July 2004 - Test - lists.nanog.org

RE: T1 short-haul vs. long-haul
by Michel Py 24 Jul '04

24 Jul '04

>> Michel Py wrote: >> I stopped by a T1 MPOE on my way home and took a few photos. > Michael Loftis wrote: > hate to say it but what is pictured is not a smart jack, > it is as you say a glorified patch. Care to post a photo of what you think a smartjack is? > a *TRUE* smart jack DOES have the tiny bit of circuitry > necess'y to cause it to loop the line back when nothing > is connected to it, some can do it via line signaling as well. This feature is part of the NIU. What makes the jack smart is that it's connected to a smart NIU (the older full-height type 400 were not smart). Michel.

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RE: T1 short-haul vs. long-haul - jack terminology
by Michel Py 24 Jul '04

24 Jul '04

> Forrest W. Christian wrote: > In Qwest land, NIU, Smart Jack, and Demarc (unless > "extended") are all in the same physical rack. > When you get a T1, qwest installs an appropriately > sized shelf. This shelf holds the adtran and > westell devices shown in earlier posts. For example, > we have one site with quite a few T1's, which they > installed a rack like the one pictured at: > http://www.westell.com/images/osp/dsawm214.jpg > Note the RJ45's on the bottom. These are the demarc > point for the circuit. When qwest says "insert a > loopback plug at the smartjack" or "unplug from the > smartjack" or whatever, they mean this device. Thanks for posting the photo. A few comments: This all-in-one unit is mechanically different but electrically equivalent to the split NIU/smartjack photos I posted before; the smartjack part which is the lower part labeled "customer interface" is a dumb PCB no smarter than the Hyperedge glorified patch panel I posted a photo of. An interesting feature of this chassis is that the rightmost card (which appears to be a full-height one) seems to be a channel bank. A channel bank is an HDSL card same as the general-purpose NIU but also demuxes the 24 TDM DS0s in that T1 and outputs them as individual phone lines, which could be the purpose of these 50-pin Centronics connectors on the smartjack part, on the right of the RJ-48 jacks. > Qwest can loop or unloop and do other tests to > this device. Indeed. As I said earlier, the brain of the smartjack is the NIU card. For antique equipment, here's an RJ48 T1 loopback plug: +---------+ +----+---------+----+ ! | | | | | | | | ! ! | | | | | | | | ! ! 1 2 3 4 5 6 7 8 ! ! | | | | ! ! | | | | ! ! | | | | ! +--|-|---|-|--------+ | | | | +-)---+ | | | +-----+ > On the newer HDSL cards, they can also plug a laptop > in to get performance data, and I believe they can > also get this data from the CO end. All depending on the age and feature set of the NIU card. > Older ones have RJ45's on the right side and the > cards are thicker - a lot thicker. Yes. As well as the photos I posted earlier, these are "half-height" type 400 NIU cards. The older ones were twice as big due in part to the size of then-manufactured large capacitors. > Also of note, I haven't seen qwest deploy anything but > HDSL2 cards for quite a while. This basically means a > full duplex, full-speed T1 over a single pair of copper > with a quarter of the repeaters (12K wire feet without > a repeater). In California my guess is that the current strategy is to leave the existing dual-spans in place and deploy fiber, single-spans being for residential use. At home I am 10kft from the CO and I get 3meg aDSL over the good old pair. Recently I had a customer order a frac-DS3 (12 mb/s) from Sprint; when you do the math it's only 8 T1s, not that much after all and will easily fit into the chassis you pictured. Instead of copper the LEC (SBC) brought in a SONET OC-12 ring and extended the demarc in the customers data room (including the optical platform, they spliced the fiber at the MPOE), which is great if the customer wants to crank up the volume. Michel.

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Re: T1 short-haul vs. long-haul - jack terminology
by frank＠dticonsulting.com 24 Jul '04

24 Jul '04

On the matter of the type of cabling to be used between the Telco Demarc and the CPE, I have found this to be one of the most shrouded of all areas in telecom standards. The jabber and deliberations that have taken place over this issue border on folk lore and hijinx, and could fill a plant man's notebook in no time flat. Prior to metallic T1s being made available to end users by the incumbent carriers (this is going back some tweny years or so), the carrier itself extended cabling to the point of the customer's CPE/DTE. Reportedly (and in fact, most of the time), they used individually shielded pairs, actually comprising two separate cables - one for each direction. The standard that was used in the latter case was the ancestor of today's ANSI 401.1 and it applied to the "telco's" EMI/RFI compliance responsibilities, not the customer's. Later on, the EIA/TIA drew up a set of commercial building wiring standards in the way of TIA568, but neglected to include the T1 niche in its writings, relegating it to an orphan state. Consequently, there has been much confusion amongst enterprise IT staff and Telco guidelines, not to mention the list of different recommendations that manufacturers of CSUs and DSUs place in their glossies. I've seen where STP (shielded twisted-pair cabling) purists have succeeded in having shielded cabling used, only to screw it up by mis-applying the necessary grounding connections causing more problems than they solved. And I've seen where wall fields of T1 demarcs in an MDF room have successfully been deployed using nothing more than Cat3 UTP between spaces that were thirty stories apart. Through all of this, the one area that is often overlooked is the area where vendors of network hardware stipulate what type of cabling they will support and will _not_ support, with pair shielding used as a determining factor. About two years ago, after a client successfully deploying several shelves of T1s for most normal enterprise purposes, they found that one certain VoIP gateway was encountering excessive errors. After all self tests came up negative, as did an end to end test on the T1, and after swapping out those T1s and their respective patch cables, the problem persisted. At one point the vendor's rep pointed to the fine print in the operator's manual. It stipulated that the only cabling that would be supported between the gateway and the telco demarc was individually shielded twisted pairs. When it was discovered that the client had chosen to use UTP patch cords to extend their T1 demarcs some fifteen or so feet, the vendor would not even begin to diagnose the problem further in depth until the client replaced those cables with shielded ones. Once replaced, the problem appeared to subside as evidenced by a lower incidence of errored seconds initially (but still unacceptable from my view), only to resurface at a later time to the same state of impairment that it was before. But the salient point here isn't whether or not the problem was solved, as much as it is the significance of abiding by vendor warranty conditions (if you've agreed to them initially, even tacitly, in your contracts and SLAs) when selecting a T1 cabling solution. If anyone on this list has a more authoritative source that stipulates the type of cabling to be used for the section in question (between the demarc and the CPE), perhaps something that has been written more recently than the experience I cited above, it would be appreciated. frank(a)fttx.org ---------- On Fri, 23 Jul 2004 23:52 , 'Forrest W. Christian' <fwc(a)mt.net> sent: > >On Fri, 23 Jul 2004, Christopher Woodfield wrote: > >> OK, from my reading in Newton's Telecom Dictionary, it appears that NIU >> is a generic term for "whatever the customer plugs their cable into", >> be it a powered or a dumb device. Mea culpa. >... >> "...installed on the premises as a semi-intelligent demarcation >> point, >> the smart jack is completely passive until activated remotely by a >> digital code, typically something like 'FACILITY 2', sent down the T-1. >> This code activates a relay [that loops the circuit]." >> >> That may not accurately define the Adtran and Westell devices that are >> pictured (they appear to have additional features beyond this), but >> it's a good guess they provide the remote loopback function described >> above in addition to the monitor points and management console port. I >> also doubt that the Hyperedge unit pictured does so, although I can't >> seem to find any online documentation on the unit (it is, as you >> described it, a 'glorified patch panel'). Feel free to correct me. > >In Qwest land, NIU, Smart Jack, and Demarc (unless "extended") are all in >the same physical rack. > >When you get a T1, qwest installs an appropriately sized shelf. This >shelf holds the adtran and westell devices shown in earlier posts. For >example, we have one site with quite a few T1's, which they installed a >rack like the one pictured at: > > http://www.westell.com/images/osp/dsawm214.jpg > >Note the RJ45's on the bottom. These are the demarc point for the >circuit. Older ones have RJ45's on the right side and the cards are >thicker - a lot thicker. > >When qwest says "insert a loopback plug at the smartjack" or "unplug from >the smartjack" or whatever, they mean this device. > >Qwest can loop or unloop and do other tests to this device. On the newer >HDSL cards, they can also plug a laptop in to get performance data, and I >believe they can also get this data from the CO end. > >Also of note, I haven't seen qwest deploy anything but HDSL2 cards for >quite a while. This basically means a full duplex, full-speed T1 over a >single pair of copper with a quarter of the repeaters (12K wire feet >without a repeater). > > -forrest On Fri, 23 Jul 2004 23:52 , 'Forrest W. Christian' <fwc(a)mt.net> sent: > >On Fri, 23 Jul 2004, Christopher Woodfield wrote: > >> OK, from my reading in Newton's Telecom Dictionary, it appears that NIU >> is a generic term for "whatever the customer plugs their cable into", >> be it a powered or a dumb device. Mea culpa. >... >> "...installed on the premises as a semi-intelligent demarcation >> point, >> the smart jack is completely passive until activated remotely by a >> digital code, typically something like 'FACILITY 2', sent down the T-1. >> This code activates a relay [that loops the circuit]." >> >> That may not accurately define the Adtran and Westell devices that are >> pictured (they appear to have additional features beyond this), but >> it's a good guess they provide the remote loopback function described >> above in addition to the monitor points and management console port. I >> also doubt that the Hyperedge unit pictured does so, although I can't >> seem to find any online documentation on the unit (it is, as you >> described it, a 'glorified patch panel'). Feel free to correct me. > >In Qwest land, NIU, Smart Jack, and Demarc (unless "extended") are all in >the same physical rack. > >When you get a T1, qwest installs an appropriately sized shelf. This >shelf holds the adtran and westell devices shown in earlier posts. For >example, we have one site with quite a few T1's, which they installed a >rack like the one pictured at: > > http://www.westell.com/images/osp/dsawm214.jpg > >Note the RJ45's on the bottom. These are the demarc point for the >circuit. Older ones have RJ45's on the right side and the cards are >thicker - a lot thicker. > >When qwest says "insert a loopback plug at the smartjack" or "unplug from >the smartjack" or whatever, they mean this device. > >Qwest can loop or unloop and do other tests to this device. On the newer >HDSL cards, they can also plug a laptop in to get performance data, and I >believe they can also get this data from the CO end. > >Also of note, I haven't seen qwest deploy anything but HDSL2 cards for >quite a while. This basically means a full duplex, full-speed T1 over a >single pair of copper with a quarter of the repeaters (12K wire feet >without a repeater). > > -forrest

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Re: Campus size Wireless LAN
by Rob Nelson 24 Jul '04

24 Jul '04

At 02:01 PM 7/21/2004, Eric Brown wrote: >Anyone have experience with Proxim's tsunami quickbridge for wireless >connectivity between buildings at line of site distances under 1 mile? >It's cheaper than Cisco and looks good on paper. Looking for the good >bad and ugly. Thanks in advance! Cheaper than Cisco? Doesn't take much! ;) Is this point to point or point to multipoint? One link, or multiple links? There's plenty of products to do campus WLAN's, and the Quickbridges are pretty good. Proxim also has the MP11 and MP11a line, which I believe is cheaper than the Quickbridges, but uses the same spectrum. Probably has slightly lower throughput, but don't know if that's as important. The Quickbridge is an older product, and as someone said, the interface shows it. The newer products (AP600, AP2500, AP4000, and the MP11/MP11a's) all have a very similar web interface that's fairly intuitive. All of it will work (especially at <1mile LOS), it's a question of what other features you're expecting/looking for. Rob Nelson ronelson(a)vt.edu

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DNC service providers
by Sean Donelan 24 Jul '04

24 Jul '04

http://www.thebostonchannel.com/news/3561756/detail.html The event monitor gives all the agencies instant access to any event to local police, fire officials, the FBI and dozens of law enforcement representatives working with utility providers. "Public safety officials from our carriers -- Verizon, Nextel, AT&T, NSTAR, Keyspan," said Perro.

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Re: that MIT paper again (Re: VeriSign's rapid DNS updates in .com/.net ) (longish)
by Simon Waters 24 Jul '04

24 Jul '04

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 | Date: Fri, 23 Jul 2004 17:01:54 +0000 | From: Paul Vixie <paul(a)vix.com> | Subject: that MIT paper again (Re: VeriSign's rapid DNS updates in .com/.net ) | |>>wrt the mit paper on why small ttl's are harmless, i recommend that |>>y'all actually read it, the whole thing, plus some of the references, |>>rather than assuming that the abstract is well supported by the body. | http://nms.lcs.mit.edu/papers/dns-imw2001.html I think most people are probably way too busy. I'll comment, and Paul can tell me where I am wrong or incomplete ;) I'm slightly concerned that the authors think web traffic is the big source of DNS, they may well be right (especially given one of the authors is talking about his own network), but my quick glance at the type of queries shouts to me that SMTP (and email related traffic, RBL's, etc) generate a disproportionate amount of wide area DNS traffic byte for byte of data. I would think this is one that is pretty easy to settle for specific networks. In particular I see a lot of retries generated by email servers for UBE and virus dross (in our case for upto 5 days), when human surfers have famously given up the domain as dead after the first 8 seconds. Perhaps if most people preview HTML in emails, surfing and email access to novel URI are one and the same. They conclude that the great bulk of benefit from sharing a DNS cache is obtained in the first 10 to 20 clients. Although they scale this only to 1000+ clients, maybe some NANOG members can comment if they have scaled DNS caches much bigger than this, but I suspect a lot of the scaling issues are driven by maintainance costs and reliability, since DNS doesn't generate much WAN traffic in comparison to HTTP for most people here (let's face it the root/tld owners are probably the only people who even think about bandwidth of DNS traffic). They conclude the TTL on A records isn't so crucial. The abstract doesn't mention that the TTL on NS records is found to be important for scalability of the DNS. Probably the main point Paul wants us to note. Just because the DNS in insensitive to slight changes in A record TTL doesn't mean TTL doesn't matter on other records. The paper leaves a lot of hanging question about "poor performance", the number of unanswered queries, and poor latency, which I'm sure can be pinned down to the generally poor state of the DNS (both forward and especially reverse), and a few bad applications. The big difference between the places/times studied, suggests to me how the DNS performs depends a lot on what mix of questions you ask it. They suggest not passing on unqualified names would lose a lot of fluff (me I still think big caches could zone transfer "." and save both traffic and, more importantly for the end users, latency, but that goes further than their proposal). Remember resolvers do various interesting things with unqualified names depending who coded them and when. The paper doesn't pass any judgement on types of lookups, but obviously not all DNS lookups are equal from the end user perspective. For example reverse DNS from HTTP server is typically done off the critical path (asynchronously), where as the same reverse lookup may be in the critical path for deciding whether to accept an email message (not that most people regard email as that time critical). Be nice to do a study classifying them along the lines of "DNS lookups you wait for", "DNS lookups that slow things down", "DNS lookups that have to be done by Friday for the weekly statistics". Some *nix vendor(s?) should make sure loghost is in /etc/hosts or not in /etc/syslog.conf by default by the sound of it ;) As regards rapid update by Verisign - bring it on - I'm always embarassed to tell clients they may have to wait upto 12 hours for a new website in this day and age. And any errors that gets made in the initial setup takes too long to fix, I don't want to be setting up a site 3PM Friday, and having to check it Monday morning to discover some typo means it is Tuesday before it works, when in a sane world one TTL + 5 minutes is long enough. I think relying on accurate DNS information to distinguish spammers from genuine senders is at best shakey currently, the only people I can think would suffer with making it easier and quicker to create new domains would be people relying on something like SPF, but I think that just reveals issues with SPF, and the design flaws of SPF shouldn't influence how we should manage the DNS. -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Debian - http://enigmail.mozdev.org iD8DBQFBAYOEGFXfHI9FVgYRApWTAKCupO6Eo5i0QtDqEuYs5d1xgEMetgCgjFJf LQBGn1G1gsdbKlg8pagoEVM= =fu+g -----END PGP SIGNATURE-----

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Re: T1 short-haul vs. long-haul - jack terminology
by Christopher Woodfield 24 Jul '04

24 Jul '04

OK, from my reading in Newton's Telecom Dictionary, it appears that NIU is a generic term for "whatever the customer plugs their cable into", be it a powered or a dumb device. Mea culpa. However, the writeup on "smart jack" reads, in part: "...installed on the premises as a semi-intelligent demarcation point, the smart jack is completely passive until activated remotely by a digital code, typically something like 'FACILITY 2', sent down the T-1. This code activates a relay [that loops the circuit]." That may not accurately define the Adtran and Westell devices that are pictured (they appear to have additional features beyond this), but it's a good guess they provide the remote loopback function described above in addition to the monitor points and management console port. I also doubt that the Hyperedge unit pictured does so, although I can't seem to find any online documentation on the unit (it is, as you described it, a 'glorified patch panel'). Feel free to correct me. Hope this serves to clarify things... -C On Jul 23, 2004, at 2:57 PM, Allen Kitchen wrote: > Christopher - FWIW, Michel's description tallies with common usage in > Bell > of PA and Bell of NJ territory (now Vz, of course). Seems like a > counter-intuitive use of "smart" in "SmartJack" but the diff between > it and > a "regular" 8-pin RJ-type jack is the self-connecting loopback > arrangement > that is SUPPOSED to be buried in these. That's why they called it > "smart" to > begin with, according to legend here. > > ..Allen > > Allen Kitchen > Special Projects Manager > Diskriter Inc. / Pittsburgh, PA / 412-344-9700 x 313 / > akitchen(a)diskriter.com > > -----Original Message----- > From: owner-nanog(a)merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of > Christopher Woodfield > Sent: Friday, July 23, 2004 2:51 PM > To: Michel Py > Cc: nanog(a)merit.edu; Andre Oppermann > Subject: Re: T1 short-haul vs. long-haul > > > I think we can probably chalk this up to a difference in dialect, for > lack > of a better word...what you're calling an NIU is exactly what I would > call a > smartjack and vice versa. Can you point to any sort of "official" > documentation that defines these? I'm looking to see if anyone in my > office > has a Newton's as I speak... > > -C > > On Jul 23, 2004, at 12:15 AM, Michel Py wrote: > >>> Christopher Woodfield wrote: >>> In the interest of complicating things further, I think you have NIU >>> and smartjack backwards in your explanation.. > >

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VeriSign's rapid DNS updates in .com/.net
by Matt Larson 24 Jul '04

24 Jul '04

VeriSign Naming and Directory Services (VNDS) currently generates new versions of the .com/.net zones files twice per day. VNDS is scheduled to deploy on September 8, 2004 a new feature that will enable VNDS to update the .com/.net zones more frequently to reflect the registration activity of the .com/.net registrars in near real time. After the rapid DNS update is implemented, the elapsed time from registrars' add or change operations to the visibility of those adds or changes in all 13 .com/.net authoritative name servers is expected to average less than five minutes. The rapid update process will batch domain name adds and domain name changes every few seconds. The serial number in the .com/.net zones' SOA records will increase with each batch of changes applied. As described in a message to the NANOG list in January [1], these serial numbers are now based on UTC time encoded as the number of seconds since the UNIX epoch (00:00:00 GMT, 1 January 1970). VNDS will continue to publish .com/.net zone files twice per day as part of the TLD Zone File Access Program. [2] These zone files will continue to reflect the state of the .com/.net registry database at the moment zone generation begins. VNDS does not anticipate any negative consequences of deployment of rapid updates to the .com/.net zones. However, as a courtesy we are providing the Internet community with 60 days advance notice of the change to the update process. Some questions and answers about rapid updates for .com/.net are available at http://www.verisign.com/nds/naming/rapid_update/faq.html. Matt -- Matt Larson <mlarson(a)verisign.com> VeriSign Naming and Directory Services [1] http://www.merit.edu/mail.archives/nanog/2004-01/msg00115.html [2] http://www.verisign.com/nds/naming/tld/

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RE: T1 short-haul vs. long-haul
by Michel Py 23 Jul '04

23 Jul '04

> Christopher Woodfield wrote: > I think we can probably chalk this up to a difference > in dialect, for lack of a better word...what you're > calling an NIU is exactly what I would call a smartjack > and vice versa. Can you point to any sort of "official" > documentation that defines these? > Christopher Woodfield wrote: > the smartjack has alarm lights and can be remotely > looped by the telco via ESF loopcodes; I have never seen an NUI (even antique ones, which did not have loopback capabilities) that was a dumb wiring box. Below are some examples of what people actually call an NIU: http://arneill-py.sacramento.ca.us/docs/3125.pdf http://www.charlesindustries.com/NIU%20400-Size.pdf As you can see, none of them feature any RJ48 jack. > Christopher Woodfield wrote: > the NIU (also known as an RJ48X) is the dumb wiring box. It is _not_ also known as an RJ48X. Below are some examples of RJ48X products: http://www.twacomm.com/Catalog/Model_AT635CX.htm http://www.suttleonline.com/trad_jacks_sfcmount.html http://www.figment.ca/Networking/Premise/PDFs/Section%20B/b9.pdf?catid=2 08 http://www.psigroup.ca/products/section-a/a9-2.htm Michel.

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RE: VeriSign's rapid DNS updates in .com/.net
by Brian Battle 23 Jul '04

23 Jul '04

Petri Helenius wrote: > What would be your suggestion to achieve the desired > effect that many seek by lower TTL's, which is changing > A records to point to available, lower load servers at > different times? On a similar note (and not viewing the issue through the usual spam-colored glasses): Some people are using low dns TTLs in disaster recovery setups, so that in the event of a disaster at a primary site, services can be switched over to new servers at a secondary site via easy and fast DNS changes? If the TTLs are too long, all the cached records will continue to point at the servers which might no longer exist -- until they expire. This is another situation where low TTLs can be beneficial. Are there any other uses for low dns TTLs that haven't been brought up in this thread? And what is a "low TTL" being classified as? 30 minutes? 10 minutes? 5 minutes? -Brian

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