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Wireless MAN product experiences?
by Jeffrey Paul 26 Jan '04

26 Jan '04

We're looking to setup a point-to-point link between two buildings circa 1.5km apart. Optical, RF, whatever. This would be in the Detroit metro area (Southfield, actually) so snow is to be expected at least part of the year. License-free would be ideal. The devices, or at least the transcievers themselves if seperate, must be weatherproof/ruggedized for outdoor use (obviously). One endpoint will go on a one-story building, the other can either be placed inside our 10th floor suite (about 140' up) and go through a green-tinted glass window, or on the roof (250' up). 100mbps is ideal, although if it's significantly cheaper to drop to 10, that might be an option. I was thinking that 54mbit 802.11g might be a good price-performance mix, but I don't know of the other products available out there. Does anyone have experience with something like this? Should we try using WiFi and directional antennas, or is that insane? What sort of experience have you guys had with different vendors gear? Please reply offlist and I'll summarize my findings to the list afterward. Thanks, -j -- Jeffrey Paul - jeffreypaul(a)diamondcard.com - (877) 748-3467 Senior Network Administrator, Diamond Financial Products "An expert is a man who has made all the mistakes which can be made in a very narrow field." -- Niels Bohr

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Re: Outbound Route Optimization
by Michael.Dillon＠radianz.com 26 Jan '04

26 Jan '04

>BGP is relatively good at determining the best path when you a major >carrier with connectivity to "everyone" (i.e. when traffic flows >"naturally"), in many locations, and you engineer your network so that you >have sufficient capacity to support the traffic flows. In other words, BGP really only works well when most networks are overbuilt so that there is a single uncongested best path through each network from every ingress to every egress and the paths within any given network's core are roughly similar in capacity. Nowadays there is a lot more variability both within networks and between different networks. How can a simple protocol provide optimal behavior between an MPLS network, an IP over ATM network, a network that is half GRE tunnels, and a network that has core links ranging from DS3 to OC48? I think BGP is another example where something that is "good enough" has risen to prominence in spite of the fact that it is not optimal. And another thing. How do we know this problem can ever be solved when we continue to use routing protocols which choose the *BEST* path. The best path is always a single path and, by definition, this is a single point of failure. How can we ever have a diverse and reliable network when its core routing paradigm is a single point of failure? Note that people have built IP networks that provide two diverse paths at all times using multicast http://www.simc-inc.org/archive9899/Jun01-1999/bach2/Default.htm and such things may also be possible with MPLS. But are any of the researchers seriously looking at how to provide a network in which all packets flow through two diverse paths to provide better reliability? --Michael Dillon

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Any 1U - 2U Ethernet switches that can handle 4K VLANs?
by sthaug＠nethelp.no 26 Jan '04

26 Jan '04

Does anybody know of 1U - 2U form factor Ethernet switches that can handle 4K VLANs, or at a minimum 2000 VLANs? Note that we're specifically looking for the ability to handle this number of VLANs operating simultaneously, not only VLAN *IDs* in the full 4K range. (This rules out popular switches like the Cisco 3550 and 3750 series, which can only handle 1024 VLANs operating simultaneously.) The switches should have 12 - 24 Fast Ethernet ports. Some form of "Q in Q" or stackable VLANs, ie. the ability to handle more than one VLAN tag, is vital. Spanning tree is needed, but can be one common spanning tree for all VLANs (per-VLAN spanning tree is not needed). Other features that would be nice to have: - RSTP (802.w) and MST (802.1s). - A couple of GigE ports (GBIC or SFP based, presumably) for uplinks. - L3 (IP routing). - DC power. Steinar Haug, Nethelp consulting, sthaug(a)nethelp.no

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Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
by sthaug＠nethelp.no 26 Jan '04

26 Jan '04

> > 1) Cisco ISL is much better than urgly 802.1q - first of all, it was > > designed many years before 802.1q. I am not even talking abiout those > > idiots, who designed 802.1q as a _spanning tree on the trunk level_, > > which > > made many configurations (which we used with ISL ain 199x years) > > impossble, > > and caused vendors to extend 802.1q. > > Is it April 1st? ISL changes the size of packets, does it not? So know > you have to deal with MTU issues. What happens when I want the biggest > MTU possible? I know it is not much a difference in size, but for some > people, size does matter. > > I am quite happy with dot1q. My gripe is with poor spanning-tree > implementations. I don't want a single spanning-tree for every vlan on > a trunk... I like standards, but I am happy with Rapid-PVST. Just my > feelings about the issue. I would never deploy ISL unless I had > something like a 1900 that did not do dot1q Amen. At my previous employer, we got rid of ISL on almost all trunks. I wouldn't dream of going back. The only thing I don't really like about 802.1q compared to ISL is the idea of "native" or "default" VLAN. I want links to be either access (untagged) or trunk (*all* packets tagged). Fortunately, reasonably new Cisco switches let me enforce that with "vlan dot1q tag native". Steinar Haug, Nethelp consulting, sthaug(a)nethelp.no

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Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
by ken emery 26 Jan '04

26 Jan '04

On Sun, 25 Jan 2004, Bill Nash wrote: > On Sun, 25 Jan 2004, ken emery wrote: > > > The point of using VLANs is that you don't need to route. There's > > > probably a good reason for switching instead of routing in the original > > > poster's scenario. (Perhaps a FTTH-like project?) > > > > Correct me if I'm wrong here, but at some point you will have to route > > all those VLAN's. To really answer the question about wether > 1000 > > VLAN's are necessary one would need to see the network design. > I would argue this point. I've got a production environment sporting > multiple vlans, none which will ever see an external subnet or even a > gateway (think databases.) The operative context inherent in the VLAN > acronym is, after all, 'local', and not every topology requires routing. This is correct, but then why spend the money on a L3 switch? Routing isn't needed so save the money and purchase a L2 switch. bye, ken emery

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test
by Andre Chapuis 26 Jan '04

26 Jan '04

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DNS Rootservers go international
by Hank Nussbacher 26 Jan '04

26 Jan '04

http://www.theregister.co.uk/content/6/35070.html -Hank

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Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
by sthaug＠nethelp.no 26 Jan '04

26 Jan '04

> 3550 runs IOS. That's an answer. I never allow any non-IOS router in > production environment (except high end devices, such as Juniper, when > benefits are very high). And 3550 is not expansive (yes, it is not cheap). If you believe that IOS solves all problems, we live on different planets. > PS. How much ethernet ports do you have in the office? Do you have 100 K > ports? If not, why do you need 128K MAC's? (I know only one case, when I > need so much - some kind of DSL service... Some kind of DSL service is indeed the background for my question. > In most cases, you have 500 - 5,000 ports in one building. If you have more, > it is unlikely that you use 3550 switches. So, it is enough for the tasks > (just as performance - it have _enough_ performance). Btw, I believed that > catalist swithes have not any limitations for the MAC tables (because they > use memory _on demand_); where did you get this limitations? /I may be wrong > here/ If you believe Catalyst switches have no MAC address limitations, I have a nice plot of land in Florida to sell you :-) Ethernet switches today use CAM to hold the MAC address tables - this CAM has a finite size. > PPS. I do not know for sure, but 3550 should support traffic shaping, which > makes bufferring. Technically, yes, CEF (with packet dropping) is not good > to provide 2 Mbit by 100 Mbit link. 3550 only supports policing. Yes, I have worked extensive with 3550 and it doesn't have the features I need right now. Steinar Haug, Nethelp consulting, sthaug(a)nethelp.no

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Interesting use of DNS glue records by spammers
by Suresh Ramasubramanian 26 Jan '04

26 Jan '04

Saw this elsewhere, sounds interesting enough to forward on. -- srs (postmaster|suresh)(a)outblaze.com // gpg : EDEDEFB9 manager, outblaze.com security and antispam operations > I just today got two spams that showed me a new spammer DNS trick (new > to me, at least). > > Rather than use fictitious domain names, I'll use the actual names from > one of the spams. The basic trick is the same either way. > > nepzzz.com is spamvertised. Its registration specifies nameservers in > nictxt.com. nictxt.com has been taken over by its registrar, > apparently for invalid contact info (and good for them). But they > didn't go quite far enough; while querying the gtld-servers.net servers > for nictxt.com returns NXDOMAIN, querying them for nepzzz.com returns > delegation NS records under nictxt.com _with glue A records_, thereby > defeating the registrar's attempted removal of the domain. > > The other spam was for ahottieiswhatiwant.com, with nameservers in > 9t5.net; the basic trick is the same. > > In each case, I sent a message suggesting that rather than just > pointing it at their own servers, they point the domain at the names > the spammers used (which require glue records) but supply glue pointing > to the registrar's server(s), thereby getting the glue the spammers > injected into the gtld-servers system replaced. > > So be careful when poking at the DNS while spamhaus-hunting. If you > query for the wrong thing you may be misled into thinking something has > been taken down when it hasn't.

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Physical Layer Switches / Smart Optical Cross-Connect Panels
by Roldan, Brad 24 Jan '04

24 Jan '04

Hey Folks, I'm looking for physical layer switch that will allow me to remotely configure how two ports are cross-connected. The two main benefits would be that a site only has to be wired once and there is also a potential for a simplified disaster recovery plan (i.e. one of my boxes melts down, and I need to bring a standby online without dispatching a tech). If I could have the perfect box, it would: - Handle fiber (serial connections, ala DS3, would be a bonus) - Be protocol agnostic. I want to switch GigE and OC fiber cross-connects. I don't want GigE / POS inter-networking. - Be completely passive. If the power fails, all connections will remain active. I suppose this implies some sort of mechanical switching mechanism. - Text based CLI mandatory. Web GUI optional. - DC powered - Did I mention cheap? After Googling around this morning, it was unable to find anything that completely fits the bill. I was only able to come up with 3 vendors that come close to fitting the bill, each with their own set of pros and cons: RAM Electronics (http://www.ramelectronics.net/apcon/patchpanels.htm) MEMX (http://www.memx.com/cross%20connect.htm) MRV (http://www.mrv.com/product/MRV-FD-SFPMCC/) Anyone have experience with any of these vendors? Are there other vendors I should be looking at? Off-list replies from sales-droids welcome. (An invitation for punishment, I'm sure ;) Thanks! Brad -- +1-408-434-2048 broldan(a)covad.com

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