March 2007 - NZNOG - lists.nznog.org

5.8GHz in Dunedin
by Stewart Fleming 29 Mar '07

29 Mar '07

We're trying to track down a potential interference problem that is affecting one of our access points in North Dunedin. Could any local operator using Trango or Motorola 5.8GHz gear in that area please contact me off-list? Thanks. -- -- Tel: 03 474 2100 Cell: 021 993 125 Web: www.wic.co.nz Co-location and Web hosting. Dunedin-wide wireless. Independent Internet Service Provider.

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Re: [nznog] Telecom's "peering" change of heart really isn't
by Alastair Johnson 28 Mar '07

28 Mar '07

[once more for good luck - maybe THIS time I'll get it on list] Matthew Poole wrote: > > On Thu, 29 Mar 2007, Alastair Johnson wrote: > >> Every ISP at Every IX? Does it end at ISPs? What about universities, >> for instance? What about satellite networks where the uplink isn't >> necessarily NZ based? >> > At their local (to their primary centre of operations) IX, obviously. > And I'm envisaging xx,000 being a sufficiently high number that only the > University of Auckland (with around 40,000 FTE students) would even come > close. Okay, but if you're only interconnecting/exchanging at your local IX then suddenly this is not as useful as it sounded. Telecom's primary center of operations is indisputably Auckland. Does that mean that, e.g. Trademe, cannot reach TNZ across an IX? Or do we come back to region-isation again? >> Are you going to pay for my long haul circuits to Palmy? >> > Is your primary centre of operations in Palmy? No? Why would you peer in > Palmy, then? Because you're regulating peering. If we must peer, then surely everyone needs to peer either everywhere (expensive), or at one IX (expensive for some). Otherwise you're significantly reducing the benefit of it before you even start. What happens if my POPs are islands and not connected to my backbone[s]? (think internap PNAPs) I'm only going to originate local prefixes anyway. What if I don't want to haul Content Provider C's traffic from Palmy to my subscribers in Auckland because it's 50+Mbps? Third option: regional based peering. My POP in PMR peers at the PNIX and only originates local prefixes. These all sound like significant business and technical issues that would need to be addressed by regulation. Unless your idea of regulation is to just focus on the big boys. Maybe that's fair, maybe that's not.... >> Doesn't sound like it would work so well, to me. If we said only the >> "major" IXs, what happens when the poor guy in Christchurch signs up his >> XX,000th customer and is forced to peer... but isn't getting access to >> the Big Boys? >> > Realistically, how many ISPs that are based outside AKL/WLG stand any > chance of getting 50+,000 users? Remembering that of the top five, > unless something has changed a lot in recent times, only Xtra and the > TCL stable are > 100k. If the government is serious about our OECD rankings, then I think many ISPs are going to hit >50k. If you believe press releases, Ihug, Orcon, and Callplus are all around (or over) the 100k mark. >> Regulated peering sounds very scary to me... >> > Only if one takes it to absurdity. If it's regulated in such a way that > only the very largest players could be affected, and the requirement on > which IX(s) is based around centre(s) of operations, it's easily > defined, easily enforced, and as I said won't really affect anyone other > than TCL and TCNZ. Which one may state is not particularly fair. Incidentally, what about Vodafone? I've noticed that traffic from a large number of smaller providers currently trombones via Tokyo and Sydney. > Oh, and on your point about universities, I think you will find that > most (all?) of them already peer. UoA, which is far-and-away the largest > university in the country, certainly peers at APE. I think you'll find that UoA in particular does not peer [any longer]. UoW also does not. aj.

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Re: [nznog] jumbo frames
by Jonathan Woolley 28 Mar '07

28 Mar '07

>Jumbo frames aside from the usefulness of bigger payload for >mpls/tunnels etc add some value in an environment where there's some >packet loss. I would have thought it makes it worse, assuming a physical fault resulting in a constant bit error rate combined with larger packet size means higher probability that a packet is corrupted (as there are more bits in it). The resulting packet is discarded which is a bigger loss than discarding a smaller one. >For example in an environment with say a 1Gbps link where packet loss >is .1% with 1500 byte MTU you get 28Mbps througput. With Jumboframes >that leaps to approx 162Mbps. Can I see the maths behind this? If you're talking about packet loss due to congestion and not using TCP then you're probably right

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Re: [nznog] Telecom's "peering" change of heart really isn't
by Matthew Poole 28 Mar '07

28 Mar '07

On Thu, 29 Mar 2007, Alastair Johnson wrote: > Every ISP at Every IX? Does it end at ISPs? What about universities, > for instance? What about satellite networks where the uplink isn't > necessarily NZ based? > At their local (to their primary centre of operations) IX, obviously. And I'm envisaging xx,000 being a sufficiently high number that only the University of Auckland (with around 40,000 FTE students) would even come close. > Are you going to pay for my long haul circuits to Palmy? > Is your primary centre of operations in Palmy? No? Why would you peer in Palmy, then? > Doesn't sound like it would work so well, to me. If we said only the > "major" IXs, what happens when the poor guy in Christchurch signs up his > XX,000th customer and is forced to peer... but isn't getting access to > the Big Boys? > Realistically, how many ISPs that are based outside AKL/WLG stand any chance of getting 50+,000 users? Remembering that of the top five, unless something has changed a lot in recent times, only Xtra and the TCL stable are > 100k. > Regulated peering sounds very scary to me... > Only if one takes it to absurdity. If it's regulated in such a way that only the very largest players could be affected, and the requirement on which IX(s) is based around centre(s) of operations, it's easily defined, easily enforced, and as I said won't really affect anyone other than TCL and TCNZ. Oh, and on your point about universities, I think you will find that most (all?) of them already peer. UoA, which is far-and-away the largest university in the country, certainly peers at APE. -- Matthew Poole "Don't use force. Get a bigger hammer."

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jumbo frames
by Ian Batterbee 28 Mar '07

28 Mar '07

Has anyone got any real world experience of the usefulness of jumbo frames on ethernet (ie, MTU > 1500 bytes). A number of 1000mbps interfaces support it, but it seems to be that it would only be useful if jumbo frames were supported and enabled on all equipment between the sending NIC and final IP destination, so I'm struggling to see how enabling it in just say the core of a network would be all that helpful.

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John Backus passes away
by Richard Naylor 27 Mar '07

27 Mar '07

For those who are a little older.... John Backus, who lead the team that developed FORTRAN passed away last week. FORTRAN was originally developed for the IBM 704 and is regarded as one of the first high-level programming languages. He was involved in the development of ALGOL 58 and ALGOL 60. ALGOL was the first language that I learned, FORTRAN the second. Theres a good obit at NYTimes http://www.nytimes.com/2007/03/19/obituaries/20cnd-backus.html?ex=133204320… Its worth reading. Slashdot also has heaps, including.... FORTRAN was the first working high level compiler language; BASIC was the first working interpreter language. Very different underlying structures. Now COBOL was the second major high level compiler language, and it was very much a reaction to FORTRAN, so I suppose using parent post's logic, we can blame Backus for COBOL. But then that cheapens the contributions of the Girl Admiral (Grace Hopper) who gave us such wonders as the nanosecond wire, and MULTIPLY 2 BY 2 GIVING FOUR. For the youngsters out there: FORTRAN (FORmula TRANslator) was the break-through from machine language and assembly to a higher level language with a compiler. Everything we do now is based on this; I believe that many mission critical engineering libraries are still in Fortran (they were a few years ago) COBOL (COmmon Business Oriented Language, Compiles Only By Odd Luck) was the second successful high level language. Its major improvement over Fortran was getting rid of triphasic logic (branch on <0, or =0, or >0) in favor of boolean logic (branch on !0 or 0). Its most noteworthy failing was the requirement to use the period punctuation mark (full stop) to end sections. This was particularly a problem for girl programmers, since at the time getting into trouble because you missed a period had serious consequences. Cobol simply put too much emphasis on a nearly invisible and easily missed period. BASIC (Beginners All-purpose Symbolic Instruction Code) made two big advances: first, it attempted to span both engineering and business computing (doing each with the same degree of imprecision); second and more important, it introduced the concept of using an interpreter rather than a compiler. Good stuff, that. Yet another baby step toward tomorrow's virtual machines. Most noteworthy program ever written in Basic: Eliza. Most significant long term contribution: the reaction to its spaghetti coding style, from which Pascal and modern procedure based programming arose. </drivel> Rich off for a scotch and to read a few punched cards......

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92/8, 93/8 allocated to the RIPE NCC
by Leo Vegoda 27 Mar '07

27 Mar '07

Hi, The IANA IPv4 registry has been updated to reflect the allocation of two /8 IPv4 blocks to the RIPE NCC in March 2007: 92/8 and 93/8. You can find the IANA IPv4 registry at: http://www.iana.org/assignments/ipv4-address-space Please update your filters as appropriate. Regards, -- Leo Vegoda IANA Numbers Liaison

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Re: [nznog] jumbo frames
by Jonathan Woolley 27 Mar '07

27 Mar '07

>>> Can I see the maths behind this? If you're talking about packet >loss >>> due to congestion and not using TCP then you're probably right >> >>I assume he's talking about my TFRC math from >>http://wand.net.nz/~perry/max_download.php >> >>Assuming you've saturated your link, a one bit in 'n' is going to >take >>out one packet every so often (if it takes out more than that you're >not >>going to get anything much worth discussing over your link in the >first >>place). So increasing the MTU isn't going to make it more likely >that a >>packet is lost, it just means you need to retransmit a larger >packet. >> >>However, since you're using larger MTU's, it's going to take you >less >>RTT's to get back up to full speed on your link, and therefore your >link >>will spend more of its time going at full rate than if you had a >lower >>MTU (since it would require more RTT's at lower throughput before it > >>starts saturating the link again). Ahh, ok. That's an interesting scenario. I'll have a look at the link Jono

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Re: [nznog] jumbo frames
by Jonathan Woolley 27 Mar '07

27 Mar '07

>>If you're fragmenting and drop one packet of a 4-packet-sequence you >waste >>the other 3 packets anyway as its gotta send the whole oversize >packet as >>multiple fragments all over again. My guess is that is his >reasoning - >>and seems fair... Sending a 9600byte packet in one frame, or fragmented into seven frames isn't really a meaningful test if you're trying to prove that jumbo frames are better when there is packet loss. In the real world, the non-jumbo frame setup would only send 1500 byte packets...

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Re: [nznog] jumbo frames
by Jonathan Woolley 27 Mar '07

27 Mar '07

So the most common real world example in NZ is UBS. Take the subscriber's 1500byte packet, add a PPP header, an extra IP and UDP header (for L2TP) and two MPLS headers (inside TNZ's netowrk) and jumbo frames look pretty useful. As alluded to below, 802.1q and especially stacking of vlans are strong reasons, even more so if transported over MPLS (Martini/VPLS). Jono > > > >---- Original Message ---- >From: nznog(a)daork.net >To: NZNOG(a)list.waikato.ac.nz >Subject: Re: [nznog] jumbo frames >Date: Wed, 28 Mar 2007 15:04:56 +1200 > >>MPLS. >>VLANs. >>L2TP with 1500byte payloads. >> >>etc. >> >>On 28/03/2007, at 3:01 PM, Ian Batterbee wrote: >> >>> Has anyone got any real world experience of the usefulness of >jumbo >>> frames on ethernet (ie, MTU > 1500 bytes). A number of 1000mbps >>> interfaces support it, but it seems to be that it would only be >useful >>> if jumbo frames were supported and enabled on all equipment >between >>> the >>> sending NIC and final IP destination, so I'm struggling to see how >>> enabling it in just say the core of a network would be all that >>> helpful. >>> >>> >>> >>> _______________________________________________ >>> NZNOG mailing list >>> NZNOG(a)list.waikato.ac.nz >>> http://list.waikato.ac.nz/mailman/listinfo/nznog >>> >>> !DSPAM:22,4609daac107231355811551! >>> >>> >> >>_______________________________________________ >>NZNOG mailing list >>NZNOG(a)list.waikato.ac.nz >>http://list.waikato.ac.nz/mailman/listinfo/nznog

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