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RE: Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Christian Kuhtz 04 Aug '98

04 Aug '98

> On Mon, Aug 03, 1998 at 06:32:35PM -0400, Christian Kuhtz wrote: > > Why not just make ATM variable cell size altogether? > > Try designing switching hardware with bound delays and delay jitter and > you will understand. Implement large-scale switching hardware with > Gigabytes of high-speed memory for buffering and keep costs low. Guys, the above was a tongue in cheek remark. :) Cheers, Chris -- Christian Kuhtz, BellSouth Corp., Sr. Network Architect <ck(a)bellsouth.net> 1100 Ashwood Parkway, Atlanta, GA 30338 <ck(a)gnu.org> "Turnaucka's Law: The attention span of a computer is only as long as its electrical cord." -- /usr/games/fortune

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RE: Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Sean M. Doran 04 Aug '98

04 Aug '98

Here is my sole contribution to this conversation. Christian Kuhtz wrote: | That is, if somebody can figure out a way to do private line (circuit | emulation) through an IP cloud. ATM will be an interim step, in my opinion. Done. Essentially what you do is emulate a connection-oriented network over a connectionless one [jnc bait], and prioritize this emulated connection-oriented service. This entails a design constraint: the aggregate input rate for this emulated CO network to any interface must be less than or equal to the output rate, and traffic shaping must be done to avoid the "bunch up" effect. This also requires a resource reservations mechanism of some nature, ranging from manual configuration coordinated by email/phone to fully dynamic "bandwidth brokerage", and a means of identifying the emulated-circuit traffic at each router where it will receive special treatment in terms of queueing, shaping or both. Please see Van Jacobson, Sally Floyd et al's interesting work on this front at http://www-nrg.ee.lbl.gov/nrg-talks.html and in particular Van Jacobson's presentation "Towards Differentiated Services for the Internet" Also very interesting and related to your question is the research and practical work on Class-Based Queueing at http://www-nrg.ee.lbl.gov/floyd/cbq.html and in particular Dr Floyd's "Notes on CBQ and Guaranteed Service" Van Jacobson also did an excellent NANOG presentation, the video clip of which lives at http://www.nanog.org/mtg-9806/agen0698.html (search down to the RealVideo Broadcast beginning at 10:45 am on Monday, June 8) While you are looking at tasty research notes, please also take a moment to consider the wonderful world of best-efforts services (rather than circuit-emulation) and examine the delicious TCP Friendly page at http://www.psc.edu/networking/tcp_friendly.html and study the paper by Jamshid Mahdavi and Sally Floyd intently. These are among the best things you will read for a while. Please send all your network application developer friends -- especially the multimedia ones -- to that document and to the page in general. The followup paper at http://www-nrg.ee.lbl.gov/floyd/end2end-paper.html and the related links at http://www-nrg.ee.lbl.gov/floyd/tcp_unfriendly.html are also wonderful. Heap scorn on the bad guys, or be prepared to police people's congestion-avoidance. For those of you who don't mind doing some digging and who want to see some practical engineering thinking behind alot of this theoretical stuff, please investigate the IETF diff-serv mailing list. Curtis Villamizar <curtis(a)ans.net> has made some excellent contributions there (from an operator's perspective) that are worth some study, although many others have had useful things to say. (Many others have not, however, but any operator, or anyone else, who reads NANOG is probably pretty good at scanning for content). Ten minutes with Noel Chiappa [the jnc being baited] is also very worthwhile. If you can't arrange that, I believe Gordon Cook did an interview with him in 1997ish that I remember was well worth reading. Finally, the ESNET people have recently done some proofs-of-concept that the equivalent of CBR can be done across a small-i internet and in principle the big-I Internet in the presence of a mix of traffic. This should encourage those people who maintain that the good bits of ATM -- and yes, even I admit that there are some -- can be subsumed into the Internet if and as actually needed. Sean.

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OUTAGE: Aug 3, 1998
by Sean Donelan 04 Aug '98

04 Aug '98

Well, there seems to be something going on. Worldcom is experiencing delays of 30+ minutes answering their customer service lines. Where is the fiber cut or a frame-relay problem this time? Yes, I already asked Worldcom customer service. They didn't know what was happening. -- Sean Donelan, Data Research Associates, Inc, St. Louis, MO Affiliation given for identification not representation

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Re: Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Tony Li 03 Aug '98

03 Aug '98

| >One other fallacy here: ATM and POS do not provide the same effective | >bandwidth when used as an IP transport. Due to the high encapsulation | >overhead and the sizing overhead of fitting packets into cells, ATM has | >proven to be about 20% less efficient at carrying packets than SONET. | >While this is probably not an issue in a campus or within a building, the | >implications for long lines is enormous. | > | | Okay, so given all the great features that ATM is supposed to have | and the only thing that really sucks about it is the overhead due to the 53 | byte cell size, the obvious question is why can't there be an ATM standard | with, say, 197 ( 4 times the current 48 byte payload) or even 389 ( 8 | times 48 ) byte cells? | Is there something magic about 53 or is the IP over ATM application | still so 'obscure' that there is no interest? Increasing the cell size lowers the efficiency further. 53 is an ATM architectural constant. Change it, and it's no longer ATM. Change it, and you're no longer interoperable. Tony

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Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Yu Ning 03 Aug '98

03 Aug '98

Hi friends, I find in an article, and it says: in 1995,1996 most nationalwide ISP face the demand of higher bandwidth than T3, and at that time the only avalible high bandwidth interface in router in ATM port(say 155M), then this makes many of them choose ATM as their backbone tech. Later, Giga router with POS(Packet over SONET/SDH) 155M(or higher) interface comes out, then the situation is changed. Then my question is: why 155M ATM interface is easier to make than 155M POS interface? Although the net capacity of 155M ATM is less than 155m POS, their capacity for IP packet is really close. I think its nearly the same challenge to pump up a 155M ATM pipe as a 155M POS pipe with IP packet for a router. Thanks for any comments. Yu Ning. _____________________________________________* Yu Ning ATM R&D Center of BUPT (Beijing U. of Posts&Telecom) Beijing (ZIP:100876, MBox:147#), P.R.China mailto:yuning@mindless.com or yuning(a)263.net _____________________________________________

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Re: Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Tony Li 03 Aug '98

03 Aug '98

> I find in an article, and it says: in 1995,1996 most nationalwide ISP > face the demand of higher bandwidth than T3, and at that time the only > avalible high bandwidth interface in router in ATM port(say 155M), then > this makes many of them choose ATM as their backbone tech. Later, Giga > router with POS(Packet over SONET/SDH) 155M(or higher) interface comes > out, then the situation is changed. > > Then my question is: why 155M ATM interface is easier to make than 155M > POS interface? Although the net capacity of 155M ATM is less than 155m > POS, their capacity for IP packet is really close. I think its nearly the > same challenge to pump up a 155M ATM pipe as a 155M POS pipe with IP > packet for a router. The ATM interface is actually harder to make than a POS interface because you have to include the segmentation and reassembly (SAR) functionality in the hardware. Also, the software gets a lot more complicated. Why then did ATM appear first? There was a great deal of publicity given to it. The vision was that it was going to be the 'media' of the future and the hype ran all out of proportion with reality. It took quite a while for the hype to give way, and for engineering and economic realities to truly settle in. And as can be seen from recent announcements, that process is not yet complete. One other fallacy here: ATM and POS do not provide the same effective bandwidth when used as an IP transport. Due to the high encapsulation overhead and the sizing overhead of fitting packets into cells, ATM has proven to be about 20% less efficient at carrying packets than SONET. While this is probably not an issue in a campus or within a building, the implications for long lines is enormous. Tony

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Re: New router technology you'll want to look into
by owen＠DeLong.SJ.CA.US 03 Aug '98

03 Aug '98

> > > Here's some new router technology that I think you'll want to look into. > > > http://www.difference.com/tech.html > > > > route-map set-condiments 10 permit > > Don't forget to account for the encapsulation problem. > Some routers use the CATSUP protocol, some KETCHUP. > > There are roumers that Bay is using something completely > different, of course.... > > Curt- > Yes, while the rest of the world has agreed on the MUSTARD protocol for packet delivery, it appears that the cooks at bay have developed the DIJONAISE protocol. While mostly flavorless, it is very high in fat and overhead. Owen

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Re: New router technology you'll want to look into
by Curt Howland 03 Aug '98

03 Aug '98

> > Here's some new router technology that I think you'll want to look into. > > http://www.difference.com/tech.html > > route-map set-condiments 10 permit Don't forget to account for the encapsulation problem. Some routers use the CATSUP protocol, some KETCHUP. There are roumers that Bay is using something completely different, of course.... Curt-

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Re: Network Abuse - Netblock x.x.x.x - IMPORTANT
by Jay Stewart 03 Aug '98

03 Aug '98

-----Original Message----- From: James Rishaw <jamie(a)dilbert.ais.net> To: nanog(a)merit.edu <nanog(a)merit.edu> Date: Thursday, July 30, 1998 10:20 AM Subject: FW: Network Abuse - Netblock x.x.x.x - IMPORTANT >A coworker's friend forwarded this to me.. kinda funny.. Kinda lame.. > > >-----Original Message----- >Sent: Thursday, July 30, 1998 7:36 AM >Subject: FW: Network Abuse - Netblock de.le.te.d - IMPORTANT > > >---------- >From: Andrew Shoemaker[SMTP:wrath@jerky.net] >Sent: Thursday, July 30, 1998 6:43 AM >Subject: Network Abuse - Netblock de.le.te.d - IMPORTANT > >Hello > >My name is Andrew Shoemaker and I am the head security consultant at JNS. We >recently were the target of a denial of service attack that saturated our >Internet connection. This attack, known as a 'smurf' attack, uses unknowing >relays to source the at >tack. By relaying the attack through your network the attack is made >anonymous and increases in strength. This type of attack causes degraded >performance on both the attacked and relay networks and is the result of an >improperly configured router at you >r site. I urge you to fix your routers. If you are unable to do so, or do >not know how I suggest you call a security consultant. JNS is willing to >fix your router permanently for a one time fee of $100 US. If you are >interested in this deal please co >ntact me and I will send you a copy of our security contract and an invoice. > >Netblock de.le.te.d was found to produce 11 replys for each packet sent. >This means if the attacker is sending at T1 speeds the amount of your >bandwidth used in relaying > the attack is equivalent to 11 T1s > >regards, >Andrew Shoemaker >JNS Security >wrath(a)jerky.net >617.442.5408 Did anyone take the time to look at this goober's web page? Here is a *nice* snippet. Jay Stewart Vice President OlyWa.Net - "Olympia's Premier Internet Service Provider" -=-=-=-=- from: http://www.jerky.net/smurf.html The Smurf Relay List This is a list of subnets that can be used for the "smurf" attack. If you find your subnet on this list FIX YOUR FUCKING ROUTERS! If you have subnets you wish to add to this list please email the wrath-mon. Once you fix your router email the above address to get your subnet removed. Until then....everyone feel free to completely FUCK these networks...and remember stupidity should never be tolerated. Updated: 07.29.98

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Re: Q:Why router with ATM interface comes out earlier than pure SONET interface?
by Sean Donelan 03 Aug '98

03 Aug '98

>Then my question is: why 155M ATM interface is easier to make than 155M POS >interface? Although the net capacity of 155M ATM is less than 155m POS, >their capacity for IP packet is really close. I think its nearly the same >challenge to pump up a 155M ATM pipe as a 155M POS pipe with IP packet for >a router. The marketplace isn't always a neat and tidy place. When companies were trying to make business decisions how they should expend their resources, ATM appeared to be a much larger marketplace. The POS marketplace was viewed as just a few niche markets like ISPs, while ATM was viewed in terms of huge telecommunications market. So many companies first put their resources into making ATM interfaces. ATM interfaces can be much more complicated, but if the marketplace is larger you can afford to spend more money and still come out with a less expensive product. So even though an ATM interface may be 10%-20% less efficient, if the pricing was 30% better, ATM could still be a good choice. On the other hand, if you are paying the same price for the underlying physical facilities, you probally want to optimize for the goodput of user data. -- Sean Donelan, Data Research Associates, Inc, St. Louis, MO Affiliation given for identification not representation

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