet against packet discrimination and his worry is that network operators may disrupt customers’ access to certain services or hinder the quality of their customers’ broadband to give priority to other applications (Pulver, 2005).


And, if PN can't see the reality, then Ofcom at least can:

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The interpretation of this situation is different in the UK. In its consultation document on the UK VoIP market, telecommunications regulator Ofcom (2006) acknowledged concern but concluded that ... customers finding they were suffering from packet degradation would... change supplier.