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MTU of the Internet?
by Peter Ford 06 Feb '98

06 Feb '98

Several people have noted to the Microsoft Support and Product groups that they want the Windows 95 PPP MTU to be set to 576 (down from 1500). this change is in Windows 98. The reason for this change cited by many customers is that many ISPs have 576 MTUs set "inside" their networks and packets get fragmented. How prevelant is this fragmentation and how prevelant is this MTU in ISPs? Are there statistics that can be shared on how much traffic they see on their networks that are IP fragments? Why do ISPs set their MTUs to 576 instead of ~1500 or even ~4K? thanks in advance for your responses, peter

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Re: High capacity wireless WAN equipment.
by Pat Darisme 06 Feb '98

06 Feb '98

Would LMDS meet your needs ? http://www.wireless-one.com/ http://www.insight-corp.com/lmds.html Or a web search on LMDS ... Once upon a time, Louis A. Destree arranged the electrons in @Home's private scaleable, ATM, OC3 BackBone to write: > Subject: High capacity wireless WAN equipment. > (Feb 5, 4:14pm) > Greetings, > > I'm trying to round up information on wireless WAN equipment. I need T1 > and above speeds. If anyone has some information on products or > experience I'd be interested in hearing it. > > Thanks, > Louis > -- > Louis A. Destree > Senior Network Engineer > FlashNet Communications > destree(a)flash.net > End of included message written by Louis A. Destree on Feb 5, 4:14pm, >

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High capacity wireless WAN equipment.
by Louis A. Destree 05 Feb '98

05 Feb '98

Greetings, I'm trying to round up information on wireless WAN equipment. I need T1 and above speeds. If anyone has some information on products or experience I'd be interested in hearing it. Thanks, Louis -- Louis A. Destree Senior Network Engineer FlashNet Communications destree(a)flash.net

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Specifying a layer 3 MLPA in the IRR
by Jake Khuon 05 Feb '98

05 Feb '98

Here are two pointers to two drafts for specifying and maintaining MLPAs in the IRR. I will be holding a presentation and discussion at the next Interprovider Ops BOF at NANOG 12. The first document is RIPE181 specific and the second is RPSL sepcific. http://espresso.merit.net/~khuon/khuon-003.txt http://espresso.merit.net/~khuon/khuon-004.txt -- /*====================[ Jake Khuon <khuon(a)Merit.Net> ]=====================+ | Systems Research Programmer, IE Group /| /|[~|)|~|~ N E T W O R K | | Vox: (734) 763-4907 Fax: (734) 747-3185 / |/ |[_|\| | Incorporated | +==[ Suite C2122, Bldg. 1 4251 Plymouth Rd. Ann Arbor, MI 48105-2785 ]==*/

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Re: MTU of the Internet?
by Dennis Simpson 05 Feb '98

05 Feb '98

> Date: Wed, 4 Feb 1998 10:51:44 -0700 (MST) > From: "Forrest W. Christian" <forrestc(a)iMach.com> > To: "Perry E. Metzger" <perry(a)piermont.com> > cc: Peter Ford <peterf(a)microsoft.com>, "'nanog(a)merit.edu'" <nanog(a)merit.edu> > Subject: Re: MTU of the Internet? > > Now it's been a while since I looked at latency vs transfer rates, so > maybe someone who works on this on an everyday basis would like to comment > on what ~200 more ms of latency on a 28.8 link would do to throughput > end-to-end across the net (totals of something like 350 and 512 ms > end-to-end). We recommend that clients who care about interactive response use small MTUs, and clients who care about download speed use higher MTUs. It seems most of them agree that smaller MTUs improve their interactive response for things like telnet, IRC, MUD, etc., particularly if they are downloading/surfing at the same time. Thx, dennis

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Agenda for the Interprovider Ops BOF at NANOG12
by Jake Khuon 05 Feb '98

05 Feb '98

Here's the final agenda for the Interprovider Operations BOF at NANOG 12. It will be held in the main room at 9PM on Monday night. Hope to see you all there. Interprovider Operations BOF - NANOG 12 AGENDA I. Introduction (Jake Khuon) A. Participant's List and Survey Form B. Notetaking Volunteer C. Agenda Bashing D. Unfinished Business NANOG OPS WG discussion (Jake Khuon) Do we need one? Publications series? Charter? II. Network-Based Denial Of Service Attacks Trends, Descriptions, and How to Protect Your Network (Craig Huegen) III. Specifying and Supporting a Layer-3 MLPA In the Internet Routing Registry (Jake Khuon) IV. PAIR Update and Other Fun Stuff (Abha Ahuja) V. Operational Issues for NAP Customers (Mark Cnota) VI. Other Discussions (open) -- /*====================[ Jake Khuon <khuon(a)Merit.Net> ]=====================+ | Systems Research Programmer, IE Group /| /|[~|)|~|~ N E T W O R K | | Vox: (734) 763-4907 Fax: (734) 747-3185 / |/ |[_|\| | Incorporated | +==[ Suite C2122, Bldg. 1 4251 Plymouth Rd. Ann Arbor, MI 48105-2785 ]==*/

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Troubleshooting Internet connections
by wthall＠vie.com 05 Feb '98

05 Feb '98

We have servers co-located at NAP sites across the country and have several thousand users connect to us daily. When the users have packetloss or latency problems I have been using traceroute and ping to troubleshoot their connections. From some recent threads here, I am concerned that these tools are giving me a false image of which routers are having problems because of the differences between the way some routers process the packets sent to them and packets sent through them (different priorities and input queues). Is there anyway other then traceroute and ping to pinpoint problems on an Internet connection? Thanks for any ideas you may have. Wayne Hall Network Manager VIE

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Re: Transparent Caching Solutions - Information Wanted
by Matt Ranney 05 Feb '98

05 Feb '98

Bill Unsworth <bill(a)u-net.net> writes: > Interesting discussion - no many comments from ISPs currently using caching > regarding the effectiveness - cache hit rates or bandwidth "saved". > > Any strategies for populating caches (in addition to user hits)? [...] I'm not sure sure that hit rate should be the primary means of measuring the effectiveness of an HTTP proxy/cache. As was discussed the SF NANOG, the penalty for packet loss on connections with higher RTTs is severe. So even if a proxy server is fetching a miss on a path with a lower RTT than the requesting client there's still a win. Of course, I know of no good way to measure this type of winnage. I guess I could claim squid's ICMP RTT measurement neighbor selection routing thing as another big win, but I'm sure it flies in the face of all that is Decent and True with the Purists out there. -- Matt Ranney - mjr(a)ranney.com Let's not let the students run the High School.

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Re: MTU of the Internet?
by Tony Li 05 Feb '98

05 Feb '98

jra(a)scfn.thpl.lib.fl.us (Jay R. Ashworth) writes: > > Unless your ISP uses BBN Butterflies and C30 IMPs in its backbone, I > > would discount the odds of running into a link with an MTU of 576. > > How do I program my router to emulate one of those? You don't need to. It's already there. You just need to configure it: conf term int serial 0 ip mtu 576 no ip route-cache <repeat for all interfaces> no router bgp 109 router egp 109 ... ^Z To simulate an IMP, you need to configure X.25 DCE interfaces. This is too gross to discuss on a family mailing list. ;-) Tony

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MTU size & IP packet size distributions
by rja＠corp.home.net 05 Feb '98

05 Feb '98

Not to interrupt a discussion by adding measured data, but there is some collected data on MTU sizes around the net. I believe kc has some packet statistics data online at NLANR. Alternately, there is some @Home packet size data (from Mike Schwartz) online in PDF format at: ftp://ftp.home.net/pub/rja/home-pkt-dist.pdf Folks perusing the @Home data should keep in mind that nearly all residential customers have 10baseT Ethernet access to the Internet. So we have near zero packets larger than Ethernet MTU. :-) Ran

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